Budding yeast SLX4 contributes to the appropriate distribution of crossovers and meiotic double-strand break formation on bivalents during meiosis

Abstract

The number and distribution of meiosis crossover (CO) events on each bivalent are strictlycontrolled by multiple mechanisms to assure proper chromosome segregation during the first meioticdivision. In Saccharomyces cerevisiae, Slx4 is a multi-functional scaffold protein for structure-selectiveendonucleases, such as Slx1 and Rad1 (which are involved in DNA damage repair), and is also a negativeregulator of the Rad9-dependent signaling pathway with Rtt107. Slx4 has been believed to play onlya minor role in meiotic recombination. Here, we report that Slx4 is involved in proper intrachromosomaldistribution of meiotic CO formation, especially in regions near centromeres. We observed an increase inuncontrolled CO formation only in a region near the centromere in the slx4Δ mutant. Interestingly, thisphenomenon was not observed in the slx1Δ, rad1Δ, or rtt107Δ mutants. In addition, we observed a reducednumber of DNA double-strand breaks (DSBs) and altered meiotic DSB distribution on chromosomes in theslx4Δ mutant. This suggests that the multi-functional Slx4 is required for proper CO formation and meioticDSB formation.