Polymerase exchange on single DNA molecules reveals processivity clamp control of translesion synthesis
RIS ID
91008
Abstract
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.
Grant Number
ARC/DP0877658
Publication Details
Kath, J. E., Jergic, S., Heltzel, J. M. H., Jacob, D. T., Dixon, N. E., Sutton, M. D., Walker, G. C. & Loparo, J. J. (2014). Polymerase exchange on single DNA molecules reveals processivity clamp control of translesion synthesis. Proceedings of the National Academy of Sciences of USA, 111 (21), 7647-7652.