Chromosome breakage after G2 checkpoint release

Deckbar, D., Birraux, J., Krempler, A., Tchouandong, L., Beucher, A., Walker, S., Stiff, T., Jeggo, P.A. and Lobrich, M. (2006) Chromosome breakage after G2 checkpoint release. Cell Biology, 176 (6). pp. 749-755. ISSN 0022-1007

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DNA double-strand break (DSB) repair and checkpoint control represent distinct mechanisms to reduce chromosomal instability. Ataxia telangiectasia (A-T) cells have checkpoint arrest and DSB repair defects. We examine the efficiency and interplay of ATM's G2 checkpoint and repair functions. Artemis cells manifest a repair defect identical and epistatic to A-T but show proficient checkpoint responses. Only a few G2 cells enter mitosis within 4 h after irradiation with 1 Gy but manifest multiple chromosome breaks. Most checkpoint-proficient cells arrest at the G2/M checkpoint, with the length of arrest being dependent on the repair capacity. Strikingly, cells released from checkpoint arrest display one to two chromosome breaks. This represents a major contribution to chromosome breakage. The presence of chromosome breaks in cells released from checkpoint arrest suggests that release occurs before the completion of DSB repair. Strikingly, we show that checkpoint release occurs at a point when approximately three to four premature chromosome condensation breaks and ~20 {gamma}H2AX foci remain.

Item Type: Article
Additional Information: GDSC207
Schools and Departments: School of Life Sciences
Depositing User: Gee Wheatley
Date Deposited: 21 Mar 2007
Last Modified: 30 Nov 2012 16:51
Google Scholar:93 Citations
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