title: Transcription-coupled repair of UV damage in the halophilic archaea.
abstract: Transcription-coupled repair (TCR) is a subpathway of nucleotide excision repair (NER) in which excision repair proteins are targeted to RNA polymerase-arresting lesions located in the transcribed strand of active genes. TCR has been documented in a variety of bacterial and eukaryotic organisms but has yet to be observed in the Archaea. We used Halobacterium sp. NRC-1 and Haloferax volcanii to determine if TCR occurs in the halophilic archaea. Following UV irradiation of exponentially growing cultures, we quantified the rate of repair of cyclobutane pyrimidine dimers in the two strands of the rpoB2B1A1A2 and the trpDFEG operons of Halobacterium sp. NRC-1 and the pts operon of H. volcanii through the use of a Southern blot assay and strand-specific probes. TCR was observed in all three operons and was dependent on the NER gene uvrA in Halobacterium sp. NRC-1, but not in H. volcanii. The halophilic archaea likely employ a novel mechanism for TCR in which an as yet unknown coupling factor recognizes the arrested archaeal RNA polymerase complex and recruits certain NER proteins to complete the process.
authors.affiliation: Natural Sciences Department, Assumption College, Worcester, MA, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Stantial
authors.affiliation: Department of Biology, Mercer University, Macon, GA, USA.
authors.forename: Jarrod
authors.initials: J
authors.lastname: Dumpe
authors.affiliation: Natural Sciences Department, Assumption College, Worcester, MA, USA.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Pietrosimone
authors.affiliation: Natural Sciences Department, Assumption College, Worcester, MA, USA.
authors.forename: Felicia
authors.initials: F
authors.lastname: Baltazar
authors.affiliation: Natural Sciences Department, Assumption College, Worcester, MA, USA; Department of Biology, Mercer University, Macon, GA, USA. Electronic address: dacrowle@assumption.edu.
authors.forename: David J
authors.initials: DJ
authors.lastname: Crowley
mesh_terms: D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects*; D005632:Fructose / Q000494:pharmacology; D006217:Halobacterium / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D019621:Haloferax / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D009876:Operon / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects / Q000528:radiation effects*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D019843:Archaeal Proteins; D005632:Fructose
keywords: Halophilic archaea; Nucleotide excision repair; Transcription-coupled repair; UV damage and repair