title: HIV-1 RNA genome dimerizes on the plasma membrane in the presence of Gag protein.
abstract: Retroviruses package a dimeric genome comprising two copies of the viral RNA. Each RNA contains all of the genetic information for viral replication. Packaging a dimeric genome allows the recovery of genetic information from damaged RNA genomes during DNA synthesis and promotes frequent recombination to increase diversity in the viral population. Therefore, the strategy of packaging dimeric RNA affects viral replication and viral evolution. Although its biological importance is appreciated, very little is known about the genome dimerization process. HIV-1 RNA genomes dimerize before packaging into virions, and RNA interacts with the viral structural protein Gag in the cytoplasm. Thus, it is often hypothesized that RNAs dimerize in the cytoplasm and the RNA-Gag complex is transported to the plasma membrane for virus assembly. In this report, we tagged HIV-1 RNAs with fluorescent proteins, via interactions of RNA-binding proteins and motifs in the RNA genomes, and studied their behavior at the plasma membrane by using total internal reflection fluorescence microscopy. We showed that HIV-1 RNAs dimerize not in the cytoplasm but on the plasma membrane. Dynamic interactions occur among HIV-1 RNAs, and stabilization of the RNA dimer requires Gag protein. Dimerization often occurs at an early stage of the virus assembly process. Furthermore, the dimerization process is probably mediated by the interactions of two RNA-Gag complexes, rather than two RNAs. These findings advance the current understanding of HIV-1 assembly and reveal important insights into viral replication mechanisms.
authors.affiliation: Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, MD 21702; chenjia@mail.nih.gov wei-shau.hu@nih.gov.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Chen
authors.affiliation: Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, MD 21702;
authors.forename: Sheikh Abdul
authors.initials: SA
authors.lastname: Rahman
authors.affiliation: Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, MD 21702;
authors.forename: Olga A
authors.initials: OA
authors.lastname: Nikolaitchik
authors.affiliation: RNA Therapeutics Institute and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605;
authors.forename: David
authors.initials: D
authors.lastname: Grunwald
authors.affiliation: Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, MD 21702;
authors.forename: Luca
authors.initials: L
authors.lastname: Sardo
authors.affiliation: Viral Mutation Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, MD 21702.
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Burdick
authors.affiliation: Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, MD 21702;
authors.forename: Sergey
authors.initials: S
authors.lastname: Plisov
authors.affiliation: Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, MD 21702;
authors.forename: Edward
authors.initials: E
authors.lastname: Liang
authors.affiliation: Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, MD 21702;
authors.forename: Sheldon
authors.initials: S
authors.lastname: Tai
authors.affiliation: Viral Mutation Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, MD 21702.
authors.forename: Vinay K
authors.initials: VK
authors.lastname: Pathak
authors.affiliation: Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, MD 21702; chenjia@mail.nih.gov wei-shau.hu@nih.gov.
authors.forename: Wei-Shau
authors.initials: WS
authors.lastname: Hu
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D019281:Dimerization; D016679:Genome, Viral; D015497:HIV-1 / Q000235:genetics*; D015498:HIV-2 / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D034443:RNA Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics*; D013194:Staining and Labeling; D013997:Time Factors; D014771:Virion / Q000378:metabolism; D055544:beta-Globins / Q000235:genetics; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D008164:Luminescent Proteins; D012333:RNA, Messenger; D012367:RNA, Viral; D055544:beta-Globins; D054301:gag Gene Products, Human Immunodeficiency Virus; C054562:yellow fluorescent protein, Bacteria
keywords: Gag–RNA complex; RNA genome; RNA-binding protein; retrovirus; virus assembly