title: Overexpression of Escherichia coli udk mimics the absence of T7 Gp2 function and thereby abrogates successful infection by T7 phage.
abstract: Successful infection of Escherichia coli by bacteriophage T7 relies upon the transcription of the T7 genome by two different RNA polymerases (RNAps). The bacterial RNAp transcribes early T7 promoters, whereas middle and late T7 genes are transcribed by the T7 RNAp. Gp2, a T7-encoded transcription factor, is a 7 kDa product of an essential middle T7 gene 2, and is a potent inhibitor of the host RNAp. The essential biological role of Gp2 is to inhibit transcription of early T7 genes that fail to terminate efficiently in order to facilitate the coordinated usage of the T7 genome by both host and phage RNAps. Overexpression of the E. coli udk gene, which encodes a uridine/cytidine kinase, interferes with T7 infection. We demonstrate that overexpression of udk antagonizes Gp2 function in E. coli in the absence of T7 infection and thus independently of T7-encoded factors. It seems that overexpression of udk reduces Gp2 stability and functionality during T7 infection, which consequently results in inadequate inhibition of host RNAp and in the accumulation of early T7 transcripts. In other words, overexpression of udk mimics the absence of Gp2 during T7 infection. Our study suggests that the transcriptional regulation of the T7 genome is surprisingly complex and might potentially be affected at many levels by phage- and host-encoded factors.
authors.affiliation: Section of Microbiology, Faculty of Medicine and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, SW7 2AZ, UK.
authors.forename: Andrey
authors.initials: A
authors.lastname: Shadrin
authors.affiliation: Section of Microbiology, Faculty of Medicine and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, SW7 2AZ, UK.
authors.forename: Carol
authors.initials: C
authors.lastname: Sheppard
authors.affiliation: Waksman Institute for Microbiology and Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
authors.forename: Dhruti
authors.initials: D
authors.lastname: Savalia
authors.affiliation: Molecular Genetics of the Russian Academy of Sciences, Moscow, Russia.|Gene Biology of the Russian Academy of Sciences, Moscow, Russia.|Waksman Institute for Microbiology and Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Severinov
authors.affiliation: Section of Microbiology, Faculty of Medicine and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, SW7 2AZ, UK.
authors.forename: Sivaramesh
authors.initials: S
authors.lastname: Wigneshweraraj
mesh_terms: D017123:Bacteriophage T7 / Q000254:growth & development*; D004926:Escherichia coli / Q000235:genetics* / Q000821:virology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D015964:Gene Expression Regulation, Bacterial; D015967:Gene Expression Regulation, Viral; D056265:Microbial Interactions; D012097:Repressor Proteins / Q000378:metabolism*; D014541:Uridine Kinase / Q000235:genetics / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C120334:gene 2 product, bacteriophage T7; D014541:Uridine Kinase