Decoding human cytomegalovirus using ribosome profiling

The human cytomegalovirus (HCMV) genome was sequenced 20 years ago. However, like other complex viruses, our understanding of its protein coding potential is far from complete. Here, we use ribosome profiling and transcript analysis to experimentally define the HCMV translation products and follow their temporal expression. We identified several hundred previously unidentified open reading frames and confirmed a fraction by mass spectrometry. We found that regulated use of alternative transcript start sites plays a broad role in enabling tight temporal control of HCMV protein expression and allowing multiple distinct polypeptides to be generated from a single genomic locus. Our results reveal an unanticipated complexity to the HCMV coding capacity and illustrate the role of regulated changes in transcript start sites in generating this complexity. Ribosome profiling and mRNA-seq from 3 time points (5hr, 24hr, 72hr) along HCMV infection. The supplementary file 'GSE41605_merlin_final_orfs.bed.gz' includes the 751 ORFs of HCMV that were identified in this study.