Role of an alternative processivity Clamp in DNA damage tolerance in E. coli

CHED 967

Michael J. Ordazzo, ordazzo.m@neu.edu and Penny J. Beuning. Department of Chemistry, Northeasten University, 360 Huntington Ave, 102 Hurtig, Boston, MA 02115
The ß subunit of DNA polymerase III holoenzyme of E. coli is a sliding clamp whose function is to tether the polymerase to the DNA allowing DNA to be replicated with high processivity. It has been shown that UV irradiation of E. coli induces a smaller form of the ß subunit termed ß* that plays a role in increasing resistance to UV irradiation. It was found previously that b interacts with UmuD and we have found that b*also interacts with UmuD, a protein involved in UV-induced mutagenesis as well as a primitive DNA damage checkpoint. These findings suggest a role for ß* in recovery from UV damage by involvement in DNA repair or reactivation of DNA replication. We are currently determining the role of ß* in DNA damage tolerance and in regulating accurate versus mutagenic DNA replication.