Roles of the Linker Region of RNA Helicase A in HIV-1 RNA Metabolism
نویسندگان
چکیده
RNA helicase A (RHA) promotes multiple steps in HIV-1 production including transcription and translation of viral RNA, annealing of primer tRNA(Lys3) to viral RNA, and elevating the ratio of unspliced to spliced viral RNA. At its amino terminus are two double-stranded RNA binding domains (dsRBDs) that are essential for RHA-viral RNA interaction. Linking the dsRBDs to the core helicase domain is a linker region containing 6 predicted helices. Working in vitro with purified mutant RHAs containing deletions of individual helices reveals that this region may regulate the enzyme's helicase activity, since deletion of helix 2 or 3 reduces the rate of unwinding RNA by RHA. The biological significance of this finding was then examined during HIV-1 production. Deletions in the linker region do not significantly affect either RHA-HIV-1 RNA interaction in vivo or the incorporation of mutant RHAs into progeny virions. While the partial reduction in helicase activity of mutant RHA containing a deletion of helices 2 or 3 does not reduce the ability of RHA to stimulate viral RNA synthesis, the promotion of tRNA(Lys3) annealing to viral RNA is blocked. In contrast, deletion of helices 4 or 5 does not affect the ability of RHA to promote tRNA(Lys3) annealing, but reduces its ability to stimulate viral RNA synthesis. Additionally, RHA stimulation of viral RNA synthesis results in an increased ratio of unspliced to spliced viral RNA, and this increase is not inhibited by deletions in the linker region, nor is the pattern of splicing changed within the ∼ 4.0 kb or ∼ 1.8 kb HIV-1 RNA classes, suggesting that RHA's effect on suppressing splicing is confined mainly to the first 5'-splice donor site. Overall, the differential responses to the mutations in the linker region of RHA reveal that RHA participates in HIV-1 RNA metabolism by multiple distinct mechanisms.
منابع مشابه
Cloning and expression of NS3 helicase fragment of hepatitis C virus and the study of its immunoreactivity in HCV infected patients
Objective(s): Hepatitis C is a major cause of liver failure worldwide. Current therapies applied for this disease are not fully effective and produce side effects in most cases. Non-structural protein 3 helicase (NS3) of HCV is one of the key enzymes in viral replication and infection. Therefore, this region is a promising target to design new drugs and therapies against HCV infection. The aim ...
متن کاملIn vitro and in vivo analysis of the interaction between RNA helicase A and HIV-1 RNA.
RNA helicase A (RHA) promotes multiple steps of HIV-1 RNA metabolism during viral replication, including transcription, translation, and the annealing of primer tRNA(3)(Lys) to the viral RNA. RHA is a member of the DExH subclass of RNA helicases that uniquely contains two double-stranded RNA binding domains (dsRBDs) at its N terminus. Here, we performed a genome-wide analysis of the interaction...
متن کاملCoordinate roles of Gag and RNA helicase A in promoting the annealing of tRNA Lys3 to HIV-1 RNA
متن کامل
Multiple functions of DDX3 RNA helicase in gene regulation, tumorigenesis, and viral infection
The DEAD-box RNA helicase DDX3 is a multifunctional protein involved in all aspects of RNA metabolism, including transcription, splicing, mRNA nuclear export, translation, RNA decay and ribosome biogenesis. In addition, DDX3 is also implicated in cell cycle regulation, apoptosis, Wnt-β-catenin signaling, tumorigenesis, and viral infection. Notably, recent studies suggest that DDX3 is a componen...
متن کاملRNA helicases
Similar to proteins, RNA molecules must fold into the correct conformation and associate with protein complexes in order to be functional within a cell. RNA helicases rearrange RNA secondary structure and RNA-protein interactions in an ATP-dependent reaction, performing crucial functions in all aspects of RNA metabolism. In prokaryotes, RNA helicase activity is associated with roles in housekee...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره 8 شماره
صفحات -
تاریخ انتشار 2013