CGC Bibliography Paper 5024

C. elegans RAD-5/CLK-2 defines a new DNA damage checkpoint protein.

Ahmed S, Alpi A, Hengartner MO, Gartner A

Medline:

11747819

Citation:

Current Biology 11: 1934-1944 2001

Type:

ARTICLE

Genes:

clk-1 clk-2 clk-3 gro-1 mrt-2 rad-5

Abstract:

Background: In response to genotoxic stress, cells activate checkpoint pathways that lead to a transient cell cycle arrest that allows for DNA repair or to apoptosis, which triggers the demise of genetically damaged cells. Results: During positional cloning of the C. elegans rad-5 DNA damage checkpoint gene, we found, surprisingly, that rad-5(mn159) is allelic with clk-2(qm37), a mutant previously implicated in regulation of biological rhythms and life span. However, clk-2(qm37) is the only C. elegans clock mutant that is defective for the DNA damage checkpoint. We show that rad-5/clk-2 acts in a pathway that partially overlaps with the conserved C. elegans mrt-2/S. cerevisiae RAD17/S. pombe rad1 (+) checkpoint pathway. In addition, rad-5/clk-2 also regulates the S phase replication checkpoint in C. elegans. Positional cloning reveals that the RAD-5/CLK-2 DNA damage checkpoint protein is homologous to S, cerevisiae Tel2p, an essential DNA binding protein that regulates telomere length in, yeast. However, the partial loss-of-function C. elegans rad-5(mn 159) and clk-2(qm37) checkpoint mutations have little effect on telomere length, and analysis of the partial loss-of-function of S. cerevisiae tel2-1 mutant failed to reveal typical DNA damage checkpoint defects. Conclusions: Using C. elegans genetics we define the novel DNA damage checkpoint protein RAD-5/CLK-2, which may play a role in oncogenesis. Given that Tel2p has been shown to bind to a variety of nucleic, acid structures in vitro, we speculate that the RAD-5/CLK-2 checkpoint protein may act at sites of DNA damage, either as a sensor of DNA damage or to aid in