The majority of the human genome does not code for proteins. Importantly, a large portion of this non-coding DNA is actively transcribed. A subset of non-coding transcripts which has gained much interest over the past decade is long (>200 nt) intergenic non-coding RNAs (lincRNAs). Over 8000 lincRNAs have been identified in human cells. LincRNAs are associated with diverse physiological and pathological conditions, yet the mechanism of action of the majority of lincRNAs remains enigmatic.
Human cytomegalovirus (HCMV) is the largest human virus with a DNA genome of 235kb. Viruses are known for their extremely compact genomes and HCMV hardly contains intergenic regions. Nonetheless, four lincRNAs have been identified in the HCMV genome : RNA2.7 (β2.7), RNA1.2, RNA4.9 and RNA5.0 (numbers representing their mature form length in kb). Interestingly, while lincRNAs genes occupy only ~6% of the viral genome HCMV lincRNAs comprise over 60% of expressed viral transcripts. The functions of these highly expressed viral transcripts are largely unknown. Our findings give preliminary insights on the functions and the molecular mechanisms of action of these intruiging lincRNAs .
