EBNA-2 and EBNA-3C extensively and mutually exclusively associate with RBPJkappa in Epstein-Barr virus-transformed B lymphocytes.
Although genetic and biochemical data indicate that the cell protein RBPJkappa is a mediator of EBNA-2 and EBNA-3C effects on transcriptional regulatory elements, the extent of association of these Epstein-Barr virus nuclear proteins with RBPJkappa in transformed B lymphocytes has not been determined. We now report that most of the EBNA-2 and at least 20% of the EBNA-3C coimmunoprecipitated with RBPJkappa from extracts of transformed B lymphocytes that contained most of the cellular EBNA-2 and EBNA3C. Both proteins are associated preferentially with the smaller of the two RBPJkappa isoforms. EBNA-2-RBPJkappa complexes do not contain EBNA-3C, and EBNA-3C-RBPJkappa complexes do not contain EBNA-2. Although EBNA-2 and EBNA-3C are extensively associated with RBPJkappa, a fraction of RBPJkappa appears to be free of EBNAs after repeated immunoprecipitations with anti-EBNA, Epstein-Barr virus-immune, human antibody. Promoters with RBPJkappa sites in their regulatory elements are likely to be differentially regulated by these RBPJkappa-EBNA-2 and RBPJkappa-EBNA-3 complexes.
Johannsen
E
E
Department of Microbiology and Molecular Genetics, Harvard University, Boston, Massachusetts 02115, USA.
Miller
C L
CL
Grossman
S R
SR
Kieff
E
E
D000956:Antigens, Viral / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D019309:Epstein-Barr Virus Nuclear Antigens; D004854:Herpesvirus 4, Human / Q000502:physiology*; D006801:Humans; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D008213:Lymphocyte Activation; D009687:Nuclear Proteins; D011233:Precipitin Tests
D000956:Antigens, Viral; D004268:DNA-Binding Proteins; D019309:Epstein-Barr Virus Nuclear Antigens; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D009687:Nuclear Proteins; C497570:RBPJ protein, human