Strong selective pressure for evolution of an Epstein-Barr virus LMP2B homologue in the rhesus lymphocryptovirus

Latent membrane protein 2B (LMP2B) is expressed during latent Epstein-Barr virus (EBV) infection, but little is known about its role. The goal of this study was to determine whether an LMP2B homologue is conserved in the rhes us monkey lymphocryptovirus (LCV). Both rhesus LCV LMP2A and LMP2B genes we re cloned and sequenced. The rhesus LCV LMP2B gene is positionally conserve d, and the EBNA-2 responsiveness and the bidirectional nature of the LMP1-L MP2B promoter have also been functionally conserved. However, this region o f the genome encoding the LMP1, LMP1-LMP2B promoter, and LMP2B first exon d emonstrates the most dramatic nucleotide sequence divergence between human and nonhuman LCV observed to date. Evolution of the rhesus LCV LMP2B promot er and transcript despite the dynamic nature of this genomic region reflect s strong selective pressure for a yet-to-be-identified LMP2B function.