Redefining Virology

摘要

Human cytomegalovirus (HCMV), a DNA herpesvirus with more than 200 genes, is a giant among viruses. Its DNA is infectious by itself, and the addition- al proteins that the virus brings into the host cell enhance the efficiency of infection. If herpes sim- plex virus (HSV), its more modest cousin with only 84 known genes, serves as a guide, HCMV brings into the host cell all that should be necessary to enable its genes to be expressed. Gene expression results in production of lots of infectious progeny and curtailment of any inimical response on the part of the host cell. Yet it seems that this is not quite enough. On page 2373 of this issue, Bresnahan and Shenk report that HCMV particles contain not only DNA (as would be expected of a DNA virus) but also four species of mRNA.