In vivo and in vitro activities of the bacteriophage T4 early promoters

Abstract

After infection, bacteriophage T4 redirects transcriptional machinery of Escherichia coli to T4 promoters. Because of the sequence properties, T4 early promoters are stronger than E. coli promoters. In this work, we studied the deviations from the consensus sequence that exist among T4 early promoters and the factors that determine their activity. We selected putative early promoter sequences from the early regions of T4 genome and tested them for their activities in vivo and in vitro. Two of the sequences tested were found to be active in vivo. Thus, we mapped two new early promoters on the T4 genome. In vitro transcription analysis of the promoter-like sequences that were inactive during phage infection shows that the presence of glucosylated hydroxymethylcytosines in phage DNA may modulate promoter activity in vivo. Keywords: bacteriophage T4, early promoters, transcription, consensus sequence