Abstract
DNA-binding proteins search for specific targets via facilitated diffusion along a crowded genome. However, little is known about how crowded DNA modulates facilitated diffusion and target recognition. Here we use DNA curtains and single-molecule fluorescence imaging to investigate how Msh2-Msh3, a eukaryotic mismatch repair complex, navigates on crowded DNA. Msh2-Msh3 hops over nucleosomes and other protein roadblocks, but maintains sufficient contact with DNA to recognize a single lesion. In contrast, Msh2-Msh6 slides without hopping and is largely blocked by protein roadblocks. Remarkably, the Msh3-specific mispair-binding domain (MBD) licences a chimeric Msh2-Msh6(3MBD) to bypass nucleosomes. Our studies contrast how Msh2-Msh3 and Msh2-Msh6 navigate on a crowded genome and suggest how Msh2-Msh3 locates DNA lesions outside of replication-coupled repair. These results also provide insights into how DNA repair factors search for DNA lesions in the context of chromatin.
| Original language | English |
|---|---|
| Article number | 10607 |
| Journal | Nature Communications |
| Volume | 7 |
| DOIs | |
| State | Published - 3 Feb 2016 |
Bibliographical note
Funding Information:We are grateful to members of the Finkelstein and Surtees laboratories for carefully reading the manuscript. This work was supported by the National Institute of General Medical Sciences of the National Institutes of Health (GM097177 to I.J.F. and GM087459 to J.A.S.), the American Cancer Society (RSG-14-235-01 to J.A.S.), CPRIT (R1214 to I.J.F.) and the Welch Foundation (F-l808 to I.J.F.). J.A.S. is an ACS Research Scholar. I.J.F. is a CPRIT Scholar in Cancer Research. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. We are indebted to our colleagues Richard Kolodner, Eric Greene, Eric Alani and Manju Hingorani for valuable reagents and helpful discussions.