hRIP, a cellular cofactor for Rev function, promotes release of HIV RNAs from the perinuclear region.
Human immunodeficiency virus Rev facilitates the cytoplasmic accumulation of viral RNAs that contain a Rev binding site. A human Rev-interacting protein (hRIP) was originally identified based on its ability to interact with the Rev nuclear export signal (NES) in yeast two-hybrid assays. To date, however, the function of hRIP and a role for hRIP in Rev-directed RNA export have remained elusive. Here we ablate hRIP activity with a dominant-negative mutant or RNA interference and analyze Rev function by RNA in situ hybridization. We find, unexpectedly, that in the absence of functional hRIP, Rev-directed RNAs mislocalize and aberrantly accumulate at the nuclear periphery, where hRIP is localized. In contrast, in the absence of Rev or the Rev cofactor CRM1, Rev-directed RNAs remain nuclear. We further show that the RNA mislocalization pattern resulting from loss of hRIP activity is highly specific to Rev function: the intracellular distribution of cellular poly(A)(+) mRNA, nuclear proteins, and, most important, NES-containing proteins, are unaffected. Thus, hRIP is an essential cellular Rev cofactor, which acts at a previously unanticipated step in HIV-1 RNA export: movement of RNAs from the nuclear periphery to the cytoplasm.
Sánchez-Velar
Nuria
N
University of Massachusetts Medical School, Program in Molecular Medicine and the UMASS Center for AIDS Research (CFAR), Worcester, Massachusetts 01605, USA.
Udofia
Enyeneama B
EB
Yu
Zhong
Z
Zapp
Maria L
ML
D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002460:Cell Line; D002467:Cell Nucleus / Q000502:physiology*; D002522:Chlorocebus aethiops; D018076:DNA, Complementary; D005455:Fluorescent Antibody Technique; D015694:Gene Products, rev / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D017403:In Situ Hybridization; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D034741:RNA, Small Interfering / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics* / Q000502:physiology; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D014162:Transfection; D054321:rev Gene Products, Human Immunodeficiency Virus
C119724:AGFG1 protein, human; D018076:DNA, Complementary; D015694:Gene Products, rev; D028861:Nuclear Pore Complex Proteins; D034741:RNA, Small Interfering; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D054321:rev Gene Products, Human Immunodeficiency Virus