UvrD helicase is required for nucleotide excision repair, although its role in this process is not well defined.By inducing backtracking, UvrD exposes DNA lesions shielded by blocked RNA polymerase, allowing nucleotide excision repair enzymes to gain access to sites of damage. UvrD is a bona fide transcription elongation factor that contributes to genomic integrity by resolving conflicts between transcription and DNA repair complexes.
Nucleotide excision repair (NER) is the most versatile and evolutionarily conserved mechanism used by prokaryotic and eukaryotic cells to repair diverse types of DNA lesions. In bacteria, the general NER pathway commences when UvrA and UvrB proteins bind damaged DNA and recruit UvrC to cleave the impaired strand on both sides of the lesion. The resulting oligonucleotide is displaced by UvrD and/or DNA polymerase I, which fills the gap using the complementary strand as a template. (Nature 505, 372–377 (16 January 2014) doi:10.1038/nature12928)