Caenorhabditis elegans brc-1 mutation increases the number of COSA-1 foci in him-8 and zim-2 mutants.

Abstract

Crossover designation factors such as COSA-1 are concentrated at the specific DNA double-strand break (DSB) sites to promote crossover formation. zim-1 mutants, which show defects in the homologous chromosome pairing of chromosomes II and III, increase the COSA-1 foci/normal bivalent state compared to the expected value. The excess designation was suppressed by an additional mutation in brc-1 in zim-1 mutants. We demonstrated that the number of COSA-1 foci in him-8 and zim-2 mutants, showing defects in the pairing of the X and V chromosomes, respectively, increased compared to the expected value, and brc-1 mutation accelerated the number of COSA-1 foci in oogenesis.