title: Identification of Epstein-Barr virus RK-BARF0-interacting proteins and characterization of expression pattern.
abstract: The Epstein-Barr virus (EBV) BamHI A transcripts are a family of transcripts that are differentially spliced and can be detected in multiple EBV-associated malignancies. Several of the transcripts may encode proteins. One transcript of interest, RK-BARF0, is proposed to encode a 279-amino-acid protein with a possible endoplasmic reticulum-targeting sequence. In this study, the properties of RK-BARF0 were examined through identification of cellular-interacting proteins through yeast two-hybrid analysis and characterization of its expression in EBV-infected cells and tumors. In addition to the interaction previously identified with cellular Notch, it was determined that RK-BARF0 also bound cellular human I-mfa domain-containing protein (HIC), epithelin, and scramblase. An interaction between RK-BARF0 and Notch or epithelin induced proteasome-dependent degradation of Notch and epithelin but not of HIC or scramblase. Low levels of endogenous Notch expression in EBV-positive cell lines may correlate with RK-BARF0 expression. However, a screen of EBV-positive cell lines and tumors with an affinity-purified alpha-RK-BARF0 antiserum did not consistently detect RK-BARF0. These data suggest that while RK-BARF0 may have important cellular functions during EBV infection, and while the phenotype of EBV-positive cells suggest its expression, RK-BARF0 levels may be too low to detect.
authors.affiliation: Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. nrt@med.unc.edu
authors.forename: Natalie J
authors.initials: NJ
authors.lastname: Thornburg
authors.forename: Shuichi
authors.initials: S
authors.lastname: Kusano
authors.forename: Nancy
authors.initials: N
authors.lastname: Raab-Traub
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000077155:Granulins; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D046988:Proteasome Endopeptidase Complex / Q000502:physiology; D011485:Protein Binding; D011817:Rabbits; D051880:Receptors, Notch; D014764:Viral Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000077155:Granulins; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C121639:RK-BARF0 protein, Human herpesvirus 4; D051880:Receptors, Notch; D014764:Viral Proteins; D046988:Proteasome Endopeptidase Complex