L Thomason | PubMed Health

PubMed2001

Growth and recombination of phage lambda in the presence of exonuclease V from Bacillus subtilis.

When expressed in Escherichia coli, the AddAB exonuclease/recombinase from Bacillus subtilis blocks the growth of phage lambda. Mutants of lambda that are deleted for ea47, a gene of unknown function which is expressed early in the lytic cycle, are not blocked for growth. The blocked-growth phenotype of lambda ea47+ in the presence of AddAB is expressed only when phage DNA replication is permitted.

Bacillus subtilis↗

PubMed1997

Annealing vs. invasion in phage lambda recombination.

Genetic recombination catalyzed by lambda's Red pathway was studied in rec+ and recA mutant bacteria by examining both intracellular lambda DNA and mature progeny particles. Recombination of nonreplicating phage chromosomes was induced by double-strand breaks delivered at unique sites in vivo. In rec+ cells, cutting only one chromosome gave nearly maximal stimulation of recombination; the recombinants formed contained relatively short hybrid regions, suggesting strand invasion. In contrast, in recA mutant cells, cutting the two parental chromosomes at non-allelic sites was required for maximal stimulation; the recombinants formed tended to be hybrid over the entire region between the two cuts, implying strand annealing. We conclude that, in the absence of RecA and the presence of non-allelic DNA ends, the Red pathway of lambda catalyzes recombination primarily by annealing.

Alleles↗