RNA polymerase structure and function

Bacteriophages provide a convenient "window" into mechanisms of transcriptional control involving the interaction of phage-encoded factors with the host RNA polymerase. Our studies have focused on two subunits of eubacterial RNA polymerase originally implicated by mutations conferring a block to growth of phage P2. The α subunit of RNA polymerase is involved in activation of phage late gene transcription by the P2 Ogr family of transcription factors. Site-directed mutagenesis and in vitro transcription studies have allowed us to define those residues on the surface of α that are required for this interaction. Additional studies have focused on a C-terminal deletion of the β' subunit of RNA polymerase that affects the action of proteins modulating the timing of lysis during phage infection. This mutant allowed the identification of an additional lysis accessory gene in P2. We are now trying to understand the change(s) in host gene expression resulting from this mutation in RNA polymerase that lead to the altered lysis characteristics.