title: Conserved cell cycle regulatory properties within the amino terminal domain of the Epstein-Barr virus nuclear antigen 3C.
abstract: The gammaherpesviruses Rhesus lymphocryptovirus (LCV) and Epstein-Barr virus (EBV) are closely related phylogenetically. Rhesus LCV efficiently immortalizes Rhesus B cells in vitro. However, despite a high degree of conservation between the Rhesus LCV and EBV genomes, Rhesus LCV fails to immortalize human B cells in vitro. This species restriction may, at least in part, be linked to the EBV nuclear antigens (EBNAs) and latent membrane proteins (LMPs), known to be essential for B cell transformation. We compared specific properties of EBNA3C, a well-characterized and essential EBV protein, with its Rhesus counterpart to determine whether EBNA3C phenotypes which contribute to cell cycle regulation are conserved in the Rhesus LCV. We show that both EBNA3C and Rhesus EBNA3C bind to a conserved region of mammalian cyclins, regulate pRb stability, and modulate SCF(Skp2)-dependent ubiquitination. These results suggest that Rhesus LCV restriction from human B cell immortalization is independent of the conserved cell cycle regulatory functions of the EBNA3C protein.
authors.affiliation: Department of Microbiology and the Abramson Comprehensive Cancer Center, University of Pennsylvania Medical School, 201E Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104, USA.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Sharma
authors.forename: Jason S
authors.initials: JS
authors.lastname: Knight
authors.forename: Erle S
authors.initials: ES
authors.lastname: Robertson
mesh_terms: D000595:Amino Acid Sequence; D000956:Antigens, Viral / Q000235:genetics / Q000502:physiology*; D001402:B-Lymphocytes / Q000821:virology; D002453:Cell Cycle / Q000502:physiology*; D002460:Cell Line; D017124:Conserved Sequence; D016213:Cyclins / Q000378:metabolism; D019309:Epstein-Barr Virus Nuclear Antigens; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D006801:Humans; D018143:Lymphocryptovirus / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D044786:S-Phase Kinase-Associated Proteins / Q000378:metabolism; D016415:Sequence Alignment; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D014452:Ubiquitins / Q000378:metabolism
chemical_list: D000956:Antigens, Viral; D016213:Cyclins; C498774:EBNA-3C, epstein-barr virus; D019309:Epstein-Barr Virus Nuclear Antigens; D044786:S-Phase Kinase-Associated Proteins; D025521:Tumor Suppressor Proteins; D014452:Ubiquitins