[Frontiers in Bioscience 16, 3164-3182, June 1, 2011]

[Frontiers in Bioscience 16, 3164-3182, June 1, 2011]

Escherichia coli Y family DNA polymerases

Jason M. Walsh¹, Lisa A. Hawver¹, Penny J. Beuning^{1, 2}

1Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Ave., Boston, MA 02115, USA, ²Center for Interdisciplinary Research on Complex Systems, Northeastern University, 360 Huntington Ave., Boston, MA 02115, USA

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Transcriptional and post-translational regulation
4. DNA polymerase IV: DinB: 4.1. DinB in general stress responses; 4.2. Specificity; 4.3. DinB variants; 4.4. Cellular interactions of DinB
5. DNA polymerase V: UmuD′2C: 5.1. Discovery of pol V and SOS mutagenesis; 5.2. Roles of Pol V in responding to replication stress; 5.3. Specificity; 5.4. UmuC variants; 5.5. Cellular interactions of UmuC
6. Polymerase switching
7. Summary
8. Acknowledgments
9. References

1. ABSTRACT

DNA damage is ubiquitous, arising from both environmental and endogenous sources. All organisms have evolved multiple pathways to respond to DNA damage and maintain genomic integrity. Escherichia coli possesses two DNA polymerases, pol IV and pol V, that are members of the Y family. These polymerases are characterized by their specialized ability to copy damaged DNA as well as their relatively low fidelity on undamaged DNA. Pol IV and pol V are regulated by the SOS response to DNA damage and by their multiple interactions with other proteins. These two Y family DNA polymerases copy DNA damaged by distinct agents. Pol IV is capable of replicating DNA containing N²-dG adducts, while pol V bypasses abasic sites and thymine-thymine dimers, which result from exposure to UV radiation. In addition to their roles in copying damaged DNA, the two Y family DNA polymerases in E. coli act in regulation of DNA replication and contribute to bacterial mutagenesis in response to cellular stress.