title: A phage P1 function that stimulates homologous recombination of the Escherichia coli chromosome.
abstract: Recombination between two different defective lacZ genes in the Escherichia coli chromosome (lac- X lac- recombination) was stimulated 2- to 8-fold by prophage P1, depending on the nature of the phage c1 repressor. The P1 BamHI restriction fragment B8 in a lambda-P1:B8 hybrid phage, stimulated lac- X lac- recombination 90-fold in the absence of P1 repressor. A gene necessary for recombination enhancement, designated ref, was localized to one end of B8. Ref expression from lambda-P1:B8 was repressed in trans by a P1 c+ prophage. Two P1 regulatory mutations, bof and lxc, derepressed prophage expression of ref and depressed a prophage function that complemented an E. coli mutant (ssb) deficient in the single-stranded DNA binding protein. Ref stimulation was dependent on preexisting E. coli recombination functions (RecA-RecBC and RecA-RecF). However, other (phage and plasmid) recombination processes involving these functions were not stimulated. ref::Tn5 phages plated and formed lysogens normally. Thus ref appears to be an integral, but not essential, phage gene that stimulates recombination of the host chromosome specifically.
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial / Q000502:physiology; D003090:Coliphages / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000235:genetics; D005786:Gene Expression Regulation; D005814:Genes, Viral; D005816:Genetic Complementation Test; D008242:Lysogeny; D011938:Rec A Recombinases / Q000235:genetics; D011995:Recombination, Genetic; D014779:Virus Replication
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004279:DNA, Viral; D029968:Escherichia coli Proteins; D011938:Rec A Recombinases; D005090:Exodeoxyribonucleases; D043211:Exodeoxyribonuclease V; C468322:exodeoxyribonuclease V, E coli