CLONING AND CHARACTERIZATION OF THE GUINEA-PIG CYTOMEGALOVIRUS GLYCOPROTEIN-B GENE

Unlike other small animals, cytomegalovirus (CMV) infection of the gui nea pig results in transplacental passage and intrauterine infection o f the fetus. These features make the guinea pig model ideal for studyi ng vaccine strategies designed to prevent congenital infection. Unfort unately, little is known about immunogenic guinea pig CMV gene product s. In other animal cytomegaloviruses, a major target of the host immun e response is the glycoprotein B (gB, gp UL 55) gene product. Using DN A probes containing human CMV gB sequences, the gB gene homolog of the guinea pig cytomegalovirus was identified, cloned, and sequenced. The gpCMV gB gene maps to a region spanning portions of the HindIII K, Q, and P fragments of the gpCMV genome. DNA sequence analysis identified an open reading frame of 2706 nucleotides capable of encoding a prote in of 901 amino acids. Extensive similarity to the human and murine gB proteins was noted with 42% identity at the amino acid level. The pre dominant gpCMV gB mRNA is a 6.8-kb transcript with the expression kine tics of an early gene. RNase protection and primer extension analyses indicated that gB mRNAs were transcribed from two different initiation sites corresponding to distinct TATA elements. Polyclonal antisera pr epared against a synthetic peptide derived from amino acid sequences w ithin the ORF identified a 58-kDa virion-associated protein representi ng the cleaved COOH-terminus (gp 58) of the gpCMV gB molecule. The mol ecular characterization of gpCMV gB should facilitate studies of vacci ne strategies in the guinea pig model of congenital CMV infection. (C) 1994 Academic Press, Inc.