DNA replication by Escherichia coli DNA polymerase III is regulated by the umuD gene products

• Online Access: http://hdl.handle.net/2047/d20003301

DNA polymerase III (DNA pol III) efficiently replicates the Escherichia coli genome, but it cannot bypass DNA damage. Instead, translesion synthesis (TLS) DNA polymerases are employed to replicate past damaged DNA; however, the exchange of replicative for TLS polymerases is not understood. The umuD gene products, which are up-regulated during the SOS response, were previously shown to bind to the alpha, beta, and epsilion subunits of DNA pol III. Full-length UmuD inhibits DNA replication and prevents mutagenic TLS, while the cleaved form UmuD' facilitates mutagenesis. In this work, we investigate the interactions between the alpha subunit of DNA pol III, the single-stranded DNA binding protein SSB, and UmuD and we find that these interactions regulate DNA replication in E. coli.