Format

Send to

Choose Destination
Nucleic Acids Res. 1992 Apr 11;20(7):1457-62.

DNA replication initiates at multiple sites on plasmid DNA in Xenopus egg extracts.

Author information

1
ICRF Clare Hall Laboratories, Potters Bar, Herts, UK.

Abstract

Cell-free extracts of Xenopus eggs will replicate plasmid DNA molecules under normal cell cycle control. We have used the neutral/neutral 2-D gel technique to map the sites at which DNA replication initiates in this system. Three different plasmids were studied: one containing the Xenopus rDNA repeat, one containing single copy Xenopus genomic DNA, and another containing the yeast 2 microns replication origin. 2-D gel profiles show that many potential sites of initiation are present on each plasmid, and are randomly situated at the level of resolution of this technique (500-1000 bp). Despite the abundance of sites capable of supporting the initiation of replication, pulse-chase experiments suggest that only a single randomly situated initiation event occurs on each DNA molecule. Once initiation has taken place, conventional replication forks appear to move away from this site at a rate of about 10nt/second, similar to the rate observed in vivo.

PMID:
1579437
PMCID:
PMC312222
DOI:
10.1093/nar/20.7.1457
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

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