Sequence analysis and variation of EBNA-1 in Epstein-Barr virus-related herpesvirus of cynomolgus monkey

Objectives:The Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA-1) is an im portant protein for immortalization and tumorigenesis of infected cells. EB NA-1 gene variants may play a role in tumorigenesis. We determined the nucl eotide and amino acid (aa) sequences of EBNA-1 in EBV-related herpesviruses from cynomolgus monkeys (cynomolgus-EBV) which induced malignant lymphomas in its natural host and in rabbits, and compared them with sequences of EB V and other lymphocryptoviruses (LCVs). Methods: Polymerase chain reaction and direct sequencing methods were performed using extracted DNA from cynom olgus-EBV-infected cell lines. Results: The amino acid sequences of cynomol gus-EBV EBNA-1 from two cell lines (SI-IIA: 588 aa; Ts-BG: 619 aa) which ar e antigenically cross-reactive to human EBV EBNA-1 showed homology with hum an EBV (SI-IIA: 53%; Ts-BG: 58%) and other LCVs from baboons (54 and 52%) a nd rhesus monkeys (60 and 58%), especially in the C-terminal unique domain. Homology of the EBNA-1 sequence between SI-IIA and Ts-BG was 92%. The sequ ence difference between EBV and the related LCVs was manifested mainly in t he length of the internal repeat 3-corresponding region, which contains ser ine in the glycine/alanine repeat region of nonhuman LCVs. Conclusion: Sequ ence variation of cynomolgus-EBV EBNA-1 from different cell lines was obser ved. However, their sequences show a relatively high homology with human EB V and share the common features of EBNA-1 of EBV and other LCVs. Copyright (C) 2000 S. Karger AG, Basel.