Decoding Human Cytomegalovirus

TLDR

Human cytomegalovirus (HCMV) infects most people, but severe disease is limited to immunocompromised individuals or newborns, and its ~240‑kb genome exhibits complex transcription suggesting extensive regulatory and coding potential. The study mapped ribosome positions on HCMV transcripts during infection of human fibroblast cells to identify translation sites. The analysis revealed novel open reading frames within existing genes, short upstream and antisense ORFs, and conserved ORFs in long RNAs, and translation of selected ORFs dramatically expanded the viral coding capacity. Stern‑Ginossar et al.

Abstract

Dissecting HCMV Gene Expression Most of us are infected with human cytomegalovirus (HCMV), but severe disease is almost always limited to immunocompromised individuals or newborn infants. The virus has a relatively large (∼240 kb) DNA genome and shows a complex pattern of gene transcription, hinting at a complex regulatory and coding capacity. Stern-Ginossar et al. (p. 1088 ) mapped ribosome positions on HCMV transcripts during the course of viral infection of human fibroblast cells. The data suggest the presence of novel open reading frames (ORFs) lying within existing ORFs; very short ORFs upstream of canonical ORFs; ORFs antisense to canonical ORFs; and short, conserved ORFs encoded by long RNAs. Select ORFs were translated, dramatically expanding the coding capacity of the HCMV genome.