RESUMO
The viral protein Rev is essential for the export of the subset of unspliced and partially spliced lentiviral mRNAs and the production of structural proteins. Rev and its RNA binding site RRE can be replaced in both human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) by the constitutive RNA transport element CTE of the simian type D retroviruses. We used neonatal macaques as a sensitive animal model to evaluate the pathogenicity of a pair of SIV mutant strains generated from Rev-independent molecular clones of SIVmac239 which differ only in the presence of the nef open reading frame. After high primary viremia, all animals remained persistently infected at levels below the threshold of detection. All macaques infected as neonates developed normally, and none showed any signs of immune dysfunction or disease during follow-up ranging from 2.3 to 4 years. Therefore, the Rev-RRE regulatory mechanism plays a key role in the maintenance of high levels of virus propagation, which is independent of the presence of nef. These data demonstrate that Rev regulation plays an important role in the pathogenicity of SIV. Replacement of Rev-RRE by the CTE provides a novel approach to dramatically lower the virulence of a pathogenic lentivirus. These data further suggest that antiretroviral strategies leading to even a partial block of Rev function may modulate disease progression in HIV-infected individuals.
Assuntos
Produtos do Gene rev/genética , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Vírus da Imunodeficiência Símia/patogenicidade , Animais , Animais Recém-Nascidos , Anticorpos Antivirais/sangue , Produtos do Gene nef/genética , Produtos do Gene rev/deficiência , Produtos do Gene rev/fisiologia , Genes env/fisiologia , Macaca mulatta , Fases de Leitura Aberta , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Vírus da Imunodeficiência Símia/genética , Fatores de Tempo , Viremia , VirulênciaRESUMO
Gene delivery via the hematopoietic stem cell (HSC) offers an attractive means to introduce antiviral genes into both T cells and macrophages for acquired immunodeficiency syndrome (AIDS) gene therapy. An amphotropic retroviral vector encoding a bicistronic gene coexpressing RevM10 and the murine CD8alpha' chain (lyt2) was developed to transduce HSC/progenitor cells. After transduction of CD34+ cells isolated from human umbilical cord blood, the lyt2 molecule detected by flow cytometry was used to monitor the level of gene transduction and expression and to enrich RevM10-expressing cells by cell sorting without drug selection. Using this quantitative method, high levels of gene transduction and expression (around 20%) were achieved by high-speed centrifugation of CD34+ cells with the retroviral supernatant (spinoculation). After reconstitution of human bone marrow implanted in SCID mice (SCID-hu bone) with the transduced HSC/progenitor cells, a significant number of donor-derived CD14+ bone marrow cells were found to express the RevM10/lyt2 gene. Finally, replication of a macrophage-tropic human immunodeficiency virus-type 1 (HIV-1) isolate was greatly inhibited in the lyt2+/CD14+ cells differentiated from transduced CD34+ cells after the enrichment of lyt2+ population. Thus, the RevM10 gene did not appear to inhibit the differentiation of HSC/progneitor cells into monocytes/macrophages. The level of retrovirus-mediated RevM10 expression in monocytes/macrophages derived from transduced HSCs is sufficient to suppress HIV-1 replication.
Assuntos
Síndrome da Imunodeficiência Adquirida/terapia , Genes rev , Terapia Genética , Transplante de Células-Tronco Hematopoéticas , Transfecção , Animais , Diferenciação Celular , Células Cultivadas , Sangue Fetal/citologia , Produtos do Gene rev/deficiência , Produtos do Gene rev/genética , Produtos do Gene rev/fisiologia , Genes Reporter , HIV-1/fisiologia , Células-Tronco Hematopoéticas/virologia , Humanos , Camundongos , Camundongos SCID , Produtos do Gene rev do Vírus da Imunodeficiência HumanaRESUMO
Replication of human immunodeficiency virus type 1 (HIV-1) is dependent on the viral Rev protein. This protein acts in concert with the cis-acting rev-responsive element present in intron-containing RNAs to facilitate nuclear export of these RNAs. Here we show that a cis-acting 219-nucleotide sequence from an unrelated "simple" retrovirus, Mason-Pfizer monkey virus (MPMV), enables Rev-independent HIV-1 replication. This sequence is present in an untranslated region near the 3' end of the MPMV genome. The MPMV element is also able to efficiently substitute for Rev in expression of Gag/Pol and Env proteins from subgenomic constructs. We hypothesize that the MPMV element functions by interacting with a cellular factor that plays a role in mRNA transport analogous to that of the Rev protein. It might be possible to exploit this element in the development of an HIV vaccine.