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CDKB2 is involved in mitosis and DNA damage response in rice
Article first published online: 15 DEC 2011
© 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd
The Plant Journal
Volume 69, Issue 6, pages 967–977, March 2012
How to Cite
Endo, M., Nakayama, S., Umeda-Hara, C., Ohtsuki, N., Saika, H., Umeda, M. and Toki, S. (2012), CDKB2 is involved in mitosis and DNA damage response in rice. The Plant Journal, 69: 967–977. doi: 10.1111/j.1365-313X.2011.04847.x
- Issue published online: 16 MAR 2012
- Article first published online: 15 DEC 2011
- Accepted manuscript online: 8 NOV 2011 10:53AM EST
- Received 30 October 2011; accepted 2 November 2011; published online 15 December 2011.
- DNA damage;
- cell cycle
DNA damage checkpoints delay mitotic cell-cycle progression in response to DNA stress, stalling the cell cycle to allow time for repair. CDKB is a plant-specific cyclin-dependent kinase (CDK) that is required for the G2/M transition of the cell cycle. In Arabidopsis, DNA damage leads the degradation of CDKB2, and the subsequent G2 arrest gives cells time to repair damaged DNA. G2 arrest also triggers transition from the mitotic cycle to endoreduplication, leading to the presence of polyploid cells in many tissues. In contrast, in rice (Oryza sativa), polyploid cells are found only in the endosperm. It was unclear whether endoreduplication contributes to alleviating DNA damage in rice (Oryza sativa). Here, we show that DNA damage neither down-regulates Orysa;CDKB2;1 nor induces endoreduplication in rice. Furthermore, we found increased levels of Orysa;CDKB2;1 protein upon DNA damage. These results suggest that CDKB2 functions differently in Arabidopsis and rice in response to DNA damage. Arabidopsis may adopt endoreduplication as a survival strategy under genotoxic stress conditions, but rice may enhance DNA repair capacity upon genotoxic stress. In addition, polyploid cells due to endomitosis were present in CDKB2;1 knockdown rice, suggesting an important role for Orysa;CDKB2;1 during mitosis.