Investigation of Break-Induced Replication in Yeast

Repair of double-strand DNA breaks (DSBs) is important for preserving genomic integrity and stability. Break-induced replication (BIR) is a mechanism aimed to repair one-ended double-strand DNA breaks, similar to those formed by replication fork collapse or by telomere erosion. Unlike S-phase replication, BIR is carried out by a migrating DNA bubble and is associated with conservative inheritance of newly synthesized DNA. This unusual DNA synthesis leads to high level of mutagenesis and chromosomal rearrangements during BIR. Here, we focus on several genetic and molecular methods to investigate BIR using our system in yeast Saccharomyces cerevisiae where BIR is initiated by a site-specific DNA break, and the repair involves two copies of chromosome III.