title: Human immunodeficiency virus-1 Nef suppresses Hsp70-mediated Tat activation.
abstract: The human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) contains binding sites for several host transcription factors that contribute to HIV-1 gene expression. Although previous reports have indicated that HIV-1 Nef positively or negatively regulates HIV-1 gene expression, the precise molecular mechanisms by which this occurs remain largely unknown. In this study, we report that Nef suppressed LTR-driven transcription only in the presence of HIV-1 Tat, which was localized to the cytoplasm and degraded by the proteasome. However, the depletion of Hsp70 was found to reduce the suppressive effect of Nef on HIV-1 gene expression. These results suggest that Nef suppresses Hsp70-mediated HIV-1 Tat activation.
authors.affiliation: Department of Life and Environmental Sciences, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Sugiyama
authors.forename: Haruki
authors.initials: H
authors.lastname: Naganuma
authors.forename: Hironori
authors.initials: H
authors.lastname: Nishitsuji
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takaku
mesh_terms: D021581:Active Transport, Cell Nucleus; D002467:Cell Nucleus / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D046188:Protein Modification, Translational; D034741:RNA, Small Interfering / Q000235:genetics; D054311:nef Gene Products, Human Immunodeficiency Virus / Q000378:metabolism*; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000378:metabolism*
chemical_list: D018840:HSP70 Heat-Shock Proteins; D034741:RNA, Small Interfering; D054311:nef Gene Products, Human Immunodeficiency Virus; C514837:nef protein, Human immunodeficiency virus 1; D054322:tat Gene Products, Human Immunodeficiency Virus; D046988:Proteasome Endopeptidase Complex