Constitutive SOS expression and damage-inducible AddAB-mediated recombinational repair systems for Coxiella burnetii as potential adaptations for survival within macrophages |
| |
Authors: | Mertens Katja Lantsheer Letty Ennis Don G Samuel James E |
| |
Institution: | Department of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, College of Medicine, College Station, TX, USA.; Department of Biology, University of Louisiana, Lafayette, LA, USA. |
| |
Abstract: | Coxiella burnetii , a Gram-negative obligate intracellular pathogen, replicates within an parasitophorous vacuole with lysosomal characteristics. To understand how C. burnetii maintains genomic integrity in this environment, a database search for genes involved in DNA repair was performed. Major components of repair, SOS response and recombination were identified, including recA and ruvABC , but lexA and recBCD were absent. Instead, C. burnetii possesses addAB orthologous genes, functional equivalents to recBCD . Survival after treatment with UV, mitomycin C (MC) or methyl methanesulfonate (MMS), as well as homologous recombination in Hfr mating was restored in Escherichia coli deletion strains by C. burnetii recA or addAB . Despite the absence of LexA, co-protease activity for C. burnetii RecA was demonstrated. Dominant-negative inhibition of C. burnetii RecA by recA mutant alleles, modelled after E. coli recA1 and recA56 , was observed and more apparent with expression of C. burnetii RecAG159D mutant protein. Expression of a subset of repair genes in C. burnetii was monitored and, in contrast to the non-inducible E. coli recBCD , addAB expression was strongly upregulated under oxidative stress. Constitutive SOS gene expression due to the lack of LexA and induction of AddAB likely reflect a unique repair adaptation of C. burnetii to its hostile niche. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|