title: MicroRNA binding to the HIV-1 Gag protein inhibits Gag assembly and virus production.
abstract: MicroRNAs (miRNAs) are small, 18-22 nt long, noncoding RNAs that act as potent negative gene regulators in a variety of physiological and pathological processes. To repress gene expression, miRNAs are packaged into RNA-induced silencing complexes (RISCs) that target mRNAs for degradation and/or translational repression in a sequence-specific manner. Recently, miRNAs have been shown to also interact with proteins outside RISCs, impacting cellular processes through mechanisms not involving gene silencing. Here, we define a previously unappreciated activity of miRNAs in inhibiting RNA-protein interactions that in the context of HIV-1 biology blocks HIV virus budding and reduces virus infectivity. This occurs by miRNA binding to the nucleocapsid domain of the Gag protein, the main structural component of HIV-1 virions. The resulting miRNA-Gag complexes interfere with viral-RNA-mediated Gag assembly and viral budding at the plasma membrane, with imperfectly assembled Gag complexes endocytosed and delivered to lysosomes. The blockade of virus production by miRNA is reversed by adding the miRNA's target mRNA and stimulated by depleting Argonaute-2, suggesting that when miRNAs are not mediating gene silencing, they can block HIV-1 production through disruption of Gag assembly on membranes. Overall, our findings have significant implications for understanding how cells modulate HIV-1 infection by miRNA expression and raise the possibility that miRNAs can function to disrupt RNA-mediated protein assembly processes in other cellular contexts.
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892;Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China;
authors.forename: Antony K
authors.initials: AK
authors.lastname: Chen
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Prabuddha
authors.initials: P
authors.lastname: Sengupta
authors.affiliation: Virus-Cell Interaction Section, HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702; and.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Waki
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Schuyler B
authors.initials: SB
authors.lastname: Van Engelenburg
authors.affiliation: Division of Molecular and Cellular Medicine, National Cancer Center Research Institute, Tokyo 104-0045, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ochiya
authors.affiliation: Virus-Cell Interaction Section, HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702; and.
authors.forename: Sherimay D
authors.initials: SD
authors.lastname: Ablan
authors.affiliation: Virus-Cell Interaction Section, HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702; and.
authors.forename: Eric O
authors.initials: EO
authors.lastname: Freed
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892; lippincj@mail.nih.gov.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Lippincott-Schwartz
mesh_terms: D060565:Argonaute Proteins / Q000378:metabolism; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D057809:HEK293 Cells; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D046912:Multiprotein Complexes / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D019065:Virus Assembly / Q000502:physiology*; D057074:Virus Release / Q000502:physiology*
chemical_list: C466422:AGO2 protein, human; D060565:Argonaute Proteins; D017931:DNA Primers; D035683:MicroRNAs; D046912:Multiprotein Complexes; D011498:Protein Precursors; D034741:RNA, Small Interfering; C059767:p55 gag precursor protein, Human immunodeficiency virus 1