Temporal coordination between chromosome mobility and homologous recombination

Abstract

Homologous recombination (HR), a principal cellular pathway for double-strand break (DSB) repair, is linked to changes in chromosome movement. Although increased chromosome mobility in response to a DSB has been observed in a variety of species, its precise role in HR remains controversial. Here, we find that end resection, the recruitment of recombination proteins, increased chromosome mobility, the pairing of homologs and gene conversion are temporally linked in response to a DSB. In mre11Δ mutant cells, which exhibit a delay in the initial processing of a DSB, chromosome mobility and all subsequent recombination events are also delayed. Overexpression of the Dna2 nuclease suppresses the mre11Δ delay in end resection and restores the original timing of chromosome mobility and all subsequent downstream HR events. Thus, changing the timing of chromosome mobility results in a corresponding change in essential downstream HR events, reinforcing its mechanistic role in the DNA repair process.