Occurrence of novel small RNAs with concomitant inhibition of host cellular U small nuclear RNA synthesis in Vero cells infected with herpes simplex virus type 1.

In eukaryotic cells, small nuclear and small cytoplasmic RNAs (sn- or scRNAs) are associated with distinct proteins, forming ribonucleoproteins (snRNPs or scRNPs). In the present study we analysed the protein composition as well as the small RNA pattern in non-infected and herpes simplex virus type 1 (HSV)-infected Vero cells. We found that concomitantly with the shut-off of host cell mRNA synthesis, synthesis of U-snRNAs was stopped. Due to their stability, however, U-snRNAs were still present in cells 36 h after HSV infection. Besides these RNAs, two novel small RNAs which we termed HVR1 and HVR2 were detected in infected cells. On the basis of their relative mobilities in urea gels, the apparent chain lengths of these newly synthesized RNAs were determined to be 255 and 154 nucleotides respectively. The small RNA-binding proteins Sm, RNP, Ro and La were found to increase up to 15-fold after HSV infection. The data presented suggest that new, virus-coded small RNPs are synthesized which might play a role in the maturation and regulation of HSV-coded RNA transcripts.