Skip to main content
NCBI home page
The EMBO Journal logoLink to The EMBO Journal
. 1988 Feb;7(2):519–523. doi: 10.1002/j.1460-2075.1988.tb02840.x

Post-transcriptional regulator (rex) of HTLV-1 initiates expression of viral structural proteins but suppresses expression of regulatory proteins.

M Hidaka 1, J Inoue 1, M Yoshida 1, M Seiki 1
PMCID: PMC454349  PMID: 2835230

Abstract

Gene expression of human T-cell leukemia virus type 1 (HTLV-1) is regulated by two trans-acting factors encoded by the pX region, p40tax and p27tax.p40tax is a transcriptional activator and p27rex is a post-transcriptional regulator. Using full-length viral DNA, we studied the regulatory effects of rex on HTLV-1 gene expression. p27rex is required for expression of both gag and env proteins, increasing the level of their mRNAs. The effect was dependent on the dose of p27rex expression plasmid. In parallel, increased doses of p27rex suppressed the expression of fully spliced pX mRNA, which encodes the regulatory proteins. These two effects of p27rex operated at the post-transcriptional level and were independent of transcriptional regulation. Lowering the level of pX mRNA down-regulates transcription of the proviral genome. These observations demonstrate that rex is a positive post-transcriptional regulator for gag, pol and env protein expression, and acts at the same time as an indirect negative regulator of viral transcription.

Full text

PDF
519

Images in this article

520Image
on p.520
520Image
on p.520
521Image
on p.521
521Image
on p.521

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Berger S. L., Birkenmeier C. S. Inhibition of intractable nucleases with ribonucleoside--vanadyl complexes: isolation of messenger ribonucleic acid from resting lymphocytes. Biochemistry. 1979 Nov 13;18(23):5143–5149. doi: 10.1021/bi00590a018. [DOI] [PubMed] [Google Scholar]
  2. Chen I. S., Slamon D. J., Rosenblatt J. D., Shah N. P., Quan S. G., Wachsman W. The x gene is essential for HTLV replication. Science. 1985 Jul 5;229(4708):54–58. doi: 10.1126/science.2990037. [DOI] [PubMed] [Google Scholar]
  3. Clarke M. F., Trainor C. D., Mann D. L., Gallo R. C., Reitz M. S. Methylation of human T-cell leukemia virus proviral DNA and viral RNA expression in short- and long-term cultures of infected cells. Virology. 1984 May;135(1):97–104. doi: 10.1016/0042-6822(84)90120-x. [DOI] [PubMed] [Google Scholar]
  4. Cross S. L., Feinberg M. B., Wolf J. B., Holbrook N. J., Wong-Staal F., Leonard W. J. Regulation of the human interleukin-2 receptor alpha chain promoter: activation of a nonfunctional promoter by the transactivator gene of HTLV-I. Cell. 1987 Apr 10;49(1):47–56. doi: 10.1016/0092-8674(87)90754-9. [DOI] [PubMed] [Google Scholar]
  5. Feinberg M. B., Jarrett R. F., Aldovini A., Gallo R. C., Wong-Staal F. HTLV-III expression and production involve complex regulation at the levels of splicing and translation of viral RNA. Cell. 1986 Sep 12;46(6):807–817. doi: 10.1016/0092-8674(86)90062-0. [DOI] [PubMed] [Google Scholar]
  6. Felber B. K., Paskalis H., Kleinman-Ewing C., Wong-Staal F., Pavlakis G. N. The pX protein of HTLV-I is a transcriptional activator of its long terminal repeats. Science. 1985 Aug 16;229(4714):675–679. doi: 10.1126/science.2992082. [DOI] [PubMed] [Google Scholar]
  7. Fujisawa J., Seiki M., Kiyokawa T., Yoshida M. Functional activation of the long terminal repeat of human T-cell leukemia virus type I by a trans-acting factor. Proc Natl Acad Sci U S A. 1985 Apr;82(8):2277–2281. doi: 10.1073/pnas.82.8.2277. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Fujisawa J., Seiki M., Sato M., Yoshida M. A transcriptional enhancer sequence of HTLV-I is responsible for trans-activation mediated by p40 chi HTLV-I. EMBO J. 1986 Apr;5(4):713–718. doi: 10.1002/j.1460-2075.1986.tb04272.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Hayward W. S., Neel B. G., Astrin S. M. Activation of a cellular onc gene by promoter insertion in ALV-induced lymphoid leukosis. Nature. 1981 Apr 9;290(5806):475–480. doi: 10.1038/290475a0. [DOI] [PubMed] [Google Scholar]
  10. Hinuma Y., Nagata K., Hanaoka M., Nakai M., Matsumoto T., Kinoshita K. I., Shirakawa S., Miyoshi I. Adult T-cell leukemia: antigen in an ATL cell line and detection of antibodies to the antigen in human sera. Proc Natl Acad Sci U S A. 1981 Oct;78(10):6476–6480. doi: 10.1073/pnas.78.10.6476. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Inoue J., Seiki M., Taniguchi T., Tsuru S., Yoshida M. Induction of interleukin 2 receptor gene expression by p40x encoded by human T-cell leukemia virus type 1. EMBO J. 1986 Nov;5(11):2883–2888. doi: 10.1002/j.1460-2075.1986.tb04583.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Inoue J., Seiki M., Yoshida M. The second pX product p27 chi-III of HTLV-1 is required for gag gene expression. FEBS Lett. 1986 Dec 15;209(2):187–190. doi: 10.1016/0014-5793(86)81108-5. [DOI] [PubMed] [Google Scholar]
  13. Inoue J., Yoshida M., Seiki M. Transcriptional (p40x) and post-transcriptional (p27x-III) regulators are required for the expression and replication of human T-cell leukemia virus type I genes. Proc Natl Acad Sci U S A. 1987 Jun;84(11):3653–3657. doi: 10.1073/pnas.84.11.3653. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Kalyanaraman V. S., Sarngadharan M. G., Robert-Guroff M., Miyoshi I., Golde D., Gallo R. C. A new subtype of human T-cell leukemia virus (HTLV-II) associated with a T-cell variant of hairy cell leukemia. Science. 1982 Nov 5;218(4572):571–573. doi: 10.1126/science.6981847. [DOI] [PubMed] [Google Scholar]
  15. Kitamura T., Takano M., Hoshino H., Shimotohno K., Shimoyama M., Miwa M., Takaku F., Sugimura T. Methylation pattern of human T-cell leukemia virus in vivo and in vitro: pX and LTR regions are hypomethylated in vivo. Int J Cancer. 1985 May 15;35(5):629–635. doi: 10.1002/ijc.2910350510. [DOI] [PubMed] [Google Scholar]
  16. Kiyokawa T., Seiki M., Imagawa K., Shimizu F., Yoshida M. Identification of a protein (p40x) encoded by a unique sequence pX of human T-cell leukemia virus type I. Gan. 1984 Sep;75(9):747–751. [PubMed] [Google Scholar]
  17. Kiyokawa T., Seiki M., Iwashita S., Imagawa K., Shimizu F., Yoshida M. p27x-III and p21x-III, proteins encoded by the pX sequence of human T-cell leukemia virus type I. Proc Natl Acad Sci U S A. 1985 Dec;82(24):8359–8363. doi: 10.1073/pnas.82.24.8359. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Lee T. H., Coligan J. E., Sodroski J. G., Haseltine W. A., Salahuddin S. Z., Wong-Staal F., Gallo R. C., Essex M. Antigens encoded by the 3'-terminal region of human T-cell leukemia virus: evidence for a functional gene. Science. 1984 Oct 5;226(4670):57–61. doi: 10.1126/science.6089350. [DOI] [PubMed] [Google Scholar]
  19. Maruyama M., Shibuya H., Harada H., Hatakeyama M., Seiki M., Fujita T., Inoue J., Yoshida M., Taniguchi T. Evidence for aberrant activation of the interleukin-2 autocrine loop by HTLV-1-encoded p40x and T3/Ti complex triggering. Cell. 1987 Jan 30;48(2):343–350. doi: 10.1016/0092-8674(87)90437-5. [DOI] [PubMed] [Google Scholar]
  20. Miwa M., Shimotohno K., Hoshino H., Fujino M., Sugimura T. Detection of pX proteins in human T-cell leukemia virus (HTLV)-infected cells by using antibody against peptide deduced from sequences of X-IV DNA of HTLV-I and Xc DNA of HTLV-II proviruses. Gan. 1984 Sep;75(9):752–755. [PubMed] [Google Scholar]
  21. Poiesz B. J., Ruscetti F. W., Gazdar A. F., Bunn P. A., Minna J. D., Gallo R. C. Detection and isolation of type C retrovirus particles from fresh and cultured lymphocytes of a patient with cutaneous T-cell lymphoma. Proc Natl Acad Sci U S A. 1980 Dec;77(12):7415–7419. doi: 10.1073/pnas.77.12.7415. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Sagata N., Yasunaga T., Ikawa Y. Two distinct polypeptides may be translated from a single spliced mRNA of the X genes of human T-cell leukemia and bovine leukemia viruses. FEBS Lett. 1985 Nov 11;192(1):37–42. doi: 10.1016/0014-5793(85)80038-7. [DOI] [PubMed] [Google Scholar]
  23. Seiki M., Hattori S., Hirayama Y., Yoshida M. Human adult T-cell leukemia virus: complete nucleotide sequence of the provirus genome integrated in leukemia cell DNA. Proc Natl Acad Sci U S A. 1983 Jun;80(12):3618–3622. doi: 10.1073/pnas.80.12.3618. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Seiki M., Hikikoshi A., Taniguchi T., Yoshida M. Expression of the pX gene of HTLV-I: general splicing mechanism in the HTLV family. Science. 1985 Jun 28;228(4707):1532–1534. doi: 10.1126/science.2990031. [DOI] [PubMed] [Google Scholar]
  25. Seiki M., Inoue J., Takeda T., Hikikoshi A., Sato M., Yoshida M. The p40x of human T-cell leukemia virus type I is a trans-acting activator of viral gene transcription. Jpn J Cancer Res. 1985 Dec;76(12):1127–1131. [PubMed] [Google Scholar]
  26. Seiki M., Inoue J., Takeda T., Yoshida M. Direct evidence that p40x of human T-cell leukemia virus type I is a trans-acting transcriptional activator. EMBO J. 1986 Mar;5(3):561–565. doi: 10.1002/j.1460-2075.1986.tb04247.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Slamon D. J., Shimotohno K., Cline M. J., Golde D. W., Chen I. S. Identification of the putative transforming protein of the human T-cell leukemia viruses HTLV-I and HTLV-II. Science. 1984 Oct 5;226(4670):61–65. doi: 10.1126/science.6089351. [DOI] [PubMed] [Google Scholar]
  28. Sodroski J. G., Rosen C. A., Haseltine W. A. Trans-acting transcriptional activation of the long terminal repeat of human T lymphotropic viruses in infected cells. Science. 1984 Jul 27;225(4660):381–385. doi: 10.1126/science.6330891. [DOI] [PubMed] [Google Scholar]
  29. Sodroski J., Goh W. C., Rosen C., Dayton A., Terwilliger E., Haseltine W. A second post-transcriptional trans-activator gene required for HTLV-III replication. Nature. 1986 May 22;321(6068):412–417. doi: 10.1038/321412a0. [DOI] [PubMed] [Google Scholar]
  30. Sodroski J., Rosen C., Goh W. C., Haseltine W. A transcriptional activator protein encoded by the x-lor region of the human T-cell leukemia virus. Science. 1985 Jun 21;228(4706):1430–1434. doi: 10.1126/science.2990028. [DOI] [PubMed] [Google Scholar]
  31. Sugamura K., Fujii M., Ueda S., Hinuma Y. Identification of a glycoprotein, gp21, of adult T cell leukemia virus by monoclonal antibody. J Immunol. 1984 Jun;132(6):3180–3184. [PubMed] [Google Scholar]
  32. Wong-Staal F., Hahn B., Manzari V., Colombini S., Franchini G., Gelmann E. P., Gallo R. C. A survey of human leukaemias for sequences of a human retrovirus. Nature. 1983 Apr 14;302(5909):626–628. doi: 10.1038/302626a0. [DOI] [PubMed] [Google Scholar]
  33. Yoshida M., Miyoshi I., Hinuma Y. Isolation and characterization of retrovirus from cell lines of human adult T-cell leukemia and its implication in the disease. Proc Natl Acad Sci U S A. 1982 Mar;79(6):2031–2035. doi: 10.1073/pnas.79.6.2031. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Yoshida M., Seiki M., Yamaguchi K., Takatsuki K. Monoclonal integration of human T-cell leukemia provirus in all primary tumors of adult T-cell leukemia suggests causative role of human T-cell leukemia virus in the disease. Proc Natl Acad Sci U S A. 1984 Apr;81(8):2534–2537. doi: 10.1073/pnas.81.8.2534. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The EMBO Journal are provided here courtesy of Nature Publishing Group

RESOURCES