EXPRESSION OF EPSTEIN-BARR-VIRUS BMRF-2 AND BDLF-3 GENES IN HAIRY LEUKOPLAKIA

The high level of Epstein-Barr virus (EBV) replication found in hairy leukoplakia (HL) provides a unique opportunity to study EBV expression in the oral epithelium. Screening of a cDNA library from an HL biopsy revealed expression of two genes not previously described in vivo: BM RF-2 and BDLF-3. Sequence analysis of the cDNAs demonstrated several n ucleotide changes from the B95-8 sequence. In all six different HL str ains studied, only one amino acid change was found in BMRF-2 relative to B95-8 and two amino acid changes were found in the BDLF-3 ORF. mRNA expression of both genes was localized to the lower prickle cell laye r of the tongue epithelium. BMRF-2 protein expression was primarily de tected in the cell nuclei of the upper prickle cell layer; immunoelect ron microscopy revealed that BMRF-2 was associated with the nuclear ch romatin. BDLF-3 protein expression was observed in the perinuclear spa ce and cytoplasm of the prickle cells. BDLF-3 has recently been identi fied as a virion-associated protein, but the functions of BMRF-2 and B DLF-3 have not been elucidated.