Skip to main content
Log in

Analysis of HIV-1 Tat effects inXenopus laevis embryos

  • Original Paper
  • Published:
Journal of Biomedical Science

Abstract

Tat is one of the regulatory proteins of the HIV-1 virus. To date, besides the transactivation activity, a myriad of effects exerted by HIV-1 Tat on cellular and viral genes have been observed. The present study investigated the in vivo effects of HIV-1 Tat protein in theXenopus embryo. We adopted theXenopus system since expression of putative regulatory factors in the embryo has been widely used as a quick and effective first screen for protein function.Xenopus' early development is well characterized by stage-specific phenotypes, therefore, an in vivo HIV-1 Tat-mediated aberrant phenotype can easily be detected and analyzed. HIV-1 Tat protein expression through injection of synthetic mRNA into zygotes produced a marked delay in gastrulation leading to altered specification of the anterior-posterior axis and to partial or total loss of anterior structures. HIV-1 Tat effects resulted in a general suppression of gene expression, including that ofXbra andgsc, two early genes whose expression is required for proper gastrulation. The specificity of Tat effects was demonstrated by injecting a ‘loss of function’ mutant (Tat-C37S), lacking a single cysteine residue, which did not yield any effect. Both Tat and Tat-C37S were found to be localized mainly in the nucleus. The importance of subcellular targeting for the effects caused by HIV-1 Tat was demonstrated by injecting a second mutant (Tat-BDM), carrying an altered nuclear localization signal sequence. The Tat-BDM protein localized in the cytoplasm and accumulated at the cell membrane. Embryos injected with Tat-BDM mRNA did not develop beyond gastrulation. The importance of proper protein conformation and subcellular localization in determining Tat effects is discussed.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Almouzni G, Khochbin S, Dimitrov S, Wolffe AP. Histone actylation influences both gene expression and development ofXenopus laevis. Dev Biol 165:654–669;1994.

    Article  PubMed  Google Scholar 

  2. Almouzni G, Wolffe AP. Replication-coupled chromatin assembly is required for the repression of basal transcription in vivo. Genes Dev 7:2033–2047;1993.

    PubMed  Google Scholar 

  3. Arya SK, Beaver B, Jagodzinski L, Ensoli B, Kanki PJ, Albert J, Fenyo E, Biberfeld G, Zagury JF, Laure F, Essex M, Norrby E, Wong-Staal F, Gallo RC. New human and simian HIV-related retroviruses possess functional transactivator (tat) gene. Nature 328:548–550;1987.

    Article  PubMed  Google Scholar 

  4. Arya SK, Guo C, Jospehs SF, Wong-Staal F. Trans-activator gene of human T-lymphotropic virus type III (HTLV-III). Science 229:69–73;1985.

    PubMed  Google Scholar 

  5. Barillari G, Gendelman R, Gallo RC, Ensoli B. The Tat protein of human immunodeficiency virus type 1, a growth factor for AIDS Kaposi sarcoma and cytokine-activated vascular cells, induces adhesion of the same cell types by using integrin receptors recognizing the RGD amino acid sequence. Proc Natl Acad Sci USA 90:7941–7945;1993.

    PubMed  Google Scholar 

  6. Battaglia PA, Longo F, Ciotta C, Del Grosso MF, Ambrosini E, Gigliani F. Genetic tests to reveal tat homo-dimer formation and select tat homodimer inhibitor. Biochem Biophys Res Commun 201:701–708;1994.

    Article  PubMed  Google Scholar 

  7. Battaglia PA, Regoli E, Gigliani F. Measurement of the range of HIV-LTR transcativation activity of HIV in vitro. Int J Oncol 11:1007–1011;1997.

    Google Scholar 

  8. Berkhout B, Silverman RH, Jeang KT. Tat trans-activates the human immunodeficiency virus through a nascent RNA target. Cell 59:273–282;1989.

    Article  PubMed  Google Scholar 

  9. Beumer TL, Veenstra GJC, Hage WJ, Destrée OHJ. Whole-mount immunohistochemistry on Xenopus embryos using far-red fluorescent dyes. Trends Genet 11:9;1995.

    Article  PubMed  Google Scholar 

  10. Braddock M, Powell R, Blanchard AD, Kingsman AJ, Kingsman SM. HIV-1 TAR RNA-binding proteins control Tat activation of translation in Xenopus oocytes. FASEB J 7:214–222;1993.

    PubMed  Google Scholar 

  11. Brown JA, Howcroft TK, Singer DS. HIV Tat protein requirements for transactivation and repression of transcription are separable. AIDS Res Hum Retroviruses 17:9–16;1998.

    Google Scholar 

  12. Buonaguro L, Barillari G, Chang HK, Bohan CA, Kao V, Morgan R, Gallo RC, Ensoli B. Effects of the human immunodeficiency virus type 1 Tat protein on the expression of inflammatory cytokines. J Virol 66:7159–7167;1992.

    PubMed  Google Scholar 

  13. Buonaguro L, Buonaguro FM, Giraldo G, Ensoli B. The human immunodeficiency virus type 1 Tat protein transactivates tumor necrosis factor beta gene expression through a TAR-like structure. J Virol 68:2677–2682;1994.

    PubMed  Google Scholar 

  14. Chang HK, Gallo RC, Ensoli B. Regulation of cellular gene expression and function by the human immunodeficiency virus type 1 Tat protein. J Biomed Sci 2:189–202;1995.

    Article  PubMed  Google Scholar 

  15. Chang HK, Samaniego F, Nair BC, Buonaguro L, Ensoli B. Hiv-1 Tat protein exits from cells via a leaderless secretory pathway and binds to extracellualr matrix-associated heparan sulfate proteoglycans through its basic region. AIDS 11:1421–1431;1997.

    PubMed  Google Scholar 

  16. Cho KWY, Blumberg B, Steinbeisser H, De Robertis EM. Molecular nature of Spemann's organizer: The role of the Xenopus homeobox gene goosecoid. Cell 67:1111–1120;1991.

    Article  PubMed  Google Scholar 

  17. Corallini A, Altavilla G, Pozzi L, Bignozzi F, Negrini M, Rimessi P, Gualandi F, Barbanti-Brodano G. Systemic expression of HIV-1 Tat gene in transgenic mice induces endothelial proliferation and tumors of different histotypes. Cancer Res 53:5569–5575;1993.

    PubMed  Google Scholar 

  18. Cujec TP, Okamoto H, Fujinaga K, Meyer J, Chamberlin H, Morgan DO, Peterlin BM. The HIV transactivator Tat binds to the cdk-activating kinase and activates the phosphorylation of the carboxy-terminal domain of RNA polymerase II. Genes Dev 11:2645–2657;1997.

    PubMed  Google Scholar 

  19. Destrée OHJ, Bendig MM, Laaf de RTM, Koster JG. Organization of Xenopus histone gene variants within clusters and their transcriptional expression. Biochim Biophys Acta 782:132–141;1984.

    PubMed  Google Scholar 

  20. Destrée OHJ, Lam KT, Peterson-Maduro LJ, Eizema K, Diller L, Gryka MA, Frebourg T, Shibuya E, Friend SH. Structure and expression of the Xenopus retinoblastoma gene. Dev Biol 153:141–149;1992.

    Article  PubMed  Google Scholar 

  21. Dingwall C, Ernberg I, Gait MJ, Green SM, Heaphy S, Karn J, Lowe AD, Singh M, Skinner MA. HIV-1 Tat protein stimulates transcription by binding to a U-rich bulge in the stem of the TAR RNA structure. EMBO J 9:4145–4153;1990.

    PubMed  Google Scholar 

  22. Dingwall C, Ernberg I, Gait MJ, Green SM, Heaphy S, Karn J, Lowe AD, Singh M, Skinner MA, Valerio R. Human immunodeficiency virus 1 tat protein binds transactivation-responsive region (TAR) RNA in vitro. Proc Natl Acad Sci USA 86:6925–6929;1989.

    PubMed  Google Scholar 

  23. Ensoli B, Buonaguro L, Barillari G, Fiorelli V, Gendelman R, Morgan RA, Wingfield P, Gallo RC. Release, uptake, and effects of extracellular human immunodeficiency virus type 1 Tat protein on cell growth and viral transactivation. J Virol 67:277–287;1993.

    PubMed  Google Scholar 

  24. Ensoli B, Gendelman R, Markham P, Fiorelli V, Colombini S, Raffeld M, Cafaro A, Chang HK, Brady JN, Gallo RC. Synergy between basic fibroblast growth factor and HIV-1 Tat protein in induction of Kaposi's sarcoma. Nature 371:674–680;1994.

    Article  Google Scholar 

  25. Frankel AD, Bredt DS, Pabo CO. Tat protein from human immunodeficiency virus forms a metal-linked dimer. Science 240:70–73;1988.

    PubMed  Google Scholar 

  26. Gait MJ, Karn J. RNA recognition by the human immunodeficiency virus Tat and Rev proteins. Trends Biochem Sci 18:255–259;1993.

    Article  PubMed  Google Scholar 

  27. Gao X. Transcriptional regulation of the Wnt-1 gene and functional analysis of the glucocorticoid receptor in early embryogenesis ofXenopus laevis. PhD thesis, Utrecht University, 1994.

  28. Garza HH, Prakash O, Carr DJJ. Aberrant regulation of cytokines in HIV-1 Tat(72)-transgenic mice. J Immunol 156:3631–3637;1996.

    PubMed  Google Scholar 

  29. Gorman CM, Moffat LF, Howard BH. Recombinant genomes which express chloramphenicol acetyltransferase in mammalian cells. Mol Cell Biol 2:1044–1051;1982.

    PubMed  Google Scholar 

  30. Guyader M, Emerman M, Sonigo P, Clavel F, Montagnier L, Alizon M. Genome organization and transactivation of the human immunodeficiency virus type 2. Nature 326:662–669;1987.

    Article  PubMed  Google Scholar 

  31. Hauber J, Malim MH, Cullen BR. Mutational analysis of the conserved basic domain of human immunodeficiency virus Tat protein. J Virol 63:1181–1187;1989.

    PubMed  Google Scholar 

  32. Howcroft TK, Strebel K, Martin MA, Singer DS. Repression of MHC class I gene promoter activity by two-exon tat of HIV. Science 260:1320–1322;1993.

    PubMed  Google Scholar 

  33. Johnson AD, Krieg PA. pXeX, a vector for efficient expression of cloned sequences in Xenopus embryos. Gene 147:223–226;1994.

    Article  PubMed  Google Scholar 

  34. Kamine J, Elangovan B, Subramanian T, Coleman D, Chinnadurai G. Identification of a cellular protein that specifically interacts with the essential cysteine region of the HIV-1 Tat transactivator. Virology 216:357–366;1996.

    Article  PubMed  Google Scholar 

  35. Kashanchi F, Piras G, Radonovich MF, Duvall JF, Fattaey A, Chiang C, Roeder RG, Brady JN. Direct interaction of human TFIID with the HIV-1 transactivator Tat. Nature 367:295–299;1994.

    Article  PubMed  Google Scholar 

  36. Koken SEC, Greijer AE, Verhoef K, van Wamel J, Bukrinskaya AG, Berkhour B. Intracellular analysis of in vitro modified HIV Tat protein. J Biol Chem 269:8366–8375;1994.

    PubMed  Google Scholar 

  37. Koster JG, Destrée OHJ, Harold Raat NJ, Westerhoff HV. Histones inXenopus laevis' early development: The race against time. Biomed Biochim Acta 49:855–877;1990.

    PubMed  Google Scholar 

  38. Kuppuswamy M, Subramanian T, Srinivasan A, Chinnadurai G. Multiple functional domains of tat, the trans-activator of HIV-1 defined by mutational analysis. Nucleic Acids Res 17:3551–3561;1989.

    PubMed  Google Scholar 

  39. Longo F, Marchetti MA, Castagnoli L, Battaglia PA, Gigliani F. A novel approach to protein-protein interaction: Complex formation between the P53 tumor suppressor and the HIV Tat proteins. Biochem Biophys Res Commun 206:326–334;1995.

    Article  PubMed  Google Scholar 

  40. Nieuwkoop PD, Faber J. A normal table ofXenopus leavis (Daudin). Amsterdam, North Holland Publishing; 1967.

    Google Scholar 

  41. Orsini MJ, Debouck CM. Inhibition of human immunodeficiency virus type I and type 2 Tat function by transdominant Tat protein localized to both the nucleus and cytoplasm. J Virol 70:8055–8063;1996.

    PubMed  Google Scholar 

  42. Orsini MJ, Debouk CM, Webb CL, Lysko PG. Extracellular human immunodeficiency virus type 1 Tat protein promotes aggregation and adhesion of cerebellar neurons. J Neurosci 16:2546–2552;1996.

    PubMed  Google Scholar 

  43. Prioleau M-N, Huet J, Sentenac A, Mechali M. Competition between chromatin and transcription complex assembly regulates gene expression during early development. Cell 77:439–449;1994.

    Article  PubMed  Google Scholar 

  44. Prioleau M-N, Buckle RS, Mechali M. Programming of a repressed but committed chromatin structure during early development. EMBO J 14:5073–5084;1995.

    PubMed  Google Scholar 

  45. Reddy MV, Desai M, Jeyapaul J, Prasad DD, Seshamma T, Palmeri D, Khan SA. Functional analysis of the N-terminal domain of Tat protein of the human immunodeficiency virus type 1. Oncogene 7:7143–1748;1992.

    Google Scholar 

  46. Rice AP, Carlotti F. Mutational analysis of the conserved cysteine-rich region of the human immunodeficiency virus type 1 Tat protein. J Virol 64:1864–1868;1990.

    PubMed  Google Scholar 

  47. Roth SY, Allis CD. Histone acetylation and chromatin assembly: A single escort, multiple dances? Cell 87:5–8;1996.

    Article  PubMed  Google Scholar 

  48. Sastry KJ, Marin MC, Nehete PN, McConnel K, el-Naggar AK, McDonnel TJ. Expression of human immunodeficiency virus type 1 tat results in down-regulation of bcl-2 and induction of apoptosis in hematopoietic cells. Oncogene 13:487–493;1996.

    PubMed  Google Scholar 

  49. Schilthuis JG. Regulation of expression of histone genes during early development ofXenopus laevis. PhD thesis, Utrecht University, 1990.

  50. Schultz RM. Regulation of zygotic gene activation in the mouse. Bioessays 15:531–538;1993.

    Article  PubMed  Google Scholar 

  51. Sive HL, Heintz N, Roeder RG. Multiple sequency elements are required for maximal in vitro transcription of a human histone H2B gene. Mol Cell Biol 6:3329–3340;1986.

    PubMed  Google Scholar 

  52. Smith JC, Price BMJ, Green JBA, Weigel D, Herrmann BG. Expression of a Xenopus homolog of Brachyury (T) is an immediate-early response to mesoderm induction. Cell 67:79–87;1991.

    Article  PubMed  Google Scholar 

  53. Veenstra GJC, Beumer TL, Peterson-Maduro J, Stegeman BI, Karg HA, van der Vliet PC, Destrée OHJ. Dynamic and differential oct-1 expression during early Xenopus embryogenesis: Persistence of oct-1 protein following down-regulation of the RNA. Mech Dev 50:103–117;1995.

    Article  PubMed  Google Scholar 

  54. Verhoef K, Klein A, Berkhout B. Paracrine activation of the HIV-1 LTR promoter by the viral Tat protein is mechanistically similar to trans-activation within a cell. Virology 225:316–327;1996.

    Article  PubMed  Google Scholar 

  55. Veschambre P, Simard P, Jalinot P. Evidence for functional interaction between HIV-1 Tat transactivator and the TATA box binding protein in vivo. J Mol Biol 250:169–180;1995.

    Article  PubMed  Google Scholar 

  56. Yamamoto T, Horikoshi M. Novel substrate specificity of the histone acetyltransferase activity of HIV-1 Tat interactive protein Tip60. J Biol Chem 272:30595–30598;1997.

    Article  PubMed  Google Scholar 

  57. Yu L, Zhang ZH, Loewenstein PM, Desai K, Tang QQ, Mao DL, Symington JS, Green M. Molecular cloning and characterization of a cellular protein that interacts with the human immunodeficiency virus type 1 Tat transactivator and encodes a strong transcriptional activation domain. J Virol 69:3007–3016;1995.

    PubMed  Google Scholar 

  58. Zauli G, Gibellini D, Caputo A, Bassini A, Negrini M, Monne M, Mazzoni M, Capitani S. The human immunodeficiency virus type-1 Tat protein upregulates Bcl-2 gene expression in Jurkat T-cell lines and primary peripheral blood mononuclear cells. Blood 86:3823–3834;1995.

    PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Venanzi, S., Destrée, O.H.J., Gigliani, F. et al. Analysis of HIV-1 Tat effects inXenopus laevis embryos. J Biomed Sci 5, 211–220 (1998). https://doi.org/10.1007/BF02253471

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02253471

Key Words

Navigation