Identification and characterization of a spliced C-type lectin-like gene encoded by rat cytomegalovirus

The English isolate of rat cytomegalovirus (RCMV) encodes a 20-kDa protein with a C-type lectin-like domain that is expressed in tbe delayed-early and late phases of the viral replication cycle. Genomic sequence analysis of t he restriction fragment KpnR of RCMV revealed significant homology to sever al C-type lectin-containing molecules implicated in natural killer (NK) and T-cell interactions, as well as genes from four poxviruses and African swi ne fever virus. The gene is spliced into five exons and shows a splicing pa ttern with er;on boundaries similar to those observed in the human differen tiation antigen CD69. The cap site of the gene was mapped by RNase protecti on, 5' rapid amplification of cDNA ends, and primer extension experiments. This analysis demonstrated that the core promoter of the RCMV lectin-like g ene contains a GATA rather than a TATA box, Splicing patterns were confirme d with isolates from an infected-cell cDNA library. A unique aspect of the protein is that its translation is not initiated by the canonical methionin e but rather by alanine. To study its role in virus replication and pathoge nesis, a recombinant virus was constructed in which the gene is interrupted . Replication in tissue culture was similar to that of wild-type virus.