6cf2
Crystal structure of HIV-1 Rev (residues 1-93)-RNA aptamer complex
Structural highlights
FunctionREV_HV1B1 Escorts unspliced or incompletely spliced viral pre-mRNAs (late transcripts) out of the nucleus of infected cells. These pre-mRNAs carry a recognition sequence called Rev responsive element (RRE) located in the env gene, that is not present in fully spliced viral mRNAs (early transcripts). This function is essential since most viral proteins are translated from unspliced or partially spliced pre-mRNAs which cannot exit the nucleus by the pathway used by fully processed cellular mRNAs. Rev itself is translated from a fully spliced mRNA that readily exits the nucleus. Rev's nuclear localization signal (NLS) binds directly to KPNB1/Importin beta-1 without previous binding to KPNA1/Importin alpha-1. KPNB1 binds to the GDP bound form of RAN (Ran-GDP) and targets Rev to the nucleus. In the nucleus, the conversion from Ran-GDP to Ran-GTP dissociates Rev from KPNB1 and allows Rev's binding to the RRE in viral pre-mRNAs. Rev multimerization on the RRE via cooperative assembly exposes its nuclear export signal (NES) to the surface. Rev can then form a complex with XPO1/CRM1 and Ran-GTP, leading to nuclear export of the complex. Conversion from Ran-GTP to Ran-GDP mediates dissociation of the Rev/RRE/XPO1/RAN complex, so that Rev can return to the nucleus for a subsequent round of export. Beside KPNB1, also seems to interact with TNPO1/Transportin-1, RANBP5/IPO5 and IPO7/RANBP7 for nuclear import. The nucleoporin-like HRB/RIP is an essential cofactor that probably indirectly interacts with Rev to release HIV RNAs from the perinuclear region to the cytoplasm (By similarity). Publication Abstract from PubMedHIV-1 Rev protein mediates nuclear export of unspliced and partially spliced viral RNAs for production of viral genomes and structural proteins. Rev assembles on a 351-nt Rev response element (RRE) within viral transcripts and recruits host export machinery. Small (<40-nt) RNA aptamers that compete with the RRE for Rev binding inhibit HIV-1 viral replication. We determined the X-ray crystal structure of a potential anti-HIV-1 aptamer that binds Rev with high affinity (Kd = 5.9 nM). The aptamer is structurally similar to the RRE high-affinity site but forms additional contacts with Rev unique to its sequence. Exposed bases of the aptamer interleave with the guanidinium groups of two arginines of Rev, forming stacking interactions and hydrogen bonds. The aptamer also obstructs an oligomerization interface of Rev, blocking Rev self-assembly. We propose that this aptamer can inhibit HIV-1 replication by interfering with Rev-RRE, Rev-Rev, and possibly Rev-host protein interactions. Structure of an RNA Aptamer that Can Inhibit HIV-1 by Blocking Rev-Cognate RNA (RRE) Binding and Rev-Rev Association.,Dearborn AD, Eren E, Watts NR, Palmer IW, Kaufman JD, Steven AC, Wingfield PT Structure. 2018 Jun 14. pii: S0969-2126(18)30207-7. doi:, 10.1016/j.str.2018.06.001. PMID:30017564[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||
