Genomic Analysis of DNA Double-Strand Break Repair in Escherichia coli

Counting DNA whole genome sequencing reads is providing new insight into DNA double-strand break repair (DSBR) in the model organism Escherichia coli. We describe the application of RecA chromatin immunoprecipitation coupled to genomic DNA sequencing (RecA-ChIP-seq) and marker frequency analysis (MFA) to analyze the genomic consequences of DSBR. We provide detailed procedures for the preparation of DNA and the analysis of data. We compare different ways of visualizing ChIP data and show that alternative protocols for the preparation of DNA for MFA differentially affect the recovery of branched DNA molecules containing Holliday junctions.