1. Regulation of CD4 expression via recycling by HRES-1/RAB4 controls susceptibility to HIV infection.
- Author
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Nagy G, Ward J, Mosser DD, Koncz A, Gergely P Jr, Stancato C, Qian Y, Fernandez D, Niland B, Grossman CE, Telarico T, Banki K, and Perl A
- Subjects
- Antigens, CD metabolism, Apoptosis, Base Sequence, CD4-Positive T-Lymphocytes metabolism, CD4-Positive T-Lymphocytes virology, Chloramphenicol O-Acetyltransferase metabolism, Dependovirus genetics, Disease Susceptibility, Exons genetics, Flow Cytometry, Gene Products, tat pharmacology, Genes, Dominant, HIV Core Protein p24 metabolism, HIV Infections virology, HIV Long Terminal Repeat genetics, HeLa Cells, Humans, Introns genetics, Jurkat Cells, Lysosomes, Molecular Sequence Data, Mutagenesis, Site-Directed, Mutation genetics, Receptors, Transferrin metabolism, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Sequence Homology, Nucleic Acid, Transfection, rab4 GTP-Binding Proteins genetics, tat Gene Products, Human Immunodeficiency Virus, CD4 Antigens metabolism, Gene Expression Regulation, Viral, Gene Products, tat genetics, HIV Infections metabolism, HIV-1 pathogenicity, rab4 GTP-Binding Proteins metabolism
- Abstract
A novel 2986-base transcript encoded by the antisense strand of the HRES-1 human endogenous retrovirus was isolated from peripheral blood lymphocytes. This transcript codes for a 218-amino acid protein, termed HRES-1/Rab4, based on homology to the Rab4 family of small GTPases. Antibody 13407 raised against recombinant HRES-1/Rab4 detected a native protein of identical molecular weight in human T cells. HRES-1 nucleotides 2151-1606, located upstream of HRES-1/Rab4 exon 1, have promoter activity when oriented in the direction of HRES-1/Rab4 transcription. The human immunodeficiency virus, type 1 (HIV-1), tat gene stimulates transcriptional activity of the HRES-1/Rab4 promoter via trans-activation of the HRES-1 long terminal repeat. Transfection of HIV-1 tat into HeLa cells or infection of H9 and Jurkat cells by HIV-1 increased HRES-1/Rab4 protein levels. Overexpression of HRES-1/Rab4 in Jurkat cells abrogated HIV infection, gag p24 production, and apoptosis, whereas dominant-negative HRES-1/Rab4(S27N) had the opposite effects. HRES-1/Rab4 inhibited surface expression of CD4 and targeted it for lysosomal degradation. HRES-1/Rab4(S27N) enhanced surface expression, recycling, and total cellular CD4 content. Infection by HIV elicited a coordinate down-regulation of CD4 and up-regulation of HRES-1/Rab4 in PBL. Moreover, overexpression of HRES-1/Rab4 reduced CD4 expression on peripheral blood CD4+ T cells. Stimulation by HIV-1 of HRES-1/Rab4 expression and its regulation of CD4 recycling reveal novel coordinate interactions between an infectious retrovirus and the human genome.
- Published
- 2006
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