Structural Basis for Promoter Recognition by Pseudomonas Phage DEV Virion Associated RNA Polymerase

Bacteriophage DEV, a member of the Schitoviridae family, encodes a large virion-associated RNA polymerase (vRNAP) and shows significant potential for use in phage therapy. However, many aspects of DEV’s biology remain poorly understood, especially how it regulates transcription once inside the host. Recent work in our lab suggests that gene product 71 (gp71) functions as a DNA- dependent vRNAP. Analogous to the vRNAP of coliphage N4, gp71 likely initiates transcription by recognizing single-stranded DNA templates that contain early gene hairpin promoters. Based on this, my working hypothesis is that specific interactions between gp71 and the DEV early promoters PE1 and PE5 are essential for transcriptional initiation and regulation. The primary goal of this study is to elucidate the structure of gp71 in complex with these promoters and determine how these interactions influence promoter specificity. Understanding this mechanism will shed light on a key step in the DEV replication cycle and deepen our understanding of transcriptional regulation among Schitoviridae phages. Finally, this knowledge could aid in the development of bioengineered phage therapies to combat multidrug-resistant bacterial infections.