| 15 matches found in 5 documents. Search time: 0.14 seconds. |
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Score: 8.00 |
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| Title: Molecular characterization of mitotic cyclins in rice plants .
| | Author: Umeda M Iwamoto N Umeda-Hara C Yamaguchi M Hashimoto J Uchimiya H | | Journal: Mol . Gen . Genet . Citation: V : 262 ( 2 ) P : 230-8 Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10517318 Accession (PMID): 10517318 | | Abstract: Cyclins are known to activate cyclin-dependent protein kinases , which are essential for cell cycle progression in eukaryotes .
We isolated full-length cDNAs encoding rice mitotic cyclins named CycA1 ; os ; 1 and CycB2 ; os ; 1 , which are related to A and B-type cyclins , respectively , from animals .
To characterize the function of these mitotic cyclins , as well as that of another B-type cyclin , CycB2 ; os ; 2 , each cDNA was introduced into yeast cells .
When cDNAs encoding CycA1 ; os ; 1 , CycB2 ; os ; or CycB2 ; os ; 2 were overexpressed in the yeast mutant DLI , which is deficient in G1 cyclins , the mutant phenotype was rescued , indicating that these mitotic cyclins are functional in yeast cells .
When the cDNA encoding CycB2 ; os ; 1 was expressed in the wild-type yeast strain , the cells lost the ability to grow , whereas the expression of either cycA1 ; os : 1 or cycB2 ; os ; 2 did not inhibit growth .
In situ hybridization of these mitotic cyclin genes with rice root apices and counterstaining of chromosomes with a DNA-specific dye revealed that cycA1 ; os ; 1 is expressed from the G2 phase to the early M phase , while transcripts of cycB2 : os ; 1 and cycB2 ; os ; 2 accumulated until the end of mitosis .
Our results indicate that these B2-type cyclins may be involved in the control of mitosis , in combination with a G2/M-phase CDK . | Matching Sentences:
[ Sen. 4, subscore: 2.00 ]: When cDNAs encoding CycA1 ; os ; 1 , CycB2 ; os ; or CycB2 ; os ; 2 were overexpressed in the yeast mutant DLI , which is deficient in G1 cyclins , the mutant phenotype was rescued , indicating that these mitotic cyclins are functional in yeast cells .
[ Sen. 5, subscore: 2.00 ]: When the cDNA encoding CycB2 ; os ; 1 was expressed in the wild-type yeast strain , the cells lost the ability to grow , whereas the expression of either cycA1 ; os : 1 or cycB2 ; os ; 2 did not inhibit growth .
[ Sen. 6, subscore: 2.00 ]: In situ hybridization of these mitotic cyclin genes with rice root apices and counterstaining of chromosomes with a DNA-specific dye revealed that cycA1 ; os ; 1 is expressed from the G2 phase to the early M phase , while transcripts of cycB2 : os ; 1 and cycB2 ; os ; 2 accumulated until the end of mitosis .
[ Sen. 2, subscore: 1.00 ]: We isolated full-length cDNAs encoding rice mitotic cyclins named CycA1 ; os ; 1 and CycB2 ; os ; 1 , which are related to A and B-type cyclins , respectively , from animals .
[ Sen. 3, subscore: 1.00 ]: To characterize the function of these mitotic cyclins , as well as that of another B-type cyclin , CycB2 ; os ; 2 , each cDNA was introduced into yeast cells .
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Score: 8.00 |
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| Title: Cell cycle function of a rice B2-type cyclin interacting with a B-type cyclin-dependent kinase .
| | Author: Lee J Das A Yamaguchi M Hashimoto J Tsutsumi N Uchimiya H Umeda M | | Journal: Plant J Citation: V : 34 ( 4 ) P : 417-25 Year: 2003 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub12753582 Accession (PMID): 12753582 | | Abstract: Cyclin-dependent kinases ( CDKs ) are involved in the control of cell cycle progression .
Plant A-type CDKs are functional homologs of yeast Cdc2/Cdc28 and are expressed throughout the cell cycle .
In contrast , B-type CDK ( CDKB ) is a family of mitotic CDKs expressed during the S/M phase , and its precise function remains unknown .
Here , we identified two B2-type cyclins , CycB2 ; 1 and CycB2 ; 2 , as a specific partner of rice CDKB2 ; 1 .
The CDKB2 ; 1-CycB2 complexes produced in insect cells showed a significant level of kinase activity in vitro , suggesting that CycB2 binds to and activates CDKB2 .
We then expressed green fluorescent protein ( GFP ) -fused CDKB2 ; 1 and CycB2 ; 2 in tobacco BY2 cells to investigate their subcellular localization during mitosis .
Surprisingly , the fluorescence signal of CDKB2 ; 1-GFP was tightly associated with chromosome alignment as well as with spindle structure during the metaphase .
During the telophase , the signal was localized to the spindle midzone and the separating sister chromosomes , and then to the phragmoplast On the other hand , the CycB2 ; 2-GFP fluorescence signal was detected in nuclei during the interphase and prophase , moved to the metaphase chromosomes , and then disappeared completely after the cells passed through the metaphase .
Co-localization of CDKB2 ; 1-GFP and CycB2 ; 2-GFP on chromosomes aligned at the center of the metaphase cells suggests that the CDKB2-CycB2 complex may function in retaining chromosomes at the metaphase plate .
Overexpression of CycB2 ; 2 in rice plants resulted in acceleration of root growth without any increase in cell size , indicating that CycB2 ; 2 promoted cell division probably through association with CDKB2 in the root meristem . | Matching Sentences:
[ Sen. 4, subscore: 2.00 ]: Here , we identified two B2-type cyclins , CycB2 ; 1 and CycB2 ; 2 , as a specific partner of rice CDKB2 ; 1 .
[ Sen. 10, subscore: 2.00 ]: Overexpression of CycB2 ; 2 in rice plants resulted in acceleration of root growth without any increase in cell size , indicating that CycB2 ; 2 promoted cell division probably through association with CDKB2 in the root meristem .
[ Sen. 5, subscore: 1.00 ]: The CDKB2 ; 1-CycB2 complexes produced in insect cells showed a significant level of kinase activity in vitro , suggesting that CycB2 binds to and activates CDKB2 .
[ Sen. 6, subscore: 1.00 ]: We then expressed green fluorescent protein ( GFP ) -fused CDKB2 ; 1 and CycB2 ; 2 in tobacco BY2 cells to investigate their subcellular localization during mitosis .
[ Sen. 8, subscore: 1.00 ]: During the telophase , the signal was localized to the spindle midzone and the separating sister chromosomes , and then to the phragmoplast On the other hand , the CycB2 ; 2-GFP fluorescence signal was detected in nuclei during the interphase and prophase , moved to the metaphase chromosomes , and then disappeared completely after the cells passed through the metaphase .
[ Sen. 9, subscore: 1.00 ]: Co-localization of CDKB2 ; 1-GFP and CycB2 ; 2-GFP on chromosomes aligned at the center of the metaphase cells suggests that the CDKB2-CycB2 complex may function in retaining chromosomes at the metaphase plate .
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Score: 3.00 |
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| Title: Exogenous cytokinin treatment maintains cyclin homeostasis in rice seedlings that show changes of cyclin expression when the photoperiod is rapidly changed .
| | Author: Lee H Auh CK Kim D Lee TK Lee S | | Journal: Plant Physiol . Biochem . Citation: V : 44 ( 4 ) P : 248-52 Year: 2006 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16713279 Accession (PMID): 16713279 | | Abstract: Cyclin is a fundamental regulator of the plant cell cycle .
Five different types of cyclin genes ( the A- , B- , C- , D- , and H-types ) have been reported in Oryza sativa .
However , except for Os ; cycA1 ; 1 , Os ; cycB2 ; 1 , and Os ; cycB2 ; 2 , the mechanisms of expression of these cyclin genes have not yet been studied .
The interactions of cyclins with cytokinin , an important trigger for cell cycle regulation , have also not been well studied .
Here we used semi-quantitative RT-PCR in rice seedlings to analyze the effect of cytokinin on photomorphogenesis and the expression of six cyclin genes .
Fifteen-day-old seedlings were grown in a 16/8 h light/dark cycle and then transferred to either constant light or constant dark .
The expression of all the cyclin genes tested , except the C-type , decreased after 1 hour in the dark , but did not change after transfer to the light or when kinetin was added to the medium .
Similarly , seedlings grown in the dark had decreased expression of the cyclin genes , except Os ; cycB2 ; 2 , after transfer to the light , a decrease that was prevented by kinetin treatment .
Thus , exogenous cytokinin plays an important role in maintaining homeostasis of cyclin gene expression following rapid changes of photoperiod . | Matching Sentences:
[ Sen. 3, subscore: 2.00 ]: However , except for Os ; cycA1 ; 1 , Os ; cycB2 ; 1 , and Os ; cycB2 ; 2 , the mechanisms of expression of these cyclin genes have not yet been studied .
[ Sen. 8, subscore: 1.00 ]: Similarly , seedlings grown in the dark had decreased expression of the cyclin genes , except Os ; cycB2 ; 2 , after transfer to the light , a decrease that was prevented by kinetin treatment .
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Score: 2.00 |
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| Title: Adventitious root growth and cell-cycle induction in deepwater rice | | Author: Lorbiecke R Sauter M | | Journal: Citation: V : 119 ( 1 ) P : 21-30 Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub9880342 Accession (PMID): 9880342 | | Abstract: Deepwater rice ( Oryza sativa ) is adapted to survive conditions of severe flooding over extended periods of time .
During such periods adventitious roots develop to provide water , nutrients , and anchorage .
In the present study the growth of adventitious roots was induced by treatment with ethylene but not auxin , cytokinin , or gibberellin .
Root elongation was enhanced between 8 and 10 h after submergence .
The population of cells in the S phase and expression of the S-phase-specific histone H3 gene increased within 4 to 6 h .
Within 6 to 8 h the G2-phase population increased .
Cell-cycle activation was accompanied by sequential induction of a cdc2-activating kinase homolog , R2 , of two cdc2 genes , cdc2Os-1 and cdc2Os-2 , and of three cyclin genes , cycA1 ; 3 , cycB2 ; 1 , and cycB2 ; 2 , but only induction of the R2 gene expression preceded the induction of the S phase , possibly contributing to cell-cycle regulation in the G1 phase .
Both cdc2 genes were expressed at slightly higher levels during DNA replication .
Transcripts of the A-type cyclin accumulated during the S and G2 phases , and transcripts of the B-type cyclins accumulated during the G2 phase .
Cyclin expression was induced at all nodes with a similar time course , suggesting that ethylene acts systemically and that root primordia respond to ethylene at an early developmental stage . | Matching Sentences:
[ Sen. 7, subscore: 2.00 ]: Cell-cycle activation was accompanied by sequential induction of a cdc2-activating kinase homolog , R2 , of two cdc2 genes , cdc2Os-1 and cdc2Os-2 , and of three cyclin genes , cycA1 ; 3 , cycB2 ; 1 , and cycB2 ; 2 , but only induction of the R2 gene expression preceded the induction of the S phase , possibly contributing to cell-cycle regulation in the G1 phase .
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Score: 1.00 |
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| Title: The syncytium-specific expression of the Orysa ; KRP3 CDK inhibitor : implication of its involvement in the cell cycle control in the rice ( Oryza sativa L ) syncytial endosperm .
| | Author: Mizutani M Naganuma T Tsutsumi K Saitoh Y | | Journal: J Exp Bot Citation: V : 61 P : 791-8 Year: 2010 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub19933315 Accession (PMID): 19933315 | | Abstract: During rice ( Oryza sativa L ) seed development , the primary endosperm nucleus undergoes a series of divisions without cytokinesis , producing a multinucleate cell , known as a syncytium .
After several rounds of rapid nuclear proliferation , the syncytium ceases to undergo mitosis ; thereafter , the syncytium is partitioned into individual cells by a specific type of cytokinesis called cellularization .
The transition between syncytium and cellularization is important in determining the final seed size and is a model for studying the cell cycle and cytokinesis .
The involvement of cyclin-dependent kinase ( CDK ) inhibitors ( CKIs ) in cell cycle control was investigated here during the transition between syncytium and cellularization .
It was found that one of the rice CKIs , Orysa ; KRP3 , is strongly expressed in the caryopsis at 2 d after flowering ( DAF ) , and its expression is significantly reduced at 3 DAF .
The other CKI transcripts did not show such a shift at 2 DAF .
In situ hybridization analysis revealed that Orysa ; KRP3 is expressed in multinucleate syncytial endosperm at 2 DAF , but not in cellularized endosperm at 3 DAF .
Two-hybrid assays showed that Orysa ; KRP3 binds Orysa ; CDKA ; 1 , Orysa ; CDKA ; 2 , Orysa ; CycA1 ; 1 , and Orysa ; CycD2 ; 2 .
By contrast , Orysa ; CDKB2 ; 1 and Orysa ; CycB2 ; 2 do not show binding to Orysa ; KRP3 .
Orysa ; KRP3 was able to rescue yeast premature cell division due to the dominant positive expression of mutant rice CDKA ; 1 indicating that Orysa ; KRP3 inhibited rice CDK .
These data suggest that Orysa ; KRP3 is involved in cell cycle control of syncytial endosperm .
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[ Sen. 9, subscore: 1.00 ]: By contrast , Orysa ; CDKB2 ; 1 and Orysa ; CycB2 ; 2 do not show binding to Orysa ; KRP3 .
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