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. 1992 Jul;66(7):4325–4330. doi: 10.1128/jvi.66.7.4325-4330.1992

Phosphorylation regulates RNA binding by the human T-cell leukemia virus Rex protein.

P L Green 1, M T Yip 1, Y Xie 1, I S Chen 1
PMCID: PMC241238  PMID: 1602546

Abstract

The Rex protein of human T-cell leukemia virus types I (HTLV-I) and II (HTLV-II) regulates the expression of the viral structural genes and is critical for viral replication. Rex acts by specifically binding to RNAs containing sequences of the R region of the 5' long terminal repeat. Two forms of Rex detected in HTLV-II-infected cells, p26rex and p24rex, differ in the extent of serine phosphorylation. Two-dimensional phosphopeptide analysis indicates that p26rex is extensively phosphorylated at multiple sites. Using a sensitive immunobinding assay, we show that the phosphorylation state of Rex determines the efficiency of binding of Rex to HTLV-II target RNAs. Thus, the phosphorylation state of Rex in the infected cell may be a switch that determines whether virus exists in a latent or productive state. These studies also suggest that phosphorylation of RNA-binding regulatory proteins is a more general mechanism of gene regulation.

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Selected References

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  1. Adachi Y., Nosaka T., Hatanaka M. Protein kinase inhibitor H-7 blocks accumulation of unspliced mRNA of human T-cell leukemia virus type I (HTLV-I). Biochem Biophys Res Commun. 1990 Jun 15;169(2):469–475. doi: 10.1016/0006-291x(90)90355-q. [DOI] [PubMed] [Google Scholar]
  2. Arrigo S. J., Chen I. S. Rev is necessary for translation but not cytoplasmic accumulation of HIV-1 vif, vpr, and env/vpu 2 RNAs. Genes Dev. 1991 May;5(5):808–819. doi: 10.1101/gad.5.5.808. [DOI] [PubMed] [Google Scholar]
  3. Bagchi S., Raychaudhuri P., Nevins J. R. Phosphorylation-dependent activation of the adenovirus-inducible E2F transcription factor in a cell-free system. Proc Natl Acad Sci U S A. 1989 Jun;86(12):4352–4356. doi: 10.1073/pnas.86.12.4352. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Ballard D. W., Böhnlein E., Lowenthal J. W., Wano Y., Franza B. R., Greene W. C. HTLV-I tax induces cellular proteins that activate the kappa B element in the IL-2 receptor alpha gene. Science. 1988 Sep 23;241(4873):1652–1655. doi: 10.1126/science.241.4873.1652. [DOI] [PubMed] [Google Scholar]
  5. Ballaun C., Farrington G. K., Dobrovnik M., Rusche J., Hauber J., Böhnlein E. Functional analysis of human T-cell leukemia virus type I rex-response element: direct RNA binding of Rex protein correlates with in vivo activity. J Virol. 1991 Aug;65(8):4408–4413. doi: 10.1128/jvi.65.8.4408-4413.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Black A. C., Chen I. S., Arrigo S., Ruland C. T., Allogiamento T., Chin E., Rosenblatt J. D. Regulation of HTLV-II gene expression by Rex involves positive and negative cis-acting elements in the 5'long terminal repeat. Virology. 1991 Apr;181(2):433–444. doi: 10.1016/0042-6822(91)90875-c. [DOI] [PubMed] [Google Scholar]
  7. Black A. C., Ruland C. T., Yip M. T., Luo J., Tran B., Kalsi A., Quan E., Aboud M., Chen I. S., Rosenblatt J. D. Human T-cell leukemia virus type II Rex binding and activity require an intact splice donor site and a specific RNA secondary structure. J Virol. 1991 Dec;65(12):6645–6653. doi: 10.1128/jvi.65.12.6645-6653.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Bogerd H. P., Huckaby G. L., Ahmed Y. F., Hanly S. M., Greene W. C. The type I human T-cell leukemia virus (HTLV-I) Rex trans-activator binds directly to the HTLV-I Rex and the type 1 human immunodeficiency virus Rev RNA response elements. Proc Natl Acad Sci U S A. 1991 Jul 1;88(13):5704–5708. doi: 10.1073/pnas.88.13.5704. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Boyle W. J., Smeal T., Defize L. H., Angel P., Woodgett J. R., Karin M., Hunter T. Activation of protein kinase C decreases phosphorylation of c-Jun at sites that negatively regulate its DNA-binding activity. Cell. 1991 Feb 8;64(3):573–584. doi: 10.1016/0092-8674(91)90241-p. [DOI] [PubMed] [Google Scholar]
  10. Boyle W. J., van der Geer P., Hunter T. Phosphopeptide mapping and phosphoamino acid analysis by two-dimensional separation on thin-layer cellulose plates. Methods Enzymol. 1991;201:110–149. doi: 10.1016/0076-6879(91)01013-r. [DOI] [PubMed] [Google Scholar]
  11. Böhnlein E., Berger J., Hauber J. Functional mapping of the human immunodeficiency virus type 1 Rev RNA binding domain: new insights into the domain structure of Rev and Rex. J Virol. 1991 Dec;65(12):7051–7055. doi: 10.1128/jvi.65.12.7051-7055.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Cann A. J., Rosenblatt J. D., Wachsman W., Shah N. P., Chen I. S. Identification of the gene responsible for human T-cell leukaemia virus transcriptional regulation. Nature. 1985 Dec 12;318(6046):571–574. doi: 10.1038/318571a0. [DOI] [PubMed] [Google Scholar]
  13. Chen I. S., Cann A. J., Shah N. P., Gaynor R. B. Functional relation between HTLV-II x and adenovirus E1A proteins in transcriptional activation. Science. 1985 Nov 1;230(4725):570–573. doi: 10.1126/science.2996140. [DOI] [PubMed] [Google Scholar]
  14. 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]
  15. Cochrane A. W., Golub E., Volsky D., Ruben S., Rosen C. A. Functional significance of phosphorylation to the human immunodeficiency virus Rev protein. J Virol. 1989 Oct;63(10):4438–4440. doi: 10.1128/jvi.63.10.4438-4440.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. 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]
  17. Daly T. J., Cook K. S., Gray G. S., Maione T. E., Rusche J. R. Specific binding of HIV-1 recombinant Rev protein to the Rev-responsive element in vitro. Nature. 1989 Dec 14;342(6251):816–819. doi: 10.1038/342816a0. [DOI] [PubMed] [Google Scholar]
  18. Fujii M., Sassone-Corsi P., Verma I. M. c-fos promoter trans-activation by the tax1 protein of human T-cell leukemia virus type I. Proc Natl Acad Sci U S A. 1988 Nov;85(22):8526–8530. doi: 10.1073/pnas.85.22.8526. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. 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]
  20. Goh W. C., Sodroski J., Rosen C., Essex M., Haseltine W. A. Subcellular localization of the product of the long open reading frame of human T-cell leukemia virus type I. Science. 1985 Mar 8;227(4691):1227–1228. doi: 10.1126/science.2983419. [DOI] [PubMed] [Google Scholar]
  21. Grassmann R., Berchtold S., Aepinus C., Ballaun C., Boehnlein E., Fleckenstein B. In vitro binding of human T-cell leukemia virus rex proteins to the rex-response element of viral transcripts. J Virol. 1991 Jul;65(7):3721–3727. doi: 10.1128/jvi.65.7.3721-3727.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Grassmann R., Dengler C., Müller-Fleckenstein I., Fleckenstein B., McGuire K., Dokhelar M. C., Sodroski J. G., Haseltine W. A. Transformation to continuous growth of primary human T lymphocytes by human T-cell leukemia virus type I X-region genes transduced by a Herpesvirus saimiri vector. Proc Natl Acad Sci U S A. 1989 May;86(9):3351–3355. doi: 10.1073/pnas.86.9.3351. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Green P. L., Xie Y. M., Chen I. S. The Rex proteins of human T-cell leukemia virus type II differ by serine phosphorylation. J Virol. 1991 Jan;65(1):546–550. doi: 10.1128/jvi.65.1.546-550.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Hanly S. M., Rimsky L. T., Malim M. H., Kim J. H., Hauber J., Duc Dodon M., Le S. Y., Maizel J. V., Cullen B. R., Greene W. C. Comparative analysis of the HTLV-I Rex and HIV-1 Rev trans-regulatory proteins and their RNA response elements. Genes Dev. 1989 Oct;3(10):1534–1544. doi: 10.1101/gad.3.10.1534. [DOI] [PubMed] [Google Scholar]
  25. Heaphy S., Dingwall C., Ernberg I., Gait M. J., Green S. M., Karn J., Lowe A. D., Singh M., Skinner M. A. HIV-1 regulator of virion expression (Rev) protein binds to an RNA stem-loop structure located within the Rev response element region. Cell. 1990 Feb 23;60(4):685–693. doi: 10.1016/0092-8674(90)90671-z. [DOI] [PubMed] [Google Scholar]
  26. Hidaka M., Inoue J., Yoshida M., Seiki M. Post-transcriptional regulator (rex) of HTLV-1 initiates expression of viral structural proteins but suppresses expression of regulatory proteins. EMBO J. 1988 Feb;7(2):519–523. doi: 10.1002/j.1460-2075.1988.tb02840.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Hofer L., Weichselbraun I., Quick S., Farrington G. K., Böhnlein E., Hauber J. Mutational analysis of the human T-cell leukemia virus type I trans-acting rex gene product. J Virol. 1991 Jun;65(6):3379–3383. doi: 10.1128/jvi.65.6.3379-3383.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Hunter T. A thousand and one protein kinases. Cell. 1987 Sep 11;50(6):823–829. doi: 10.1016/0092-8674(87)90509-5. [DOI] [PubMed] [Google Scholar]
  29. Hunter T. Protein-tyrosine phosphatases: the other side of the coin. Cell. 1989 Sep 22;58(6):1013–1016. doi: 10.1016/0092-8674(89)90496-0. [DOI] [PubMed] [Google Scholar]
  30. Hunter T., Sefton B. M. Transforming gene product of Rous sarcoma virus phosphorylates tyrosine. Proc Natl Acad Sci U S A. 1980 Mar;77(3):1311–1315. doi: 10.1073/pnas.77.3.1311. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. 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]
  32. 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]
  33. 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]
  34. Lazinski D., Grzadzielska E., Das A. Sequence-specific recognition of RNA hairpins by bacteriophage antiterminators requires a conserved arginine-rich motif. Cell. 1989 Oct 6;59(1):207–218. doi: 10.1016/0092-8674(89)90882-9. [DOI] [PubMed] [Google Scholar]
  35. Luo K. X., Hurley T. R., Sefton B. M. Cyanogen bromide cleavage and proteolytic peptide mapping of proteins immobilized to membranes. Methods Enzymol. 1991;201:149–152. doi: 10.1016/0076-6879(91)01014-s. [DOI] [PubMed] [Google Scholar]
  36. Lüscher B., Christenson E., Litchfield D. W., Krebs E. G., Eisenman R. N. Myb DNA binding inhibited by phosphorylation at a site deleted during oncogenic activation. Nature. 1990 Apr 5;344(6266):517–522. doi: 10.1038/344517a0. [DOI] [PubMed] [Google Scholar]
  37. Malim M. H., Böhnlein S., Hauber J., Cullen B. R. Functional dissection of the HIV-1 Rev trans-activator--derivation of a trans-dominant repressor of Rev function. Cell. 1989 Jul 14;58(1):205–214. doi: 10.1016/0092-8674(89)90416-9. [DOI] [PubMed] [Google Scholar]
  38. Malim M. H., Hauber J., Fenrick R., Cullen B. R. Immunodeficiency virus rev trans-activator modulates the expression of the viral regulatory genes. Nature. 1988 Sep 8;335(6186):181–183. doi: 10.1038/335181a0. [DOI] [PubMed] [Google Scholar]
  39. Manak J. R., de Bisschop N., Kris R. M., Prywes R. Casein kinase II enhances the DNA binding activity of serum response factor. Genes Dev. 1990 Jun;4(6):955–967. doi: 10.1101/gad.4.6.955. [DOI] [PubMed] [Google Scholar]
  40. 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]
  41. Nagashima K., Yoshida M., Seiki M. A single species of pX mRNA of human T-cell leukemia virus type I encodes trans-activator p40x and two other phosphoproteins. J Virol. 1986 Nov;60(2):394–399. doi: 10.1128/jvi.60.2.394-399.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Nerenberg M., Hinrichs S. H., Reynolds R. K., Khoury G., Jay G. The tat gene of human T-lymphotropic virus type 1 induces mesenchymal tumors in transgenic mice. Science. 1987 Sep 11;237(4820):1324–1329. doi: 10.1126/science.2888190. [DOI] [PubMed] [Google Scholar]
  43. Nimer S. D., Gasson J. C., Hu K., Smalberg I., Williams J. L., Chen I. S., Rosenblatt J. D. Activation of the GM-CSF promoter by HTLV-I and -II tax proteins. Oncogene. 1989 Jun;4(6):671–676. [PubMed] [Google Scholar]
  44. Nosaka T., Siomi H., Adachi Y., Ishibashi M., Kubota S., Maki M., Hatanaka M. Nucleolar targeting signal of human T-cell leukemia virus type I rex-encoded protein is essential for cytoplasmic accumulation of unspliced viral mRNA. Proc Natl Acad Sci U S A. 1989 Dec;86(24):9798–9802. doi: 10.1073/pnas.86.24.9798. [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Ofir R., Dwarki V. J., Rashid D., Verma I. M. Phosphorylation of the C terminus of Fos protein is required for transcriptional transrepression of the c-fos promoter. Nature. 1990 Nov 1;348(6296):80–82. doi: 10.1038/348080a0. [DOI] [PubMed] [Google Scholar]
  46. Ohta M., Nyunoya H., Tanaka H., Okamoto T., Akagi T., Shimotohno K. Identification of a cis-regulatory element involved in accumulation of human T-cell leukemia virus type II genomic mRNA. J Virol. 1988 Dec;62(12):4445–4451. doi: 10.1128/jvi.62.12.4445-4451.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Raychaudhuri P., Bagchi S., Nevins J. R. DNA-binding activity of the adenovirus-induced E4F transcription factor is regulated by phosphorylation. Genes Dev. 1989 May;3(5):620–627. doi: 10.1101/gad.3.5.620. [DOI] [PubMed] [Google Scholar]
  48. Rosenblatt J. D., Cann A. J., Slamon D. J., Smalberg I. S., Shah N. P., Fujii J., Wachsman W., Chen I. S. HTLV-II transactivation is regulated by the overlapping tax/rex nonstructural genes. Science. 1988 May 13;240(4854):916–919. doi: 10.1126/science.2834826. [DOI] [PubMed] [Google Scholar]
  49. Seiki M., Inoue J., Hidaka M., Yoshida M. Two cis-acting elements responsible for posttranscriptional trans-regulation of gene expression of human T-cell leukemia virus type I. Proc Natl Acad Sci U S A. 1988 Oct;85(19):7124–7128. doi: 10.1073/pnas.85.19.7124. [DOI] [PMC free article] [PubMed] [Google Scholar]
  50. 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]
  51. Shima H., Takano M., Shimotohno K., Miwa M. Identification of p26Xb and p24Xb of human T-cell leukemia virus type II. FEBS Lett. 1986 Dec 15;209(2):289–294. doi: 10.1016/0014-5793(86)81129-2. [DOI] [PubMed] [Google Scholar]
  52. Siomi H., Shida H., Nam S. H., Nosaka T., Maki M., Hatanaka M. Sequence requirements for nucleolar localization of human T cell leukemia virus type I pX protein, which regulates viral RNA processing. Cell. 1988 Oct 21;55(2):197–209. doi: 10.1016/0092-8674(88)90043-8. [DOI] [PubMed] [Google Scholar]
  53. Slamon D. J., Boyle W. J., Keith D. E., Press M. F., Golde D. W., Souza L. M. Subnuclear localization of the trans-activating protein of human T-cell leukemia virus type I. J Virol. 1988 Mar;62(3):680–686. doi: 10.1128/jvi.62.3.680-686.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  54. Slamon D. J., Press M. F., Souza L. M., Murdock D. C., Cline M. J., Golde D. W., Gasson J. C., Chen I. S. Studies of the putative transforming protein of the type I human T-cell leukemia virus. Science. 1985 Jun 21;228(4706):1427–1430. doi: 10.1126/science.2990027. [DOI] [PubMed] [Google Scholar]
  55. Tanaka A., Takahashi C., Yamaoka S., Nosaka T., Maki M., Hatanaka M. Oncogenic transformation by the tax gene of human T-cell leukemia virus type I in vitro. Proc Natl Acad Sci U S A. 1990 Feb;87(3):1071–1075. doi: 10.1073/pnas.87.3.1071. [DOI] [PMC free article] [PubMed] [Google Scholar]
  56. Wano Y., Feinberg M., Hosking J. B., Bogerd H., Greene W. C. Stable expression of the tax gene of type I human T-cell leukemia virus in human T cells activates specific cellular genes involved in growth. Proc Natl Acad Sci U S A. 1988 Dec;85(24):9733–9737. doi: 10.1073/pnas.85.24.9733. [DOI] [PMC free article] [PubMed] [Google Scholar]
  57. Yip M. T., Dynan W. S., Green P. L., Black A. C., Arrigo S. J., Torbati A., Heaphy S., Ruland C., Rosenblatt J. D., Chen I. S. Human T-cell leukemia virus (HTLV) type II Rex protein binds specifically to RNA sequences of the HTLV long terminal repeat but poorly to the human immunodeficiency virus type 1 Rev-responsive element. J Virol. 1991 May;65(5):2261–2272. doi: 10.1128/jvi.65.5.2261-2272.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]

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