Escherichia coli radD (yejH) gene: a novel function involved in radiation resistance and double‐strand break repair

Abstract

Summary A transposon insertion screen implicated the yejH gene in the repair of ionizing radiation-induced damage. The yejH gene, which exhibits significant homology to the human transcription-coupled DNA repair gene XPB, is involved in the repair of double strand DNA breaks. Deletion of yejH significantly sensitized cells to agents that cause double strand breaks (ionizing radiation, UV radiation, ciprofloxacin). In addition, deletion of both yejH and radA hypersensitized the cells to ionizing radiation, UV, and ciprofloxacin damage, indicating that these two genes have complementary repair functions. The ΔyejH ΔradA double deletion also showed a substantial decline in viability following an induced double-strand DNA break, of a magnitude comparable to the defect measured when the recA, recB, recG, or priA genes are deleted. The ATPase activity and C-terminal zinc finger motif of yejH play an important role in its repair function, as targeted mutant alleles of yejH did not rescue sensitivity. We propose that yejH be re-named radD, reflecting its role in the DNA repair of radiation damage.

Escherichia coli RadD Protein Functionally Interacts with the Single-stranded DNA-binding Protein

“…All of the proteins that interact with SSB to date have a role in some aspect of DNA metabolism. Therefore, an interaction with the C terminus of SSB provides an increasingly reliable indicator of DNA metabolic function.The radD gene (formerly yejH) was recently implicated in the repair of DNA double-strand breaks after radiation or chemical damage (10,11). The peptide sequence of the RadD protein includes all seven of the motifs associated with a superfamily 2 (SF2) helicase (10).…”

“…The radD gene (formerly yejH) was recently implicated in the repair of DNA double-strand breaks after radiation or chemical damage (10,11). The peptide sequence of the RadD protein includes all seven of the motifs associated with a superfamily 2 (SF2) helicase (10).…”

“…The peptide sequence of the RadD protein includes all seven of the motifs associated with a superfamily 2 (SF2) helicase (10). Although there is little homology outside of these regions, the helicase motifs align well to other E. coli SF2 helicases including RecG and RecQ.…”

“…RadD also contains a putative zinc finger motif in the C terminus that could aid in binding to DNA substrates. Both the ATPase and zinc binding domains are necessary for the rescue of DNA repair activities of radD deletion strains in vivo (10).…”

Stress resistance in naturalised waste water E. coli strains

“…In addition to the study of Alcantara-Diaz et al (2004) and in terms of the development of E. coli resistance to UV doses relevant to water treatment standards, Chen et al (2015) observed that a genetically modified UVC-resistant E. coli strain possessing the radD/radA genes was relatively unaffected by exposure to 10 mJ/cm 2 (i.e. highest dose tested).…”