Sister Chromatids Fail to Separate during an Induced Endoreplication Cycle in Drosophila Embryos Export

@article{citeulike:4502637, abstract = {When mitosis is bypassed, as in some cancer cells or in natural endocycles, sister chromosomes remain paired and produce four-stranded diplochromosomes or polytene chromosomes. Cyclin/Cdk1 inactivation blocks entry into mitosis and can reset G2 cells to G1, allowing another round of replication [1] . Reciprocally, persistent expression of Cyclin A/Cdk1 or Cyclin E/Cdk2 blocks Drosophila endocycles [2] and [3] . Inactivation of Cyclin A/Cdk1 by mutation or overexpression of the Cyclin/Cdk1 inhibitor, Roughex (Rux), converts the 16 th embryonic mitotic cycle to an endocycle [4] , [5] and [6] ; however, we show that Rux expression fails to convert earlier cell cycles unless Cyclin E is also downregulated. Following induction of a Rux transgene in Cyclin E mutant embryos during G2 of cell cycle 14 (G2 14 ), Cyclins A, B, and B3 disappeared and cells reentered S phase. This rereplication produced diplochromosomes that segregated abnormally at a subsequent mitosis. Thus, like the yeast CKIs Rum1 and Sic1, Drosophila Rux can reset G2 cells to G1 [7] , [8] and [9] . The observed cyclin destruction suggests that cell cycle resetting by Rux was associated with activation of the anaphase-promoting complex (APC), while the presence of diplochromosomes implies that this activation of APC outside of mitosis was not sufficient to trigger sister disjunction.}, author = {Vidwans, Smruti J. and Digregorio, Paul J. and Shermoen, Antony W. and Foat, Barrett and Iwasa, Janet and Yakubovich, Nikita and O'Farrell, Patrick H.}, citeulike-article-id = {4502637}, citeulike-linkout-0 = {http://dx.doi.org/10.1016/S0960-9822(02)00845-X}, citeulike-linkout-1 = {http://linkinghub.elsevier.com/retrieve/pii/S096098220200845X}, day = {14}, doi = {10.1016/S0960-9822(02)00845-X}, issn = {09609822}, journal = {Current Biology}, keywords = {endoreplication}, month = {May}, number = {10}, pages = {829--833}, posted-at = {2009-05-11 13:43:44}, priority = {2}, title = {Sister Chromatids Fail to Separate during an Induced Endoreplication Cycle in Drosophila Embryos}, url = {http://dx.doi.org/10.1016/S0960-9822(02)00845-X}, volume = {12}, year = {2002} }

TY - JOUR ID - citeulike:4502637 L3 - citeulike-article-id:4502637 N2 - When mitosis is bypassed, as in some cancer cells or in natural endocycles, sister chromosomes remain paired and produce four-stranded diplochromosomes or polytene chromosomes. Cyclin/Cdk1 inactivation blocks entry into mitosis and can reset G2 cells to G1, allowing another round of replication [1] . Reciprocally, persistent expression of Cyclin A/Cdk1 or Cyclin E/Cdk2 blocks Drosophila endocycles [2] and [3] . Inactivation of Cyclin A/Cdk1 by mutation or overexpression of the Cyclin/Cdk1 inhibitor, Roughex (Rux), converts the 16 th embryonic mitotic cycle to an endocycle [4] , [5] and [6] ; however, we show that Rux expression fails to convert earlier cell cycles unless Cyclin E is also downregulated. Following induction of a Rux transgene in Cyclin E mutant embryos during G2 of cell cycle 14 (G2 14 ), Cyclins A, B, and B3 disappeared and cells reentered S phase. This rereplication produced diplochromosomes that segregated abnormally at a subsequent mitosis. Thus, like the yeast CKIs Rum1 and Sic1, Drosophila Rux can reset G2 cells to G1 [7] , [8] and [9] . The observed cyclin destruction suggests that cell cycle resetting by Rux was associated with activation of the anaphase-promoting complex (APC), while the presence of diplochromosomes implies that this activation of APC outside of mitosis was not sufficient to trigger sister disjunction. IS - 10 JF - Current Biology SN - 09609822 EP - 833 TI - Sister Chromatids Fail to Separate during an Induced Endoreplication Cycle in Drosophila Embryos VL - 12 SP - 829 KW - endoreplication AU - Vidwans, Smruti AU - Digregorio, Paul AU - Shermoen, Antony AU - Foat, Barrett AU - Iwasa, Janet AU - Yakubovich, Nikita AU - O'Farrell, Patrick PY - 2002/05/14/ UR - http://dx.doi.org/10.1016/S0960-9822(02)00845-X ER -