Expression of Epstein-Barr virus latent genes in oral epithelium: determinants of the pathogenesis of oral hairy leukoplakia.

This retrospective study examined expression of Epstein-Barr virus (EBV) latent genes in oral epithelium from human immunodeficiency virus-seropositive subjects, to identify genes associated with the pathogenesis of oral hairy leukoplakia (HLP). Transcription of EBV latent genes was detected in tissues with productive EBV replication and, also, in normal oral epithelial tissues without EBV replication. Expression of the EBV EBNA-2 open-reading frame in oral epithelium was identified as an important cofactor associated with the pathogenesis of HLP.

EBNA2 amino acids 3 to 30 are required for induction of LMP-1 and immortalization maintenance.

Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA2), a direct transcriptional activator of viral and cellular genes, is required for EBV-induced B-cell transformation. The functional role of conserved regions within the amino terminus of the protein preceding the poly-proline region has yet to be fully characterized. Thus, we tested whether the EBNA2 amino-terminal 30 amino acid residues, containing evolutionarily conserved region 1, are required for stimulating viral and cellular gene expression necessary for B-cell transformation in a viral transcomplementation assay.

The EBNA2 polyproline region is dispensable for Epstein-Barr virus-mediated immortalization maintenance.

Epstein-Barr virus nuclear antigen 2 (EBNA2) is required for EBV-mediated immortalization of primary human B cells and is a direct transcriptional activator of viral and cellular genes. The prototype EBNA2 protein contains a unique motif in which 43 out of 45 amino acids are prolines (polyproline region [PPR]). Previous genetic analysis has shown that deletion of the PPR resulted in viruses unable to immortalize B cells, although the protein did appear transcriptionally functional (R.