RRC ID 30131
著者 Cao Y, Kogoma T.
タイトル Requirement for the polymerization and 5'-->3' exonuclease activities of DNA polymerase I in initiation of DNA replication at oriK sites in the absence of RecA in Escherichia coli rnhA mutants.
ジャーナル J Bacteriol
Abstract In previous studies, we found that the requirement for RecA protein in constitutive stable DNA replication (cSDR) can be bypassed by derepression of the LexA regulon and that DNA polymerase I (DNA PolI) is essential for this Rip (RecA-independent process) pathway of cSDR (Y. Cao, R. R. Rowland, and T. Kogoma, J. Bacteriol. 175:7247-7253, 1993). In this study, the role of DNA PolI in the Rip pathway was further examined. By using F' plasmids carrying different parts of the polA gene, a series of complementation tests was carried out to investigate the requirement for the three enzymatic activities, polymerization, 3'-->5' exonuclease, and 5'-->3' exonuclease activities, of DNA PolI. The result indicated that both the 5'-->3' exonuclease and polymerization activities of DNA PolI are essential for bypassing the requirement for RecA in cSDR but that the 3'-->5' exonuclease activity can be dispensed with. Complementation experiments with rat DNA Pol beta also supported the hypothesis that a nick translation activity is probably involved in cSDR in the absence of RecA. An analysis of DNA synthesis suggested that DNA PolI is involved in the initiation but not the elongation stage of cSDR. Moreover, the dnaE293(Ts) mutation was shown to render the bypass replication temperature sensitive despite the presence of active DNA PolI, suggesting that DNA PolIII is responsible for the elongation stage of the Rip pathway. A model which describes the possible roles of RecA in cSDR and the possible function of DNA PolI in the Rip pathway is proposed.
巻・号 175(22)
ページ 7254-9
公開日 1993-11-1
DOI 10.1128/jb.175.22.7254-7259.1993
PMID 8226672
PMC PMC206868
MeSH DNA Polymerase I / metabolism* DNA Polymerase II / metabolism DNA Polymerase III / metabolism DNA Replication* DNA, Bacterial / biosynthesis* DNA, Bacterial / chemistry Escherichia coli / genetics* Escherichia coli / metabolism* Exodeoxyribonuclease V Exodeoxyribonucleases / metabolism* Genes, Bacterial* Genetic Complementation Test Kinetics Models, Structural Mutagenesis Nucleic Acid Conformation Plasmids Rec A Recombinases / genetics Rec A Recombinases / metabolism* Restriction Mapping
IF 3.006
引用数 14
WOS 分野 MICROBIOLOGY
リソース情報
原核生物(大腸菌) ME9482 ME9479 ME9481 ME9506 ME9509 ME9502 ME9496 ME9124