| Autor: |
Zhao T; Environmental Toxicology Graduate Program, University of California, Riverside, Riverside, California 92521-0403, United States., He X; Department of Chemistry, University of California, Riverside, Riverside, California 92521-0403, United States., Liang X; Environmental Toxicology Graduate Program, University of California, Riverside, Riverside, California 92521-0403, United States., Kellum AH Jr; Department of Chemistry, University of California, Riverside, Riverside, California 92521-0403, United States., Tang F; Department of Chemistry, University of California, Riverside, Riverside, California 92521-0403, United States., Yin J; Environmental Toxicology Graduate Program, University of California, Riverside, Riverside, California 92521-0403, United States., Guo S; Environmental Toxicology Graduate Program, University of California, Riverside, Riverside, California 92521-0403, United States., Wang Y; Department of Chemistry, University of California, Riverside, Riverside, California 92521-0403, United States., Gao Z; Department of Chemistry, University of California, Riverside, Riverside, California 92521-0403, United States., Wang Y; Environmental Toxicology Graduate Program, University of California, Riverside, Riverside, California 92521-0403, United States.; Department of Chemistry, University of California, Riverside, Riverside, California 92521-0403, United States. |
| Abstrakt: |
N 2 -Alkyl-2'-deoxyguanosine ( N 2 -alkyl-dG) is a major type of minor-groove DNA lesions arising from endogenous metabolic processes and exogenous exposure to environmental contaminants. The N 2 -alkyl-dG lesions, if left unrepaired, can block DNA replication and transcription and induce mutations in these processes. Nevertheless, the repair pathways for N 2 -alkyl-dG lesions remain incompletely elucidated. By utilizing a photo-cross-linking coupled with mass spectrometry-based quantitative proteomic analysis, we identified a series of candidate N 2 -alkyl-dG-binding proteins. We found that two of these proteins, i.e., high-mobility group protein B3 (HMGB3) and SUB1, could bind directly to N 2 - n Bu-dG-containing duplex DNA in vitro and promote the repair of this lesion in cultured human cells. In addition, HMGB3 and SUB1 protected cells against benzo[ a ]pyrene-7,8-diol-9,10-epoxide (BPDE). SUB1 exhibits preferential binding to both the cis and trans diastereomers of N 2 -BPDE-dG over unmodified dG. On the other hand, HMGB3 binds favorably to trans - N 2 -BPDE-dG; the protein, however, does not distinguish cis - N 2 -BPDE-dG from unmodified dG. Consistently, genetic ablation of HMGB3 conferred diminished repair of trans - N 2 -BPDE-dG, but not its cis counterpart, whereas loss of SUB1 conferred attenuated repair of both diastereomers. Together, we identified proteins involved in the cellular sensing and repair of minor-groove N 2 -alkyl-dG lesions and documented a unique role of HMGB3 in the stereospecific recognition and repair of N 2 -BPDE-dG. |
