| 26 matches found in 14 documents. Search time: 0.123 seconds. |
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| Title: PAIR2 is essential for homologous chromosome synapsis in rice meiosis I | | Author: Nonomura K Nakano M Eiguchi M Suzuki T Kurata N | | Journal: J Cell . Sci . Citation: V : 119 ( Pt 2 ) P : 217-25 Year: 2006 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16410547 Accession (PMID): 16410547 | | Abstract: The PAIR2 gene is required for homologous chromosome synapsis at meiosis I in rice ( Oryza sativa L ) and encodes a HORMA-domain protein that is homologous to Saccharomyces cerevisiae HOP1 and Arabidopsis ASY1 .
Immunocytological and electron microscopic analyses indicate that PAIR2 proteins associate with axial elements ( AEs ) at leptotene and zygotene , and is removed from the AEs of arm regions when homologous chromosomes have been synapsed .
Immunocytology against a centromeric histone H3 variant revealed that PAIR2 remains at centromeres until diakinesis , by which time the homologous centromeres had already been synapsed .
However , neither precocious segregation of sister chromatids nor kinetochore dysfunction is observed , and AEs are normally assembled in the mutant .
In the pair2-null mutant , homologous chromosome synapsis is completely eliminated .
This study provides the first description of AE-associated protein in monocot plants and indicates that PAIR2 plays an essential role in promoting homologous chromosome synapsis .
However , PAIR2 does not play a role in AE formation , sister chromatid cohesion at centromeres or kinetochore assembly in meiosis I of rice . | Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: The PAIR2 gene is required for homologous chromosome synapsis at meiosis I in rice ( Oryza sativa L ) and encodes a HORMA-domain protein that is homologous to Saccharomyces cerevisiae HOP1 and Arabidopsis ASY1 .
[ Sen. 2, subscore: 1.00 ]: Immunocytological and electron microscopic analyses indicate that PAIR2 proteins associate with axial elements ( AEs ) at leptotene and zygotene , and is removed from the AEs of arm regions when homologous chromosomes have been synapsed .
[ Sen. 3, subscore: 1.00 ]: Immunocytology against a centromeric histone H3 variant revealed that PAIR2 remains at centromeres until diakinesis , by which time the homologous centromeres had already been synapsed .
[ Sen. 5, subscore: 1.00 ]: In the pair2-null mutant , homologous chromosome synapsis is completely eliminated .
[ Sen. 6, subscore: 1.00 ]: This study provides the first description of AE-associated protein in monocot plants and indicates that PAIR2 plays an essential role in promoting homologous chromosome synapsis .
[ Sen. 7, subscore: 1.00 ]: However , PAIR2 does not play a role in AE formation , sister chromatid cohesion at centromeres or kinetochore assembly in meiosis I of rice .
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Score: 5.00 |
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| Title: An insertional mutation in the rice PAIR2 gene , the ortholog of Arabidopsis ASY1 , results in a defect in homologous chromosome pairing during meiosis .
| | Author: Nonomura KI Nakano M Murata K Miyoshi K Eiguchi M Miyao A Hirochika H Kurata N | | Journal: Mol . Genet . Genomics Citation: V : 271 ( 2 ) P : 121-9 Year: 2004 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub14758540 Accession (PMID): 14758540 | | Abstract: To elucidate the genetic system that establishes homologous chromosome pairing in monocot plants , we have isolated an asynaptic mutant of rice , designated pair2 ( homologous pairing aberration in rice meiosis 2 ) , in which 24 completely unpaired univalents are observed at pachytene and diakinesis .
The mutation was caused by an insertion of the retrotransposon Tos17 , as demonstrated by complementation of the mutation by transformation with the corresponding wild-type gene .
The gene in which the element was inserted is orthologous to the ASY1 gene of Arabidopsis thaliana and the HOP1 gene of Saccharomyces cerevisiae .
Mature PAIR2 mRNA and several splicing variants were found to be highly expressed in wild-type reproductive it issues , and lower expression was also detected in vegetative it issues .
In situ hybridization and BrdU incorporation experiments revealed that PAIR2 expression is specifically enhanced in male and female meiocytes , but not in those at pre-meiotic S phase or in the pollen maturation stages .
The results obtained in this study suggest that the PAIR2 gene is essential for homologous chromosome pairing in meiosis , as in the case of the genes ASY1 and HOP1 .
The study also suggested the possibility that a highly homologous copy of the PAIR2 gene located on a different chromosome is in fact a pseudogene . | Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: To elucidate the genetic system that establishes homologous chromosome pairing in monocot plants , we have isolated an asynaptic mutant of rice , designated pair2 ( homologous pairing aberration in rice meiosis 2 ) , in which 24 completely unpaired univalents are observed at pachytene and diakinesis .
[ Sen. 4, subscore: 1.00 ]: Mature PAIR2 mRNA and several splicing variants were found to be highly expressed in wild-type reproductive it issues , and lower expression was also detected in vegetative it issues .
[ Sen. 5, subscore: 1.00 ]: In situ hybridization and BrdU incorporation experiments revealed that PAIR2 expression is specifically enhanced in male and female meiocytes , but not in those at pre-meiotic S phase or in the pollen maturation stages .
[ Sen. 6, subscore: 1.00 ]: The results obtained in this study suggest that the PAIR2 gene is essential for homologous chromosome pairing in meiosis , as in the case of the genes ASY1 and HOP1 .
[ Sen. 7, subscore: 1.00 ]: The study also suggested the possibility that a highly homologous copy of the PAIR2 gene located on a different chromosome is in fact a pseudogene .
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Score: 5.00 |
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| Title: MER3 is required for normal meiotic crossover formation , but not for presynaptic alignment in rice .
| | Author: Wang K Tang D Wang M Lu J Yu H Liu J Qian B Gong Z Wang X Chen J Gu M Cheng Z | | Journal: J Cell Sci Citation: V : P : Year: 2009 Type: Publisher | | Literature: oryza Field: abstract Doc ID: pub19470578 Accession (PMID): 19470578 | | Abstract: MER3 , a ZMM protein , is required for the formation of crossovers in Saccharomyces cerevisiae and Arabidopsis .
Here , MER3 , the first identified ZMM gene in a monocot , is characterized by map-based cloning in rice ( Oryza sativa ) .
The null mutation of MER3 results in complete sterility without any vegetative defects .
Cytological analyses show that chiasma frequency is reduced dramatically in mer3 mutants and the remaining chiasmata distribute randomly among different pollen mother cells , implying possible coexistence of two kinds of crossover in rice .
Immunocytological analyses reveal that MER3 only exists as foci in prophase I meiocytes .
In addition , MER3 does not colocalize with PAIR2 at the beginning of prophase I , but locates on one end of PAIR2 fragments at later stages , whereas MER3 foci merely locate on one end of REC8 fragments when signals start to be seen in early prophase I The normal loading of PAIR2 and REC8 in mer3 implies that their loading is independent of MER3 .
On the contrary , the absence of MER3 signal in pair2 mutants indicates that PAIR2 is essential for the loading and further function of MER3 .
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[ Sen. 6, subscore: 3.00 ]: In addition , MER3 does not colocalize with PAIR2 at the beginning of prophase I , but locates on one end of PAIR2 fragments at later stages , whereas MER3 foci merely locate on one end of REC8 fragments when signals start to be seen in early prophase I The normal loading of PAIR2 and REC8 in mer3 implies that their loading is independent of MER3 .
[ Sen. 7, subscore: 2.00 ]: On the contrary , the absence of MER3 signal in pair2 mutants indicates that PAIR2 is essential for the loading and further function of MER3 .
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Score: 2.00 |
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| Title: OsSPO11-1 is essential for both homologous chromosome pairing and crossover formation in rice .
| | Author: Yu H Wang M Tang D Wang K Chen F Gong Z Gu M Cheng Z | | Journal: Chromosoma Citation: V : 119 P : 625-36 Year: 2010 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub20625906 Accession (PMID): 20625906 | | Abstract: Spo11 is a homolog of a subunit of archaebacterial topoisomerase , which catalyzes DNA double-strand breaks and initiates homologous chromosome recombination .
In the present study , we silenced the SPO11-1 gene in rice ( Oryza sativa ) using RNAi .
Rice plants with loss-of-function of OsSPO11-1 have no apparent growth defects during vegetative development , but homologous chromosome pairing and recombination are significantly obstructed .
Telomeres can be assembled as bouquet during the zygotene stage of the OsSPO11-1-deficient plants , just as that in wild type .
Although the two axial-associated proteins , REC8 and PAIR2 , are loaded onto the chromosomes , the depletion of PAIR2 from the chromosomes is much later than in wild type .
The central element of the synaptonemal complex ( SC ) , ZEP1 , does not load onto the chromosomes normally , implying that SC formation is disturbed severely .
The crossover protein , MER3 , isnt efficiently assembled onto chromosomes and the lack of bivalent suggests that crossovers are also affected in the absence of OsSPO11-1 .
Thus , OsSPO11-1 is essential for both homologous chromosomes pairing and crossover formation during meiosis in rice .
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[ Sen. 5, subscore: 2.00 ]: Although the two axial-associated proteins , REC8 and PAIR2 , are loaded onto the chromosomes , the depletion of PAIR2 from the chromosomes is much later than in wild type .
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Score: 2.00 |
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| Title: PAIR3 , an axis-associated protein , is essential for the recruitment of recombination elements onto meiotic chromosomes in rice .
| | Author: Wang K Wang M Tang D Shen Y Qin B Li M Cheng Z | | Journal: Mol Biol Cell Citation: V : 22 P : 12-9 Year: 2011 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub21119003 Accession (PMID): 21119003 | | Abstract: During meiosis , the paired homologous chromosomes are tightly held together by the synaptonemal complex ( SC ) .
This complex consists of two parallel axial/lateral elements ( AEs/LEs ) and one central element .
Here , we observed that PAIR3 localized to the chromosome core during prophase I and associated with both unsynapsed AEs and synapsed LEs .
Analyses of the severe pair3 mutant demonstrated that PAIR3 was essential for bouquet formation , homologous pairing and normal recombination , and SC assembly .
In addition , we showed that although PAIR3 was not required for the initial recruitment of PAIR2 , it was required for the proper association of PAIR2 with chromosomes .
Dual immunostaining revealed that PAIR3 highly colocalized with REC8 .
Moreover , studies using a rec8 mutant indicated that PAIR3 localized to chromosomes in a REC8-dependent manner .
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[ Sen. 5, subscore: 2.00 ]: In addition , we showed that although PAIR3 was not required for the initial recruitment of PAIR2 , it was required for the proper association of PAIR2 with chromosomes .
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Score: 2.00 |
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| Title: OsAM1 is required for leptotene-zygotene transition in rice .
| | Author: Che L Tang D Wang K Wang M Zhu K Yu H Gu M Cheng Z | | Journal: Cell Res Citation: V : 21 P : 654-65 Year: 2011 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub21221128 Accession (PMID): 21221128 | | Abstract: The events occurring at the onset of meiosis have not been fully elucidated .
In the present study , OsAM1 was identified in rice ( Oryza sativa L ) by map-based cloning .
OsAM1 , a homolog of Arabidopsis SWI1 and maize AM1 , encodes a protein with a coiled-coil domain in its central region .
In the Osam1 mutant , pollen mother cells are arrested at leptotene , showing that OsAM1 is required for the leptotene-zygotene transition .
Immunocytological analysis revealed that OsAM1 exists as foci in early prophase I meiocytes .
Very faint OsREC8 foci persisted in the Osam1 mutant , indicating that OsAM1 is not required for the initial meiotic recruitment of OsREC8 .
In the absence of OsAM1 , many other critical meiotic components , including PAIR2 , ZEP1 and OsMER3 , could not be correctly installed onto chromosomes .
In contrast , in pair2 , Osmer3 and zep1 mutants , OsAM1 could be loaded normally , suggesting that OsAM1 plays a fundamental role in building the proper chromosome structure at the beginning of meiosis .
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[ Sen. 7, subscore: 1.00 ]: In the absence of OsAM1 , many other critical meiotic components , including PAIR2 , ZEP1 and OsMER3 , could not be correctly installed onto chromosomes .
[ Sen. 8, subscore: 1.00 ]: In contrast , in pair2 , Osmer3 and zep1 mutants , OsAM1 could be loaded normally , suggesting that OsAM1 plays a fundamental role in building the proper chromosome structure at the beginning of meiosis .
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Score: 2.00 |
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| Title: OsREC8 is essential for chromatid cohesion and metaphase I monopolar orientation in rice meiosis .
| | Author: Shao T Tang D Wang K Wang M Che L Qin B Yu H Li M Gu M Cheng Z | | Journal: Plant Physiol Citation: V : 156 P : 1386-96 Year: 2011 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub21606318 Accession (PMID): 21606318 | | Abstract: The successful transmission of chromosomes during mitosis and meiosis relies on the establishment and subsequent release of cohesion between replicated chromatids .
Cohesion is mediated by a four-subunit structural maintenance of chromosome complex , called cohesins .
REC8 is a key component of this meiotic cohesion complex in most model organisms studied to date .
Here , we isolated and dissected the functions of OsREC8 , a rice ( Oryza sativa ) REC8 homolog , using two null Osrec8 mutants .
We showed that OsREC8 encodes a protein that localized to meiotic chromosomes from approximately meiotic interphase to metaphase I Homologous pairing and telomere bouquet formation were abnormal in Osrec8 meiocytes .
Furthermore , fluorescent in situ hybridization experiments on Osrec8 meiocytes demonstrated that the mutation eliminated meiotic centromeric cohesion completely during prophase I and also led to the bipolar orientation of the kinetochores during the first meiotic division and accordingly resulted in premature separation of sister chromatid during meiosis I Immunolocalization analyses revealed that the loading of PAIR2 , PAIR3 , OsMER3 , and ZEP1 all depended on OsREC8 .
By contrast , the presence of the OsREC8 signal in pair2 , pair3 , Osmer3 , and zep1 mutants indicated that the loading of OsREC8 did not rely on these four proteins .
These results suggest that OsREC8 has several essential roles in the meiotic processes .
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[ Sen. 6, subscore: 1.00 ]: Furthermore , fluorescent in situ hybridization experiments on Osrec8 meiocytes demonstrated that the mutation eliminated meiotic centromeric cohesion completely during prophase I and also led to the bipolar orientation of the kinetochores during the first meiotic division and accordingly resulted in premature separation of sister chromatid during meiosis I Immunolocalization analyses revealed that the loading of PAIR2 , PAIR3 , OsMER3 , and ZEP1 all depended on OsREC8 .
[ Sen. 7, subscore: 1.00 ]: By contrast , the presence of the OsREC8 signal in pair2 , pair3 , Osmer3 , and zep1 mutants indicated that the loading of OsREC8 did not rely on these four proteins .
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Score: 2.00 |
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| Title: The role of OsCOM1 in homologous chromosome synapsis and recombination in rice meiosis .
| | Author: Ji J Tang D Wang K Wang M Che L Li M Cheng Z | | Journal: Plant J Citation: V : P : Year: 2012 Type: Publisher | | Literature: oryza Field: abstract Doc ID: pub22507309 Accession (PMID): 22507309 | | Abstract: COM1/SAE2 is a highly conserved gene from yeast to higher eukaryotes .
Its orthologs , known to cooperate with the MRX complex ( Mre11/Rad50/Xrs2 ) , are required for meiotic DNA double-strand break ( DSB ) ends resection and specific mitotic DSB repair events .
Here , the rice ( Oryza sativa , 2n=2x=24 ) COM1/SAE2 homolog was identified through positional cloning , termed OsCOM1 .
Four independent mutants of OsCOM1 were isolated and characterized .
In Oscom1 mutants , synaptonemal complex ( SC ) formation , homologous pairing and recombination were severely inhibited , while aberrant nonhomologous chromosome entanglements occurred constantly .
Several key meiotic proteins , including ZEP1 and OsMER3 , were not loaded normally onto chromosomes in Oscom1 mutants , whereas the localization of OsREC8 , PAIR2 and PAIR3 seemed to be normal Moreover , OsCOM1 was loaded normally onto meiotic chromosomes in Osrec8 , zep1 , and Osmer3 mutants , but could not be properly loaded in Osam1 , pair2 , and OsSPO11-1 ( RNAi ) plants .
These results provide direct evidence for the functions of OsCOM1 in promoting homologous synapsis and recombination in rice meiosis .
( c ) 2012 The Authors .
The Plant Journal ( c ) 2012 Blackwell Publishing Ltd .
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[ Sen. 6, subscore: 2.00 ]: Several key meiotic proteins , including ZEP1 and OsMER3 , were not loaded normally onto chromosomes in Oscom1 mutants , whereas the localization of OsREC8 , PAIR2 and PAIR3 seemed to be normal Moreover , OsCOM1 was loaded normally onto meiotic chromosomes in Osrec8 , zep1 , and Osmer3 mutants , but could not be properly loaded in Osam1 , pair2 , and OsSPO11-1 ( RNAi ) plants .
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Score: 1.00 |
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| Title: The central element protein ZEP1 of the synaptonemal complex regulates the number of crossovers during meiosis in rice .
| | Author: Wang M Wang K Tang D Wei C Li M Shen Y Chi Z Gu M Cheng Z | | Journal: Plant Cell Citation: V : 22 P : 417-30 Year: 2010 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub20154151 Accession (PMID): 20154151 | | Abstract: ZEP1 , a transverse filament ( TF ) protein , is the rice ( Oryza sativa ) homolog of Arabidopsis thaliana ZYP1 .
In the Tos17-insertional zep1 mutants , homologous chromosomes align along the entire length of the chromosome , but the synaptonemal complex is not assembled in early prophase I Crossovers are well formed , and 12 bivalents could be detected from diakinesis to metaphase I , which leads to equal chromosomal segregation in anaphase I Moreover , the number of crossovers has a tendency to be increased compared with that in the wild type .
These phenomena are different from the TF mutants identified so far in other organisms .
Chiasma terminalization of the bivalent , which occurs frequently in the wild type , seldom occurred in zep1 .
Transmission electron micrographs and immunodetection using an antibody against ZEP1 showed that ZEP1 is the central element of the synaptonemal complex Although PAIR2 and MER3 were loaded normally in zep1 , their dissociation was delayed severely compared with the wild type .
In addition , ZEP1 is reloaded onto chromosomes in early microspores as the chromosome decondense , suggesting that ZEP1 might have other biological functions during this process .
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[ Sen. 5, subscore: 1.00 ]: Transmission electron micrographs and immunodetection using an antibody against ZEP1 showed that ZEP1 is the central element of the synaptonemal complex Although PAIR2 and MER3 were loaded normally in zep1 , their dissociation was delayed severely compared with the wild type .
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Score: 1.00 |
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| Title: Non-homologous chromosome pairing and crossover formation in haploid rice meiosis .
| | Author: Gong Z Liu X Tang D Yu H Yi C Cheng Z Gu M | | Journal: Chromosoma Citation: V : 120 P : 47-60 Year: 2011 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub20706730 Accession (PMID): 20706730 | | Abstract: While many studies have provided significant insight into homolog pairing during meiosis , information on non-homologous pairing is much less abundant .
In the present study , fluorescence in situ hybridization ( FISH ) was used to investigate non-homologous pairing in haploid rice during meiosis .
At pachytene , non-homologous chromosomes paired and formed synaptonemal complexes .
FISH analysis data indicated that chromosome pairing could be grouped into three major types : ( 1 ) single chromosome paired fold-back as the univalent structure , ( 2 ) two non-homologous chromosomes paired as the bivalent structure , and ( 3 ) three or more non-homologous chromosomes paired as the multivalent structure .
In the survey of 70 cells , 65 contained univalents , 45 contained bivalents , and 49 contained multivalent .
Moreover , chromosomes 9 and 10 as well as chromosomes 11 and 12 formed non-homologous bivalents at a higher frequency than the other chromosomes .
However , chiasma was always detected in the bivalent only between chromosomes 11 and 12 at diakinesis or metaphase I , indicating the pairing between these two chromosomes leads non-homologous recombination during meiosis .
The synaptonemal complex formation between non-homologs was further proved by immunodetection of RCE8 , PAIR2 , and ZEP1 .
Especially , ZEP1 only loaded onto the paired chromosomes other than the un-paired chromosomes at pachytene in haploid .
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[ Sen. 8, subscore: 1.00 ]: The synaptonemal complex formation between non-homologs was further proved by immunodetection of RCE8 , PAIR2 , and ZEP1 .
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