Characterization of a second C-type lectin-like gene in rat cytomegalovirus (92.8)

Abstract

Abstract Gene capture has been a prominent feature in herpesvirus evolution, and many of these hijacked genes serve immunomodulatory purposes. Recently, we characterised a lectin-like gene (RCTL) in the English isolate of rat cytomegalovirus (RCMV) that interacts with an inhibitory receptor on Natural Killer (NK) cells. Here, we show that RCMV encodes an additional, spliced lectin-like gene (RCTL2) that, compared to RCTL, is located at the opposite end of the viral genome. RCTL2 consists of four exons and is expressed in the early phase of viral replication. To analyse if RCTL2 can be expressed as a protein, we tagged the ORF with the FLAG sequence. After transfection of 293 cells, RCTL2 was detected by fluorescent microscopy and Western blot analysis. Treatment with tunicamycin reduced the protein size, thereby confirming predicted N-linked glycosylation sites. The sequence similarity of RCTL2 with RCTL and the reported interaction with NK cells of the latter suggest that RCTL2 is similarly involved in the modulation of the innate immune response and that the capture of lectin-like genes is beneficial for viral replication. This notion is supported by the existence of lectin-like genes in poxviruses.