Nucleotide sequence and mutational analysis of an immunity repressor gene from Bacillus subtilis temperate phage phi 105.
We have identified and sequenced a bacteriophage phi 105 gene encoding an immunity repressor, the first to be characterized from a temperate phage infecting a Gram-positive host. Using superinfection immunity as an assay for repressor function, the phi 105 repressor gene was located within a 740-bp PvuII-HindIII subfragment near the left end of the phi 105 EcoRI-F fragment. We show that the repressor is specified by the 5'-proximal coding sequence of a translationally overlapping gene pair, transcribed from right to left on the conventional phi 105 map. Comparison of its amino acid sequence (146 residues) with that of a large number of Gram-negative bacterial and phage repressors revealed a putative DNA-binding region between positions 20 and 39. The coding region is preceded by a strong Shine-Dalgarno sequence 5' AAAGGAG 3'. Deletion analysis of the 5'-flanking DNA allowed to identify transcriptional control elements. Their structure, 5' TTGTAT 3' at -35 and 5' TATAAT 3' at -10, strongly suggests that the phi 105 repressor gene is transcribed by the major vegetative form of B. subtilis RNA polymerase, as would be expected for an early phage gene.
Dhaese
P
P
Seurinck
J
J
De Smet
B
B
Van Montagu
M
M
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000276:immunology; D001435:Bacteriophages / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D003062:Codon; D004262:DNA Restriction Enzymes; D004274:DNA, Recombinant; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism; D005814:Genes, Viral; D010957:Plasmids; D011487:Protein Conformation; D012097:Repressor Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
D003062:Codon; D004274:DNA, Recombinant; D004279:DNA, Viral; D012097:Repressor Proteins; D014157:Transcription Factors; D004262:DNA Restriction Enzymes