DNA sequence of the int-xis-P1 region of the bacteriophage lambda; overlap of the int and xis genes

Abstract

The DNA sequence of the int and xis genes of lambda bacteriophage, as well as that of the P1 promoter and a region of unknown function beyond this, was determined by the chain teimination procedure. The Pribnow box sequence of the P1 promoter lies just within the xis gene, and both possible sites of mRNA initiation from P1 are within tHe xis gene. The end of the xis gene in its turn overlaps the start of the int gene by 23 base pairs, in a different reading frame. This overlap may play a role in ensuring efficient excision of the prophage in response to natural induction signals. © 1980 IRL Press Limited.