title: Integration of plasmids into the bacteriophage T4 genome.
abstract: We have analyzed the integration of plasmids into the bacteriophage T4 genome via homologous recombination. As judged by genetic selection for a plasmid-borne marker, a mutation in phage gene uvsX or uvsY essentially blocked the integration of a plasmid with homology to the T4 genome but no phage replication origin (non-origin plasmid). The strict requirement for these two proteins suggests that plasmid integration can proceed via a strand-invasion reaction similar to that catalyzed in vitro by the T4-encoded strand-exchange protein (UvsX) in concert with UvsY and gp32. In contrast to the results with the non-origin plasmid, a mutation in uvsX or uvsY reduced the integration of a T4 replication origin-containing plasmid by only 3-10-fold. These results suggest that the origin-containing plasmid integrates by both the UvsXY-dependent pathway used by the non-origin plasmid and by a UvsXY-independent pathway. The origin-containing plasmid integrated into the phage genome during a uvsX- or uvsY-mutant infection of a recA-mutant host, and therefore origin-dependent integration can occur in the absence of both phage- and host-encoded strand-exchange proteins (UvsX and RecA, respectively).
authors.affiliation: Department of Microbiology, Duke University Medical Center, Durham, North Carolina.
authors.forename: H W
authors.initials: HW
authors.lastname: Kreuzer
authors.forename: K N
authors.initials: KN
authors.lastname: Kreuzer
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000502:physiology*; D017122:Bacteriophage T4 / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics; D016679:Genome, Viral; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D008957:Models, Genetic; D010957:Plasmids / Q000235:genetics*; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic; D014764:Viral Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; D008565:Membrane Proteins; C092863:UvsX protein, Enterobacteria phage T4; C092864:UvsY protein, Enterobacteria phage T4; D014764:Viral Proteins; D011938:Rec A Recombinases; D000251:Adenosine Triphosphatases