DNA motif associated with meiotic double-strand break regions in Saccharomyces cerevisiae

Meiotic recombination in yeast is initiated by DNA double-strand breaks (DS Bs) that occur at preferred sites, distributed along the chromosomes. These DSB sites undergo changes in chromatin structure early in meiosis, hut the ir common features at the level of DNA sequence have not been defined until now. Alignment of 1 kb sequences flanking six well-mapped DSBs has allowed us to define a flexible sequence motif, the CoHR profile, which predicts t he great majority of meiotic DSB locations, The 50 bp profile contains a po ly(A) tract in its centre and may have several gaps of unrelated sequences over a total length of up to 250 bp. The major exceptions to the correlatio n between CoHRs and preferred DSB sites are at telomeric regions, where DSB s do not occur. The CoHR sequence may provide the basis for understanding m eiosis-induced chromatin changes that enable DSBs to occur at defined chrom osomal sites.