Wikipedia
HSURs (Herpesvirus saimiri U RNAs) are viral small regulatory RNAs. They are found in Herpesvirus saimiri which is responsible for aggressive T-cell leukemias in primates. They are nuclear RNAs which bind host proteins to form small nuclear ribonucleoproteins (snRNPs). The RNAs are 114-143 nucleotides in length and the HSUR family has been subdivided into HSURs numbered 1 to 7. The function of HSURs has not yet been identified; they do not affect transcription so are thought to act post-transcriptionally, potentially influencing the stability of host mRNAs.
HSUR1 and 2 are the most conserved members of the family within HSV subgroups. HSUR1 has been shown to bind the host heterogeneous ribonucleoprotein particle protein hnRNPD in vivo. Other HSURs bind HuR/ELAVL1. They are transcribed by RNA polymerase II with promoters similar to that of U RNAs
Features shared by all HSURs include:
- 5ยด-trimethylguanosine caps
- 3' terminal stem-loops
- canonical Sm protein-binding site (AUUUUUG)
A proposed role for HSURs is that they use the RNA interference (RNAi) pathway to manipulate host-cell gene expression. One identified miRNA which responds to HSURs is miR-27.