Stationary-Phase Mutation in the Bacterial Chromosome: Recombination Protein and DNA Polymerase IV Dependence

• Published in: Proceedings of the National Academy of Sciences - PNAS 2001-07, Vol.98 (15), p.8334-8341
• Main Authors: Bull, H J, Lombardo, M J, Rosenberg, S M
• Format: Article
• Language: English
• Subjects: Alleles; Bacteria; Bacterial Proteins - genetics; Cell growth; Chromosomes; Chromosomes, Bacterial; Colloquium: Links between Recombination and Replication: Vital Roles of Recombination; Deoxyribonucleic acid; DNA; DNA Polymerase beta - metabolism; double-strand break repair; Endodeoxyribonucleases - genetics; Escherichia coli; Escherichia coli Proteins; Evolution; Exodeoxyribonuclease V; Exodeoxyribonucleases - genetics; Genes; Genes, Bacterial; Genetic mutation; Lactose - metabolism; Microbial genetics; Mutagenesis; Mutation; Plasmids; Proteins; Rec A Recombinases - genetics; Recombination, Genetic; Repressor Proteins - metabolism; Starvation; stationary phase
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.151009798

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.