Genetic and Biochemical Strategies to Elucidate the Architecture and Targets of a Processive Transcription Antiterminator from Bacteriophage Lambda

Abstract

Publisher Summary This chapter discusses the genetic and biochemical strategies to elucidate the architecture and targets of a processive transcription antiterminator from bacteriophage lambda. Antitermination of transcription is a gene activation mechanism by which cells regulate genes in response to environmental and developmental cues. This chapter discusses the strategies involved and the genetic and biochemical methods used to elucidate the architecture of N protein and its interaction with the various targets. A remarkable feature of antitermination in different lambdoid phages is their demonstrated genome specificity: N and Q proteins act preferentially on the cognate genomes to turn on the early and the late operons, respectively. Although the lambda N protein has served as an important model for understanding the basic mechanisms of processive antitermination, the homologous proteins from lambda's cousins show considerable variation in primary structures. Like the studies of different repressors and activators, a molecular genetic analysis of some of these N protein homologs (from P21 and Phi-80, for example) promises to reveal interesting variations in terms of the basic mechanisms by which RNA polymerase is transformed to a termination- resistant state. At the same time, these studies would provide a better understanding of the structure-function of RNA polymerase itself.