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. 1990 Mar;64(3):1143–1155. doi: 10.1128/jvi.64.3.1143-1155.1990

The zta transactivator involved in induction of lytic cycle gene expression in Epstein-Barr virus-infected lymphocytes binds to both AP-1 and ZRE sites in target promoter and enhancer regions.

P M Lieberman 1, J M Hardwick 1, J Sample 1, G S Hayward 1, S D Hayward 1
PMCID: PMC249228  PMID: 2154599

Abstract

The BZLF1 or zta immediate-early gene of Epstein-Barr virus (EBV) encodes a 33-kilodalton phosphorylated nuclear protein that is a specific transcriptional activator of the EBV lytic cycle when introduced into latently infected B lymphocytes. We have shown previously that the divergent EBV DSL target promoter contains two zta-response regions, one within the minimal promoter and the other in an upstream lymphocyte-dependent enhancer region. In this study, we used footprinting and gel mobility retardation assays to reveal that bacterially synthesized Zta fusion proteins bound directly to six TGTGCAA-like motifs within DSL. Four of the Zta-binding sites lay adjacent to cellular TATA and CAAT factor-binding sites within the minimal promoter, and two mapped within the enhancer region. Single-copy oligonucleotides containing these Zta-binding sites conferred Zta responsiveness to heterologous promoters. In addition, the Zta protein, which possesses a similar basic domain to the conserved DNA-binding region of the c-Fos, c-Jun, GCN4, and CREB protein family, proved to bind directly to the consensus AP-1 site in the collagenase 12-O-tetradecanoylphorbol-13-acetate response element. Cotransfection with zta also trans activated a target reporter gene containing inserted wild-type 12-O-tetradecanoylphorbol-13-acetate response element oligonucleotides. Cellular AP-1 binding activity proved to be low in latently EBV-infected Raji cells but was induced (together with the Zta protein) after activation of the lytic cycle with 12-O-tetradecanoylphorbol-13-acetate. We conclude that EBV may have captured and modified a cellular gene encoding a c-jun-like DNA-binding protein during its evolutionary divergence from other herpesviruses and that this protein is used to specifically redirect transcriptional activity toward expression of EBV lytic-cycle genes in infected cells.

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Selected References

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

  1. Androphy E. J., Lowy D. R., Schiller J. T. Bovine papillomavirus E2 trans-activating gene product binds to specific sites in papillomavirus DNA. Nature. 1987 Jan 1;325(6099):70–73. doi: 10.1038/325070a0. [DOI] [PubMed] [Google Scholar]
  2. Angel P., Hattori K., Smeal T., Karin M. The jun proto-oncogene is positively autoregulated by its product, Jun/AP-1. Cell. 1988 Dec 2;55(5):875–885. doi: 10.1016/0092-8674(88)90143-2. [DOI] [PubMed] [Google Scholar]
  3. Angel P., Imagawa M., Chiu R., Stein B., Imbra R. J., Rahmsdorf H. J., Jonat C., Herrlich P., Karin M. Phorbol ester-inducible genes contain a common cis element recognized by a TPA-modulated trans-acting factor. Cell. 1987 Jun 19;49(6):729–739. doi: 10.1016/0092-8674(87)90611-8. [DOI] [PubMed] [Google Scholar]
  4. Biggin M., Bodescot M., Perricaudet M., Farrell P. Epstein-Barr virus gene expression in P3HR1-superinfected Raji cells. J Virol. 1987 Oct;61(10):3120–3132. doi: 10.1128/jvi.61.10.3120-3132.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bohmann D., Bos T. J., Admon A., Nishimura T., Vogt P. K., Tjian R. Human proto-oncogene c-jun encodes a DNA binding protein with structural and functional properties of transcription factor AP-1. Science. 1987 Dec 4;238(4832):1386–1392. doi: 10.1126/science.2825349. [DOI] [PubMed] [Google Scholar]
  6. Chang Y. N., Crawford S., Stall J., Rawlins D. R., Jeang K. T., Hayward G. S. The palindromic series I repeats in the simian cytomegalovirus major immediate-early promoter behave as both strong basal enhancers and cyclic AMP response elements. J Virol. 1990 Jan;64(1):264–277. doi: 10.1128/jvi.64.1.264-277.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Chavrier P., Gruffat H., Chevallier-Greco A., Buisson M., Sergeant A. The Epstein-Barr virus (EBV) early promoter DR contains a cis-acting element responsive to the EBV transactivator EB1 and an enhancer with constitutive and inducible activities. J Virol. 1989 Feb;63(2):607–614. doi: 10.1128/jvi.63.2.607-614.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Chevallier-Greco A., Gruffat H., Manet E., Calender A., Sergeant A. The Epstein-Barr virus (EBV) DR enhancer contains two functionally different domains: domain A is constitutive and cell specific, domain B is transactivated by the EBV early protein R. J Virol. 1989 Feb;63(2):615–623. doi: 10.1128/jvi.63.2.615-623.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Chevallier-Greco A., Manet E., Chavrier P., Mosnier C., Daillie J., Sergeant A. Both Epstein-Barr virus (EBV)-encoded trans-acting factors, EB1 and EB2, are required to activate transcription from an EBV early promoter. EMBO J. 1986 Dec 1;5(12):3243–3249. doi: 10.1002/j.1460-2075.1986.tb04635.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Chiu R., Boyle W. J., Meek J., Smeal T., Hunter T., Karin M. The c-Fos protein interacts with c-Jun/AP-1 to stimulate transcription of AP-1 responsive genes. Cell. 1988 Aug 12;54(4):541–552. doi: 10.1016/0092-8674(88)90076-1. [DOI] [PubMed] [Google Scholar]
  11. Cho M. S., Bornkamm G. W., zur Hausen H. Structure of defective DNA molecules in Epstein-Barr virus preparations from P3HR-1 cells. J Virol. 1984 Jul;51(1):199–207. doi: 10.1128/jvi.51.1.199-207.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Cleary M. L., Smith S. D., Sklar J. Cloning and structural analysis of cDNAs for bcl-2 and a hybrid bcl-2/immunoglobulin transcript resulting from the t(14;18) translocation. Cell. 1986 Oct 10;47(1):19–28. doi: 10.1016/0092-8674(86)90362-4. [DOI] [PubMed] [Google Scholar]
  13. Cox M. A., Leahy J., Hardwick J. M. An enhancer within the divergent promoter of Epstein-Barr virus responds synergistically to the R and Z transactivators. J Virol. 1990 Jan;64(1):313–321. doi: 10.1128/jvi.64.1.313-321.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Curran T., Franza B. R., Jr Fos and Jun: the AP-1 connection. Cell. 1988 Nov 4;55(3):395–397. doi: 10.1016/0092-8674(88)90024-4. [DOI] [PubMed] [Google Scholar]
  15. Dignam J. D., Lebovitz R. M., Roeder R. G. Accurate transcription initiation by RNA polymerase II in a soluble extract from isolated mammalian nuclei. Nucleic Acids Res. 1983 Mar 11;11(5):1475–1489. doi: 10.1093/nar/11.5.1475. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Evans R. M. The steroid and thyroid hormone receptor superfamily. Science. 1988 May 13;240(4854):889–895. doi: 10.1126/science.3283939. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Farrell P. J., Rowe D. T., Rooney C. M., Kouzarides T. Epstein-Barr virus BZLF1 trans-activator specifically binds to a consensus AP-1 site and is related to c-fos. EMBO J. 1989 Jan;8(1):127–132. doi: 10.1002/j.1460-2075.1989.tb03356.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Ferguson B., Jones N., Richter J., Rosenberg M. Adenovirus E1a gene product expressed at high levels in Escherichia coli is functional. Science. 1984 Jun 22;224(4655):1343–1346. doi: 10.1126/science.6374895. [DOI] [PubMed] [Google Scholar]
  19. Freese U. K., Laux G., Hudewentz J., Schwarz E., Bornkamm G. W. Two distant clusters of partially homologous small repeats of Epstein-Barr virus are transcribed upon induction of an abortive or lytic cycle of the virus. J Virol. 1983 Dec;48(3):731–743. doi: 10.1128/jvi.48.3.731-743.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Gerster T., Roeder R. G. A herpesvirus trans-activating protein interacts with transcription factor OTF-1 and other cellular proteins. Proc Natl Acad Sci U S A. 1988 Sep;85(17):6347–6351. doi: 10.1073/pnas.85.17.6347. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Hager D. A., Burgess R. R. Elution of proteins from sodium dodecyl sulfate-polyacrylamide gels, removal of sodium dodecyl sulfate, and renaturation of enzymatic activity: results with sigma subunit of Escherichia coli RNA polymerase, wheat germ DNA topoisomerase, and other enzymes. Anal Biochem. 1980 Nov 15;109(1):76–86. doi: 10.1016/0003-2697(80)90013-5. [DOI] [PubMed] [Google Scholar]
  22. Halazonetis T. D., Georgopoulos K., Greenberg M. E., Leder P. c-Jun dimerizes with itself and with c-Fos, forming complexes of different DNA binding affinities. Cell. 1988 Dec 2;55(5):917–924. doi: 10.1016/0092-8674(88)90147-x. [DOI] [PubMed] [Google Scholar]
  23. Hammerschmidt W., Sugden B. Identification and characterization of oriLyt, a lytic origin of DNA replication of Epstein-Barr virus. Cell. 1988 Nov 4;55(3):427–433. doi: 10.1016/0092-8674(88)90028-1. [DOI] [PubMed] [Google Scholar]
  24. Hardwick J. M., Lieberman P. M., Hayward S. D. A new Epstein-Barr virus transactivator, R, induces expression of a cytoplasmic early antigen. J Virol. 1988 Jul;62(7):2274–2284. doi: 10.1128/jvi.62.7.2274-2284.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Hoeffler J. P., Meyer T. E., Yun Y., Jameson J. L., Habener J. F. Cyclic AMP-responsive DNA-binding protein: structure based on a cloned placental cDNA. Science. 1988 Dec 9;242(4884):1430–1433. doi: 10.1126/science.2974179. [DOI] [PubMed] [Google Scholar]
  26. Hoeffler W. K., Kovelman R., Roeder R. G. Activation of transcription factor IIIC by the adenovirus E1A protein. Cell. 1988 Jun 17;53(6):907–920. doi: 10.1016/s0092-8674(88)90409-6. [DOI] [PubMed] [Google Scholar]
  27. Hope I. A., Struhl K. GCN4 protein, synthesized in vitro, binds HIS3 regulatory sequences: implications for general control of amino acid biosynthetic genes in yeast. Cell. 1985 Nov;43(1):177–188. doi: 10.1016/0092-8674(85)90022-4. [DOI] [PubMed] [Google Scholar]
  28. Jeang K. T., Hayward S. D. Organization of the Epstein-Barr virus DNA molecule. III. Location of the P3HR-1 deletion junction and characterization of the NotI repeat units that form part of the template for an abundant 12-O-tetradecanoylphorbol-13-acetate-induced mRNA transcript. J Virol. 1983 Oct;48(1):135–148. doi: 10.1128/jvi.48.1.135-148.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Johnson P. F., Landschulz W. H., Graves B. J., McKnight S. L. Identification of a rat liver nuclear protein that binds to the enhancer core element of three animal viruses. Genes Dev. 1987 Apr;1(2):133–146. doi: 10.1101/gad.1.2.133. [DOI] [PubMed] [Google Scholar]
  30. Kenney S., Kamine J., Holley-Guthrie E., Lin J. C., Mar E. C., Pagano J. The Epstein-Barr virus (EBV) BZLF1 immediate-early gene product differentially affects latent versus productive EBV promoters. J Virol. 1989 Apr;63(4):1729–1736. doi: 10.1128/jvi.63.4.1729-1736.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. King W., Thomas-Powell A. L., Raab-Traub N., Hawke M., Kieff E. Epstein-Barr virus RNA. V. Viral RNA in a restringently infected, growth-transformed cell line. J Virol. 1980 Nov;36(2):506–518. doi: 10.1128/jvi.36.2.506-518.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Kouzarides T., Ziff E. The role of the leucine zipper in the fos-jun interaction. Nature. 1988 Dec 15;336(6200):646–651. doi: 10.1038/336646a0. [DOI] [PubMed] [Google Scholar]
  33. Kovesdi I., Reichel R., Nevins J. R. Identification of a cellular transcription factor involved in E1A trans-activation. Cell. 1986 Apr 25;45(2):219–228. doi: 10.1016/0092-8674(86)90386-7. [DOI] [PubMed] [Google Scholar]
  34. Landschulz W. H., Johnson P. F., Adashi E. Y., Graves B. J., McKnight S. L. Isolation of a recombinant copy of the gene encoding C/EBP. Genes Dev. 1988 Jul;2(7):786–800. doi: 10.1101/gad.2.7.786. [DOI] [PubMed] [Google Scholar]
  35. Landschulz W. H., Johnson P. F., McKnight S. L. The leucine zipper: a hypothetical structure common to a new class of DNA binding proteins. Science. 1988 Jun 24;240(4860):1759–1764. doi: 10.1126/science.3289117. [DOI] [PubMed] [Google Scholar]
  36. Laux G., Freese U. K., Bornkamm G. W. Structure and evolution of two related transcription units of Epstein-Barr virus carrying small tandem repeats. J Virol. 1985 Dec;56(3):987–995. doi: 10.1128/jvi.56.3.987-995.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Laux G., Freese U. K., Fischer R., Polack A., Kofler E., Bornkamm G. W. TPA-inducible Epstein-Barr virus genes in Raji cells and their regulation. Virology. 1988 Feb;162(2):503–507. doi: 10.1016/0042-6822(88)90496-5. [DOI] [PubMed] [Google Scholar]
  38. Lee W., Haslinger A., Karin M., Tjian R. Activation of transcription by two factors that bind promoter and enhancer sequences of the human metallothionein gene and SV40. Nature. 1987 Jan 22;325(6102):368–372. doi: 10.1038/325368a0. [DOI] [PubMed] [Google Scholar]
  39. Lee W., Mitchell P., Tjian R. Purified transcription factor AP-1 interacts with TPA-inducible enhancer elements. Cell. 1987 Jun 19;49(6):741–752. doi: 10.1016/0092-8674(87)90612-x. [DOI] [PubMed] [Google Scholar]
  40. Lieberman P. M., Hardwick J. M., Hayward S. D. Responsiveness of the Epstein-Barr virus NotI repeat promoter to the Z transactivator is mediated in a cell-type-specific manner by two independent signal regions. J Virol. 1989 Jul;63(7):3040–3050. doi: 10.1128/jvi.63.7.3040-3050.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Lieberman P. M., O'Hare P., Hayward G. S., Hayward S. D. Promiscuous trans activation of gene expression by an Epstein-Barr virus-encoded early nuclear protein. J Virol. 1986 Oct;60(1):140–148. doi: 10.1128/jvi.60.1.140-148.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Lillie J. W., Loewenstein P. M., Green M. R., Green M. Functional domains of adenovirus type 5 E1a proteins. Cell. 1987 Sep 25;50(7):1091–1100. doi: 10.1016/0092-8674(87)90175-9. [DOI] [PubMed] [Google Scholar]
  43. Miller G., Rabson M., Heston L. Epstein-Barr virus with heterogeneous DNA disrupts latency. J Virol. 1984 Apr;50(1):174–182. doi: 10.1128/jvi.50.1.174-182.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Milman G., Scott A. L., Cho M. S., Hartman S. C., Ades D. K., Hayward G. S., Ki P. F., August J. T., Hayward S. D. Carboxyl-terminal domain of the Epstein-Barr virus nuclear antigen is highly immunogenic in man. Proc Natl Acad Sci U S A. 1985 Sep;82(18):6300–6304. doi: 10.1073/pnas.82.18.6300. [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Miskimins W. K., Roberts M. P., McClelland A., Ruddle F. H. Use of a protein-blotting procedure and a specific DNA probe to identify nuclear proteins that recognize the promoter region of the transferrin receptor gene. Proc Natl Acad Sci U S A. 1985 Oct;82(20):6741–6744. doi: 10.1073/pnas.82.20.6741. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Moskaluk C., Bastia D. The E2 "gene" of bovine papillomavirus encodes an enhancer-binding protein. Proc Natl Acad Sci U S A. 1987 Mar;84(5):1215–1218. doi: 10.1073/pnas.84.5.1215. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Nakabeppu Y., Ryder K., Nathans D. DNA binding activities of three murine Jun proteins: stimulation by Fos. Cell. 1988 Dec 2;55(5):907–915. doi: 10.1016/0092-8674(88)90146-8. [DOI] [PubMed] [Google Scholar]
  48. O'Hare P., Goding C. R. Herpes simplex virus regulatory elements and the immunoglobulin octamer domain bind a common factor and are both targets for virion transactivation. Cell. 1988 Feb 12;52(3):435–445. doi: 10.1016/s0092-8674(88)80036-9. [DOI] [PubMed] [Google Scholar]
  49. Peale F. V., Jr, Ludwig L. B., Zain S., Hilf R., Bambara R. A. Properties of a high-affinity DNA binding site for estrogen receptor. Proc Natl Acad Sci U S A. 1988 Feb;85(4):1038–1042. doi: 10.1073/pnas.85.4.1038. [DOI] [PMC free article] [PubMed] [Google Scholar]
  50. Pearson G. R., Luka J., Petti L., Sample J., Birkenbach M., Braun D., Kieff E. Identification of an Epstein-Barr virus early gene encoding a second component of the restricted early antigen complex. Virology. 1987 Sep;160(1):151–161. doi: 10.1016/0042-6822(87)90055-9. [DOI] [PubMed] [Google Scholar]
  51. Preston C. M., Frame M. C., Campbell M. E. A complex formed between cell components and an HSV structural polypeptide binds to a viral immediate early gene regulatory DNA sequence. Cell. 1988 Feb 12;52(3):425–434. doi: 10.1016/s0092-8674(88)80035-7. [DOI] [PubMed] [Google Scholar]
  52. Rauscher F. J., 3rd, Cohen D. R., Curran T., Bos T. J., Vogt P. K., Bohmann D., Tjian R., Franza B. R., Jr Fos-associated protein p39 is the product of the jun proto-oncogene. Science. 1988 May 20;240(4855):1010–1016. doi: 10.1126/science.3130660. [DOI] [PubMed] [Google Scholar]
  53. Rawlins D. R., Milman G., Hayward S. D., Hayward G. S. Sequence-specific DNA binding of the Epstein-Barr virus nuclear antigen (EBNA-1) to clustered sites in the plasmid maintenance region. Cell. 1985 Oct;42(3):859–868. doi: 10.1016/0092-8674(85)90282-x. [DOI] [PubMed] [Google Scholar]
  54. Rawlins D. R., Rosenfeld P. J., Wides R. J., Challberg M. D., Kelly T. J., Jr Structure and function of the adenovirus origin of replication. Cell. 1984 May;37(1):309–319. doi: 10.1016/0092-8674(84)90327-1. [DOI] [PubMed] [Google Scholar]
  55. Reisman D., Sugden B. trans activation of an Epstein-Barr viral transcriptional enhancer by the Epstein-Barr viral nuclear antigen 1. Mol Cell Biol. 1986 Nov;6(11):3838–3846. doi: 10.1128/mcb.6.11.3838. [DOI] [PMC free article] [PubMed] [Google Scholar]
  56. Ryder K., Lau L. F., Nathans D. A gene activated by growth factors is related to the oncogene v-jun. Proc Natl Acad Sci U S A. 1988 Mar;85(5):1487–1491. doi: 10.1073/pnas.85.5.1487. [DOI] [PMC free article] [PubMed] [Google Scholar]
  57. Sassone-Corsi P., Lamph W. W., Kamps M., Verma I. M. fos-associated cellular p39 is related to nuclear transcription factor AP-1. Cell. 1988 Aug 12;54(4):553–560. doi: 10.1016/0092-8674(88)90077-3. [DOI] [PubMed] [Google Scholar]
  58. Sassone-Corsi P., Ransone L. J., Lamph W. W., Verma I. M. Direct interaction between fos and jun nuclear oncoproteins: role of the 'leucine zipper' domain. Nature. 1988 Dec 15;336(6200):692–695. doi: 10.1038/336692a0. [DOI] [PubMed] [Google Scholar]
  59. Spalholz B. A., Yang Y. C., Howley P. M. Transactivation of a bovine papilloma virus transcriptional regulatory element by the E2 gene product. Cell. 1985 Aug;42(1):183–191. doi: 10.1016/s0092-8674(85)80114-8. [DOI] [PubMed] [Google Scholar]
  60. Struhl K. The DNA-binding domains of the jun oncoprotein and the yeast GCN4 transcriptional activator protein are functionally homologous. Cell. 1987 Sep 11;50(6):841–846. doi: 10.1016/0092-8674(87)90511-3. [DOI] [PubMed] [Google Scholar]
  61. Takada K., Ono Y. Synchronous and sequential activation of latently infected Epstein-Barr virus genomes. J Virol. 1989 Jan;63(1):445–449. doi: 10.1128/jvi.63.1.445-449.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  62. Takada K., Shimizu N., Sakuma S., Ono Y. trans activation of the latent Epstein-Barr virus (EBV) genome after transfection of the EBV DNA fragment. J Virol. 1986 Mar;57(3):1016–1022. doi: 10.1128/jvi.57.3.1016-1022.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  63. Vogt P. K., Bos T. J., Doolittle R. F. Homology between the DNA-binding domain of the GCN4 regulatory protein of yeast and the carboxyl-terminal region of a protein coded for by the oncogene jun. Proc Natl Acad Sci U S A. 1987 May;84(10):3316–3319. doi: 10.1073/pnas.84.10.3316. [DOI] [PMC free article] [PubMed] [Google Scholar]
  64. Wu L., Rosser D. S., Schmidt M. C., Berk A. A TATA box implicated in E1A transcriptional activation of a simple adenovirus 2 promoter. Nature. 1987 Apr 2;326(6112):512–515. doi: 10.1038/326512a0. [DOI] [PubMed] [Google Scholar]
  65. apRhys C. M., Ciufo D. M., O'Neill E. A., Kelly T. J., Hayward G. S. Overlapping octamer and TAATGARAT motifs in the VF65-response elements in herpes simplex virus immediate-early promoters represent independent binding sites for cellular nuclear factor III. J Virol. 1989 Jun;63(6):2798–2812. doi: 10.1128/jvi.63.6.2798-2812.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  66. van Straaten F., Müller R., Curran T., Van Beveren C., Verma I. M. Complete nucleotide sequence of a human c-onc gene: deduced amino acid sequence of the human c-fos protein. Proc Natl Acad Sci U S A. 1983 Jun;80(11):3183–3187. doi: 10.1073/pnas.80.11.3183. [DOI] [PMC free article] [PubMed] [Google Scholar]
  67. zur Hausen H., O'Neill F. J., Freese U. K., Hecker E. Persisting oncogenic herpesvirus induced by the tumour promotor TPA. Nature. 1978 Mar 23;272(5651):373–375. doi: 10.1038/272373a0. [DOI] [PubMed] [Google Scholar]

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