Summary auto-generated
This study examined Epstein-Barr virus (EBV) gene expression in hairy leukoplakia (HL), a white lesion on the tongue of immunosuppressed individuals, particularly those with HIV infection. The researchers screened a cDNA library from an HL biopsy and identified expression of two EBV genes, BMRF-2 and BDLF-3, which had not been previously described in vivo. Sequence analysis revealed several nucleotide variations from the reference B95-8 strain, with one consistent amino acid change in BMRF-2 and two in BDLF-3 across six different HL strains. mRNA expression of both genes was localized to the lower prickle cell layer of tongue epithelium. BMRF-2 protein was primarily detected in cell nuclei of the upper prickle cell layer and associated with nuclear chromatin by immunoelectron microscopy. BDLF-3 protein was observed in the perinuclear space and cytoplasm of prickle cells. BDLF-3 was recently identified as a virion-associated protein, while the functions of BMRF-2 remain unclear. This work demonstrates active EBV lytic gene expression in HL and provides insights into the molecular biology of this condition.
Key findings
- BMRF-2 and BDLF-3 genes were identified and expressed in HL tissue for the first time in vivo, detected through cDNA library screening
- Sequence analysis revealed conserved nucleotide variations in HL strains compared to B95-8 reference strain, with one amino acid change in BMRF-2 and two in BDLF-3 across all studied strains
- mRNA of both genes localized to lower prickle cell layers, while BMRF-2 protein was found in upper prickle cell nuclei associated with chromatin, and BDLF-3 was located in perinuclear space and cytoplasm
- Expression was specific to HL lesions and absent in normal tongue tissue and non-HL hyperkeratotic lesions
- BMRF-2 protein is approximately 55 kDa and detected during lytic EBV replication in cell culture
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
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: BMRF- 2 and BDLF-3. Sequence analysis of the cDNAs demonstrated several nucleotide changes from the B95-8 sequence. In all six different HL strains 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 layer of the tongue epithelium. BMRF-2 protein expression was primarily detected in the cell nuclei of the upper prickle cell layer; immunoelectron microscopy revealed that BMRF-2 was associated with the nuclear chromatin. BDLF-3 protein expression was observed in the perinuclear space and cytoplasm of the prickle cells. BDLF-3 has recently been identified as a virion-associated protein, but the functions of BMRF-2 and BDLF-3 have not been elucidated.