CONVERGENT TRANSCRIPTION IN BACTERIOPHAGE-LAMBDA - INTERFERENCE WITH GENE-EXPRESSION

λtrp transducing phages have been used to study the effects of convergent transcription between the trp and λPL promoters. Gene expression directed by both promoters is mutually impaired, that from the trp promoter being totally blocked. The interference with expression from the trp promoter is rapidly alleviated once opposing transcription from PL is turned off. We propose that collision of RNA polymerase molecules moving in opposing directions can terminate transcription. This transcriptional interference may result in a complete block in gene expression or it may merely reduce and delay expression. Modification of RNA polymerase by the λN protein is not a requirement for transcriptional interference. The application of these results to provide a mechanism for how lambda decides whether to enter the lysogenic or lytic pathways is discussed. © 1979.