Genes of coliphage T1 whose products promote general recombination.
The RecE bacterial recombination pathway, expressed in strains carrying a sbcA mutation, can substitute for the function of gene 4 of phage T1. RecE will also substitute for the function of a newly discovered phage gene, 3.5. Like mutants in gene 4, gene 3.5 mutants have a DA (DNA synthesis arrest) phenotype under nonpermissive conditions. In addition to their effects on DNA synthesis, mutations in genes 3.5 and 4 profoundly depress recombination in T1. Inhibition of DNA synthesis by nalidixic acid does not effect the frequency of recombinants among the small population of progeny phage that are produced. Isolation of T1 mutants dependent on the RecE function has yielded additional mutants specifically in genes 3.5 and 4. Together, these results are interpreted to mean that these two phage genes encode components of a general recombination system, referred to as T1 Grn. During replication of T1 in conventional hosts the essential function of this system is to provide for the formation, via recombination, of concatameric DNA molecules, which are the substrates for the packaging of DNA into T1 heads.
Ritchie
D A
DA
Department of Genetics, University of Liverpool, Liverpool L69 3BX, England.
Christensen
J R
JR
Pugh
J C
JC
Bourquet
L W
LW