1. Thymine DNA glycosylase combines sliding, hopping, and nucleosome interactions to efficiently search for 5-formylcytosine.
- Author
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Schnable BL, Schaich MA, Roginskaya V, Leary LP, Weaver TM, Freudenthal BD, Drohat AC, and Van Houten B
- Subjects
- Humans, Catalytic Domain, Single Molecule Imaging, Cytosine metabolism, Cytosine analogs & derivatives, DNA metabolism, DNA chemistry, DNA Repair, Nucleosomes metabolism, Thymine DNA Glycosylase metabolism, Thymine DNA Glycosylase chemistry
- Abstract
Base excision repair is the main pathway involved in active DNA demethylation. 5-formylcytosine and 5-carboxylcytosine, two oxidized moieties of methylated cytosine, are recognized and removed by thymine DNA glycosylase (TDG) to generate an abasic site. Using single molecule fluorescence experiments, we study TDG in the presence and absence of 5-formylcytosine. TDG exhibits multiple modes of linear diffusion, including hopping and sliding, in search of base modifications. TDG active site variants and truncated N-terminus, reveals these variants alter base modification search and recognition mechanism of TDG. On DNA containing an undamaged nucleosome, TDG is found to either bypass, colocalize with, or encounter but not bypass the nucleosome. Truncating the N-terminus reduces the number of interactions with the nucleosome. Our findings provide mechanistic insights into how TDG searches for modified DNA bases in chromatin., (© 2024. The Author(s).)
- Published
- 2024
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