title: Stationary-phase mutation in the bacterial chromosome: recombination protein and DNA polymerase IV dependence.
abstract: Several microbial systems have been shown to yield advantageous mutations in slowly growing or nongrowing cultures. In one assay system, the stationary-phase mutation mechanism differs from growth-dependent mutation, demonstrating that the two are different processes. This system assays reversion of a lac frameshift allele on an F' plasmid in Escherichia coli. The stationary-phase mutation mechanism at lac requires recombination proteins of the RecBCD double-strand-break repair system and the inducible error-prone DNA polymerase IV, and the mutations are mostly -1 deletions in small mononucleotide repeats. This mutation mechanism is proposed to occur by DNA polymerase errors made during replication primed by recombinational double-strand-break repair. It has been suggested that this mechanism is confined to the F plasmid. However, the cells that acquire the adaptive mutations show hypermutation of unrelated chromosomal genes, suggesting that chromosomal sites also might experience recombination protein-dependent stationary-phase mutation. Here we test directly whether the stationary-phase mutations in the bacterial chromosome also occur via a recombination protein- and pol IV-dependent mechanism. We describe an assay for chromosomal mutation in cells carrying the F' lac. We show that the chromosomal mutation is recombination protein- and pol IV-dependent and also is associated with general hypermutation. The data indicate that, at least in these male cells, recombination protein-dependent stationary-phase mutation is a mechanism of general inducible genetic change capable of affecting genes in the bacterial chromosome.
authors.affiliation: Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030-3411, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Bull
authors.forename: M J
authors.initials: MJ
authors.lastname: Lombardo
authors.forename: S M
authors.initials: SM
authors.lastname: Rosenberg
mesh_terms: D000483:Alleles; D001426:Bacterial Proteins / Q000235:genetics; D002876:Chromosomes, Bacterial; D019951:DNA Polymerase beta / Q000378:metabolism*; D004706:Endodeoxyribonucleases / Q000235:genetics; D029968:Escherichia coli Proteins; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000235:genetics; D005798:Genes, Bacterial; D007785:Lactose / Q000378:metabolism; D016296:Mutagenesis; D011938:Rec A Recombinases / Q000235:genetics; D011995:Recombination, Genetic; D012097:Repressor Proteins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C069806:ruvC protein, E coli; C034811:tetracycline resistance-encoding transposon repressor protein; C071446:RecG protein, E coli; D011938:Rec A Recombinases; D019951:DNA Polymerase beta; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; D043211:Exodeoxyribonuclease V; D007785:Lactose