High impact information on chk-2

• Nuclear reorganization and homologous chromosome pairing during meiotic prophase require C. elegans chk-2 [1].
• Although chk-2 encodes a C. elegans ortholog of the Cds1/Chk2 checkpoint protein kinases, germ-line nuclei in chk-2 mutants are competent to arrest proliferation in response to replication inhibition and to trigger DNA damage checkpoint responses to ionizing radiation [1].
• However, chk-2 mutants are defective in triggering the pachytene DNA damage checkpoint in response to an intermediate block in the meiotic recombination pathway, suggesting that chk-2 is required either for initiation of meiotic recombination or for monitoring a specific subset of DNA damage lesions [1].
• We propose that chk-2 functions during premeiotic S phase to enable chromosomes to become competent for subsequent meiotic prophase events and/or to coordinate replication with entry into prophase [1].
• Despite failures in pairing, nuclear reorganization, and crossover recombination, chk-2 mutants undergo many other aspects of meiotic chromosome morphogenesis and complete gametogenesis [1].

Biological context of chk-2

• Ce-chk-2 gene expression increased in the adult stage, and their expression level decreased in the glp-4 mutant, which is defective in germ line proliferation [2].
• Moreover, it seems that exogenous DSBs in the Ce-chk-2 defective nuclei at the pachytene stage can be repaired between sister chromatids in a Ce-rdh-1/rad-51-dependent manner [3].

Other interactions of chk-2

• RAD-51 localization requires the recombination genes spo-11 and mre-11 as well as chk-2, which is necessary for homology recognition and presynaptic alignment [4].

References