Differential apoptosis effects of primate lentiviral Vpr and Vpx in mammalian cells.
The growth inhibitory effects of Vpr and Vpx are species- and cell type-dependent. HIV-1, HIV-2 and SIV Vpr are primarily cytostatic in mammalian cells and HIV-1 Vpr has been reported to induce apoptosis in human cells. Our previous studies have shown that HIV-1, HIV-2 and SIV Vpr and Vpx have differential cytostatic and cytotoxic effects in the yeast cells [Zhang et al.: Virology, 230:103-112; 1997]. Here, we further examined the apoptosis function of HIV-1 Vpr in different species of mammalian cells and investigated if other primate lentiviral Vpr and Vpx exert similar functions. Our results show that none of the primate lentiviral Vpr or Vpx we tested induces apoptosis in nonhuman species of mammalian cells. However, HIV-1 Vpr, but not HIV-2 or SIV Vpr and/or Vpx, induced apoptosis in different types of human cell lines. Further, the apoptotic effect of HIV-1 Vpr can be distinguished from that of the human interferon-gamma, a known proapoptotic protein, that HIV-1 Vpr shows little to no paracrine and/or bystander effect. When coexpressed with Bcl-2 or Bcl-X(L), the apoptotic effect of HIV-1 Vpr became markedly attenuated. These results indicate that the apoptotic effect of HIV-1 Vpr is species-dependent and is intracellularly modulated by the Bcl-2 family of proteins. Our study also suggests that the proapoptotic function of HIV-1 Vpr is developmentally associated with human but not nonhuman primate species.
Chang
L J
LJ
Department of Molecular Genetics and Microbiology, Gene Therapy Center and Brain Institute, University of Florida, Gainesville, FL, USA. lchang@mgm.ufl.edu
Chen
C H
CH
Urlacher
V
V
Lee
T Z
TZ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D016336:Gene Products, vpr / Q000235:genetics / Q000378:metabolism*; D005822:Genetic Vectors / Q000235:genetics; D049452:Green Fluorescent Proteins; D015497:HIV-1 / Q000235:genetics; D015498:HIV-2 / Q000235:genetics; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D017958:Lentiviruses, Primate / Q000235:genetics; D008164:Luminescent Proteins; D008856:Microscopy, Fluorescence; D005810:Multigene Family; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D012191:Retroviridae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D015302:Simian Immunodeficiency Virus / Q000235:genetics; D013045:Species Specificity; D014162:Transfection; D054334:Viral Regulatory and Accessory Proteins / Q000235:genetics / Q000378:metabolism*; D054325:vpr Gene Products, Human Immunodeficiency Virus
D016336:Gene Products, vpr; D008164:Luminescent Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012191:Retroviridae Proteins; C074286:VPX protein, Human immunodeficiency virus 2; C513059:VPX protein, Simian immunodeficiency virus; D054334:Viral Regulatory and Accessory Proteins; D054325:vpr Gene Products, Human Immunodeficiency Virus; D049452:Green Fluorescent Proteins; D007371:Interferon-gamma; D003513:Cycloheximide