| 133 matches found in 48 documents. Search time: 0.342 seconds. |
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Score: 15.00 |
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| Title: Purification and characterization of a high molecular mass serine carboxypeptidase from Monascus pilosus .
| | Author: Liu F Tachibana S Taira T Ishihara M Kato F Yasuda M | | Journal: J Ind . Microbiol . Biotechnol . Citation: V : 31 ( 12 ) P : 572-80 Year: 2004 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub15592905 Accession (PMID): 15592905 | | Abstract: Two serine carboxypeptidases , MpiCP-1 and MpiCP-2 , were purified to homogeneity from Monascus pilosus IFO 4480 .
MpiCP-1 is a homodimer with a native molecular mass of 125 kDa composed of two identical subunits of 61 kDa , while MpiCP-2 is a high mass homooligomer with a native molecular mass of 2 , 263 kDa composed of about 38 identical subunits of 59 kDa .
This is unique among carboxypeptidases and distinguishes MpiCP-2 as the largest known carboxypeptidase .
The two purified enzymes were both acidic glycoproteins .
MpiCP-1 has an isoelectric point of 3 . 7 and a carbohydrate content of 11% , while for MpiCP-2 these values were 4 . 0 and 33% , respectively .
The optimum pH and temperature were around 4 . 0 and 50 degrees C for MpiCP-1 , and 3 . 5 and 50 degrees C for MpiCP-2 .
MpiCP-1 was stable over a broad range of pH between 2 . 0 and 8 . 0 at 37 degrees C for 1 h , and up to 55 degrees C for 15 min at pH 6 . 0 , but MpiCP-2 was stable in a narrow range of pH between 5 . 5 and 6 . 5 , and up to 50 degrees C for 15 min at pH 6 . 0 .
Phenylmethylsulfonylfluoride strongly inhibited MpiCP-1 and completely inhibited MpiCP-2 , suggesting that they are both serine carboxypeptidases .
Of the substrates tested , benzyloxycarbonyl-L : -tyrosyl-L : -glutamic acid ( Z-Tyr-Glu ) was the best for both enzymes .
The Km , Vmax , Kcat and Kcat/Km values of MpiCP-1 for Z-Tyr-Glu at pH 4 . 0 and 37 degrees C were 1 . 33 mM , 1 . 49 mM min ( -1 ) , 723 s ( -1 ) and 545 mM ( -1 ) s ( -1 ) , and those of MpiCP-2 at pH 3 . 5 and 37 degrees C were 1 . 55 mM , 1 . 54 mM min ( -1 ) , 2 , 039 s ( -1 ) and 1 , 318 mM ( -1 ) s ( -1 ) , respectively . | Matching Sentences:
[ Sen. 1, subscore: 2.00 ]: Two serine carboxypeptidases , MpiCP-1 and MpiCP-2 , were purified to homogeneity from Monascus pilosus IFO 4480 .
[ Sen. 2, subscore: 2.00 ]: MpiCP-1 is a homodimer with a native molecular mass of 125 kDa composed of two identical subunits of 61 kDa , while MpiCP-2 is a high mass homooligomer with a native molecular mass of 2 , 263 kDa composed of about 38 identical subunits of 59 kDa .
[ Sen. 5, subscore: 2.00 ]: MpiCP-1 has an isoelectric point of 3 . 7 and a carbohydrate content of 11% , while for MpiCP-2 these values were 4 . 0 and 33% , respectively .
[ Sen. 6, subscore: 2.00 ]: The optimum pH and temperature were around 4 . 0 and 50 degrees C for MpiCP-1 , and 3 . 5 and 50 degrees C for MpiCP-2 .
[ Sen. 7, subscore: 2.00 ]: MpiCP-1 was stable over a broad range of pH between 2 . 0 and 8 . 0 at 37 degrees C for 1 h , and up to 55 degrees C for 15 min at pH 6 . 0 , but MpiCP-2 was stable in a narrow range of pH between 5 . 5 and 6 . 5 , and up to 50 degrees C for 15 min at pH 6 . 0 .
[ Sen. 8, subscore: 2.00 ]: Phenylmethylsulfonylfluoride strongly inhibited MpiCP-1 and completely inhibited MpiCP-2 , suggesting that they are both serine carboxypeptidases .
[ Sen. 10, subscore: 2.00 ]: The Km , Vmax , Kcat and Kcat/Km values of MpiCP-1 for Z-Tyr-Glu at pH 4 . 0 and 37 degrees C were 1 . 33 mM , 1 . 49 mM min ( -1 ) , 723 s ( -1 ) and 545 mM ( -1 ) s ( -1 ) , and those of MpiCP-2 at pH 3 . 5 and 37 degrees C were 1 . 55 mM , 1 . 54 mM min ( -1 ) , 2 , 039 s ( -1 ) and 1 , 318 mM ( -1 ) s ( -1 ) , respectively .
[ Sen. 3, subscore: 1.00 ]: This is unique among carboxypeptidases and distinguishes MpiCP-2 as the largest known carboxypeptidase .
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Score: 15.00 |
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| Title: Tissue culture-induced transpositional activity of mPing is correlated with cytosine methylation in rice .
| | Author: Ngezahayo F Xu C Wang H Jiang L Pang J Liu B | | Journal: BMC Plant Biol Citation: V : 9 P : 91 Year: 2009 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub19604382 Accession (PMID): 19604382 | | Abstract: BACKGROUND : mPing is an endogenous MITE in the rice genome , which is quiescent under normal conditions but can be induced towards mobilization under various stresses .
The cellular mechanism responsible for modulating the activity of mPing remains unknown .
Cytosine methylation is a major epigenetic modification in most eukaryotes , and the primary function of which is to serve as a genome defense system including taming activity of transposable elements ( TEs ) .
Given that it issue-culture is capable of inducing both methylation alteration and mPing transposition in certain rice genotypes , it provides a tractable system to investigate the possible relationship between the two phenomena .
RESULTS : mPing transposition and cytosine methylation alteration were measured in callus and regenerated plants in three rice ( ssp . indica ) genotypes , V14 , V27 and R09 .
All three genotypes showed transposition of mPing , though at various frequencies .
Cytosine methylation alteration occurred both at the mPing-flanks and at random loci sampled globally in callus and regenerated plants of all three genotypes .
However , a sharp difference in the changing patterns was noted between the mPing-flanks and random genomic loci , with a particular type of methylation modification , ie , CNG hypermethylation , occurred predominantly at the mPing-flanks .
Pearsons test on pairwise correlations indicated that mPing activity is positively correlated with specific patterns of methylation alteration at random genomic loci , while the elements immobility is positively correlated with methylation levels of the mPings 5-flanks .
Bisulfite sequencing of two mPing-containing loci showed that whereas for the immobile locus loss of CG methylation in the 5-flank was accompanied by an increase in CHG methylation , together with an overall increase in methylation of all three types ( CG , CHG and CHH ) in the mPing-body region , for the active locus erasure of CG methylation in the 5-flank was not followed by such a change .
CONCLUSION : Our results documented that it issue culture-induced mPing activity in rice ssp . indica is correlated with alteration in cytosine methylation patterns at both random genomic loci and the elements flanks , while the stability of mPing positively correlates with enhanced methylation levels of both the flanks and probably the elements per se .
Thus , our results implicate a possible role of cytosine methylation in maintaining mPing stability under normal conditions , and in releasing the elements activity as a consequence of epigenetic perturbation in a locus-specific manner under certain stress conditions .
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[ Sen. 8, subscore: 2.00 ]: However , a sharp difference in the changing patterns was noted between the mPing-flanks and random genomic loci , with a particular type of methylation modification , ie , CNG hypermethylation , occurred predominantly at the mPing-flanks .
[ Sen. 9, subscore: 2.00 ]: Pearsons test on pairwise correlations indicated that mPing activity is positively correlated with specific patterns of methylation alteration at random genomic loci , while the elements immobility is positively correlated with methylation levels of the mPings 5-flanks .
[ Sen. 10, subscore: 2.00 ]: Bisulfite sequencing of two mPing-containing loci showed that whereas for the immobile locus loss of CG methylation in the 5-flank was accompanied by an increase in CHG methylation , together with an overall increase in methylation of all three types ( CG , CHG and CHH ) in the mPing-body region , for the active locus erasure of CG methylation in the 5-flank was not followed by such a change .
[ Sen. 11, subscore: 2.00 ]: CONCLUSION : Our results documented that it issue culture-induced mPing activity in rice ssp . indica is correlated with alteration in cytosine methylation patterns at both random genomic loci and the elements flanks , while the stability of mPing positively correlates with enhanced methylation levels of both the flanks and probably the elements per se .
[ Sen. 1, subscore: 1.00 ]: BACKGROUND : mPing is an endogenous MITE in the rice genome , which is quiescent under normal conditions but can be induced towards mobilization under various stresses .
[ Sen. 2, subscore: 1.00 ]: The cellular mechanism responsible for modulating the activity of mPing remains unknown .
[ Sen. 4, subscore: 1.00 ]: Given that it issue-culture is capable of inducing both methylation alteration and mPing transposition in certain rice genotypes , it provides a tractable system to investigate the possible relationship between the two phenomena .
[ Sen. 5, subscore: 1.00 ]: RESULTS : mPing transposition and cytosine methylation alteration were measured in callus and regenerated plants in three rice ( ssp . indica ) genotypes , V14 , V27 and R09 .
[ Sen. 6, subscore: 1.00 ]: All three genotypes showed transposition of mPing , though at various frequencies .
[ Sen. 7, subscore: 1.00 ]: Cytosine methylation alteration occurred both at the mPing-flanks and at random loci sampled globally in callus and regenerated plants of all three genotypes .
[ Sen. 12, subscore: 1.00 ]: Thus , our results implicate a possible role of cytosine methylation in maintaining mPing stability under normal conditions , and in releasing the elements activity as a consequence of epigenetic perturbation in a locus-specific manner under certain stress conditions .
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Score: 13.00 |
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| Title: In planta mobilization of mPing and its putative autonomous element Pong in rice by hydrostatic pressurization .
| | Author: Lin X Long L Shan X Zhang S Shen S Liu B | | Journal: J Exp . Bot . Citation: V : 57 ( 10 ) P : 2313-23 Year: Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16818484 Accession (PMID): 16818484 | | Abstract: The miniature Ping ( mPing ) is a recently discovered endogenous miniature inverted repeat transposable element ( MITE ) in rice , which can be mobilized by it issue culture or irradiation .
It is reported here that mPing , together with one of its putative transposase-encoding partners , Pong , was efficiently mobilized in somatic cells of intact rice plants of two distinct cultivars derived from germinating seeds subjected to high hydrostatic pressure , whereas the other autonomous element of mPing , Ping , remained static in the plants studied . mPing excision was detected in several plants of both cultivars in the treated generation ( P0 ) , which were selected based on their novel phenotypes .
Southern blot analysis and transposon-display assay on selfed progenies ( P1 generation ) of two selected P0 plants , one from each of the cultivars , revealed polymorphic banding patterns consistent with mobilization of mPing and Pong .
Various mPing excisions and de novo insertions , as detected by element-bracketing , locus-specific PCR assays , occurred in the different P1 plants of both cultivars .
Pong excision at one locus for each cultivar was also detected by using a Pong internal primer together with locus-specific flanking primers in the P1 plants .
In contrast to the pressurized plants , immobility of both mPing and Pong in control plants , and the absence of within-cultivar heterozygosity at the analysed loci were verified by Southern blotting and/or locus-assay .
Sequencing at 18 mPing empty donor sites isolated from the pressurized plants indicated properties characteristic of the element excision .
Sequence-based mapping of 10 identified mPing de novo insertions from P1 progenies of pressurized plants indicated that all were in unique or low-copy regions , conforming with the targeting propensity of mPing .
No evidence for further mPing activity was detected in the P2 plants tested .
In spite of the high activity of mPing and Pong in the pressurized plants , amplified fragment length polymorphism ( AFLP ) analysis denoted their general genomic stability , and several potentially active retrotransposons also remained largely immobile .
Further investigation showed that the same hydrostatic pressure treatments also caused mobilization of mPing in the standard laboratory cultivar for japonica rice , Nipponbare .
Thus , a simple and robust approach for in planta MITE-mobilization in rice has been established by using high hydrostatic pressure treatment , which may be useful as an alternative for gene-tagging in this important crop plant . | Matching Sentences:
[ Sen. 2, subscore: 3.00 ]: It is reported here that mPing , together with one of its putative transposase-encoding partners , Pong , was efficiently mobilized in somatic cells of intact rice plants of two distinct cultivars derived from germinating seeds subjected to high hydrostatic pressure , whereas the other autonomous element of mPing , Ping , remained static in the plants studied . mPing excision was detected in several plants of both cultivars in the treated generation ( P0 ) , which were selected based on their novel phenotypes .
[ Sen. 8, subscore: 2.00 ]: Sequence-based mapping of 10 identified mPing de novo insertions from P1 progenies of pressurized plants indicated that all were in unique or low-copy regions , conforming with the targeting propensity of mPing .
[ Sen. 1, subscore: 1.00 ]: The miniature Ping ( mPing ) is a recently discovered endogenous miniature inverted repeat transposable element ( MITE ) in rice , which can be mobilized by it issue culture or irradiation .
[ Sen. 3, subscore: 1.00 ]: Southern blot analysis and transposon-display assay on selfed progenies ( P1 generation ) of two selected P0 plants , one from each of the cultivars , revealed polymorphic banding patterns consistent with mobilization of mPing and Pong .
[ Sen. 4, subscore: 1.00 ]: Various mPing excisions and de novo insertions , as detected by element-bracketing , locus-specific PCR assays , occurred in the different P1 plants of both cultivars .
[ Sen. 6, subscore: 1.00 ]: In contrast to the pressurized plants , immobility of both mPing and Pong in control plants , and the absence of within-cultivar heterozygosity at the analysed loci were verified by Southern blotting and/or locus-assay .
[ Sen. 7, subscore: 1.00 ]: Sequencing at 18 mPing empty donor sites isolated from the pressurized plants indicated properties characteristic of the element excision .
[ Sen. 9, subscore: 1.00 ]: No evidence for further mPing activity was detected in the P2 plants tested .
[ Sen. 10, subscore: 1.00 ]: In spite of the high activity of mPing and Pong in the pressurized plants , amplified fragment length polymorphism ( AFLP ) analysis denoted their general genomic stability , and several potentially active retrotransposons also remained largely immobile .
[ Sen. 11, subscore: 1.00 ]: Further investigation showed that the same hydrostatic pressure treatments also caused mobilization of mPing in the standard laboratory cultivar for japonica rice , Nipponbare .
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Score: 13.00 |
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| Title: Expression of the maize proteinase inhibitor ( mpi ) gene in rice plants enhances resistance against the striped stem borer ( Chilo suppressalis ) : effects on larval growth and insect gut proteinases .
| | Author: Vila L Quilis J Meynard D Breitler JC MarfEV Murillo I Vassal JM Messeguer J Guiderdoni E San Segundo B | | Journal: Plant Biotechnol .
J Citation: V : 3 ( 2 ) P : 187-202 Year: 2005 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub17173619 Accession (PMID): 17173619 | | Abstract: The maize proteinase inhibitor ( mpi ) gene was introduced into two elite japonica rice varieties .
Both constitutive expression of the mpi gene driven by the maize ubiquitin 1 promoter and wound-inducible expression of the mpi gene driven by its own promoter resulted in the accumulation of MPI protein in the transgenic plants .
No effect on plant phenotype was observed in mpi-expressing lines .
The stability of transgene expression through successive generations of mpi rice lines ( up to the T ( 4 ) generation ) and the production of functional MPI protein were confirmed .
Expression of the mpi gene in rice enhanced resistance to the striped stem borer ( Chilo suppressalis ) , one of the most important pests of rice .
In addition , transgenic mpi plants were evaluated in terms of their effects on the growth of C suppressalis larvae and the insect digestive proteolytic system .
An important dose-dependent reduction of larval weight of C suppressalis larvae fed on mpi rice , compared with larvae fed on untransformed rice plants , was observed .
Analysis of the digestive proteolytic activity from the gut of C suppressalis demonstrated that larvae adapted to mpi transgene expression by increasing the complement of digestive proteolytic activity : the serine and cysteine endoproteinases as well as the exopeptidases leucine aminopeptidase and carboxypeptidases A and B However , the induction of such proteolytic activity did not prevent the deleterious effects of MPI on larval growth .
The introduction of the mpi gene into rice plants can thus be considered as a promising strategy to protect rice plants against striped stem borer .
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[ Sen. 2, subscore: 3.00 ]: Both constitutive expression of the mpi gene driven by the maize ubiquitin 1 promoter and wound-inducible expression of the mpi gene driven by its own promoter resulted in the accumulation of MPI protein in the transgenic plants .
[ Sen. 4, subscore: 2.00 ]: The stability of transgene expression through successive generations of mpi rice lines ( up to the T ( 4 ) generation ) and the production of functional MPI protein were confirmed .
[ Sen. 8, subscore: 2.00 ]: Analysis of the digestive proteolytic activity from the gut of C suppressalis demonstrated that larvae adapted to mpi transgene expression by increasing the complement of digestive proteolytic activity : the serine and cysteine endoproteinases as well as the exopeptidases leucine aminopeptidase and carboxypeptidases A and B However , the induction of such proteolytic activity did not prevent the deleterious effects of MPI on larval growth .
[ Sen. 1, subscore: 1.00 ]: The maize proteinase inhibitor ( mpi ) gene was introduced into two elite japonica rice varieties .
[ Sen. 3, subscore: 1.00 ]: No effect on plant phenotype was observed in mpi-expressing lines .
[ Sen. 5, subscore: 1.00 ]: Expression of the mpi gene in rice enhanced resistance to the striped stem borer ( Chilo suppressalis ) , one of the most important pests of rice .
[ Sen. 6, subscore: 1.00 ]: In addition , transgenic mpi plants were evaluated in terms of their effects on the growth of C suppressalis larvae and the insect digestive proteolytic system .
[ Sen. 7, subscore: 1.00 ]: An important dose-dependent reduction of larval weight of C suppressalis larvae fed on mpi rice , compared with larvae fed on untransformed rice plants , was observed .
[ Sen. 9, subscore: 1.00 ]: The introduction of the mpi gene into rice plants can thus be considered as a promising strategy to protect rice plants against striped stem borer .
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Score: 7.00 |
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| Title: Transpositional activation of mPing in an asymmetric nuclear somatic cell hybrid of rice and Zizania latifolia was accompanied by massive element loss .
| | Author: Shan XH Ou XF Liu ZL Dong YZ Lin XY Li XW Liu B | | Journal: Theor Appl Genet Citation: V : 119 P : 1325-33 Year: 2009 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub19711051 Accession (PMID): 19711051 | | Abstract: We have reported previously that the most active miniature inverted terminal repeat transposable element ( MITE ) of rice , mPing , was transpositionally mobilized in several rice recombinant inbred lines ( RILs ) derived from an introgressive hybridization between rice and wild rice ( Zizania latifolia Griseb . ) .
To further study the phenomenon of hybridization-induced mPing activity , we undertook the present study to investigate the elements behavior in a highly asymmetric somatic nuclear hybrid ( SH6 ) of rice and Z latifolia , which is similar in genomic composition to that of the RILs , though probably contains more introgressed alien chromatins from the donor species than the RILs .
We found that mPing , together with its transposase-donor , Pong , underwent rampant transpositional activation in the somatic hybrid ( SH6 ) .
Because possible effects of protoplast isolation and cell culture can be ruled out , we attribute the transpositional activation of mPing and Pong in SH6 to the process of asymmetric somatic hybridization , namely , one-step introgression of multiple chromatin segments of the donor species Z latifolia into the recipient rice genome .
A salient feature of mPing transposition in the somatic hybrid is that the elements activation was accompanied by massive loss of its original copies , ie , abortive transpositions , which was not observed in previously reported cases of mPing activity .
These data not only corroborated our earlier finding that wide hybridization and introgression may trigger transpositional activation of otherwise quiescent transposable elements , but also suggest that transpositional mobilization of a MITE like mPing can be accompanied by dramatic reduction of its original copy numbers under certain conditions , thus provide novel insights into the dynamics of MITEs in the course of genome evolution .
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[ Sen. 5, subscore: 2.00 ]: A salient feature of mPing transposition in the somatic hybrid is that the elements activation was accompanied by massive loss of its original copies , ie , abortive transpositions , which was not observed in previously reported cases of mPing activity .
[ Sen. 1, subscore: 1.00 ]: We have reported previously that the most active miniature inverted terminal repeat transposable element ( MITE ) of rice , mPing , was transpositionally mobilized in several rice recombinant inbred lines ( RILs ) derived from an introgressive hybridization between rice and wild rice ( Zizania latifolia Griseb . ) .
[ Sen. 2, subscore: 1.00 ]: To further study the phenomenon of hybridization-induced mPing activity , we undertook the present study to investigate the elements behavior in a highly asymmetric somatic nuclear hybrid ( SH6 ) of rice and Z latifolia , which is similar in genomic composition to that of the RILs , though probably contains more introgressed alien chromatins from the donor species than the RILs .
[ Sen. 3, subscore: 1.00 ]: We found that mPing , together with its transposase-donor , Pong , underwent rampant transpositional activation in the somatic hybrid ( SH6 ) .
[ Sen. 4, subscore: 1.00 ]: Because possible effects of protoplast isolation and cell culture can be ruled out , we attribute the transpositional activation of mPing and Pong in SH6 to the process of asymmetric somatic hybridization , namely , one-step introgression of multiple chromatin segments of the donor species Z latifolia into the recipient rice genome .
[ Sen. 6, subscore: 1.00 ]: These data not only corroborated our earlier finding that wide hybridization and introgression may trigger transpositional activation of otherwise quiescent transposable elements , but also suggest that transpositional mobilization of a MITE like mPing can be accompanied by dramatic reduction of its original copy numbers under certain conditions , thus provide novel insights into the dynamics of MITEs in the course of genome evolution .
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Score: 6.00 |
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| Title: Mobilization of a transposon in the rice genome .
| | Author: Nakazaki T Okumoto Y Horibata A Yamahira S Teraishi M Nishida H Inoue H Tanisaka T | | Journal: Nature Citation: V : 421 ( 6919 ) P : 170-2 Year: 2003 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub12520304 Accession (PMID): 12520304 | | Abstract: Rice ( Oryza sativa L ) is an important crop worldwide and , with the availability of the draft sequence , a useful model for analysing the genome structure of grasses .
To practice efficient rice breeding through genetic engineering techniques , it is important to identify the economically important genes in this crop .
The use of mobile transposons as gene tags in intact plants is a powerful tool for functional analysis because transposon insertions often inactivate genes .
Here we identify an active rice transposon named miniature Ping ( mPing ) through analysis of the mutability of a slender mutation of the glume-the seed structure that encloses and determines the shape of the grain .
The mPing transposon is inserted in the slender glume ( slg ) mutant allele but not in the wild-type allele .
Search of the O sativa variety Nipponbare genome identified 34 sequences with high nucleotide similarity to mPing , indicating that mPing constitutes a family of transposon elements .
Excision of mPing from slg plants results in reversion to a wild-type phenotype .
The mobility of the transposon mPing in intact rice plants represents a useful alternative tool for the functional analysis of rice genes . | Matching Sentences:
[ Sen. 6, subscore: 2.00 ]: Search of the O sativa variety Nipponbare genome identified 34 sequences with high nucleotide similarity to mPing , indicating that mPing constitutes a family of transposon elements .
[ Sen. 4, subscore: 1.00 ]: Here we identify an active rice transposon named miniature Ping ( mPing ) through analysis of the mutability of a slender mutation of the glume-the seed structure that encloses and determines the shape of the grain .
[ Sen. 5, subscore: 1.00 ]: The mPing transposon is inserted in the slender glume ( slg ) mutant allele but not in the wild-type allele .
[ Sen. 7, subscore: 1.00 ]: Excision of mPing from slg plants results in reversion to a wild-type phenotype .
[ Sen. 8, subscore: 1.00 ]: The mobility of the transposon mPing in intact rice plants represents a useful alternative tool for the functional analysis of rice genes .
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Score: 6.00 |
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| Title: Transposition of the rice miniature inverted repeat transposable element mPing in Arabidopsis thaliana .
| | Author: Yang G Zhang F Hancock CN Wessler SR | | Journal: Proc Natl Acad Sci U S A Citation: V : 104 P : 10962-7 Year: 2007 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub17578919 Accession (PMID): 17578919 | | Abstract: An active miniature inverted repeat transposable element ( MITE ) , mPing , was discovered by computer-assisted analysis of rice genome sequence .
The mPing element is mobile in rice cell culture and in a few rice strains where it has been amplified to >1 , 000 copies during recent domestication .
However , determination of the transposase source and characterization of the mechanism of transposition have been hampered by the high copy number of mPing and the presence of several candidate autonomous elements in the rice genome .
Here , we report that mPing is active in Arabidopsis thaliana , where its transposition is catalyzed by three sources of transposase from rice : the autonomous Ping and Pong elements and by a cDNA derived from a Ping transcript .
In addition to transposase , the product of a second element-encoded ORF of unknown function is also required for mPing transposition .
Excision of mPing in A thaliana is usually precise , and transposed copies usually insert into unlinked sites in the genome that are preferentially in or near genes .
As such , this will be a valuable assay system for the dissection of MITE transposition and a potentially powerful tagging system for gene discovery in eukaryotes .
| Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: An active miniature inverted repeat transposable element ( MITE ) , mPing , was discovered by computer-assisted analysis of rice genome sequence .
[ Sen. 2, subscore: 1.00 ]: The mPing element is mobile in rice cell culture and in a few rice strains where it has been amplified to >1 , 000 copies during recent domestication .
[ Sen. 3, subscore: 1.00 ]: However , determination of the transposase source and characterization of the mechanism of transposition have been hampered by the high copy number of mPing and the presence of several candidate autonomous elements in the rice genome .
[ Sen. 4, subscore: 1.00 ]: Here , we report that mPing is active in Arabidopsis thaliana , where its transposition is catalyzed by three sources of transposase from rice : the autonomous Ping and Pong elements and by a cDNA derived from a Ping transcript .
[ Sen. 5, subscore: 1.00 ]: In addition to transposase , the product of a second element-encoded ORF of unknown function is also required for mPing transposition .
[ Sen. 6, subscore: 1.00 ]: Excision of mPing in A thaliana is usually precise , and transposed copies usually insert into unlinked sites in the genome that are preferentially in or near genes .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 6.00 |
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| Title: Transposition of the Tourist-MITE mPing in yeast : an assay that retains key features of catalysis by the class 2 PIF/Harbinger superfamily .
| | Author: Hancock CN Zhang F Wessler SR | | Journal: Mob DNA Citation: V : 1 P : 5 Year: 2010 Type: PubMed-not-MEDLINE | | Literature: oryza Field: abstract Doc ID: pub20226077 Accession (PMID): 20226077 | | Abstract: BACKGROUND : PIF/Harbinger is the most recently discovered DNA transposon superfamily and is now known to populate genomes from fungi to plants to animals .
Mobilization of superfamily members requires two separate element-encoded proteins ( ORF1 and TPase ) .
Members of this superfamily also mobilize Tourist-like miniature inverted repeat transposable elements ( MITEs ) , which are the most abundant transposable elements associated with the genes of plants , especially the cereal grasses .
The phylogenetic analysis of many plant genomes indicates that MITEs can amplify rapidly from one or a few elements to hundreds or thousands . The most active DNA transposon identified to date in plants or animals is mPing , a rice Tourist-like MITE that is a deletion derivative of the autonomous Ping element .
Ping and the closely related Pong are the only known naturally active PIF/Harbinger elements .
Some rice strains accumulate 40 new mPing insertions per plant per generation .
In this study we report the development of a yeast transposition assay as a first step in deciphering the mechanism underlying the amplification of Tourist-MITEs .
RESULTS : The ORF1 and TPase proteins encoded by Ping and Pong have been shown to mobilize mPing in rice and in transgenic Arabidopsis .
Initial tests of the native proteins in a yeast assay resulted in very low transposition .
Significantly higher activities were obtained by mutation of a putative nuclear export signal ( NES ) in the TPase that increased the amount of TPase in the nucleus .
When introduced into Arabidopsis , the NES mutant protein also catalyzed higher frequencies of mPing excision from the gfp reporter gene .
Our yeast assay retains key features of excision and insertion of mPing including precise excision , extended insertion sequence preference , and a requirement for two proteins that can come from either Ping or Pong or both elements .
CONCLUSIONS : The yeast transposition assay provides a robust platform for analysis of the mechanism underlying transposition catalyzed by the two proteins of PIF/Harbinger elements .
It recapitulates all of the features of excision and reinsertion of mPing as seen in plant systems .
Furthermore , a mutation of a putative NES in the TPase increased transposition both in yeast and plants .
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[ Sen. 4, subscore: 1.00 ]: The phylogenetic analysis of many plant genomes indicates that MITEs can amplify rapidly from one or a few elements to hundreds or thousands . The most active DNA transposon identified to date in plants or animals is mPing , a rice Tourist-like MITE that is a deletion derivative of the autonomous Ping element .
[ Sen. 6, subscore: 1.00 ]: Some rice strains accumulate 40 new mPing insertions per plant per generation .
[ Sen. 8, subscore: 1.00 ]: RESULTS : The ORF1 and TPase proteins encoded by Ping and Pong have been shown to mobilize mPing in rice and in transgenic Arabidopsis .
[ Sen. 11, subscore: 1.00 ]: When introduced into Arabidopsis , the NES mutant protein also catalyzed higher frequencies of mPing excision from the gfp reporter gene .
[ Sen. 12, subscore: 1.00 ]: Our yeast assay retains key features of excision and insertion of mPing including precise excision , extended insertion sequence preference , and a requirement for two proteins that can come from either Ping or Pong or both elements .
[ Sen. 14, subscore: 1.00 ]: It recapitulates all of the features of excision and reinsertion of mPing as seen in plant systems .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 6.00 |
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| Title: The rice miniature inverted repeat transposable element mPing is an effective insertional mutagen in soybean .
| | Author: Hancock CN Zhang F Floyd K Richardson AO Lafayette P Tucker D Wessler SR Parrott WA | | Journal: Plant Physiol Citation: V : 157 P : 552-62 Year: 2011 Type: In-Process | | Literature: oryza Field: abstract Doc ID: pub21844309 Accession (PMID): 21844309 | | Abstract: Insertional mutagenesis of legume genomes such as soybean ( Glycine max ) should aid in identifying genes responsible for key traits such as nitrogen fixation and seed quality .
The relatively low throughput of soybean transformation necessitates the use of a transposon-tagging strategy where a single transformation event will produce many mutations over a number of generations .
However , existing transposon-tagging tools being used in legumes are of limited utility because of restricted transposition ( Ac/Ds : soybean ) or the requirement for it issue culture activation ( Tnt1 : Medicago truncatula ) .
A recently discovered transposable element from rice ( Oryza sativa ) , mPing , and the genes required for its mobilization , were transferred to soybean to determine if it will be an improvement over the other available transposon-tagging tools .
Stable transformation events in soybean were tested for mPing transposition .
Analysis of mPing excision at early and late embryo developmental stages revealed increased excision during late development in most transgenic lines , suggesting that transposition is developmentally regulated .
Transgenic lines that produced heritable mPing insertions were identified , with the plants from the highest activity line producing at least one new insertion per generation .
Analysis of the mPing insertion sites in the soybean genome revealed that features displayed in rice were retained including transposition to unlinked sites and a preference for insertion within 2 . 5 kb of a gene .
Taken together these findings indicate that mPing has the characteristics necessary for an effective transposon-tagging resource .
| Matching Sentences:
[ Sen. 4, subscore: 1.00 ]: A recently discovered transposable element from rice ( Oryza sativa ) , mPing , and the genes required for its mobilization , were transferred to soybean to determine if it will be an improvement over the other available transposon-tagging tools .
[ Sen. 5, subscore: 1.00 ]: Stable transformation events in soybean were tested for mPing transposition .
[ Sen. 6, subscore: 1.00 ]: Analysis of mPing excision at early and late embryo developmental stages revealed increased excision during late development in most transgenic lines , suggesting that transposition is developmentally regulated .
[ Sen. 7, subscore: 1.00 ]: Transgenic lines that produced heritable mPing insertions were identified , with the plants from the highest activity line producing at least one new insertion per generation .
[ Sen. 8, subscore: 1.00 ]: Analysis of the mPing insertion sites in the soybean genome revealed that features displayed in rice were retained including transposition to unlinked sites and a preference for insertion within 2 . 5 kb of a gene .
[ Sen. 9, subscore: 1.00 ]: Taken together these findings indicate that mPing has the characteristics necessary for an effective transposon-tagging resource .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 6.00 |
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| Title: Analysis of copy-number variation , insertional polymorphism , and methylation status of the tiniest class I ( TRIM ) and class II ( MITE ) transposable element families in various rice strains .
| | Author: Baruch O Kashkush K | | Journal: Plant Cell Rep Citation: V : 31 P : 885-93 Year: 2012 Type: In-Process | | Literature: oryza Field: abstract Doc ID: pub22183295 Accession (PMID): 22183295 | | Abstract: Transposable elements ( TEs ) dominate the genetic capacity of most eukaryotes , especially plants , where they may compose up to 90% of the genome .
Many studies , both in plants and animals reported that in fact non-autonomous elements that have lost their protein-coding sequences and became miniature elements were highly associated with genes , and showed a high level of transpositional activity such as mPing family in rice .
In this study , we have investigated in detail the copy number , insertional polymorphism and the methylation status of the tiniest LTR retrotransposon family , termed TRIM , in nine rice strains , in comparison with mPing .
While TRIM showed similar copy numbers ( average of 79 insertions ) in all the nine rice strains , the copy number of mPing varied dramatically ( ranging from 6 to 203 insertions ) in the same strains .
Site-specific PCR analysis revealed that 58% of the TRIM elements have identical insertion sites among the nine rice strains , while none of the mPing elements ( 100% polymorphism ) have identical insertion sites in the same strains .
Finally , over 65% of the TRIM insertion sites were cytosine methylated in all nine rice strains , while the level of the methylated mPing insertion sites ranged between 43 and 81 . 5% .
The findings of this study indicate that unlike mPing , TRIM is most probably a fossil TE family in rice .
In addition , the data shows that there might be a strong correlation between TE methylation and copy number .
| Matching Sentences:
[ Sen. 2, subscore: 1.00 ]: Many studies , both in plants and animals reported that in fact non-autonomous elements that have lost their protein-coding sequences and became miniature elements were highly associated with genes , and showed a high level of transpositional activity such as mPing family in rice .
[ Sen. 3, subscore: 1.00 ]: In this study , we have investigated in detail the copy number , insertional polymorphism and the methylation status of the tiniest LTR retrotransposon family , termed TRIM , in nine rice strains , in comparison with mPing .
[ Sen. 4, subscore: 1.00 ]: While TRIM showed similar copy numbers ( average of 79 insertions ) in all the nine rice strains , the copy number of mPing varied dramatically ( ranging from 6 to 203 insertions ) in the same strains .
[ Sen. 5, subscore: 1.00 ]: Site-specific PCR analysis revealed that 58% of the TRIM elements have identical insertion sites among the nine rice strains , while none of the mPing elements ( 100% polymorphism ) have identical insertion sites in the same strains .
[ Sen. 6, subscore: 1.00 ]: Finally , over 65% of the TRIM insertion sites were cytosine methylated in all nine rice strains , while the level of the methylated mPing insertion sites ranged between 43 and 81 . 5% .
[ Sen. 7, subscore: 1.00 ]: The findings of this study indicate that unlike mPing , TRIM is most probably a fossil TE family in rice .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
