Cloning and characterization of transcriptional promoters fromBacillus subtilisphage 2C

Abstract

Phage 2C is a Bacillus subtilis lytic phage, whose genome contains hydroxymethyluracil in place of thymine. To isolate promoters of early phage genes involved in the take-over of cellular metabolism, 2C DNA libraries were constructed in promoter-probe plasmids replicating in Escherichia coli and B. subtilis. Four different 2C DNA fragments strongly expressed reporter genes in E. coli but not in B. subtilis. All fragments originated from unique sequences of the genome and not from its terminal redundancies. One fragment was sequenced. Despite the presence of an σA-RNA polymerase binding site upstream of the transcriptional initiation site of a 2C early gene, this fragment did not promote transcription in B. subtilis.Key words: hydroxymethyluracil, lytic phage, promoter-probe plasmid, Bacillus subtilis, gene expression.