Figure 1.

A schematic depiction of the HCMV UL133-UL138 gene locus. The UL133-UL138 gene locus, located within the ULb’ region, is present in clinical isolates and low passage viruses but lost in serially passaged laboratory strains. The 3 major transcripts that accumulate at early times of infection or additional transcripts encoding UL136 and UL138 that accumulate at late times of infection in fibroblasts are depicted. Alternative transcription/translation initiation sites lead to at least 2 UL135, 5 UL136 and 2 UL138 isoforms. Area shaded grey indicated putative or confirmed transmembrane domains.