The Epstein-Barr virus EBNA-2 gene in oral hairy leukoplakia: strain variation, genetic recombination, and transcriptional expression.
Oral hairy leukoplakia (HLP) lesions frequently contain defective Epstein-Barr virus (EBV) genomes with deletions in the EBNA-2 gene that abundantly replicate and persist within the lesion. To characterize these viral strains and recombinant variants, the EBNA-2 gene in EBV DNA from several different HLP biopsy specimens was analyzed. Amplification of EBNA-2 coding sequences by PCR demonstrated the presence in HLP of intact EBNA-2 genes as well as a variety of internally deleted variants of both EBNA-2A and EBNA-2B. Some of the deletion variants evolved within the HLP lesion from intact EBNA-2 genes, while other variants appeared to be transmissible strains that directly infected the lesion. Intrastrain recombination within the HLP lesion also generated variation within the EBNA-2 polyproline region. Cloning and sequencing of HLP cDNA demonstrated transcription from the internally deleted EBNA-2 open reading frame, indicating that these variant genes are expressed in HLP. Comparative analysis of the HLP EBNA-2 sequences confirmed previous findings of EBV coinfection with multiple types and strains. Sequence variation of these wild-type genes demonstrated that EBNA-2A sequences distinguish at least two separate strains and a variety of substrains of EBV type 1. Two of the HLP EBNA-2A sequences contained amino acid changes in a cytotoxic T-cell epitope within an otherwise highly conserved region of the gene. These data indicate that EBV coinfection, strain variation, and recombination within the EBNA-2 gene are common features of HLP and suggest that the expression of internally deleted EBNA-2 variants could contribute to EBV pathogenesis in permissive infection.
Division of Infectious Diseases, University of North Carolina, Chapel Hill 27599.
D M
DM
Walling
A G
AG
Perkins
J
J
Webster-Cyriaque
L
L
Resnick
N
N
Raab-Traub
D000595:Amino Acid Sequence; D000956:Antigens, Viral / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D003062:Codon / Q000235:genetics; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D019309:Epstein-Barr Virus Nuclear Antigens; D015870:Gene Expression; D005814:Genes, Viral; D014644:Genetic Variation; D006679:HIV Seropositivity / Q000821:virology; D004854:Herpesvirus 4, Human / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D007972:Leukoplakia, Oral / Q000473:pathology / Q000821:virology*; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D011995:Recombination, Genetic; D015534:Trans-Activators / Q000235:genetics*; D014158:Transcription, Genetic
D000956:Antigens, Viral; D003062:Codon; D004268:DNA-Binding Proteins; D019309:Epstein-Barr Virus Nuclear Antigens; D015345:Oligonucleotide Probes; D012367:RNA, Viral; D015534:Trans-Activators