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. 1993 Sep;67(9):5206–5215. doi: 10.1128/jvi.67.9.5206-5215.1993

cdc2 phosphorylation of threonine 124 activates the origin-unwinding functions of simian virus 40 T antigen.

D McVey 1, S Ray 1, Y Gluzman 1, L Berger 1, A G Wildeman 1, D R Marshak 1, P Tegtmeyer 1
PMCID: PMC237918  PMID: 8394445

Abstract

Phosphorylation of simian virus 40 (SV40) T antigen on threonine 124 activates viral DNA replication in vivo and in vitro. We have manipulated the modification of T-antigen residue 124 both genetically and biochemically and have investigated individual replication functions of T antigen under conditions suitable for in vitro DNA replication. We find that the hexamer assembly, helicase, DNA polymerase alpha-binding, and transcriptional-autoregulation functions are independent of phosphorylation of threonine 124. In contrast, neither T antigen with an alanine mutation of threonine 124 made in human cells nor unphosphorylated T antigen made in Escherichia coli binds the SV40 replication origin as stably as phosphorylated wild-type T antigen does. Furthermore, modification of threonine 124 is essential for complete unwinding of the SV40 replication origin. We conclude that phosphorylation of threonine 124 enhances specific interactions of T antigen with SV40 origin DNA. Our findings do not exclude the possibility that phosphorylation of threonine 124 may affect additional undefined steps in DNA replication. We also show that DNase footprinting and KMnO4 modification assays are not as stringent as immunoprecipitation and origin-dependent strand displacement assays for detecting defects in the origin-binding and -unwinding functions of T antigen. Differences in the assays may explain discrepancies in previous reports on the role of T-antigen phosphorylation in DNA binding.

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Selected References

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

  1. Arthur A. K., Höss A., Fanning E. Expression of simian virus 40 T antigen in Escherichia coli: localization of T-antigen origin DNA-binding domain to within 129 amino acids. J Virol. 1988 Jun;62(6):1999–2006. doi: 10.1128/jvi.62.6.1999-2006.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Baumann E. A. DNA-binding properties of phosphorylated and dephosphorylated D2-T antigen, a simian-virus-40 T-antigen-related protein. Eur J Biochem. 1985 Mar 15;147(3):495–501. doi: 10.1111/j.0014-2956.1985.00495.x. [DOI] [PubMed] [Google Scholar]
  3. Bergsma D. J., Olive D. M., Hartzell S. W., Subramanian K. N. Territorial limits and functional anatomy of the simian virus 40 replication origin. Proc Natl Acad Sci U S A. 1982 Jan;79(2):381–385. doi: 10.1073/pnas.79.2.381. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Borowiec J. A., Hurwitz J. ATP stimulates the binding of simian virus 40 (SV40) large tumor antigen to the SV40 origin of replication. Proc Natl Acad Sci U S A. 1988 Jan;85(1):64–68. doi: 10.1073/pnas.85.1.64. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Borowiec J. A., Hurwitz J. Localized melting and structural changes in the SV40 origin of replication induced by T-antigen. EMBO J. 1988 Oct;7(10):3149–3158. doi: 10.1002/j.1460-2075.1988.tb03182.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Copeland W. C., Wang T. S. Catalytic subunit of human DNA polymerase alpha overproduced from baculovirus-infected insect cells. Structural and enzymological characterization. J Biol Chem. 1991 Nov 25;266(33):22739–22748. [PubMed] [Google Scholar]
  7. Coulombe J., Berger L., Smith D. B., Hehl R. K., Wildeman A. G. Activation of simian virus 40 transcription in vitro by T antigen. J Virol. 1992 Jul;66(7):4591–4596. doi: 10.1128/jvi.66.7.4591-4596.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. DeLucia A. L., Deb S., Partin K., Tegtmeyer P. Functional interactions of the simian virus 40 core origin of replication with flanking regulatory sequences. J Virol. 1986 Jan;57(1):138–144. doi: 10.1128/jvi.57.1.138-144.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. DeLucia A. L., Lewton B. A., Tjian R., Tegtmeyer P. Topography of simian virus 40 A protein-DNA complexes: arrangement of pentanucleotide interaction sites at the origin of replication. J Virol. 1983 Apr;46(1):143–150. doi: 10.1128/jvi.46.1.143-150.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Dean F. B., Bullock P., Murakami Y., Wobbe C. R., Weissbach L., Hurwitz J. Simian virus 40 (SV40) DNA replication: SV40 large T antigen unwinds DNA containing the SV40 origin of replication. Proc Natl Acad Sci U S A. 1987 Jan;84(1):16–20. doi: 10.1073/pnas.84.1.16. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Deb S. P., Tegtmeyer P. ATP enhances the binding of simian virus 40 large T antigen to the origin of replication. J Virol. 1987 Dec;61(12):3649–3654. doi: 10.1128/jvi.61.12.3649-3654.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Deb S., DeLucia A. L., Baur C. P., Koff A., Tegtmeyer P. Domain structure of the simian virus 40 core origin of replication. Mol Cell Biol. 1986 May;6(5):1663–1670. doi: 10.1128/mcb.6.5.1663. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Deb S., DeLucia A. L., Koff A., Tsui S., Tegtmeyer P. The adenine-thymine domain of the simian virus 40 core origin directs DNA bending and coordinately regulates DNA replication. Mol Cell Biol. 1986 Dec;6(12):4578–4584. doi: 10.1128/mcb.6.12.4578. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Deb S., Tsui S., Koff A., DeLucia A. L., Parsons R., Tegtmeyer P. The T-antigen-binding domain of the simian virus 40 core origin of replication. J Virol. 1987 Jul;61(7):2143–2149. doi: 10.1128/jvi.61.7.2143-2149.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Dornreiter I., Erdile L. F., Gilbert I. U., von Winkler D., Kelly T. J., Fanning E. Interaction of DNA polymerase alpha-primase with cellular replication protein A and SV40 T antigen. EMBO J. 1992 Feb;11(2):769–776. doi: 10.1002/j.1460-2075.1992.tb05110.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Dornreiter I., Höss A., Arthur A. K., Fanning E. SV40 T antigen binds directly to the large subunit of purified DNA polymerase alpha. EMBO J. 1990 Oct;9(10):3329–3336. doi: 10.1002/j.1460-2075.1990.tb07533.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Gralla J. D. Rapid "footprinting" on supercoiled DNA. Proc Natl Acad Sci U S A. 1985 May;82(10):3078–3081. doi: 10.1073/pnas.82.10.3078. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Grässer F. A., Mann K., Walter G. Removal of serine phosphates from simian virus 40 large T antigen increases its ability to stimulate DNA replication in vitro but has no effect on ATPase and DNA binding. J Virol. 1987 Nov;61(11):3373–3380. doi: 10.1128/jvi.61.11.3373-3380.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Hansen U., Tenen D. G., Livingston D. M., Sharp P. A. T antigen repression of SV40 early transcription from two promoters. Cell. 1981 Dec;27(3 Pt 2):603–613. doi: 10.1016/0092-8674(81)90402-5. [DOI] [PubMed] [Google Scholar]
  20. Harlow E., Crawford L. V., Pim D. C., Williamson N. M. Monoclonal antibodies specific for simian virus 40 tumor antigens. J Virol. 1981 Sep;39(3):861–869. doi: 10.1128/jvi.39.3.861-869.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Johnson L. N. Glycogen phosphorylase: control by phosphorylation and allosteric effectors. FASEB J. 1992 Mar;6(6):2274–2282. doi: 10.1096/fasebj.6.6.1544539. [DOI] [PubMed] [Google Scholar]
  22. Loeber G., Stenger J. E., Ray S., Parsons R. E., Anderson M. E., Tegtmeyer P. The zinc finger region of simian virus 40 large T antigen is needed for hexamer assembly and origin melting. J Virol. 1991 Jun;65(6):3167–3174. doi: 10.1128/jvi.65.6.3167-3174.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Manley J. L., Fire A., Cano A., Sharp P. A., Gefter M. L. DNA-dependent transcription of adenovirus genes in a soluble whole-cell extract. Proc Natl Acad Sci U S A. 1980 Jul;77(7):3855–3859. doi: 10.1073/pnas.77.7.3855. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Mastrangelo I. A., Hough P. V., Wall J. S., Dodson M., Dean F. B., Hurwitz J. ATP-dependent assembly of double hexamers of SV40 T antigen at the viral origin of DNA replication. Nature. 1989 Apr 20;338(6217):658–662. doi: 10.1038/338658a0. [DOI] [PubMed] [Google Scholar]
  25. McKay R. D. Binding of a simian virus 40 T antigen-related protein to DNA. J Mol Biol. 1981 Jan 25;145(3):471–488. doi: 10.1016/0022-2836(81)90540-4. [DOI] [PubMed] [Google Scholar]
  26. McVey D., Brizuela L., Mohr I., Marshak D. R., Gluzman Y., Beach D. Phosphorylation of large tumour antigen by cdc2 stimulates SV40 DNA replication. Nature. 1989 Oct 12;341(6242):503–507. doi: 10.1038/341503a0. [DOI] [PubMed] [Google Scholar]
  27. McVey D., Strauss M., Gluzman Y. Properties of the DNA-binding domain of the simian virus 40 large T antigen. Mol Cell Biol. 1989 Dec;9(12):5525–5536. doi: 10.1128/mcb.9.12.5525. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Mohr I. J., Gluzman Y., Fairman M. P., Strauss M., McVey D., Stillman B., Gerard R. D. Production of simian virus 40 large tumor antigen in bacteria: altered DNA-binding specificity and dna-replication activity of underphosphorylated large tumor antigen. Proc Natl Acad Sci U S A. 1989 Sep;86(17):6479–6483. doi: 10.1073/pnas.86.17.6479. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Mohr I. J., Stillman B., Gluzman Y. Regulation of SV40 DNA replication by phosphorylation of T antigen. EMBO J. 1987 Jan;6(1):153–160. doi: 10.1002/j.1460-2075.1987.tb04733.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Pages J., Manteuil S., Stehelin D., Fiszman M., Marx M., Girard M. Relationship between replication of simian virus 40 DNA and specific events of the host cell cycle. J Virol. 1973 Jul;12(1):99–107. doi: 10.1128/jvi.12.1.99-107.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Parsons R. E., Stenger J. E., Ray S., Welker R., Anderson M. E., Tegtmeyer P. Cooperative assembly of simian virus 40 T-antigen hexamers on functional halves of the replication origin. J Virol. 1991 Jun;65(6):2798–2806. doi: 10.1128/jvi.65.6.2798-2806.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Parsons R., Anderson M. E., Tegtmeyer P. Three domains in the simian virus 40 core origin orchestrate the binding, melting, and DNA helicase activities of T antigen. J Virol. 1990 Feb;64(2):509–518. doi: 10.1128/jvi.64.2.509-518.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Paucha E., Kalderon D., Harvey R. W., Smith A. E. Simian virus 40 origin DNA-binding domain on large T antigen. J Virol. 1986 Jan;57(1):50–64. doi: 10.1128/jvi.57.1.50-64.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Pauly M., Treger M., Westhof E., Chambon P. The initiation accuracy of the SV40 early transcription is determined by the functional domains of two TATA elements. Nucleic Acids Res. 1992 Mar 11;20(5):975–982. doi: 10.1093/nar/20.5.975. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Prives C. The replication functions of SV40 T antigen are regulated by phosphorylation. Cell. 1990 Jun 1;61(5):735–738. doi: 10.1016/0092-8674(90)90179-i. [DOI] [PubMed] [Google Scholar]
  36. Ray S., Anderson M. E., Loeber G., McVey D., Tegtmeyer P. Functional characterization of temperature-sensitive mutants of simian virus 40 large T antigen. J Virol. 1992 Nov;66(11):6509–6516. doi: 10.1128/jvi.66.11.6509-6516.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Rio D. C., Tjian R. SV40 T antigen binding site mutations that affect autoregulation. Cell. 1983 Apr;32(4):1227–1240. doi: 10.1016/0092-8674(83)90305-7. [DOI] [PubMed] [Google Scholar]
  38. Ryder K., Vakalopoulou E., Mertz R., Mastrangelo I., Hough P., Tegtmeyer P., Fanning E. Seventeen base pairs of region I encode a novel tripartite binding signal for SV40 T antigen. Cell. 1985 Sep;42(2):539–548. doi: 10.1016/0092-8674(85)90111-4. [DOI] [PubMed] [Google Scholar]
  39. Scheidtmann K. H., Buck M., Schneider J., Kalderon D., Fanning E., Smith A. E. Biochemical characterization of phosphorylation site mutants of simian virus 40 large T antigen: evidence for interaction between amino- and carboxy-terminal domains. J Virol. 1991 Mar;65(3):1479–1490. doi: 10.1128/jvi.65.3.1479-1490.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Scheidtmann K. H., Echle B., Walter G. Simian virus 40 large T antigen is phosphorylated at multiple sites clustered in two separate regions. J Virol. 1982 Oct;44(1):116–133. doi: 10.1128/jvi.44.1.116-133.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Scheidtmann K. H., Virshup D. M., Kelly T. J. Protein phosphatase 2A dephosphorylates simian virus 40 large T antigen specifically at residues involved in regulation of DNA-binding activity. J Virol. 1991 Apr;65(4):2098–2101. doi: 10.1128/jvi.65.4.2098-2101.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Schneider J., Fanning E. Mutations in the phosphorylation sites of simian virus 40 (SV40) T antigen alter its origin DNA-binding specificity for sites I or II and affect SV40 DNA replication activity. J Virol. 1988 May;62(5):1598–1605. doi: 10.1128/jvi.62.5.1598-1605.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  43. Shaw S. B., Tegtmeyer P. Binding of dephosphorylated A protein to SV40 DNA. Virology. 1981 Nov;115(1):88–96. doi: 10.1016/0042-6822(81)90091-x. [DOI] [PubMed] [Google Scholar]
  44. Simanis V., Lane D. P. An immunoaffinity purification procedure for SV40 large T antigen. Virology. 1985 Jul 15;144(1):88–100. doi: 10.1016/0042-6822(85)90308-3. [DOI] [PubMed] [Google Scholar]
  45. Simmons D. T., Chou W., Rodgers K. Phosphorylation downregulates the DNA-binding activity of simian virus 40 T antigen. J Virol. 1986 Dec;60(3):888–894. doi: 10.1128/jvi.60.3.888-894.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Smale S. T., Tjian R. T-antigen-DNA polymerase alpha complex implicated in simian virus 40 DNA replication. Mol Cell Biol. 1986 Nov;6(11):4077–4087. doi: 10.1128/mcb.6.11.4077. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Stahl H., Dröge P., Knippers R. DNA helicase activity of SV40 large tumor antigen. EMBO J. 1986 Aug;5(8):1939–1944. doi: 10.1002/j.1460-2075.1986.tb04447.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  48. Stillman B. W., Gluzman Y. Replication and supercoiling of simian virus 40 DNA in cell extracts from human cells. Mol Cell Biol. 1985 Aug;5(8):2051–2060. doi: 10.1128/mcb.5.8.2051. [DOI] [PMC free article] [PubMed] [Google Scholar]
  49. Stillman B., Gerard R. D., Guggenheimer R. A., Gluzman Y. T antigen and template requirements for SV40 DNA replication in vitro. EMBO J. 1985 Nov;4(11):2933–2939. doi: 10.1002/j.1460-2075.1985.tb04026.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  50. Strauss M., Argani P., Mohr I. J., Gluzman Y. Studies on the origin-specific DNA-binding domain of simian virus 40 large T antigen. J Virol. 1987 Oct;61(10):3326–3330. doi: 10.1128/jvi.61.10.3326-3330.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  51. Tjian R. The binding site on SV40 DNA for a T antigen-related protein. Cell. 1978 Jan;13(1):165–179. doi: 10.1016/0092-8674(78)90147-2. [DOI] [PubMed] [Google Scholar]
  52. Tsurimoto T., Stillman B. Replication factors required for SV40 DNA replication in vitro. II. Switching of DNA polymerase alpha and delta during initiation of leading and lagging strand synthesis. J Biol Chem. 1991 Jan 25;266(3):1961–1968. [PubMed] [Google Scholar]
  53. Virshup D. M., Russo A. A., Kelly T. J. Mechanism of activation of simian virus 40 DNA replication by protein phosphatase 2A. Mol Cell Biol. 1992 Nov;12(11):4883–4895. doi: 10.1128/mcb.12.11.4883. [DOI] [PMC free article] [PubMed] [Google Scholar]
  54. Wessel R., Schweizer J., Stahl H. Simian virus 40 T-antigen DNA helicase is a hexamer which forms a binary complex during bidirectional unwinding from the viral origin of DNA replication. J Virol. 1992 Feb;66(2):804–815. doi: 10.1128/jvi.66.2.804-815.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  55. Wun-Kim K., Simmons D. T. Mapping of helicase and helicase substrate-binding domains on simian virus 40 large T antigen. J Virol. 1990 May;64(5):2014–2020. doi: 10.1128/jvi.64.5.2014-2020.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]

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