RRC ID 30130
著者 Cao Y, Rowland RR, Kogoma T.
タイトル DNA polymerase I and the bypassing of RecA dependence of constitutive stable DNA replication in Escherichia coli rnhA mutants.
ジャーナル J Bacteriol
Abstract In Escherichia coli rnhA mutants, several normally repressed origins (oriK sites) of DNA replication are activated. The type of DNA replication initiated from these origins, termed constitutive stable DNA replication, does not require DnaA protein or the oriC site, which are essential for normal DNA replication. It requires active RecA protein. We previously found that the lexA71(Def)::Tn5 mutation can suppress this RecA requirement and postulated that the derepression of a LexA regulon gene(s) leads to the activation of a bypass pathway, Rip (for RecA-independent process). In this study, we isolated a miniTn10spc insertion mutant that abolishes the ability of the lexA(Def) mutation to suppress the RecA requirement of constitutive stable DNA replication. Cloning and DNA sequencing analysis of the mutant revealed that the insertion occurs at the 3' end of the coding region of the polA gene, which encodes DNA polymerase I. The mutant allele, designated polA25::miniTn10spc, is expected to abolish the polymerization activity but not the 5'-->3' or 3'-->5' exonuclease activity. Thus, the Rip bypass pathway requires active DNA polymerase I. Since the lethal combination of recA(Def) and polA25::miniTn10spc could be suppressed by derepression of the LexA regulon only when DNA replication is driven by the oriC system, it was suggested that the bypass pathway has a specific requirement for DNA polymerase I at the initiation step in the absence of RecA. An accompanying paper (Y. Cao and T. Kogoma, J. Bacteriol. 175:7254-7259, 1993) describes experiments to determine which activities of DNA polymerase I are required at the initiation step and discusses possible roles for DNA polymerase in the Rip bypass pathway.
巻・号 175(22)
ページ 7247-53
公開日 1993-11-1
DOI 10.1128/jb.175.22.7247-7253.1993
PMID 8226671
PMC PMC206867
MeSH Amino Acid Sequence Bacterial Proteins / genetics Bacterial Proteins / metabolism Base Sequence Cloning, Molecular DNA Polymerase I / genetics DNA Polymerase I / metabolism* DNA Replication* DNA, Bacterial / biosynthesis* DNA, Bacterial / metabolism Escherichia coli / genetics* Escherichia coli / growth & development Escherichia coli / metabolism* Genes, Bacterial* Genes, Lethal Genotype Kinetics Molecular Sequence Data Mutagenesis, Insertional Rec A Recombinases / metabolism* Restriction Mapping Serine Endopeptidases* Suppression, Genetic Temperature
IF 3.006
引用数 9
WOS 分野 MICROBIOLOGY
リソース情報
原核生物(大腸菌) ME9274 ME9522 ME9524 ME9526 ME9531 ME9491 ME9486 ME9487 ME9484 ME9454 ME9260 ME9472 ME9474 ME9469 ME9471 ME9466 ME9383 ME9448 ME9450 ME9490