Characterization of two early promoters of cyanophage N-1

Restriction fragments of cyanophage N-1 DNA, containing genes transcribed early in infection of Anabaena, were identified by hybridization with RNA prepared from infected cells. Two of these fragments were isolated by binding to Anabaena RNA polymerase on filters and were subsequently cloned. The start sites for transcription by Anabaena RNA polymerase were determined by run-off assays. The sequences of the two promoter regions thus localized were similar to each other in the -35 and -10 regions and nearly identical to the consensus sequence for promoters in Escherichia coli.