Two types of recombination hotspots in bacteriophage T4: one requires DNA damage and a replication origin and the other does not.
Journal Article (Journal Article)
Recombination hotspots have previously been discovered in bacteriophage T4 by two different approaches, marker rescue recombination from heavily damaged phage genomes and recombination during co-infection by two undamaged phage genomes. The phage replication origin ori(34) is located in a region that has a hotspot in both assays. To determine the relationship between the origin and the two kinds of hotspots, we generated phage carrying point mutations that should inactivate ori(34) but not affect the gene 34 reading frame (within which ori(34) is located). The mutations eliminated the function of the origin, as judged by both autonomous replication of plasmids during T4 infection and two-dimensional gel analysis of phage genomic replication intermediates. As expected from past studies, the ori(34) mutations also eliminated the hotspot for marker rescue recombination from UV-irradiated genomes. However, the origin mutations had no effect on the recombination hotspot that is observed with co-infecting undamaged phage genomes, demonstrating that some DNA sequence other than the origin is responsible for inflated recombination between undamaged genomes. The hotspots for marker rescue recombination may result from a replication fork restart process that acts upon origin-initiated replication forks that become blocked at nearby DNA damage. The two-dimensional gel analysis also revealed phage T4 replication intermediates not previously detected by this method, including origin theta forms.
Full Text
Duke Authors
Cited Authors
- Doan, PL; Belanger, KG; Kreuzer, KN
Published Date
- March 2001
Published In
Volume / Issue
- 157 / 3
Start / End Page
- 1077 - 1087
PubMed ID
- 11238396
Pubmed Central ID
- PMC1461569
International Standard Serial Number (ISSN)
- 0016-6731
Digital Object Identifier (DOI)
- 10.1093/genetics/157.3.1077
Language
- eng
Conference Location
- United States