title: Host RNA polymerase inhibitors encoded by ϕKMV-like phages of Pseudomonas.
abstract: Escherichia coli bacteriophage T7 is a founding member of a large clade of podoviruses encoding a single-subunit RNA polymerase (RNAP). Phages of the family rely on host RNAP for transcription of early viral genes; viral RNAP transcribes non-early viral genes. T7 and its close relatives encode an inhibitor of host RNAP, the gp2 protein. Gp2 is essential for phage development and ensures that host RNAP does not interfere with viral RNAP transcription at late stages of infection. Here, we identify host RNAP inhibitors encoded by a subset of T7 clade phages related to ϕKMV phage of Pseudomonas aeruginosa. We demonstrate that these proteins are functionally identical to T7 gp2 in vivo and in vitro. The ability of some Pseudomonas phage gp2-like proteins to inhibit RNAP is modulated by N-terminal domains, which are absent from the T7 phage homolog. This finding indicates that Pseudomonas phages may use external or internal cues to initiate inhibition of host RNAP transcription and that gp2-like proteins from these phages may be receptors of these cues.
authors.affiliation: Institutes of Molecular Genetics and Gene Biology of the Russian Academy of Sciences, Moscow, Russia.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Klimuk
authors.forename: Natalia
authors.initials: N
authors.lastname: Akulenko
authors.forename: Kira S
authors.initials: KS
authors.lastname: Makarova
authors.forename: Pieter-Jan
authors.initials: PJ
authors.lastname: Ceyssens
authors.forename: Ivan
authors.initials: I
authors.lastname: Volchenkov
authors.forename: Rob
authors.initials: R
authors.lastname: Lavigne
authors.forename: Konstantin
authors.initials: K
authors.lastname: Severinov
mesh_terms: D017123:Bacteriophage T7 / Q000235:genetics* / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D004926:Escherichia coli / Q000821:virology; D005814:Genes, Viral; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D017105:Pseudomonas Phages / Q000235:genetics* / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000821:virology*; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D014158:Transcription, Genetic; D014764:Viral Proteins
chemical_list: D004791:Enzyme Inhibitors; D012097:Repressor Proteins; D014764:Viral Proteins; C120334:gene 2 product, bacteriophage T7; D012321:DNA-Directed RNA Polymerases