Bacteriophage lambda provides continuingly evolving grounds for molecular biological research.
A particular line of interest has been a mode of transcription regulation peculiar to lambda and its many relatives. To overcome these barriers, each of the lambdoid phages provides two proteins whose role is to prevent transcription termination. One of these, the 'N' protein, functions by connecting with a particular sequence in the early RNA transcripts, then engaging four 'Nus' proteins of its host, Escherichia coli, and through the Nus proteins the cistranscribing RNA polymerase itself. This transcription elongation complex is stable over long distances and blind to all known transcription terminators. The anti-termination mechanism ensures complete transcription of the phage genome.