Genetic expression in bacteriophage lambda. IV. Effects of P2 prophage on lambda inhibition of host synthesis and lambda gene expression.

The effects of P2 prophage on lambda-mediated depression of host metabolism, and on lambda macromolecular synthesis have been studied. Experiments employing certain lambdabio deletion mutants and lambda-related phages suggest that the same gene products are involved in inhibition of host metabolism (Hin+ function) and susceptibility to P2 inhibition (Spi+ function). Synthesis of early lambda mRNA and protein occurs normally during the first 10 min after lambda infection of P2 lysogens, but subsequent expression of early and late lambda genes is interfered with by the combined actions of the P2 old gene and lambda Hin+ (Spi+) function. In addition, the P2 old+ product enhances the inhibitory effects of lambda Hin+ function on host metabolism, and can substitute for a component of this function lacking in lambdabio 72 and lambdabio 69.