期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2006
卷号：103
期号：32
页码：11964-11969
DOI：10.1073/pnas.0604987103
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Although the essential function of checkpoint kinase 1 (Chk1) in DNA damage response has been well established, the role of Chk1 in normal cell cycle progression is unclear. By using RNAi to specifically deplete Chk1, we determined loss-of-function phenotypes in HeLa cells. A vector-based RNAi approach showed that Chk1 is required for normal cell proliferation and survival, inasmuch as a dramatic cell-cycle arrest at G2/M phase and massive apoptosis were observed in Chk1-deficient cells. Coupling of siRNA with cell synchronization further revealed that Chk1 depletion leads to metaphase block, as indicated by various mitotic markers. Neither bipolar spindle formation nor centrosome functions were affected by Chk1 depletion; however, the depleted cells exhibited chromosome misalignment during metaphase, chromosome lagging during anaphase, and kinetochore defects within the regions of misaligned/lagging chromosomes. Moreover, we showed that Chk1 is a negative regulator of polo-like kinase 1 (Plk1), in either the absence or presence of DNA damage. Finally, Chk1 depletion leads to the activation of the spindle checkpoint because codepletion of spindle checkpoint proteins rescues the Chk1 depletion-induced mitotic arrest.
