New genes and promoters suggested by the DNA sequence near the end of the coliphage T7 early operon

Abstract

We have employed the dideoxynucleotide chain-terminating method to deter-mine the nucleotide sequence of T7 DNA between the physical map positions 18.9% and 19.8%. The most striking features of this sequence are two perfect 21-basepair repeats, each of which appears to contain a promoter for late transcription. In each case the promoter sequence incorporates a putative translational terminator on its left (5′-side of the “sense” strand), and overlaps a potential rihosome-binding site on its right. The region probably lies immediately distal to the early operon, and may contain two short, hitherto unreported protein-coding sequences.