title: Identification of DNA-damage DNA-binding protein 1 as a conditional essential factor for cytomegalovirus replication in interferon-γ-stimulated cells.
abstract: The mouse cytomegaloviral (MCMV) protein pM27 represents an indispensable factor for viral fitness in vivo selectively, antagonizing signal transducer and activator of transcription 2 (STAT2)-mediated interferon signal transduction. We wished to explore by which molecular mechanism pM27 accomplishes this effect. We demonstrate that pM27 is essential and sufficient to curtail the protein half-life of STAT2 molecules. Pharmacologic inhibition of the proteasome restored STAT2 amounts, leading to poly-ubiquitin-conjugated STAT2 forms. PM27 was found in complexes with an essential host ubiquitin ligase complex adaptor protein, DNA-damage DNA-binding protein (DDB) 1. Truncation mutants of pM27 showed a strict correlation between DDB1 interaction and their ability to degrade STAT2. SiRNA-mediated knock-down of DDB1 restored STAT2 in the presence of pM27 and strongly impaired viral replication in interferon conditioned cells, thus phenocopying the growth attenuation of M27-deficient virus. In a constructive process, pM27 recruits DDB1 to exploit ubiquitin ligase complexes catalyzing the obstruction of the STAT2-dependent antiviral state of cells to permit viral replication.
authors.affiliation: Institute for Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
authors.forename: Mirko
authors.initials: M
authors.lastname: Trilling
authors.forename: Vu Thuy Khanh
authors.initials: VT
authors.lastname: Le
authors.forename: Manuela
authors.initials: M
authors.lastname: Fiedler
authors.forename: Albert
authors.initials: A
authors.lastname: Zimmermann
authors.forename: Elke
authors.initials: E
authors.lastname: Bleifuss
authors.forename: Hartmut
authors.initials: H
authors.lastname: Hengel
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000502:physiology*; D003586:Cytomegalovirus Infections / Q000235:genetics / Q000473:pathology / Q000821:virology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D051379:Mice; D018345:Mice, Knockout; D008954:Models, Biological; D041681:NIH 3T3 Cells; D014162:Transfection; D014779:Virus Replication / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; C490415:Ddb1 protein, mouse; D007371:Interferon-gamma