RNA Viruses: RNA Roles in Pathogenesis, Coreplication and Viral Load

Poltronieri, Palmiro; Sun, Binlian; Mallardo, Massimo

In a recent publication [45] numerous small RNAs were found deriving from HIV-1 RNA genome. Most of the sequences, with positive polarity (98.1%) could be structured RNAs (sRNAs) or miRNA-like (vmiRNAs). A small portion of the viRNAs, with negative polarity, is encoded within the 3 -UTR. These viral siRNAs (vsiRNAs) were shown to act inhibiting virus replication, since their inhibition using an-tagomiRs increases virus replication. Three of the HIV-1 small RNAs were shown to be processed by the RNAi machinery. There are data showing that HIV-1 can express an antisense transcript from the 3'-end of its genome that forms long RNA duplexes with counterpart sense HIV-1 RNAs [46] [47] [48] . Most HIV sRNAs are not supposed to function as miRNAs, because of lack of evolutionary conservation amongst strains, but may still assume a hairpin structure in the regions containing the conserved bases.