title: The c1 genes of P1 and P7.
abstract: The c1 genes of the heteroimmune phages P1 and P7 were sequenced and their products were compared. P7c1 expression was correlated with the translation in vitro of a protein whose predicted molecular weight (33,000 daltons) is indistinguishable from that of the P1c1 repressor. The c1 regions from both P1 and P7 were found to contain open reading frames capable of coding for a 283-amino acid protein whose predicted secondary structure lacks the helix-turn-helix motif commonly associated with repressor proteins. Two P1c1 amber mutations were localized to the 283-amino acid open reading frame. The P1c1 and P7c1 sequences were found to differ at only 18 positions, all but two of which alter the third position of the affected codon and do not alter the amino acid sequence of the protein. Plasmids expressing the c1 gene from either phage cause the repression of transcription from a cloned promoter situated upstream of P1c1.
authors.affiliation: Department of Biology, Georgia State University, Atlanta 30303.
authors.forename: F A
authors.initials: FA
authors.lastname: Osborne
authors.forename: S R
authors.initials: SR
authors.lastname: Stovall
authors.forename: B R
authors.initials: BR
authors.lastname: Baumstark
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003090:Coliphages / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics*; D005814:Genes, Viral; D008242:Lysogeny; D008969:Molecular Sequence Data; D010641:Phenotype; D010957:Plasmids; D014176:Protein Biosynthesis; D012097:Repressor Proteins / Q000235:genetics*; D015183:Restriction Mapping; D014157:Transcription Factors / Q000235:genetics*; D015678:Viral Structural Proteins / Q000235:genetics*
chemical_list: D012097:Repressor Proteins; D014157:Transcription Factors; D015678:Viral Structural Proteins