Polymerase exchange on single DNA molecules reveals processivity clamp control of translesion synthesis.
Translesion synthesis (TLS) by Y-family DNA polymerases alleviates replication stalling at DNA damage. Ring-shaped processivity clamps play a critical but ill-defined role in mediating exchange between Y-family and replicative polymerases during TLS. By reconstituting TLS at the single-molecule level, we show that the Escherichia coli β clamp can simultaneously bind the replicative polymerase (Pol) III and the conserved Y-family Pol IV, enabling exchange of the two polymerases and rapid bypass of a Pol IV cognate lesion. Furthermore, we find that a secondary contact between Pol IV and β limits Pol IV synthesis under normal conditions but facilitates Pol III displacement from the primer terminus following Pol IV induction during the SOS DNA damage response. These results support a role for secondary polymerase clamp interactions in regulating exchange and establishing a polymerase hierarchy.
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115;
James E
JE
Kath
Centre for Medical and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia;
Slobodan
S
Jergic
Department of Biochemistry andWitebsky Center for Microbial Pathogenesis and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14214; and.
Justin M H
JM
Heltzel
Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139.
Deena T
DT
Jacob
Centre for Medical and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia;
Nicholas E
http://orcid.org/0000-0002-5958-6945
NE
Dixon
Department of Biochemistry andWitebsky Center for Microbial Pathogenesis and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14214; and.
Mark D
MD
Sutton
Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139.
Graham C
GC
Walker
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115; joseph_loparo@hms.harvard.edu.
Joseph J
JJ
Loparo
D004247:DNA / Q000378:metabolism*; D004258:DNA Polymerase III / Q000378:metabolism*; D019951:DNA Polymerase beta / Q000378:metabolism*; D004926:Escherichia coli; D046210:Microfluidic Analytical Techniques; D008957:Models, Genetic; D011485:Protein Binding; D013014:SOS Response, Genetics / Q000502:physiology*; D018709:Statistics, Nonparametric
D004247:DNA; C101139:beta subunit, DNA polymerase III; D004258:DNA Polymerase III; D019951:DNA Polymerase beta
DNA repair; DNA replication; DinB; lesion bypass; single-molecule techniques