Control of gene expression in the P2-related temperate coliphages. IV. Concerning the late control gene and control of its transcription.
In this paper we have sequenced four amber mutants and thereby confirmed the gene D (CP65) and gene B (CP67) assignments made in the accompanying paper (Kalionis et al., 1986). We have also studied, by gel electrophoresis, the transcription patterns of gene B in vivo. In a lysogen, gene B is present on a short transcript under autogenous (negative) control. Upon prophage induction, this transcript is amplified, but later in the cycle gene B is present on a larger transcript that originates in the late region. We have detected two copies of an inverted repeat in the promoter region of the B gene that we predict is recognized by the B protein. One arm of this repeat is associated with three of four P2 late promoters, downstream from the start point of transcription. The repeat is not present in the promoter region of P2 ogr. We describe the considerable homology in amino acid sequence seen with the late control proteins 186 gpB, P4 gp delta and P2 gpOgr, and present a working model for control of late gene transcription.
D000595:Amino Acid Sequence; D001483:Base Sequence; D003090:Coliphages / Q000235:genetics*; D005786:Gene Expression Regulation; D005814:Genes, Viral; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D014158:Transcription, Genetic; D014775:Virus Activation