Epstein-Barr Virus Protein (LMP) Expression is Enhanced by Serum, TPA or Butyrate

Abstract

So far, four viral genes are found to be expressed in latently EBV-infected cells (1, 2, 3, 4, 5, 6). These genes are coding for at least three EBNA associated nuclear proteins and one membrane protein (1, 3, 4, 5, 7, 8). The potential membrane protein is encoded by the BamHI Nhet region (3, 5, 9) and is found to be approximately of 60 000 daltons with varying molecular weights in different EBV genome harbouring lymphoid cell lines. Since two promoters (ED-LI and ED-L1A) map in the BamHI Nhet region two proteins were predicted sharing a common C-terminal region (5). This second protein has been unidentified so far and is supposed to be two thirds in size of the 60 000 Dalton protein. Antisera against both proteins were generated by immunizing rabbits either with a fusion protein containing 155 amino acids of the C-terminus and a 37 000 Daltons part of the bacterial anthranilate synthase (10, 12) or with a C-terminal synthetic peptide of 7 amino acids (H-Val-Gln-Leu-Ser-Tyr-Tyr-Asp-OH). These sera reacted specifically with a protein varying in size between 60 000 and 65 000 Daltons found in all cell lines harbouring EBV (Fig. 1).