title: A RecB-like helicase in Helicobacter pylori is important for DNA repair and host colonization.
abstract: The human gastric pathogen Helicobacter pylori encounters frequent oxidative and acid stress in its specific niche, and this causes bacterial DNA damage. H. pylori exhibits a very high degree of DNA recombination, which is required for repairing both DNA double-stranded (ds) breaks and blocked replication forks. Nevertheless, few genes encoding components of DNA recombinational repair processes have been identified in H. pylori. An H. pylori mutant defective in a putative helicase gene (HP1553) was constructed and characterized herein. The HP1553 mutant strain was much more sensitive to mitomycin C than the WT strain, indicating that HP1553 is required for repair of DNA ds breaks. Disruption of HP1553 resulted in a significant decrease in the DNA recombination frequency, suggesting that HP1553 is involved in DNA recombination processes, probably functioning as a RecB-like helicase. HP1553 was shown to be important for H. pylori protection against oxidative stress-induced DNA damage, as the exposure of the HP1553 mutant cells to air for 6 h caused significant fragmentation of genomic DNA and led to cell death. In a mouse infection model, the HP1553 mutant strain displayed a greatly reduced ability to colonize the host stomachs, indicating that HP1553 plays a significant role in H. pylori survival/colonization in the host.
authors.affiliation: Department of Microbiology, University of Georgia, Athens, GA 30602, USA.
authors.forename: Ge
authors.initials: G
authors.lastname: Wang
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Maier
mesh_terms: D000477:Alkylating Agents / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015169:Colony Count, Microbial; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity*; D051379:Mice; D008810:Mice, Inbred C57BL; D050296:Microbial Viability; D016685:Mitomycin / Q000494:pharmacology; D010100:Oxygen / Q000494:pharmacology; D011995:Recombination, Genetic; D013270:Stomach / Q000382:microbiology; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000477:Alkylating Agents; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D037521:Virulence Factors; D016685:Mitomycin; D004265:DNA Helicases; D010100:Oxygen