[Effect of superhelical DNA on the transcription of cloned genes of the T4 phage].

The effect of DNA superhelicity on the transcription of T4 DNA fragments containing early genes uvs W, Y and late genes 25-29 was studied. RNA polymerase transcribes both early and late phage genes within the supercoiled recombinant plasmid. Late genes relative transcription increases essentially when T4-modified RNA polymerase is used.

[The region of phage T4 W-29 genes: cloning and expression].

The EcoRI fragment of T4 DNA containing the W-29 genes and its subfragments were cloned in the pBR322 and the singlestranded M13 phage. Hybridization with a cloned DNA showed that in T4 infected cells the transcription of the late genes 25-29 depends on the phage-induced RNA polymerase changes and on replication of phage DNA. At a late infection stage one also observes an enhanced transcription of the (early) genes uvsW and uvsY, which depends on viral DNA replication.