title: Sequence analysis of Epstein-Barr virus EBNA-2 gene coding amino acid 148-487 in nasopharyngeal and gastric carcinomas.
abstract: BACKGROUND
  The Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA-2) plays a key role in the B-cell growth transformation by initiating and maintaining the proliferation of infected B-cell upon EBV infection in vitro. Most studies about EBNA-2 have focused on its functions yet little is known for its intertypic polymorphisms.
  
  
  RESULTS
  Coding region for amino acid (aa) 148-487 of the EBNA-2 gene was sequenced in 25 EBV-associated gastric carcinomas (EBVaGCs), 56 nasopharyngeal carcinomas (NPCs) and 32 throat washings (TWs) from healthy donors in Northern China. Three variations (g48991t, c48998a, t49613a) were detected in all of the samples (113/113, 100%). EBNA-2 could be classified into four distinct subtypes: E2-A, E2-B, E2-C and E2-D based on the deletion status of three aa (294Q, 357K and 358G). Subtypes E2-A and E2-C were detected in 56/113 (49.6%), 38/113 (33.6%) samples, respectively. E2-A was observed more in EBVaGCs samples and subtype E2-D was only detected in the NPC samples. Variation analysis in EBNA-2 functional domains: the TAD residue (I438L) and the NLS residues (E476G, P484H and I486T) were only detected in NPC samples which located in the carboxyl terminus of EBNA-2 gene.
  
  
  CONCLUSIONS
  The subtypes E2-A and E2-C were the dominant genotypes of the EBNA-2 gene in Northern China. The subtype E2-D may be associated with the tumorigenesis of NPC. The NPC isolates were prone harbor to more mutations than the other two groups in the functional domains.
authors.affiliation: Department of Medical Microbiology, Qingdao University Medical College, 38 Dengzhou Road, Qingdao 266021, China.
authors.forename: Xinying
authors.initials: X
authors.lastname: Wang
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.forename: Guocai
authors.initials: G
authors.lastname: Wu
authors.forename: Yan
authors.initials: Y
authors.lastname: Chao
authors.forename: Zhifu
authors.initials: Z
authors.lastname: Sun
authors.forename: Bing
authors.initials: B
authors.lastname: Luo
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D002277:Carcinoma / Q000821:virology*; D019309:Epstein-Barr Virus Nuclear Antigens / Q000737:chemistry* / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000821:virology*; D011110:Polymorphism, Genetic; D017434:Protein Structure, Tertiary; D017422:Sequence Analysis, DNA; D013274:Stomach Neoplasms / Q000821:virology*; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics*
chemical_list: C402641:EBNA-2 protein, Human herpesvirus 4; D019309:Epstein-Barr Virus Nuclear Antigens; D014764:Viral Proteins