The SOS system of Escherichia coli in the regulation of bacteriophage λ development

Abstract
A sequence homologous to the known SOS boxes is found in the Po promoter of phage λ. It is suggested that the sequence found is a binding site for the LexA repressor. The mechanism of the LexA part in regulation of λ development is discussed. It is based on the competitive transcription of the RNA encoding CII protein and the short OOP‐RNA transcribed from the Po promoter.