The double-stranded RNA-binding protein Staufen is incorporated in human immunodeficiency virus type 1: evidence for a role in genomic RNA encapsidation.
Human Staufen (hStau), a double-stranded RNA (dsRNA)-binding protein that is involved in mRNA transport, is incorporated in human immunodeficiency virus type 1 (HIV-1) and in other retroviruses, including HIV-2 and Moloney murine leukemia virus. Sucrose and Optiprep gradient analyses reveal cosedimentation of hStau with purified HIV-1, while subtilisin assays demonstrate that it is internalized. hStau incorporation in HIV-1 is selective, is dependent on an intact functional dsRNA-binding domain, and quantitatively correlates with levels of encapsidated HIV-1 genomic RNA. By coimmunoprecipitation and reverse transcription-PCR analyses, we demonstrate that hStau is associated with HIV-1 genomic RNA in HIV-1-expressing cells and purified virus. Overexpression of hStau enhances virion incorporation levels, and a corresponding, threefold increase in HIV-1 genomic RNA encapsidation levels. This coordinated increase in hStau and genomic RNA packaging had a significant negative effect on viral infectivity. This study is the first to describe hStau within HIV-1 particles and provides evidence that hStau binds HIV-1 genomic RNA, indicating that it may be implicated in retroviral genome selection and packaging into assembling virions.
Mouland
A J
AJ
Departments of Microbiology & Immunology, Université de Montréal, Montreal, Quebec H3C 3J7, Canada.
Mercier
J
J
Luo
M
M
Bernier
L
L
DesGroseillers
L
L
Cohen
E A
EA
D001665:Binding Sites; D002460:Cell Line; D002499:Centrifugation, Density Gradient; D003001:Cloning, Molecular; D029721:Drosophila Proteins; D015870:Gene Expression; D015683:Gene Products, gag / Q000235:genetics / Q000378:metabolism; D016679:Genome, Viral; D015497:HIV-1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D015498:HIV-2 / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008979:Moloney murine leukemia virus / Q000737:chemistry / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D011233:Precipitin Tests; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D012330:RNA, Double-Stranded / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013379:Substrate Specificity; D020860:Subtilisin / Q000378:metabolism; D014162:Transfection; D019065:Virus Assembly
D029721:Drosophila Proteins; D015683:Gene Products, gag; D011498:Protein Precursors; D012330:RNA, Double-Stranded; D012367:RNA, Viral; D016601:RNA-Binding Proteins; C059767:p55 gag precursor protein, Human immunodeficiency virus 1; C069927:stau protein, Drosophila; D020860:Subtilisin