This research was supported by grants MCB1518142 from the National Science Foundation and R15ES025953 from the National Institute of Environmental Health Sciences.
Journal of Bacteriology
Endonucleases, DNA repair, Psoralens, Escherichia coli -- Genetics
DNA interstrand crosslinks are complex lesions that covalently link both strands of the duplex DNA. Lesion removal is proposed to initiate via the UvrABC nucleotide excision repair complex, however less is known about the subsequent steps of this complex repair pathway. In this study, we characterized the contribution of nucleotide excision repair mutants to survival in the presence of psoralen-induced damage. Unexpectedly, we observed that the nucleotide excision repair mutants exhibit differential sensitivity to psoralen-induced damage, with uvrC mutants being less sensitive than either uvrA or uvrB. We show that Cho, an alternative endonuclease, acts with UvrAB and is responsible for the reduced hypersensitivity of uvrC mutants. We find that Cho's contribution to survival correlates with the presence of DNA interstrand crosslinks, rather than monoadducts, and operates at a step after, or independent from, the initial incision during the global repair of psoralen DNA adducts from the genome.
Perera, A. V., Mendenhall, J. B., Courcelle, C. T., & Courcelle, J. (2016). Cho Endonuclease Functions during DNA Interstrand Cross-Link Repair in Escherichia coli. Journal of Bacteriology, 198(22), 3099-3108.