Cloning and characterization of rhesus cytomegalovirus glycoprotein B.

Rhesus cytomegalovirus (RhCMV) infection of rhesus macaques is an important model to investigate critical issues of cytomegalovirus biology. To better understand host immunological responses to viral glycoproteins, the glycoprotein B (gB) gene of RhCMV was molecularly cloned, sequenced and characterized. Transcription analysis revealed that RhCMV gB was transcribed as a late gene. The RhCMV gB gene encoded a predicted protein of 854 amino acids that was 60% identical/75% similar to the human CMV (HCMV) gB protein. The region of HCMV gB proposed to be responsible for virus binding to host cells, fusion and cell-to-cell spread was the most highly conserved region with RhCMV gB (74% identity/85% similarity). Conserved elements included 11 of 12 cysteine residues, 14 of 16 potential N-linked glycosylation sites and cross-reactive epitopes. Metabolic labelling experiments demonstrated that RhCMV gB was proteolytically processed similarly to HCMV gB. These results are critical for investigating virus-host relationships in CMV-infected primates.