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Score: 10.00 |
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| Title: Expression of a rice homeobox gene causes altered morphology of transgenic plants .
| | Author: Matsuoka M Ichikawa H Saito A Tada Y Fujimura T Kano-Murakami Y | | Journal: Plant Cell Citation: V : 5 ( 9 ) P : 1039-48 Year: 1993 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub8104574 Accession (PMID): 8104574 | | Abstract: We have isolated a cDNA clone encoding a homeobox sequence from rice .
DNA sequence analysis of this clone , which was designated as Oryza sativa homeobox 1 ( OSH1 ) , and a genomic clone encoding the OSH1 sequence have shown that the OSH1 gene consists of five exons and encodes a polypeptide of 361 amino acid residues .
Restriction fragment length polymorphism analysis has shown that OSH1 is a single-copy gene located near the phytochrome gene on chromosome 3 .
Introduction of the cloned OSH1 gene into rice resulted in altered leaf morphology , which was similar to that of the maize morphological mutant Knotted-1 ( Kn1 ) , indicating that OSH1 is a rice gene homologous to the maize Kn1 gene .
RNA gel blot analysis has shown that the gene is primarily expressed in the shoot apices of young rice seedlings .
This finding is supported by results of transformation experiments in which the 5 flanking region of the gene directed expression of a reporter gene in the shoot apex , particularly in stipules , of transgenic Arabidopsis .
To elucidate the biological function of the OSH1 gene product , the coding region was introduced into Arabidopsis under the control of the cauliflower mosaic virus 35S promoter .
Almost all transformants showed abnormal morphology .
The typical phenotype was the formation of clumps of abundant vegetative and reproductive shoot apices containing meristems and leaf primordia , which did not form elongated shoots .
Some transformants with a less severe phenotype formed elongated shoots but had abnormally shaped leaves and flowers with stunted sepals , petals , and stamens .
The abnormal phenotypes were inherited , and the level of expression of the introduced OSH1 correlates with the severity of the phenotype .
These findings indicate that the abnormal morphologies of the transgenic plants are caused by the expression of the OSH1 gene product and , therefore , that OSH1 is related to the plant development process . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 9.00 |
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| Title: Isolation and characterization of a rice homebox gene , OSH15 .
| | Author: Sato Y Sentoku N Nagato Y Matsuoka M | | Journal: Plant Mol . Biol . Citation: V : 38 ( 6 ) P : 983-98 Year: 1998 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub9869405 Accession (PMID): 9869405 | | Abstract: In many eukaryotic organisms including plants , homeobox genes are thought to be master regulators that establish the cellular or regional identities and specify the fundamental body plan .
We isolated and characterized a cDNA designated OSH15 ( Oryza sativa homeobox 15 ) that encodes a KNOTTED-type homeodomain protein .
Transgenic tobacco plants overexpressing the OSH15 cDNA showed a dramatically altered morphological phenotype caused by disturbance of specific aspects of tobacco development , thereby indicating the involvement of OSH15 in plant development .
We analyzed the in situ mRNA localization of OSH15 through the whole plant life cycle , comparing the expression pattern with that of another rice homeobox gene , OSH1 .
In early embryogenesis , both genes were expressed as the same pattern at a region where the shoot apical meristem would develop later .
In late embryogenesis , the expression pattern of the two genes became different .
Whereas the expression of OSH1 continued within the shoot apical meristem , OSH15 expression within the shoot apical meristem ceased but became observable in a ring shaped pattern at the boundaries of some embryonic organs .
This pattern of expression was similar to that observed around vegetative or reproductive shoots , or the floral meristem in mature plants .
RNA in situ localization data suggest that OSH15 may play roles in the shoot organization during early embryogenesis and thereafter , OSH15 may be involved in morphogenetic events around the shoot apical meristem . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 8.00 |
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| Title: Positive Autoregulation of a KNOX Gene Is Essential for Shoot Apical Meristem Maintenance in Rice .
| | Author: Tsuda K Ito Y Sato Y Kurata N | | Journal: Plant Cell Citation: V : P : Year: 2011 Type: Publisher | | Literature: oryza Field: abstract Doc ID: pub22207572 Accession (PMID): 22207572 | | Abstract: Self-maintenance of the shoot apical meristem ( SAM ) , from which aerial organs are formed throughout the life cycle , is crucial in plant development .
Class I Knotted1-like homeobox ( KNOX ) genes restrict cell differentiation and play an indispensable role in maintaining the SAM .
However , the mechanism that positively regulates their expression is unknown .
Here , we show that expression of a rice ( Oryza sativa ) KNOX gene , Oryza sativa homeobox1 ( OSH1 ) , is positively regulated by direct autoregulation .
Interestingly , loss-of-function mutants of OSH1 lose the SAM just after germination but can be rescued to grow until reproductive development when they are regenerated from callus .
Double mutants of osh1 and d6 , a loss-of-function mutant of OSH15 , fail to establish the SAM both in embryogenesis and regeneration .
Expression analyses in these mutants reveal that KNOX gene expression is positively regulated by the phytohormone cytokinin and by KNOX genes themselves .
We demonstrate that OSH1 directly binds to five KNOX loci , including OSH1 and OSH15 , through evolutionarily conserved cis-elements and that the positive autoregulation of OSH1 is indispensable for its own expression and SAM maintenance .
Thus , the maintenance of the indeterminate state mediated by positive autoregulation of a KNOX gene is an indispensable mechanism of self-maintenance of the SAM .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 7.00 |
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| Title: A rice homeobox gene , OSH1 , is expressed before organ differentiation in a specific region during early embryogenesis .
| | Author: Sato Y Hong SK Tagiri A Kitano H Yamamoto N Nagato Y Matsuoka M | | Journal: Proc . Natl . Acad . Sci . USA Citation: V : 93 ( 15 ) P : 8117-22 Year: 1996 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub8755613 Accession (PMID): 8755613 | | Abstract: Homeobox genes encode a large family of homeodomain proteins that play a key role in the pattern formation of animal embryos .
By analogy , homeobox genes in plants are thought to mediate important processes in their embryogenesis , but there is very little evidence to support this notion .
Here we described the temporal and spatial expression patterns of a rice homeobox gene , OSH1 , during rice embryogenesis .
In situ hybridization analysis revealed that in the wild-type embryo , OSH1 was first expressed at the globular stage , much earlier than organogenesis started , in a ventral region where shoot apical meristem and epiblast would later develop .
This localized expression of OSH1 indicates that the cellular differentiation has already occurred at this stage .
At later stages after organogenesis had initiated , OSH1 expression was observed in shoot apical meristem [ except in the L1 ( tunica ) layer ] , epiblast , radicle , and their intervening it issues in descending strength of expression level with embryonic maturation .
We also performed in situ hybridization analysis with a rice organless embryo mutant , orl1 , that develops no embryonic organs .
In the orl1 embryo , the expression pattern of OSH1 was the same as that in the wild-type embryo in spite of the lack of embryonic organs .
This shows that OSH1 is not directly associated with organ differentiation , but may be related to a regulatory process before or independent of the organ determination .
The results described here strongly suggest that , like animal homeobox genes , OSH1 plays an important role in regionalization of cell identity during early embryogenesis . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 6.00 |
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| Title: A rice homeotic gene , OSH1 , causes unusual phenotypes in transgenic tobacco | | Author: Kano-Murakami Y Yanai T Tagiri A Matsuoka M | | Journal: FEBS Lett .
Citation: V : 334 ( 3 ) P : 365-8 Year: 1993 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub7902297 Accession (PMID): 7902297 | | Abstract: A rice gene , OSH1 , which shares homology with animal homeobox genes , has been isolated .
We have introduced the OSH1 cDNA into tobacco in order to examine its function .
Expression of the OSH1 cDNA in tobacco induced morphological abnormalities in the leaves , petals and stems of the transformants suggesting that OSH1 functions as a morphological regulator .
OSH1 cDNA expression was analyzed under the control of three different promoters .
This work revealed that not only the level of OSH1 expression but also the site and timing of the expression affect the morphology of the plant . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 6.00 |
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| Title: Decreased GA1 content caused by the overexpression of OSH1 is accompanied by suppression of GA 20-oxidase gene expression .
| | Author: Kusaba S Fukumoto M Honda C Yamaguchi I Sakamoto T Kano-Murakami Y | | Journal: Plant Physiol .
Citation: V : 117 ( 4 ) P : 1179-84 Year: 1998 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub9701574 Accession (PMID): 9701574 | | Abstract: We previously reported that overexpression of the rice homeobox gene OSH1 led to altered morphology and hormone levels in transgenic tobacco ( Nicotiana tabacum L ) plants .
Among the hormones whose levels were changed , GA1 was dramatically reduced .
Here we report the results of our analysis on the regulatory mechanism ( s ) of OSH1 on GA metabolism .
GA53 and GA20 , precursors of GA1 , were applied separately to transgenic tobacco plants exhibiting severely changed morphology due to overexpression of OSH1 .
Only treatment with the end product of GA 20-oxidase , GA20 , resulted in a striking promotion of stem elongation in transgenic tobacco plants .
The internal GA1 and GA20 contents in OSH1-transformed tobacco were dramatically reduced compared with those of wild-type plants , whereas the level of GA19 , a mid-product of GA 20-oxidase , was 25% of the wild-type level .
We have isolated a cDNA encoding a putative tobacco GA 20-oxidase , which is mainly expressed in vegetative stem it issue .
RNA-blot analysis revealed that GA 20-oxidase gene expression was suppressed in stem it issue of OSH1-transformed tobacco plants .
Based on these results , we conclude that overexpression of OSH1 causes a reduction of the level of GA1 by suppressing GA 20-oxidase expression . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 5.00 |
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| Title: Loss-of-function mutations in the rice homeobox gene OSH15 affect the architecture of internodes resulting in dwarf plants .
| | Author: Sato Y Sentoku N Miura Y Hirochika H Kitano H Matsuoka M | | Journal: EMBO J Citation: V : 18 ( 4 ) P : 992-1002 Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10022841 Accession (PMID): 10022841 | | Abstract: The rice homeobox gene OSH15 ( Oryza sativa homeobox ) is a member of the knotted1-type homeobox gene family .
We report here on the identification and characterization of a loss-of-function mutation in OSH15 from a library of retrotransposon-tagged lines of rice .
Based on the phenotype and map position , we have identified three independent deletion alleles of the locus among conventional morphological mutants .
All of these recessive mutations , which are considered to be null alleles , exhibit defects in internode elongation .
Introduction of a 14 kbp genomic DNA fragment that includes all exons , introns and 5- and 3- flanking sequences of OSH15 complemented the defects in internode elongation , confirming that they were caused by the loss-of-function of OSH15 .
Internodes of the mutants had abnormal-shaped epidermal and hypodermal cells and showed an unusual arrangement of small vascular bundles .
These mutations demonstrate a role for OSH15 in the development of rice internodes .
This is the first evidence that the knotted1-type homeobox genes have roles other than shoot apical meristem formation and/or maintenance in plant development . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 5.00 |
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| Title: Initiation of shoot apical meristem in rice : characterization of four SHOOTLESS genes .
| | Author: Satoh N Hong SK Nishimura A Matsuoka M Kitano H Nagato Y | | Journal: Development Citation: V : 126 ( 16 ) P : 3629-36 Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10409508 Accession (PMID): 10409508 | | Abstract: The regulatory mechanism of shoot apical meristem ( SAM ) initiation is an important subject in developmental plant biology .
We characterized nine recessive mutations derived from four independent loci ( SHL1-SHL4 ) causing the deletion of the SAM .
Radicles were produced in these mutant embryos .
Concomitant with the loss of SAM , two embryo-specific organs , coleoptile and epiblast , were lost , but the scutellum was formed normally .
Therefore , differentiation of radicle and scutellum is regulated independently of SAM , but that of coleoptile and epiblast may depend on SAM .
Regeneration experiments using adventitious shoots from the scutellum-derived calli showed that no adventitious shoots were regenerated in any shl mutant .
However , small adventitious leaves were observed in both mutant and wild-type calli , but they soon became necrotic and showed no extensive growth .
Thus , leaf primordia can initiate in the absence of SAM , but their extensive growth requires the SAM .
An in situ hybridization experiment using a rice homeobox gene , OSH1 , as a probe revealed that shl1 and shl2 modified the expression domain of OSH1 , but normal expression of OSH1 was observed in shl3 and shl4 embryos .
Accordingly , SHL1 and SHL2 function upstream of OSH1 , and SHL3 and SHL4 downstream or independently of OSH1 .
These shl mutants are useful for elucidating the genetic program driving SAM initiation and for unraveling the interrelationships among various organs in grass embryos . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 4.00 |
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| Title: KNOX homeobox genes are sufficient in maintaining cultured cells in an undifferentiated state in rice .
| | Author: Ito Y Eiguchi M Kurata N | | Journal: Genesis Citation: V : 30 ( 4 ) P : 231-8 Year: 2001 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11536429 Accession (PMID): 11536429 | | Abstract: We produced transgenic rice calli , which constitutively express each of four KNOX family class 1 homeobox genes of rice , OSH1 , OSH16 , OSH15 , and OSH71 , and found that constitutive and ectopic expression of such genes inhibits normal regeneration from transformed calli , which showed continuous growth around their shoot-regenerating stages .
Transgenic calli transferred onto regeneration medium began to display green spots , a sign of regeneration , but most of the transformants continued to propagate green spots at given stages .
In the normal shoot-regeneration process of calli , expression of endogenous OSH1 was restricted in presumptive shoot-regenerating regions of calli and not observed in other areas .
This restricted expression pattern should be required for further differentiation of the regenerating shoots .
Thus our present results support the proposed function that KNOX family class 1 homeobox genes play a role in the formation and maintenance of the undetermined meristematic state of cells . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 4.00 |
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| Title: Abnormal cell divisions in leaf primordia caused by the expression of the rice homeobox gene OSH1 lead to altered morphology of leaves in transgenic tobacco | | Author: Sato Y Tamaoki M Murakami T Yamamoto N Kano-Murakami Y Matsuoka M | | Journal: Mol . Gen . Genet . Citation: V : 251 ( 1 ) P : 13-22 Year: 1996 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub8628242 Accession (PMID): 8628242 | | Abstract: Transgenic tobacco plants were generated carrying a rice homeobox gene , OSH1 , controlled by the promoter of a gene encoding a tobacco pathogenesis-related protein ( PR1a ) .
These lines were morphologically abnormal , with wrinkled and/or lobed leaves .
Histological analysis of shoot apex primordia indicates arrest of lateral leaf blade expansion , often resulting in asymmetric and anisotrophic growth of leaf blades .
Other notable abnormalities included abnormal or arrested development of leaf lateral veins .
Interestingly , OHS1 expression was undetectable in mature leaves with the aberrant morphological features .
Thus , OSH1 expression in mature leaves is not necessary for abnormal leaf development .
Northern blot and in situ hybridization analyses indicate that PR1a-OSH1 is expressed only in the shoot apical meristem and in very young leaf primordia .
Therefore , the aberrant morphological features are an indirect consequence of ectopic OSH1 gene expression .
The only abnormality observed in it issues expressing the transgene was periclinal ( rather than anticlinal ) division in mesophyll cells during leaf blade initiation .
This generates thicker leaf blades and disrupts the mesophyll cell layers , from which vascular it issues differentiate .
The OSH1 product appears to affect the mechanism controlling the orientation of the plane of cell division , resulting in abnormal periclinal division of mesophyll cell , which in turn results in the gross morphological abnormalities observed in the transgenic lines . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 4.00 |
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| Title: Alteration of hormone levels in transgenic tobacco plants overexpressing the rice homeobox gene OSH1 .
| | Author: Kusaba S Kano-Murakami Y Matsuoka M Tamaoki M Sakamoto T Yamaguchi I Fukumoto M | | Journal: Plant Physiol .
Citation: V : 116 ( 2 ) P : 471-6 Year: 1998 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub9489007 Accession (PMID): 9489007 | | Abstract: The rice ( Oryza sativa L ) homeobox gene OSH1 causes morphological alterations when ectopically expressed in transgenic rice , Arabidopsis thaliana , and tobacco ( Nicotiana tabacum L ) and is therefore believed to function as a morphological regulator gene .
To determine the relationship between OSH1 expression and morphological alterations , we analyzed the changes in hormone levels in transgenic tobacco plants exhibiting abnormal morphology .
Levels of the plant hormones indole-3-acetic acid , abscisic acid , gibberellin ( GA ) , and cytokinin ( zeatin and trans-zeatin [ Z ] ) were measured in leaves of OSH1-transformed and wild-type tobacco Altered plant morphology was found to correlate with changes in hormone levels .
The more severe the alteration in phenotype of transgenic tobacco , the greater were the changes in endogenous hormone levels .
Overall , GA1 and GA4 levels decreased and abscisic acid levels increased compared with wild-type plants .
Moreover , in the transformants , Z ( active form of cytokinin ) levels were higher and the ratio of Z to Z riboside ( inactive form ) also increased .
When GA3 was supplied to the shoot apex of transformants , internode extension was restored and normal leaf morphology was also partially restored .
However , such GA3-treated plants still exhibited some morphological abnormalities compared with wild-type plants .
Based on these data , we propose the hypothesis that OSH1 affects plant hormone metabolism either directly or indirectly and thereby causes changes in plant development . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 3.00 |
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| Title: Characterization of the KNOX class homeobox genes Oskn2 and Oskn3 identified in a collection of cDNA libraries covering the early stages of rice embryogenesis .
| | Author: Postma-Haarsma AD Verwoert II Stronk OP Koster J Lamers GE Hoge JH Meijer AH .
| | Journal: Plant Mol . Biol . Citation: V : 39 ( 2 ) P : 257-71 Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10080693 Accession (PMID): 10080693 | | Abstract: For identification of genes involved in embryogenesis in the model cereal rice , we have constructed a collection of cDNA libraries of well-defined stages of embryo development before , during and after organ differentiation .
Here , we focus on the possible role of KNOX ( maize Knotted1-like ) class homeobox genes in regulation of rice embryogenesis .
Three types of KNOX clones were identified in libraries of early zygotic embryos .
Two of these , Oskn2 and Oskn3 , encode newly described KNOX genes , whereas the third ( Oskn1 ) corresponds to the previously described OSH1 gene .
In situ hybridizations showed that during the early stages of embryo development , all three KNOX genes are expressed in the region where the shoot apical meristem ( SAM ) is organizing , suggesting that these genes are involved in regulating SAM formation .
Whereas OSH1 was previously proposed to function also in SAM maintenance , Oskn3 may be involved in patterning organ positions , as its expression was found to mark the boundaries of different embryonic organs following SAM formation .
The expression pattern of Oskn2 suggested an additional role in scutellum and epiblast development .
Transgenic expression of Oskn2 and Oskn3 in tobacco further supported their involvement in cell fate determination , like previously reported for Knotted1 and OSH1 ectopic expression .
Whereas Oskn3 transformants showed the most pronounced phenotypic effects during vegetative development , Oskn2 transformants showed relatively mild alterations in the vegetative phase but a more severely affected flower morphology .
The observation that the KNOX genes produce similar though distinct phenotypic reponses in tobacco , indicates that their gene products act on overlapping but different sets of target genes , or that cell-type specific factors determine their precise action . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 3.00 |
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| Title: Functional analysis of the conserved domains of a rice KNOX homeodomain protein , OSH15 .
| | Author: Nagasaki H Sakamoto T Sato Y Matsuoka M | | Journal: Plant Cell Citation: V : 13 ( 9 ) P : 2085-98 Year: 2001 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11549765 Accession (PMID): 11549765 | | Abstract: The rice KNOX protein OSH15 consists of four conserved domains : the MEINOX domain , which can be divided into two subdomains ( KNOX1 and KNOX2 ) ; the GSE domain ; the ELK domain ; and the homeodomain ( HD ) .
To investigate the function of each domain , we generated 10 truncated proteins with deletions in the conserved domains and four proteins with mutations in the conserved amino acids in the HD .
Transgenic analysis suggested that KNOX2 and HD are essential for inducing the abnormal phenotype and that the KNOX1 and ELK domains affect phenotype severity .
We also found that both KNOX2 and HD are necessary for homodimerization and that only HD is needed for binding of OSH15 to its target sequence .
Transactivation studies suggested that both the KNOX1 and ELK domains play a role in suppressing target gene expression .
On the basis of these findings , we propose that overproduced OSH15 probably acts as a dimer and may ectopically suppress the expression of target genes that induce abnormal morphology in transgenic plants . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 3.00 |
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| Title: Members of TALE and WUS subfamilies of homeodomain proteins with potentially important functions in development form dimers within each subfamily in rice .
| | Author: Nagasaki H Matsuoka M Sato Y | | Journal: Genes Genet .
Syst Citation: V : 80 ( 4 ) P : 261-7 Year: 2005 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16284419 Accession (PMID): 16284419 | | Abstract: Transacting factors often form homo and heterodimers and regulate various targets , the type of regulation depending on the dimeric combination .
The WUS and TALE subfamilies are two atypical homeodomains in plants .
A homeodomain mediates sequence-specific binding to its target DNA and usually consists of 60 amino acid residues , whereas atypical homeodomains have extra amino acid residues in the well-conserved region .
The genes OsWUS and OsPRS , which encode atypical homeodomain proteins from the WUS subfamily , and OsBEL and OSH15 , which encode those from the TALE subfamily , were isolated from rice and tested for their interactions by yeast two-hybrid analysis .
OsWUS and OsPRS formed homodimers and formed heterodimers with each other but did not form dimers with the TALE family homeodomain proteins OSH15 or OsBEL .
Likewise , OSH15 and OsBEL formed homodimers and heterodimers but did not form dimers with the WUS family homeodomain proteins OsWUS and OsPRS .
These findings suggest that the combinations of dimers are well correlated with the classification of these proteins on the basis of sequence similarity .
RT-PCR analysis revealed that expression of OsWUS and OsPRS was detected in the same organs , namely floral buds , roots , and suspension cells .
Therefore , it is possible that the proteins encoded by both of these genes function as homo and heterodimers in planta .
These results suggest that , during the evolution of these subfamilies , various combinations of dimers within proteins encoded by paralogous genes were formed and generated independent regulatory networks that enabled complex patterns of plant development . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 2.00 |
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| Title: Rice globular embryo 4 ( gle4 ) mutant is defective in radial pattern formation during embryogenesis .
| | Author: Kamiya N Nishimura A Sentoku N Takabe E Nagato Y Kitano H Matsuoka M | | Journal: Plant Cell Physiol .
Citation: V : 44 ( 9 ) P : 875-83 Year: 2003 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub14519768 Accession (PMID): 14519768 | | Abstract: In higher plants , the main elements of the fundamental body plan , the apical-basal and radial patterns , are established during embryogenesis .
We have isolated several globular embryo ( gle ) mutants of rice that fail to develop any embryonic organs .
We expected that these gle mutants might include mutants defective in their radial pattern formation ability .
We developed two markers specifically staining the L2 and L3 layers ( OsSCR and OsPNH1 , respectively ) and characterized the gle mutants by using these markers in addition to the already developed markers Roc1 ( marker for the L1 layer ) , Ramy1A ( marker of the L1 layer of the epithelium ) , and OSH1 ( marker of the apical region ) .
One of the gle mutants , gle4 , expressed Roc1 and Ramy1A at the normal positions , but other markers exhibited an abnormal expression pattern ; that is , both OsPNH1 and OsSCR were expressed in the central region of the embryo and OSH1 expression was not observed .
Calli from the gle4 epithelium regenerated plants with abnormal morphologies .
These results indicate that the GLE4 gene is involved in radial pattern formation during rice embryogenesis to differentiate the L2 and L3 layers , but is not involved in the establishment of the L1 layer or in the formation of embryonic organs . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Shoot organization genes regulate shoot apical meristem organization and the pattern of leaf primordium initiation in rice .
| | Author: Itoh JI Kitano H Matsuoka M Nagato Y | | Journal: Plant Cell Citation: V : 12 ( 11 ) P : 2161-74 Year: 2000 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11090216 Accession (PMID): 11090216 | | Abstract: The mechanism regulating the pattern of leaf initiation was analyzed by using shoot organization ( sho ) mutants derived from three loci ( SHO1 , SHO2 , and SHO3 ) .
In the early vegetative phase , sho mutants show an increased rate of leaf production with random phyllotaxy .
The resulting leaves are malformed , threadlike , or short and narrow .
Their shoot apical meristems are relatively low and wide , that is , flat shaped , although their shape and size are highly variable among plants of the same genotype .
Statistical analysis reveals that the shape of the shoot meristem rather than its size is closely correlated with the variations of plastochron and phyllotaxy .
Rapid and random leaf production in sho mutants is correlated with the frequent and disorganized cell divisions in the shoot meristem and with a reduction of expression domain of a rice homeobox gene , OSH1 .
These changes in the organization and behavior of the shoot apical meristems suggest that sho mutants have fewer indeterminate cells and more determinate cells than wild type , with many cells acting as leaf founder cells .
Thus , the SHO genes have an important role in maintaining the proper organization of the shoot apical meristem , which is essential for the normal initiation pattern of leaf primordia . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: The LAX1 and FRIZZY PANICLE 2 genes determine the inflorescence architecture of rice by controlling rachis-branch and spikelet development .
| | Author: Komatsu M Maekawa M Shimamoto K Kyozuka J | | Journal: Dev . Biol . Citation: V : 231 ( 2 ) P : 364-73 Year: 2001 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11237465 Accession (PMID): 11237465 | | Abstract: We have analyzed two mutants that exhibit altered panicle architecture in rice ( Oryza sativa L ) .
In lax1-2 , which is a new and stronger allele of the previously reported lax mutant , initiation and/or maintenance of rachis-branches , lateral spikelets , and terminal spikelets was severely prevented .
In situ hybridization analysis using OSH1 , a rice knotted1 ( kn1 ) ortholog , confirmed the absence of lateral meristems in lax1-2 panicles .
These defects indicate that the LAX1 gene is required for the initiation/maintenance of axillary meristems in the rice panicle .
In addition to its role in forming lateral meristems , the wild-type LAX1 gene acts as a floral meristem identity gene which specifies the terminal spikelet meristem .
A comparison of the defects in lax1-1 and lax1-2 plants suggested that the sensitivities to reduced LAX1 activity were not uniform among different types of meristems .
In the fzp2 mutant panicle , the basic branching pattern of the panicle was indistinguishable from that of the wild type ; however , specification of both terminal and lateral spikelet meristems was blocked , and sequential rounds of branching occurred at the point where the spikelet meristems are initiated in the wild-type panicle .
This resulted in the generation of a panicle composed of excessive ramification of rachis-branches .
The lax1-1 fzp2 double mutants exhibited a novel , basically additive , phenotype , which suggests that LAX1 and FZP2 function in genetically independent pathways . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: The SHOOTLESS2 and SHOOTLESS1 genes are involved in both initiation and maintenance of the shoot apical meristem through regulating the number of indeterminate cells .
| | Author: Satoh N Itoh J Nagato Y | | Journal: Genetics Citation: V : 164 ( 1 ) P : 335-46 Year: 2003 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub12750344 Accession (PMID): 12750344 | | Abstract: To characterize the SHL2 and SHL1 genes in detail , we analyzed three strains carrying weak alleles of SHL2 , shl2-6 , shl2-7 , and shl2-8 , and one weak allele of SHL1 , shl1-3 .
In contrast to strong alleles , which result in lack of shoot meristem , strains bearing these weak alleles formed shoot meristem frequently during embryogenesis .
In shl2-6 and shl2-7 mutants , the meristem was lost during seed development .
Only the shl2-8 mutant could survive after germination , but it showed abnormal initiation pattern and morphology of leaves .
In strains bearing the weak alleles , the shoot meristem was composed of a small number of indeterminate cells and ultimately converted into leaf primordium .
The shl1-3 mutant showed phenotypes similar to those of shl2-8 .
Thus SHL2 and SHL1 are required for both initiation and maintenance of shoot meristem .
In shl2 mutants , there was a positive correlation between the size of the expression domain of OSH1 representing the number of indeterminate cells , the frequency of shoot meristem initiation , and the duration of meristem survival Thus the shoot meristem will not initiate in an "all-or-nothing" fashion , but is formed in various degrees depending on the strength of the alleles .
Double-mutant analyses indicate that SHL2 functions upstream of SHO to establish proper organization of the shoot meristem . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: The gene FLORAL ORGAN NUMBER1 regulates floral meristem size in rice and encodes a leucine-rich repeat receptor kinase orthologous to Arabidopsis CLAVATA1 .
| | Author: Suzaki T Sato M Ashikari M Miyoshi M Nagato Y Hirano HY .
| | Journal: Development Citation: V : 131 ( 22 ) P : 5649-57 Year: 2004 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub15509765 Accession (PMID): 15509765 | | Abstract: The regulation of floral organ number is closely associated with floral meristem size .
Mutations in the gene FLORAL ORGAN NUMBER1 ( FON1 ) cause enlargement of the floral meristem in Oryza sativa ( rice ) , resulting in an increase in the number of all floral organs .
Ectopic floral organs develop in the whorl of each organ and/or in the additional whorls that form .
Inner floral organs are more severely affected than outer floral organs .
Many carpel primordia develop indeterminately , and undifferentiated meristematic it issues remain in the center in almost-mature flowers .
Consistent with this result , OSH1 , a molecular marker of meristematic indeterminate cells in rice , continues to be expressed in this region .
Although floral meristems are strongly affected by the fon1-2 mutation , vegetative and inflorescence meristems are largely normal , even in this strong allele .
We isolated the FON1 gene by positional cloning and found that it encodes a leucine-rich repeat receptor-like kinase most similar to CLAVATA1 ( CLV1 ) in Arabidopsis thaliana .
This suggests that a pathway similar to the CLV signaling system that regulates meristem maintenance in Arabidopsis is conserved in the grass family .
Unlike CLV1 , which is predominantly expressed in the L3 layer of the shoot meristem , FON1 is expressed throughout the whole floral meristem , suggesting that small modifications to the CLV signaling pathway may be required to maintain the floral meristem in rice .
In addition , FON1 transcripts are detected in all meristems responsible for development of the aerial part of rice , suggesting that genes sharing functional redundancy with FON1 act in the vegetative and inflorescence meristems to mask the effects of the fon1 mutation . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Gypsy embryo specifies ovule curvature by regulating ovule/integument development in rice .
| | Author: Yamaki S Satoh H Nagato Y | | Journal: Planta Citation: V : 222 ( 3 ) P : 408-17 Year: 2005 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16001259 Accession (PMID): 16001259 | | Abstract: The embryo position in a seed is stable in most plant species , indicating the existence of a strict regulatory mechanism that specifies the embryo position in the seed .
To elucidate this mechanism , we analyzed the gypsy embryo ( gym ) mutant of rice , in which the position of the mature embryo in the seed is altered at a low frequency .
Analyses of early embryogenesis and ovule development showed that the ectopic embryo was derived from an ill-positioned egg cell , which resulted from the incomplete curvature of the ovule .
Although the development of both the inner and outer integuments was impaired , the ovule curvature was associated closely with the extent of inner integument growth .
Therefore , inner integument development controls ovule curvature in rice .
The expression patterns of OSH1 and OsMADS13 indicated that , in gym , a small number of indeterminate cells are maintained on the style side of the ovule and then in the integument primordium at a low frequency .
The prolonged survival of these indeterminate cells disturbs normal integument development .
The gym fon2 double mutant suggests that GYM and FON2 are involved redundantly in floral meristem determinacy .
Possible functions of the GYM gene and the ovule developmental mechanism are discussed . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: A class I KNOX gene from the palm species Elaeis guineensis ( Arecaceae ) is associated with meristem function and a distinct mode of leaf dissection .
| | Author: Jouannic S Collin M Vidal B Verdeil JL Tregear JW | | Journal: New Phytol Citation: V : 174 P : 551-68 Year: 2007 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub17447911 Accession (PMID): 17447911 | | Abstract: Class I Knotted-like homeobox ( KNOX ) transcription factors are important regulators of shoot apical meristem function and leaf morphology by their contribution to dissected leaf development .
Palms are of particular interest as they produce dissected leaves generated by a distinct mechanism compared with eudicots .
The question addressed here was whether class I KNOX genes might be involved in meristem function and leaf dissection in palms .
Here , we characterized the EgKNOX1 gene from oil palm ( Elaeis guineensis , Arecaceae ) and compared it with available sequences from other plant species using phylogenetic analysis .
Gene expression pattern was investigated using reverse transcription-polymerase chain reaction ( RT-PCR ) and in situ hybridization .
Functional analysis was carried out by ectopic expression in Arabidopsis and rice .
EgKNOX1 was orthologous to STM from Arabidopsis and to OSH1 from rice .
It was expressed in the central zone of both vegetative and reproductive meristems .
During leaf development , its expression was associated with plications from which the leaflets originate .
Different modes of leaf dissection are seen to involve a similar class of genes to control meristematic activities , which govern the production of dissected morphologies .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: A rice tryptophan deficient dwarf mutant , tdd1 , contains a reduced level of indole acetic acid and develops abnormal flowers and organless embryos .
| | Author: Sazuka T Kamiya N Nishimura T Ohmae K Sato Y Imamura K Nagato Y Koshiba T Nagamura Y Ashikari M Kitano H Matsuoka M | | Journal: Plant J Citation: V : 60 P : 227-41 Year: 2009 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub19682283 Accession (PMID): 19682283 | | Abstract: Indole-3-acetic acid ( IAA ) plays a critical role in many aspects of plant growth and development ; however , complete pathways of biosynthesis , localization and many aspects of functions of IAA in rice remain unclear .
Here , we report the analysis of a rice tryptophan ( Trp- ) and IAA-deficient mutant , tryptophan deficient dwarf1 ( tdd1 ) , which is embryonic lethal because of a failure to develop most organs during embryogenesis .
Regenerated tdd1 plants showed pleiotropic phenotypes : dwarfing , narrow leaves , short roots and abnormal flowers .
TDD1 encodes a protein homologous to anthranilate synthase beta-subunit , which catalyses the first step of the Trp biosynthesis pathway and functions upstream of Trp-dependent IAA biosynthesis .
TDD1-uidA and DR5-uidA expression overlapped at many sites in WT plants but was lacking in tdd1 , indicating that TDD1 is involved in auxin biosynthesis .
Both Trp and IAA levels in flowers and embryos were much lower in tdd1 than in wild type ( WT ) .
Trp feeding completely rescued the mutant phenotypes and moderate expression of OsYUCCA1 , which encodes a key enzyme in Trp-dependent IAA biosynthesis , also rescued plant height and root length , indicating that the abnormal phenotypes of tdd1 are caused predominantly by Trp and IAA deficiency .
In tdd1 embryos , the expression patterns of OSH1 and OsSCR , which mark the presumptive apical region and the L2 layer , respectively , are identical to those in WT , suggesting a possibility either that different IAA levels are required for basic pattern formation than for organ formation or that an orthologous gene compensates for TDD1 deficiency during pattern formation .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: The homeobox gene ATK1 of Arabidopsis thaliana is expressed in the shoot apex of the seedling and in flowers and inflorescence stems of mature plants .
| | Author: Dockx J Quaedvlieg N Keultjes G Kock P Weisbeek P Smeekens S | | Journal: Plant Mol . Biol . Citation: V : 28 ( 4 ) P : 723-37 Year: 1995 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub7647303 Accession (PMID): 7647303 | | Abstract: The homeodomain is a DNA-binding domain present in a large family of eukaryotic regulatory proteins .
Homeodomain proteins have been shown to play key roles in controlling developmental programs in various organisms .
Here we report the isolation and characterisation of a homeobox gene from Arabidopsis thaliana designated ATK1 .
The gene was isolated using as a probe the homeobox domain of the KN1 gene from maize .
The homeodomain of ATK1 is highly homologous to the homeodomain of the KN1 gene of maize ( 81% ) but shows only poor homology outside the homeodomain .
Therefore ATK1 is probably not the Arabidopsis homologue of the KN1 gene from maize .
It contains the four invariant amino acid residues present in the recognition helix 3 of all other homeodomain proteins .
Outside the homeodomain a region rich in aspartate and glutamate residues is found suggesting that ATK1 is a transcriptional activator .
The gene contains four introns which is similar in the KN1 gene of maize and the Osh1 gene of rice .
Primer extension reveals the presence of two transcription initiation sites .
The leader sequence of the genuine transcript is 342 nucleotides long and contains two upstream open reading frames .
ATK1 is strongly expressed in the shoot apex of seedlings , while in mature plants the gene is primarily expressed in flowers and inflorescence stems .
Such an expression pattern is reminiscent of that of the KN1 gene of maize and therefore ATK1 could similarly be involved in determining cell fate .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Two transcripts with different sizes derived from a rice homeobox gene , OSH1 .
| | Author: Tamaoki M Ichikawa H Kayano T Kano-Murakami Y Yamamoto N Matsuoka M | | Journal: Biochem . Biophys . Res . Commun . Citation: V : 221 ( 2 ) P : 408-13 Year: 1996 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub8619869 Accession (PMID): 8619869 | | Abstract: A rice homeobox gene , OSH1 , contains two functionally independent promoters which generate a larger transcript and a smaller transcript .
In Arabidopsis , each promoter can drive the expression of a reporter gene in a different manner , indicating that the expression of different sized transcripts is independently regulated by each promoter .
Over-expression of the larger transcript in transformed plants caused altered morphologies ( Matsuoka et al , Plant Cell , 1993 , 5 , 1039-1048 ) ; in contrast , over-expression of the smaller transcript did not cause any morphological changes .
The results suggest that the product of the smaller transcript fails to alter the expression of its target gene ( s ) in the transformants , while that of the larger transcript is capable of altering the expression of its target gene ( s ) . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Isolation and characterization of cDNA clones with enhanced expression in tobacco plants expressing the rice homeobox gene , OSH1 .
| | Author: Tamaoki M Yamamoto N Matsuoka M | | Journal: Plant Cell Physiol .
Citation: V : 38 ( 5 ) P : 638-42 Year: 1997 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub9210336 Accession (PMID): 9210336 | | Abstract: We have used subtractive hybridization to isolate cDNA clones whose expression were up-regulated in transgenic tobacco ectopically expressing the rice homeobox gene , OSH1 .
Thirty-nine distinct cDNA clones , which we term HRGs ( Homeobox Regulated Genes ) , were identified .
Some of them were specifically expressed in transformants , indicating that their expression was possibly regulated by transgene . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Loss-of-function mutations in the rice homeobox gene OSH15 affect the architecture of internodes resulting in dwarf plants .
| | Author: Sato Y Sentoku N Miura Y Hirochika H Kitano H Matsuoka M | | Journal: EMBO J Citation: V : 18 ( 4 ) P : 992-1002 Year: 1999 Type: ARTICLE | | Literature: oryza Field: title Doc ID: pub10022841 Accession (PMID): 10022841 | | Abstract: The rice homeobox gene OSH15 ( Oryza sativa homeobox ) is a member of the knotted1-type homeobox gene family .
We report here on the identification and characterization of a loss-of-function mutation in OSH15 from a library of retrotransposon-tagged lines of rice .
Based on the phenotype and map position , we have identified three independent deletion alleles of the locus among conventional morphological mutants .
All of these recessive mutations , which are considered to be null alleles , exhibit defects in internode elongation .
Introduction of a 14 kbp genomic DNA fragment that includes all exons , introns and 5- and 3- flanking sequences of OSH15 complemented the defects in internode elongation , confirming that they were caused by the loss-of-function of OSH15 .
Internodes of the mutants had abnormal-shaped epidermal and hypodermal cells and showed an unusual arrangement of small vascular bundles .
These mutations demonstrate a role for OSH15 in the development of rice internodes .
This is the first evidence that the knotted1-type homeobox genes have roles other than shoot apical meristem formation and/or maintenance in plant development . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Functional analysis of the conserved domains of a rice KNOX homeodomain protein , OSH15 .
| | Author: Nagasaki H Sakamoto T Sato Y Matsuoka M | | Journal: Plant Cell Citation: V : 13 ( 9 ) P : 2085-98 Year: 2001 Type: ARTICLE | | Literature: oryza Field: title Doc ID: pub11549765 Accession (PMID): 11549765 | | Abstract: The rice KNOX protein OSH15 consists of four conserved domains : the MEINOX domain , which can be divided into two subdomains ( KNOX1 and KNOX2 ) ; the GSE domain ; the ELK domain ; and the homeodomain ( HD ) .
To investigate the function of each domain , we generated 10 truncated proteins with deletions in the conserved domains and four proteins with mutations in the conserved amino acids in the HD .
Transgenic analysis suggested that KNOX2 and HD are essential for inducing the abnormal phenotype and that the KNOX1 and ELK domains affect phenotype severity .
We also found that both KNOX2 and HD are necessary for homodimerization and that only HD is needed for binding of OSH15 to its target sequence .
Transactivation studies suggested that both the KNOX1 and ELK domains play a role in suppressing target gene expression .
On the basis of these findings , we propose that overproduced OSH15 probably acts as a dimer and may ectopically suppress the expression of target genes that induce abnormal morphology in transgenic plants . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: A rice homeotic gene , OSH1 , causes unusual phenotypes in transgenic tobacco | | Author: Kano-Murakami Y Yanai T Tagiri A Matsuoka M | | Journal: FEBS Lett .
Citation: V : 334 ( 3 ) P : 365-8 Year: 1993 Type: ARTICLE | | Literature: oryza Field: title Doc ID: pub7902297 Accession (PMID): 7902297 | | Abstract: A rice gene , OSH1 , which shares homology with animal homeobox genes , has been isolated .
We have introduced the OSH1 cDNA into tobacco in order to examine its function .
Expression of the OSH1 cDNA in tobacco induced morphological abnormalities in the leaves , petals and stems of the transformants suggesting that OSH1 functions as a morphological regulator .
OSH1 cDNA expression was analyzed under the control of three different promoters .
This work revealed that not only the level of OSH1 expression but also the site and timing of the expression affect the morphology of the plant . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Two transcripts with different sizes derived from a rice homeobox gene , OSH1 .
| | Author: Tamaoki M Ichikawa H Kayano T Kano-Murakami Y Yamamoto N Matsuoka M | | Journal: Biochem . Biophys . Res . Commun . Citation: V : 221 ( 2 ) P : 408-13 Year: 1996 Type: ARTICLE | | Literature: oryza Field: title Doc ID: pub8619869 Accession (PMID): 8619869 | | Abstract: A rice homeobox gene , OSH1 , contains two functionally independent promoters which generate a larger transcript and a smaller transcript .
In Arabidopsis , each promoter can drive the expression of a reporter gene in a different manner , indicating that the expression of different sized transcripts is independently regulated by each promoter .
Over-expression of the larger transcript in transformed plants caused altered morphologies ( Matsuoka et al , Plant Cell , 1993 , 5 , 1039-1048 ) ; in contrast , over-expression of the smaller transcript did not cause any morphological changes .
The results suggest that the product of the smaller transcript fails to alter the expression of its target gene ( s ) in the transformants , while that of the larger transcript is capable of altering the expression of its target gene ( s ) . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Abnormal cell divisions in leaf primordia caused by the expression of the rice homeobox gene OSH1 lead to altered morphology of leaves in transgenic tobacco | | Author: Sato Y Tamaoki M Murakami T Yamamoto N Kano-Murakami Y Matsuoka M | | Journal: Mol . Gen . Genet . Citation: V : 251 ( 1 ) P : 13-22 Year: 1996 Type: ARTICLE | | Literature: oryza Field: title Doc ID: pub8628242 Accession (PMID): 8628242 | | Abstract: Transgenic tobacco plants were generated carrying a rice homeobox gene , OSH1 , controlled by the promoter of a gene encoding a tobacco pathogenesis-related protein ( PR1a ) .
These lines were morphologically abnormal , with wrinkled and/or lobed leaves .
Histological analysis of shoot apex primordia indicates arrest of lateral leaf blade expansion , often resulting in asymmetric and anisotrophic growth of leaf blades .
Other notable abnormalities included abnormal or arrested development of leaf lateral veins .
Interestingly , OHS1 expression was undetectable in mature leaves with the aberrant morphological features .
Thus , OSH1 expression in mature leaves is not necessary for abnormal leaf development .
Northern blot and in situ hybridization analyses indicate that PR1a-OSH1 is expressed only in the shoot apical meristem and in very young leaf primordia .
Therefore , the aberrant morphological features are an indirect consequence of ectopic OSH1 gene expression .
The only abnormality observed in it issues expressing the transgene was periclinal ( rather than anticlinal ) division in mesophyll cells during leaf blade initiation .
This generates thicker leaf blades and disrupts the mesophyll cell layers , from which vascular it issues differentiate .
The OSH1 product appears to affect the mechanism controlling the orientation of the plane of cell division , resulting in abnormal periclinal division of mesophyll cell , which in turn results in the gross morphological abnormalities observed in the transgenic lines . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: A rice homeobox gene , OSH1 , is expressed before organ differentiation in a specific region during early embryogenesis .
| | Author: Sato Y Hong SK Tagiri A Kitano H Yamamoto N Nagato Y Matsuoka M | | Journal: Proc . Natl . Acad . Sci . USA Citation: V : 93 ( 15 ) P : 8117-22 Year: 1996 Type: ARTICLE | | Literature: oryza Field: title Doc ID: pub8755613 Accession (PMID): 8755613 | | Abstract: Homeobox genes encode a large family of homeodomain proteins that play a key role in the pattern formation of animal embryos .
By analogy , homeobox genes in plants are thought to mediate important processes in their embryogenesis , but there is very little evidence to support this notion .
Here we described the temporal and spatial expression patterns of a rice homeobox gene , OSH1 , during rice embryogenesis .
In situ hybridization analysis revealed that in the wild-type embryo , OSH1 was first expressed at the globular stage , much earlier than organogenesis started , in a ventral region where shoot apical meristem and epiblast would later develop .
This localized expression of OSH1 indicates that the cellular differentiation has already occurred at this stage .
At later stages after organogenesis had initiated , OSH1 expression was observed in shoot apical meristem [ except in the L1 ( tunica ) layer ] , epiblast , radicle , and their intervening it issues in descending strength of expression level with embryonic maturation .
We also performed in situ hybridization analysis with a rice organless embryo mutant , orl1 , that develops no embryonic organs .
In the orl1 embryo , the expression pattern of OSH1 was the same as that in the wild-type embryo in spite of the lack of embryonic organs .
This shows that OSH1 is not directly associated with organ differentiation , but may be related to a regulatory process before or independent of the organ determination .
The results described here strongly suggest that , like animal homeobox genes , OSH1 plays an important role in regionalization of cell identity during early embryogenesis . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Isolation and characterization of cDNA clones with enhanced expression in tobacco plants expressing the rice homeobox gene , OSH1 .
| | Author: Tamaoki M Yamamoto N Matsuoka M | | Journal: Plant Cell Physiol .
Citation: V : 38 ( 5 ) P : 638-42 Year: 1997 Type: ARTICLE | | Literature: oryza Field: title Doc ID: pub9210336 Accession (PMID): 9210336 | | Abstract: We have used subtractive hybridization to isolate cDNA clones whose expression were up-regulated in transgenic tobacco ectopically expressing the rice homeobox gene , OSH1 .
Thirty-nine distinct cDNA clones , which we term HRGs ( Homeobox Regulated Genes ) , were identified .
Some of them were specifically expressed in transformants , indicating that their expression was possibly regulated by transgene . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Alteration of hormone levels in transgenic tobacco plants overexpressing the rice homeobox gene OSH1 .
| | Author: Kusaba S Kano-Murakami Y Matsuoka M Tamaoki M Sakamoto T Yamaguchi I Fukumoto M | | Journal: Plant Physiol .
Citation: V : 116 ( 2 ) P : 471-6 Year: 1998 Type: ARTICLE | | Literature: oryza Field: title Doc ID: pub9489007 Accession (PMID): 9489007 | | Abstract: The rice ( Oryza sativa L ) homeobox gene OSH1 causes morphological alterations when ectopically expressed in transgenic rice , Arabidopsis thaliana , and tobacco ( Nicotiana tabacum L ) and is therefore believed to function as a morphological regulator gene .
To determine the relationship between OSH1 expression and morphological alterations , we analyzed the changes in hormone levels in transgenic tobacco plants exhibiting abnormal morphology .
Levels of the plant hormones indole-3-acetic acid , abscisic acid , gibberellin ( GA ) , and cytokinin ( zeatin and trans-zeatin [ Z ] ) were measured in leaves of OSH1-transformed and wild-type tobacco Altered plant morphology was found to correlate with changes in hormone levels .
The more severe the alteration in phenotype of transgenic tobacco , the greater were the changes in endogenous hormone levels .
Overall , GA1 and GA4 levels decreased and abscisic acid levels increased compared with wild-type plants .
Moreover , in the transformants , Z ( active form of cytokinin ) levels were higher and the ratio of Z to Z riboside ( inactive form ) also increased .
When GA3 was supplied to the shoot apex of transformants , internode extension was restored and normal leaf morphology was also partially restored .
However , such GA3-treated plants still exhibited some morphological abnormalities compared with wild-type plants .
Based on these data , we propose the hypothesis that OSH1 affects plant hormone metabolism either directly or indirectly and thereby causes changes in plant development . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Decreased GA1 content caused by the overexpression of OSH1 is accompanied by suppression of GA 20-oxidase gene expression .
| | Author: Kusaba S Fukumoto M Honda C Yamaguchi I Sakamoto T Kano-Murakami Y | | Journal: Plant Physiol .
Citation: V : 117 ( 4 ) P : 1179-84 Year: 1998 Type: ARTICLE | | Literature: oryza Field: title Doc ID: pub9701574 Accession (PMID): 9701574 | | Abstract: We previously reported that overexpression of the rice homeobox gene OSH1 led to altered morphology and hormone levels in transgenic tobacco ( Nicotiana tabacum L ) plants .
Among the hormones whose levels were changed , GA1 was dramatically reduced .
Here we report the results of our analysis on the regulatory mechanism ( s ) of OSH1 on GA metabolism .
GA53 and GA20 , precursors of GA1 , were applied separately to transgenic tobacco plants exhibiting severely changed morphology due to overexpression of OSH1 .
Only treatment with the end product of GA 20-oxidase , GA20 , resulted in a striking promotion of stem elongation in transgenic tobacco plants .
The internal GA1 and GA20 contents in OSH1-transformed tobacco were dramatically reduced compared with those of wild-type plants , whereas the level of GA19 , a mid-product of GA 20-oxidase , was 25% of the wild-type level .
We have isolated a cDNA encoding a putative tobacco GA 20-oxidase , which is mainly expressed in vegetative stem it issue .
RNA-blot analysis revealed that GA 20-oxidase gene expression was suppressed in stem it issue of OSH1-transformed tobacco plants .
Based on these results , we conclude that overexpression of OSH1 causes a reduction of the level of GA1 by suppressing GA 20-oxidase expression . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Isolation and characterization of a rice homebox gene , OSH15 .
| | Author: Sato Y Sentoku N Nagato Y Matsuoka M | | Journal: Plant Mol . Biol . Citation: V : 38 ( 6 ) P : 983-98 Year: 1998 Type: ARTICLE | | Literature: oryza Field: title Doc ID: pub9869405 Accession (PMID): 9869405 | | Abstract: In many eukaryotic organisms including plants , homeobox genes are thought to be master regulators that establish the cellular or regional identities and specify the fundamental body plan .
We isolated and characterized a cDNA designated OSH15 ( Oryza sativa homeobox 15 ) that encodes a KNOTTED-type homeodomain protein .
Transgenic tobacco plants overexpressing the OSH15 cDNA showed a dramatically altered morphological phenotype caused by disturbance of specific aspects of tobacco development , thereby indicating the involvement of OSH15 in plant development .
We analyzed the in situ mRNA localization of OSH15 through the whole plant life cycle , comparing the expression pattern with that of another rice homeobox gene , OSH1 .
In early embryogenesis , both genes were expressed as the same pattern at a region where the shoot apical meristem would develop later .
In late embryogenesis , the expression pattern of the two genes became different .
Whereas the expression of OSH1 continued within the shoot apical meristem , OSH15 expression within the shoot apical meristem ceased but became observable in a ring shaped pattern at the boundaries of some embryonic organs .
This pattern of expression was similar to that observed around vegetative or reproductive shoots , or the floral meristem in mature plants .
RNA in situ localization data suggest that OSH15 may play roles in the shoot organization during early embryogenesis and thereafter , OSH15 may be involved in morphogenetic events around the shoot apical meristem . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
