title: O-GlcNAc transferase inhibits KSHV propagation and modifies replication relevant viral proteins as detected by systematic O-GlcNAcylation analysis.
abstract: O-GlcNAcylation is an inducible, highly dynamic and reversible post-translational modification, mediated by a unique enzyme named O-linked N-acetyl-d-glucosamine (O-GlcNAc) transferase (OGT). In response to nutrients, O-GlcNAc levels are differentially regulated on many cellular proteins involved in gene expression, translation, immune reactions, protein degradation, protein-protein interaction, apoptosis and signal transduction. In contrast to eukaryotic cells, little is known about the role of O-GlcNAcylation in the viral life cycle. Here, we show that the overexpression of the OGT reduces the replication efficiency of Kaposi's sarcoma-associated herpesvirus (KSHV) in a dose-dependent manner. In order to investigate the global impact of O-GlcNAcylation in the KSHV life cycle, we systematically analyzed the 85 annotated KSHV-encoded open reading frames for O-GlcNAc modification. For this purpose, an immunoprecipitation (IP) strategy with three different approaches was carried out and the O-GlcNAc signal of the identified proteins was properly controlled for specificity. Out of the 85 KSHV-encoded proteins, 18 proteins were found to be direct targets for O-GlcNAcylation. Selected proteins were further confirmed by mass spectrometry for O-GlcNAc modification. Correlation of the functional annotation and the O-GlcNAc status of KSHV proteins showed that the predominant targets were proteins involved in viral DNA synthesis and replication. These results indicate that O-GlcNAcylation plays a major role in the regulation of KSHV propagation.
authors.affiliation: Division of Molecular and Experimental Surgery, University Medical Center Erlangen, Friedrich-Alexander University of Erlangen-Nuremberg, Schwabachanlage 10, 91054 Erlangen, Germany.
authors.forename: Ramona
authors.initials: R
authors.lastname: Jochmann
authors.forename: Jens
authors.initials: J
authors.lastname: Pfannstiel
authors.forename: Priya
authors.initials: P
authors.lastname: Chudasama
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kuhn
authors.forename: Andreas
authors.initials: A
authors.lastname: Konrad
authors.forename: Michael
authors.initials: M
authors.lastname: Stürzl
mesh_terms: D057809:HEK293 Cells; D019288:Herpesvirus 8, Human / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics / Q000378:metabolism*; D016366:Open Reading Frames; D014764:Viral Proteins / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D014764:Viral Proteins; D017351:N-Acetylglucosaminyltransferases
keywords: DNA replication; DNA synthesis; KSHV; Kaposi's sarcoma; O-GlcNAc