Role of the nucleotide excision repair pathway proteins (UvrB and UvrD2) in recycling UdgB, a base excision repair enzyme in Mycobacterium smegmatis.

Cross-talks between DNA repair pathways are emerging as a crucial strategy in the maintenance of the genomic integrity. A double-stranded (ds) DNA specific DNA glycosylase, UdgB is known to excise uracil, hypoxanthine and ethenocytosine. We earlier showed that Mycobacterium smegmatis (Msm) UdgB stays back on the AP-sites it generates in the DNA upon excision of the damaged bases. Here, we show that in an Msm strain deleted for a nucleotide excision repair (NER) protein, UvrB (uvrB-), UdgB expression is toxic, and its deletion from the genome (udgB-) rescues the strain from the genotoxic stress. However, UdgB bound AP-site is not a direct substrate for NER in vitro. We show that UvrD2 and UvrB, known helicases with single-stranded (ss) DNA translocase activity, facilitate recycling of UdgB from AP-DNA. Our studies reveal that the helicases play an important role in exposing the AP-sites in DNA and make them available for further repair. Copyright © 2022 Elsevier B.V. All rights reserved.

Citation

Indu Kapoor, Abhirup Shaw, Arindam Naha, Elhassan Ali Fathi Emam, Umesh Varshney. Role of the nucleotide excision repair pathway proteins (UvrB and UvrD2) in recycling UdgB, a base excision repair enzyme in Mycobacterium smegmatis. DNA repair. 2022 Mar 04;113:103316

PMID: 35306347

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