title: Complementation of bacteriophage induction and recombination defects in Escherichia coli RecA(-) mutants by expression of the cloned T4 bacteriophage uvsX gene.
abstract: Previous workers reported that the T4 bacteriophage UvsX protein could promote neither RecA-LexA-mediated DNA repair nor induction of lysogenized bacteriophage, only recombination. Reexamination of these phenotypes demonstrated that, in contrast to these prior studies, when this gene was cloned into a medium but not a low-copy-number vector, it stimulated both a high frequency of spontaneous induction and mitomycin C-stimulated bacteriophage induction in a strain containing a recA13 mutation, but not a recA1 defect. The gene when cloned into a low- or medium- copy-number vector also promoted a low frequency of recombination of two duplicated genes in Escherichia coli in a strain with a complete recA gene deletion. These results suggest that a narrow concentration range of T4 UvsX protein is required to promote both high-frequency spontaneous and mitomycin C-stimulated bacteriophage induction in a recA13 gene mutant, but it facilitates recombination of duplicated genes at only a very low frequency in E. coli RecA(-) mutants with a complete recA deletion. These results also suggest that the different UvsX phenotypes are affected differentially by the concentration of UvsX protein present.
authors.affiliation: Department of Biology, Indiana University and Purdue University, Fort Wayne, Fort Wayne, IN 46805-1499, USA. kuhls@ipfw.edu
authors.forename: Steven A
authors.initials: SA
authors.lastname: Kuhl
authors.forename: Jay A
authors.initials: JA
authors.lastname: Zimmer
authors.forename: Pratik
authors.initials: P
authors.lastname: Rohatgi
mesh_terms: D017122:Bacteriophage T4 / Q000235:genetics / Q000502:physiology*; D002876:Chromosomes, Bacterial; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000821:virology; D018628:Gene Dosage; D005816:Genetic Complementation Test; D008242:Lysogeny; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010957:Plasmids; D011938:Rec A Recombinases / Q000235:genetics* / Q000378:metabolism; D011995:Recombination, Genetic; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014775:Virus Activation
chemical_list: D004268:DNA-Binding Proteins; D008565:Membrane Proteins; C092863:UvsX protein, Enterobacteria phage T4; D014764:Viral Proteins; D011938:Rec A Recombinases