GSBS Student Publications


Superinfection exclusion (sieB) genes of bacteriophages P22 and lambda

GSBS Program

Biochemistry & Molecular Pharmacology

UMMS Affiliation

Department of Molecular Genetics and Microbiology



Document Type


Medical Subject Headings

Amino Acid Sequence; Bacteriophage P22; Bacteriophage lambda; Base Sequence; Gene Deletion; Genes, Viral; Molecular Sequence Data; Open Reading Frames; Promoter Regions (Genetics)


Life Sciences | Medicine and Health Sciences


The superinfection exclusion gene (sieB) of Salmonella phage P22 was mapped with phage deletion mutants. The DNA sequence in the region was reexamined in order to find an open reading frame consistent with the deletion mapping. Several discrepancies with the previously published sequence were discovered. The revised sequence revealed a single open reading frame of 242 codons with six likely translation initiation codons. On the basis of deletion and amber mutant phenotypes, the second of these six sites was inferred to be the translation initiation site of the sieB gene. The sieB gene encodes a polypeptide with 192 amino acid residues with a calculated molecular weight of 22,442, which is in reasonable agreement with that estimated from polyacrylamide gels. The transcription start site of sieB was identified by the use of an RNase protection assay. The sieB promoter thus identified was inactivated by a 2-base substitution in its -10 hexamer. The sieB gene of coliphage lambda was also identified. The promoter for lambda sieB was identified by homology to that of P22 sieB.

Rights and Permissions

Citation: J Bacteriol. 1993 Aug;175(15):4712-8.

Related Resources

Link to article in PubMed

Journal Title

Journal of bacteriology

PubMed ID