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. 1993 Jul;67(7):3703–3711. doi: 10.1128/jvi.67.7.3703-3711.1993

Genetic analysis of the cofactor requirement for human immunodeficiency virus type 1 Tat function.

S J Madore 1, B R Cullen 1
PMCID: PMC237733  PMID: 8389901

Abstract

The Tat protein of human immunodeficiency virus type 1 is a potent transcriptional trans activator of the viral long terminal repeat promoter element. Tat function requires the direct interaction of Tat with a cis-acting viral RNA target sequence termed the trans-activation response (TAR) element and has also been proposed to require at least one cellular cofactor. We have used a genetic approach to attempt to experimentally define the role of the cellular cofactor in Tat function and TAR binding. Our data suggest that neither Tat nor the cellular cofactor binds to TAR alone in vivo and indicate, instead, that the interaction of Tat with its cellular cofactor is a prerequisite for TAR binding. The known species tropism of lentivirus Tat proteins appears to arise from the fact that not only Tat but also the cellular cofactor can markedly influence the RNA sequence specificity of the resultant protein complex. These data also suggest that the Tat cofactor is likely a cellular transcription factor that has been highly conserved during vertebrate evolution. We hypothesize that the primary function of Tat is to redirect this cellular factor to a novel viral RNA target site and to thereby induce activation of viral gene expression.

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Selected References

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  1. Alexandersen S., Carpenter S. Characterization of variable regions in the envelope and S3 open reading frame of equine infectious anemia virus. J Virol. 1991 Aug;65(8):4255–4262. doi: 10.1128/jvi.65.8.4255-4262.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Alonso A., Derse D., Peterlin B. M. Human chromosome 12 is required for optimal interactions between Tat and TAR of human immunodeficiency virus type 1 in rodent cells. J Virol. 1992 Jul;66(7):4617–4621. doi: 10.1128/jvi.66.7.4617-4621.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Berkhout B., Jeang K. T. trans activation of human immunodeficiency virus type 1 is sequence specific for both the single-stranded bulge and loop of the trans-acting-responsive hairpin: a quantitative analysis. J Virol. 1989 Dec;63(12):5501–5504. doi: 10.1128/jvi.63.12.5501-5504.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Berkhout B., Silverman R. H., Jeang K. T. Tat trans-activates the human immunodeficiency virus through a nascent RNA target. Cell. 1989 Oct 20;59(2):273–282. doi: 10.1016/0092-8674(89)90289-4. [DOI] [PubMed] [Google Scholar]
  5. Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
  6. Calnan B. J., Biancalana S., Hudson D., Frankel A. D. Analysis of arginine-rich peptides from the HIV Tat protein reveals unusual features of RNA-protein recognition. Genes Dev. 1991 Feb;5(2):201–210. doi: 10.1101/gad.5.2.201. [DOI] [PubMed] [Google Scholar]
  7. Calnan B. J., Tidor B., Biancalana S., Hudson D., Frankel A. D. Arginine-mediated RNA recognition: the arginine fork. Science. 1991 May 24;252(5009):1167–1171. doi: 10.1126/science.252.5009.1167. [DOI] [PubMed] [Google Scholar]
  8. Carroll R., Martarano L., Derse D. Identification of lentivirus tat functional domains through generation of equine infectious anemia virus/human immunodeficiency virus type 1 tat gene chimeras. J Virol. 1991 Jul;65(7):3460–3467. doi: 10.1128/jvi.65.7.3460-3467.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Carroll R., Peterlin B. M., Derse D. Inhibition of human immunodeficiency virus type 1 Tat activity by coexpression of heterologous trans activators. J Virol. 1992 Apr;66(4):2000–2007. doi: 10.1128/jvi.66.4.2000-2007.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Carvalho M., Derse D. Mutational analysis of the equine infectious anemia virus Tat-responsive element. J Virol. 1991 Jul;65(7):3468–3474. doi: 10.1128/jvi.65.7.3468-3474.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Cullen B. R. Mechanism of action of regulatory proteins encoded by complex retroviruses. Microbiol Rev. 1992 Sep;56(3):375–394. doi: 10.1128/mr.56.3.375-394.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Cullen B. R. Use of eukaryotic expression technology in the functional analysis of cloned genes. Methods Enzymol. 1987;152:684–704. doi: 10.1016/0076-6879(87)52074-2. [DOI] [PubMed] [Google Scholar]
  13. Derse D., Carvalho M., Carroll R., Peterlin B. M. A minimal lentivirus Tat. J Virol. 1991 Dec;65(12):7012–7015. doi: 10.1128/jvi.65.12.7012-7015.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Dingwall C., Ernberg I., Gait M. J., Green S. M., Heaphy S., Karn J., Lowe A. D., Singh M., Skinner M. A. HIV-1 tat protein stimulates transcription by binding to a U-rich bulge in the stem of the TAR RNA structure. EMBO J. 1990 Dec;9(12):4145–4153. doi: 10.1002/j.1460-2075.1990.tb07637.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Feinberg M. B., Baltimore D., Frankel A. D. The role of Tat in the human immunodeficiency virus life cycle indicates a primary effect on transcriptional elongation. Proc Natl Acad Sci U S A. 1991 May 1;88(9):4045–4049. doi: 10.1073/pnas.88.9.4045. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Feng S., Holland E. C. HIV-1 tat trans-activation requires the loop sequence within tar. Nature. 1988 Jul 14;334(6178):165–167. doi: 10.1038/334165a0. [DOI] [PubMed] [Google Scholar]
  17. Garcia J. A., Harrich D., Pearson L., Mitsuyasu R., Gaynor R. B. Functional domains required for tat-induced transcriptional activation of the HIV-1 long terminal repeat. EMBO J. 1988 Oct;7(10):3143–3147. doi: 10.1002/j.1460-2075.1988.tb03181.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Hart C. E., Ou C. Y., Galphin J. C., Moore J., Bacheler L. T., Wasmuth J. J., Petteway S. R., Jr, Schochetman G. Human chromosome 12 is required for elevated HIV-1 expression in human-hamster hybrid cells. Science. 1989 Oct 27;246(4929):488–491. doi: 10.1126/science.2683071. [DOI] [PubMed] [Google Scholar]
  19. Hauber J., Perkins A., Heimer E. P., Cullen B. R. Trans-activation of human immunodeficiency virus gene expression is mediated by nuclear events. Proc Natl Acad Sci U S A. 1987 Sep;84(18):6364–6368. doi: 10.1073/pnas.84.18.6364. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Herskowitz I. Functional inactivation of genes by dominant negative mutations. Nature. 1987 Sep 17;329(6136):219–222. doi: 10.1038/329219a0. [DOI] [PubMed] [Google Scholar]
  21. Hope T. J., Huang X. J., McDonald D., Parslow T. G. Steroid-receptor fusion of the human immunodeficiency virus type 1 Rev transactivator: mapping cryptic functions of the arginine-rich motif. Proc Natl Acad Sci U S A. 1990 Oct;87(19):7787–7791. doi: 10.1073/pnas.87.19.7787. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Kamine J., Loewenstein P., Green M. Mapping of HIV-1 Tat protein sequences required for binding to Tar RNA. Virology. 1991 Jun;182(2):570–577. doi: 10.1016/0042-6822(91)90598-6. [DOI] [PubMed] [Google Scholar]
  23. Kao S. Y., Calman A. F., Luciw P. A., Peterlin B. M. Anti-termination of transcription within the long terminal repeat of HIV-1 by tat gene product. Nature. 1987 Dec 3;330(6147):489–493. doi: 10.1038/330489a0. [DOI] [PubMed] [Google Scholar]
  24. Kato H., Sumimoto H., Pognonec P., Chen C. H., Rosen C. A., Roeder R. G. HIV-1 Tat acts as a processivity factor in vitro in conjunction with cellular elongation factors. Genes Dev. 1992 Apr;6(4):655–666. doi: 10.1101/gad.6.4.655. [DOI] [PubMed] [Google Scholar]
  25. 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. 1989 May 11;17(9):3551–3561. doi: 10.1093/nar/17.9.3551. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Laspia M. F., Rice A. P., Mathews M. B. HIV-1 Tat protein increases transcriptional initiation and stabilizes elongation. Cell. 1989 Oct 20;59(2):283–292. doi: 10.1016/0092-8674(89)90290-0. [DOI] [PubMed] [Google Scholar]
  27. Liu Z. Q., Sheridan D., Wood C. Identification and characterization of the bovine immunodeficiency-like virus tat gene. J Virol. 1992 Aug;66(8):5137–5140. doi: 10.1128/jvi.66.8.5137-5140.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Malim M. H., McCarn D. F., Tiley L. S., Cullen B. R. Mutational definition of the human immunodeficiency virus type 1 Rev activation domain. J Virol. 1991 Aug;65(8):4248–4254. doi: 10.1128/jvi.65.8.4248-4254.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Malim M. H., Tiley L. S., McCarn D. F., Rusche J. R., Hauber J., Cullen B. R. HIV-1 structural gene expression requires binding of the Rev trans-activator to its RNA target sequence. Cell. 1990 Feb 23;60(4):675–683. doi: 10.1016/0092-8674(90)90670-a. [DOI] [PubMed] [Google Scholar]
  30. Marciniak R. A., Garcia-Blanco M. A., Sharp P. A. Identification and characterization of a HeLa nuclear protein that specifically binds to the trans-activation-response (TAR) element of human immunodeficiency virus. Proc Natl Acad Sci U S A. 1990 May;87(9):3624–3628. doi: 10.1073/pnas.87.9.3624. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Marciniak R. A., Sharp P. A. HIV-1 Tat protein promotes formation of more-processive elongation complexes. EMBO J. 1991 Dec;10(13):4189–4196. doi: 10.1002/j.1460-2075.1991.tb04997.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Mitchell P. J., Tjian R. Transcriptional regulation in mammalian cells by sequence-specific DNA binding proteins. Science. 1989 Jul 28;245(4916):371–378. doi: 10.1126/science.2667136. [DOI] [PubMed] [Google Scholar]
  33. Mullis K. B., Faloona F. A. Specific synthesis of DNA in vitro via a polymerase-catalyzed chain reaction. Methods Enzymol. 1987;155:335–350. doi: 10.1016/0076-6879(87)55023-6. [DOI] [PubMed] [Google Scholar]
  34. Nelbock P., Dillon P. J., Perkins A., Rosen C. A. A cDNA for a protein that interacts with the human immunodeficiency virus Tat transactivator. Science. 1990 Jun 29;248(4963):1650–1653. doi: 10.1126/science.2194290. [DOI] [PubMed] [Google Scholar]
  35. Newstein M., Stanbridge E. J., Casey G., Shank P. R. Human chromosome 12 encodes a species-specific factor which increases human immunodeficiency virus type 1 tat-mediated trans activation in rodent cells. J Virol. 1990 Sep;64(9):4565–4567. doi: 10.1128/jvi.64.9.4565-4567.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Ptashne M. How eukaryotic transcriptional activators work. Nature. 1988 Oct 20;335(6192):683–689. doi: 10.1038/335683a0. [DOI] [PubMed] [Google Scholar]
  37. Puglisi J. D., Tan R., Calnan B. J., Frankel A. D., Williamson J. R. Conformation of the TAR RNA-arginine complex by NMR spectroscopy. Science. 1992 Jul 3;257(5066):76–80. doi: 10.1126/science.1621097. [DOI] [PubMed] [Google Scholar]
  38. Rappaport J., Lee S. J., Khalili K., Wong-Staal F. The acidic amino-terminal region of the HIV-1 Tat protein constitutes an essential activating domain. New Biol. 1989 Oct;1(1):101–110. [PubMed] [Google Scholar]
  39. Roy S., Delling U., Chen C. H., Rosen C. A., Sonenberg N. A bulge structure in HIV-1 TAR RNA is required for Tat binding and Tat-mediated trans-activation. Genes Dev. 1990 Aug;4(8):1365–1373. doi: 10.1101/gad.4.8.1365. [DOI] [PubMed] [Google Scholar]
  40. Ruben S., Perkins A., Purcell R., Joung K., Sia R., Burghoff R., Haseltine W. A., Rosen C. A. Structural and functional characterization of human immunodeficiency virus tat protein. J Virol. 1989 Jan;63(1):1–8. doi: 10.1128/jvi.63.1.1-8.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Selby M. J., Peterlin B. M. Trans-activation by HIV-1 Tat via a heterologous RNA binding protein. Cell. 1990 Aug 24;62(4):769–776. doi: 10.1016/0092-8674(90)90121-t. [DOI] [PubMed] [Google Scholar]
  42. Southgate C. D., Green M. R. The HIV-1 Tat protein activates transcription from an upstream DNA-binding site: implications for Tat function. Genes Dev. 1991 Dec;5(12B):2496–2507. doi: 10.1101/gad.5.12b.2496. [DOI] [PubMed] [Google Scholar]
  43. Southgate C., Zapp M. L., Green M. R. Activation of transcription by HIV-1 Tat protein tethered to nascent RNA through another protein. Nature. 1990 Jun 14;345(6276):640–642. doi: 10.1038/345640a0. [DOI] [PubMed] [Google Scholar]
  44. Subramanian T., Kuppuswamy M., Venkatesh L., Srinivasan A., Chinnadurai G. Functional substitution of the basic domain of the HIV-1 trans-activator, Tat, with the basic domain of the functionally heterologous Rev. Virology. 1990 May;176(1):178–183. doi: 10.1016/0042-6822(90)90242-j. [DOI] [PubMed] [Google Scholar]
  45. Sullenger B. A., Gallardo H. F., Ungers G. E., Gilboa E. Analysis of trans-acting response decoy RNA-mediated inhibition of human immunodeficiency virus type 1 transactivation. J Virol. 1991 Dec;65(12):6811–6816. doi: 10.1128/jvi.65.12.6811-6816.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Tiley L. S., Brown P. H., Cullen B. R. Does the human immunodeficiency virus Tat trans-activator contain a discrete activation domain? Virology. 1990 Oct;178(2):560–567. doi: 10.1016/0042-6822(90)90354-t. [DOI] [PubMed] [Google Scholar]
  47. Tiley L. S., Madore S. J., Malim M. H., Cullen B. R. The VP16 transcription activation domain is functional when targeted to a promoter-proximal RNA sequence. Genes Dev. 1992 Nov;6(11):2077–2087. doi: 10.1101/gad.6.11.2077. [DOI] [PubMed] [Google Scholar]
  48. Weeks K. M., Ampe C., Schultz S. C., Steitz T. A., Crothers D. M. Fragments of the HIV-1 Tat protein specifically bind TAR RNA. Science. 1990 Sep 14;249(4974):1281–1285. doi: 10.1126/science.2205002. [DOI] [PubMed] [Google Scholar]
  49. Wu F., Garcia J., Sigman D., Gaynor R. tat regulates binding of the human immunodeficiency virus trans-activating region RNA loop-binding protein TRP-185. Genes Dev. 1991 Nov;5(11):2128–2140. doi: 10.1101/gad.5.11.2128. [DOI] [PubMed] [Google Scholar]
  50. Zapp M. L., Green M. R. Sequence-specific RNA binding by the HIV-1 Rev protein. Nature. 1989 Dec 7;342(6250):714–716. doi: 10.1038/342714a0. [DOI] [PubMed] [Google Scholar]

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