title: Compromised DNA damage repair promotes genetic instability of the genomic magnetosome island in Magnetospirillum magneticum AMB-1.
abstract: Magnetotactic bacteria (MTB) are capable of synthesizing nano-sized, intracellular membrane-bound magnetosomes. To learn more about the genetic factors involved in magnetosome formation, transposon mutagenesis was carried out by conjugation using a hyperactive mariner transposon to obtain nonmagnetic mutants of Magnetospirillum magneticum AMB-1. A mutant with defect in uvrA gene encoding the DNA binding subunit of the UvrABC complex responsible for the process of nucleotide excision repair, was obtained. Growth, magnetosome formation and maintenance of magnetosome island (MAI) were further analyzed in the absence of UvrA. Interruption of uvrA led to decreased capacity to form magnetosome when cultured in the presence of oxygen. The deficiency in UvrA also resulted in an accelerated loss of the MAI under aerobic conditions indicating that the nucleotide excision repair system guards against the instability of the MAI. The incapacity of MTB to efficiently initiate recombination mediated by RecA rescued the instability of MAI observed in uvrA mutant. Elevated recombination activity resulting from the accumulation of unrepaired mutations may thus account for the instability of MAI in the absence of UvrA.
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Bo
authors.forename: Kuan
authors.initials: K
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Ge
authors.forename: Guanjun
authors.initials: G
authors.lastname: Chen
authors.forename: Weifeng
authors.initials: W
authors.lastname: Liu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage / Q000528:radiation effects; D004260:DNA Repair / Q000528:radiation effects; D042822:Genomic Instability / Q000528:radiation effects; D044404:Genomic Islands / Q000528:radiation effects; D055944:Magnetosomes / Q000235:genetics* / Q000378:metabolism; D042201:Magnetospirillum / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D016296:Mutagenesis; D011995:Recombination, Genetic; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins