Role of RNA helicases in HIV-1 replication

Jeang, Kuan-Teh; Yedavalli, Venkat

Separate from reverse transcription, the unwinding of highly structured RNAs might also be reasoned to be important for transcription (35) . However, direct evidence for an RNA helicase role has been somewhat elusive. There are several examples which seemingly support an activity for RNA helicase in transcription. First, in vaccinia virus, it has been postulated that the NPH-II helicase assists transcription by strand-separating duplexed RNA structures to prevent R-loop formation behind the elongating RNA polymerase (36) . Second, RHA has been invoked to provide a factorrecruitment role, bridging at the promoter the CREB-binding protein (37) and RNA polymerase II (37) . Third, the p68 DEAD-box helicase was shown recently to be a novel transcriptional co-activator for p53's transcriptional function (38) . Interestingly, in the latter two instances, neither the ATPase nor the helicase activity of RHA and p68 is apparently required for their attributed transcriptional roles.