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Abstract: Epstein-Barr virus (EBV) BZLF1 gene can trigger EBV from latent infection to lytic replicative phase. The functions of BZLF1 are well known, while little is known about its gene polymorphism. In order to elucidate the sequence variations of BZLF1 and its association with malignancies, we analyzed BZLF1 gene in 24 EBV-associated gastric carcinomas, 41 nasopharyngeal carcinomas and 24 throat washing samples from healthy donors in Northern China using PCR-direct sequencing method. Three types and 8 subtypes of BZLF1 were identified. A dominant type BZLF1-A was found in 67 of 89 (75.3%) isolates. Type BZLF1-B was characterized by a common Ala deletion at residue 127, which was detected in 21 of 89 isolates (23.6%). Type BZLF1-C contained only one isolate (GC103), which had the same sequence with the prototype B95-8. Among 3 functional domains of BZLF1 protein, the transactivation domain had most mutations, followed by the bZIP domains (the DNA binding domain and dimerization domain). No prevalence of any subtypes or mutations in the functional domains among three specimen groups was found (P > 0.05). Our study indicates that BZLF1 subtypes and amino acid changes in functional domains are not preferentially associated with EBV-associated gastric carcinomas or nasopharyngeal carcinomas in Northern China. BZLF1 gene variations are geographically restricted rather than tumor-specific polymorphisms. [Copyright &y& Elsevier]

As a member of the Bam HI-A rightward transcripts family of the Epstein-Barr virus (EBV), RPMS1 expression has been confirmed in all EBV-associated tumors. However, few studies have investigated the single-nucleotide polymorphisms (SNPs) of RPMS1 , and only one SNP site (g155391a) has been reported to be associated with nasopharyngeal carcinoma occurrence. The objective of this study was to investigate the polymorphism of RPMS1 in EBV-associated tumors (gastric carcinoma, nasopharyngeal carcinoma, and lymphoma). In this research, nested-PCR was performed to analyze DNA sequences of 420 EBV-associated samples. Phylogenetic analysis revealed four RPMS1 genotypes (RPMS1-A, RPMS1-B, RPMS1-C, and RPMS1-D). A significant difference ( p  < 0.05) among northern and southern China samples was observed. Furthermore, there was a significant difference between EBV-associated tumors and healthy controls for RPMS1 ( p  < 0.05). These findings demonstrated that RPMS1 variation was not only tumor-specific but also geographically restricted in EBV-associated samples. [ABSTRACT FROM AUTHOR]

Abstract: The Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1), the only viral protein consistently expressed in all EBV-associated tumors, is classified into five distinct subtypes: P-ala, P-thr, V-leu, V-val and V-pro based on the signature changes at amino acid residue 487. By now, whether the EBNA1 subtypes preferentially associate with particular malignancies or represent geographical polymorphism remains controversial. In China, most studies of the EBNA1 variations focused on nasopharyngeal carcinoma (NPC) in endemic area, among which some suggested the V-val subtype is preferentially associated with NPC. To characterize the variations of EBNA1 in NPC non-endemic area in China and to explore the association of EBNA1 variations with EBV-associated gastric carcinoma (EBVaGC) and NPC, the C-terminal sequences of EBNA1 were analyzed for 41 EBVaGC, 41 NPC biopsies and 55 throat washing (TW) samples from healthy donors in Northern China. Three major patterns of the EBNA1 variations, V-val, P-thrV and V-leuV, were observed, and V-val was the most common subtype in all the three groups, followed by P-thrV and V-leuV. The distribution of the EBNA1 subtypes among EBVaGC, NPC and healthy donors was not significantly different (P >0.05). In addition, preferential linkages between EBNA1 subtypes and EBNA3C variants were found to exist. There was no evidence that particular EBNA1 subtypes are preferentially associated with EBVaGC or NPC in Northern China, suggesting that EBNA1 gene variations are geographically restricted rather than tumor-specific polymorphisms. [Copyright &y& Elsevier]