Gorman J, et al. (2010) Visualizing one-dimensional diffusion of eukaryotic DNA repair factors along a chromatin lattice. Nat Struct Mol Biol 17(8):932-8
Abstract: DNA-binding proteins survey genomes for targets using facilitated diffusion, which typically includes a one-dimensional (1D) scanning component for sampling local regions. Eukaryotic proteins must accomplish this task while navigating through chromatin. Yet it is unknown whether nucleosomes disrupt 1D scanning or eukaryotic DNA-binding factors can circumnavigate nucleosomes without falling off DNA. Here we use single-molecule microscopy in conjunction with nanofabricated curtains of DNA to show that the postreplicative mismatch repair protein complex Mlh1-Pms1 diffuses in 1D along DNA via a hopping/stepping mechanism and readily bypasses nucleosomes. This is the first experimental demonstration that a passively diffusing protein can traverse stationary obstacles. In contrast, Msh2-Msh6, a mismatch repair protein complex that slides while maintaining continuous contact with DNA, experiences a boundary upon encountering nucleosomes. These differences reveal important mechanistic constraints affecting intranuclear trafficking of DNA-binding proteins.
|Status: Published||Type: Journal Article | Research Support, N.I.H., Extramural | Research Support, Non-U.S. Gov't | Research Support, U.S. Gov't, Non-P.H.S.||PubMed ID: 20657586|
Topics addressed in this paper
Number of different genes curated to this paper: 4
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