title: Epstein-Barr virus encoded nuclear protein EBNA-3 binds XAP-2, a protein associated with Hepatitis B virus X antigen.
abstract: EBNA-3 (also called EBNA-3A) is one of the EBV encoded nuclear antigens that are necessary for B-cell transformation. EBNA-3 is known to target RBPs, nuclear proteins that also interacts with EBNA-2, EBNA-4 and EBNA-6. In order to identify additional EBNA-3 targets, an EBV-transformed human lymphocyte cDNA library was screened in the yeast two-hybrid system with N-terminus truncated EBNA-3 that cannot interact with RBP-Jkappa. A clone, encoding Xap-2 protein, a cellular partner of Hepatitis B virus X-antigen was isolated. This protein is also known as the p38 subunit of the aryl hydrocarbon receptor complex (ARA9). The specific binding to EBNA-3 was confirmed by showing that the GST-Xap-2 precipitated EBNA-3 from CV1 cells that were infected with recombinant vaccinia virus expressing EBNA-3. Deletion of the C-terminus of Xap-2 eliminated the binding. Fusion with green fluorescent protein showed that Xap-2 is preferentially cytoplasmic but translocates to the nucleus upon expression of EBNA-3.
authors.affiliation: Microbiology and Tumor Biology Centre (MTC) Karolinska Institute, Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Kashuba
authors.forename: V
authors.initials: V
authors.lastname: Kashuba
authors.forename: K
authors.initials: K
authors.lastname: Pokrovskaja
authors.forename: G
authors.initials: G
authors.lastname: Klein
authors.forename: L
authors.initials: L
authors.lastname: Szekely
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002461:Cell Line, Transformed; D018076:DNA, Complementary; D019309:Epstein-Barr Virus Nuclear Antigens / Q000235:genetics / Q000378:metabolism*; D006511:Hepatitis B Antigens / Q000378:metabolism*; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008969:Molecular Sequence Data; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism*; D013347:Subcellular Fractions; D015534:Trans-Activators / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D002352:Carrier Proteins; D018076:DNA, Complementary; D019309:Epstein-Barr Virus Nuclear Antigens; D006511:Hepatitis B Antigens; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins; D018336:Receptors, Aryl Hydrocarbon; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C103265:aryl hydrocarbon receptor-interacting protein; C057628:hepatitis B virus X protein