Regulation of λ exonuclease synthesis: Role of the N gene product and λ repressor

Abstract

The positive regulatory effect of the N gene product on early λ functions has been studied through its effects on λ exonuclease synthesis. It has been shown that the N product supplied by a superinfecting exonuclease −N + phage to an N − prophage elicits, in trans, exonuclease synthesis only when the prophage repressor has been previously inactivated. The implications of this cis effect of λ repressor on the punctuation signals on λ DNA and the possible function of N product in modifying “stop signals” for Escherichia coli polymerase are discussed.