Format

Send to

Choose Destination
Nucleic Acids Res. 1995 Oct 25;23(20):4196-201.

Initiation of unidirectional ColE2 DNA replication by a unique priming mechanism.

Author information

1
Department of Biology, Faculty of Science, Osaka University, Japan.

Abstract

The ColE2 DNA can be replicated in an in vitro system consisting of a crude extract of Escherichia coli cells. DNA synthesis requires a plasmid-coded protein (Rep) and host DNA polymerase I but not host RNA polymerase. Replication starts at a fixed region containing the origin and proceeds unidirectionally. The leading- and lagging-strand DNA fragments synthesized around the origin were identified from early replicative intermediates. The 5' end of the leading-strand DNA fragment was mapped at a unique position in the minimal origin and carried RNA of a few residues. The results suggested that the initiation of the leading-strand DNA synthesis does not require the host DnaG protein. Thus the Rep protein itself seems to be a primase. Synthesis of the primer RNA at a fixed site in the origin region on a double-stranded DNA template is a unique property of the ColE2 Rep protein among other known primases. The 3' end of the lagging-strand DNA fragment was mapped at a unique position just at the end of the minimal origin region. Termination of the lagging-strand DNA fragment at that position seems to be the mechanism of the unidirectional replication of ColE2 plasmid.

PMID:
7479084
PMCID:
PMC307362
DOI:
10.1093/nar/23.20.4196
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center