Role of RNA helicases in HIV-1 replication

Jeang, Kuan-Teh; Yedavalli, Venkat

HIV-1 is a retrovirus of the lentivirus genus with an RNA genome of 9 kilobases which encodes nine polypeptides. The major HIV-1 structural proteins are encoded by three genes, gag (group-specific antigen), pol (polymerase) and env (envelope), while the accessory proteins, Vif, Vpu, Vpr and Nef, and the regulatory proteins, Tat and Rev, are the primary translation products of multiply-spliced mRNA. HIV-1 infects CD4+ human T-cells and macrophages and integrates as a provirus into the host cell's DNA. Gene expression of HIV-1 is governed transcriptionally by a viral protein, Tat (28, 29) , via its binding to a nascent viral TAR RNA (30) , and post-transcriptionally by a second viral protein Rev (31,32) through its association with the viral RRE RNA. Both Tat and Rev interact with several host cell proteins in their transcriptional and post-transcriptional functions (33) . HIV-1 does not encode for any RNA helicase; however, findings suggest that host cell RNA helicases may be involved in the reverse transcription of HIV-1 RNA, in HIV-1 mRNA transcription and in the nucleus-to-cytoplasm transport of viral mRNA.