Single-Molecule Imaging Reveals that Rad4 Employs a Dynamic DNA Damage Recognition Process.
作者信息
Kong Muwen, Liu Lili, Chen Xuejing, Driscoll Katherine I, Mao Peng, Böhm Stefanie, Kad Neil M, Watkins Simon C, Bernstein Kara A, Wyrick John J, Min Jung-Hyun, Van Houten Bennett
机构信息
Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA.
出版信息
Mol Cell. 2016 Oct 20;64(2):376-387. doi: 10.1016/j.molcel.2016.09.005. Epub 2016 Oct 6.
Nucleotide excision repair (NER) is an evolutionarily conserved mechanism that processes helix-destabilizing and/or -distorting DNA lesions, such as UV-induced photoproducts. Here, we investigate the dynamic protein-DNA interactions during the damage recognition step using single-molecule fluorescence microscopy. Quantum dot-labeled Rad4-Rad23 (yeast XPC-RAD23B ortholog) forms non-motile complexes or conducts a one-dimensional search via either random diffusion or constrained motion. Atomic force microcopy analysis of Rad4 with the β-hairpin domain 3 (BHD3) deleted reveals that this motif is non-essential for damage-specific binding and DNA bending. Furthermore, we find that deletion of seven residues in the tip of β-hairpin in BHD3 increases Rad4-Rad23 constrained motion at the expense of stable binding at sites of DNA lesions, without diminishing cellular UV resistance or photoproduct repair in vivo. These results suggest a distinct intermediate in the damage recognition process during NER, allowing dynamic DNA damage detection at a distance.