Abstract
The cell cycle-regulating transcription factors E2F1/DP1 activate genes whose products are required for S phase progression. During most of the G1 phase, E2F1/DP1 activity is repressed by the retinoblastoma gene product RB, which directly contacts the E2F1 activation domain and silences it. The E2F1 activation domain has sequence similarity to the N-terminal activation domain of E1A(12S), which contains binding sites for CBP as well as RB. Here, we present evidence that the CBP protein directly contacts E2F1/DP1 and stimulates its activation capacity. We show that CBP interacts with the activation domain of E2F1 both in vitro and in vivo. Deletion of four residues from the E2F1 activation domain reduces CBP binding as well as transcriptional activation, but still allows the binding of RB and MDM2. This deletion removes residues which are conserved in the N-terminal activation domain of E1A and which are required for the binding of CBP to E1A. When the E1A N-terminus is used as a competitor in squelshing experiments it abolishes CBP-induced activation of E2F1/DP1, whereas an E1A mutant lacking CBP binding ability fails to do so. These results indicate that CBP can act as a coactivator for E2F1 and suggest that CBP recognises a similar motif within the E1A and E2F1 activation domains. The convergence of the RB and CBP pathways on the regulation of E2F1 activity may explain the cooperativity displayed by these proteins in mediating the biological functions of E1A. We propose a model in which E1A activates E2F not only by removing the RB repression but also by providing the CBP co-activator.
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- Arany Z., Newsome D., Oldread E., Livingston D. M., Eckner R. A family of transcriptional adaptor proteins targeted by the E1A oncoprotein. Nature. 1995 Mar 2;374(6517):81–84. doi: 10.1038/374081a0. [DOI] [PubMed] [Google Scholar]
- Arany Z., Sellers W. R., Livingston D. M., Eckner R. E1A-associated p300 and CREB-associated CBP belong to a conserved family of coactivators. Cell. 1994 Jun 17;77(6):799–800. doi: 10.1016/0092-8674(94)90127-9. [DOI] [PubMed] [Google Scholar]
- Arias J., Alberts A. S., Brindle P., Claret F. X., Smeal T., Karin M., Feramisco J., Montminy M. Activation of cAMP and mitogen responsive genes relies on a common nuclear factor. Nature. 1994 Jul 21;370(6486):226–229. doi: 10.1038/370226a0. [DOI] [PubMed] [Google Scholar]
- Bannister A. J., Cook A., Kouzarides T. In vitro DNA binding activity of Fos/Jun and BZLF1 but not C/EBP is affected by redox changes. Oncogene. 1991 Jul;6(7):1243–1250. [PubMed] [Google Scholar]
- Bannister A. J., Kouzarides T. CBP-induced stimulation of c-Fos activity is abrogated by E1A. EMBO J. 1995 Oct 2;14(19):4758–4762. doi: 10.1002/j.1460-2075.1995.tb00157.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bannister A. J., Oehler T., Wilhelm D., Angel P., Kouzarides T. Stimulation of c-Jun activity by CBP: c-Jun residues Ser63/73 are required for CBP induced stimulation in vivo and CBP binding in vitro. Oncogene. 1995 Dec 21;11(12):2509–2514. [PubMed] [Google Scholar]
- Chrivia J. C., Kwok R. P., Lamb N., Hagiwara M., Montminy M. R., Goodman R. H. Phosphorylated CREB binds specifically to the nuclear protein CBP. Nature. 1993 Oct 28;365(6449):855–859. doi: 10.1038/365855a0. [DOI] [PubMed] [Google Scholar]
- Eckner R., Ewen M. E., Newsome D., Gerdes M., DeCaprio J. A., Lawrence J. B., Livingston D. M. Molecular cloning and functional analysis of the adenovirus E1A-associated 300-kD protein (p300) reveals a protein with properties of a transcriptional adaptor. Genes Dev. 1994 Apr 15;8(8):869–884. doi: 10.1101/gad.8.8.869. [DOI] [PubMed] [Google Scholar]
- Flemington E. K., Speck S. H., Kaelin W. G., Jr E2F-1-mediated transactivation is inhibited by complex formation with the retinoblastoma susceptibility gene product. Proc Natl Acad Sci U S A. 1993 Aug 1;90(15):6914–6918. doi: 10.1073/pnas.90.15.6914. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hagemeier C., Bannister A. J., Cook A., Kouzarides T. The activation domain of transcription factor PU.1 binds the retinoblastoma (RB) protein and the transcription factor TFIID in vitro: RB shows sequence similarity to TFIID and TFIIB. Proc Natl Acad Sci U S A. 1993 Feb 15;90(4):1580–1584. doi: 10.1073/pnas.90.4.1580. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hagemeier C., Cook A., Kouzarides T. The retinoblastoma protein binds E2F residues required for activation in vivo and TBP binding in vitro. Nucleic Acids Res. 1993 Nov 11;21(22):4998–5004. doi: 10.1093/nar/21.22.4998. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Helin K., Harlow E., Fattaey A. Inhibition of E2F-1 transactivation by direct binding of the retinoblastoma protein. Mol Cell Biol. 1993 Oct;13(10):6501–6508. doi: 10.1128/mcb.13.10.6501. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Helin K., Lees J. A., Vidal M., Dyson N., Harlow E., Fattaey A. A cDNA encoding a pRB-binding protein with properties of the transcription factor E2F. Cell. 1992 Jul 24;70(2):337–350. doi: 10.1016/0092-8674(92)90107-n. [DOI] [PubMed] [Google Scholar]
- Helin K., Wu C. L., Fattaey A. R., Lees J. A., Dynlacht B. D., Ngwu C., Harlow E. Heterodimerization of the transcription factors E2F-1 and DP-1 leads to cooperative trans-activation. Genes Dev. 1993 Oct;7(10):1850–1861. doi: 10.1101/gad.7.10.1850. [DOI] [PubMed] [Google Scholar]
- Johnson D. G., Cress W. D., Jakoi L., Nevins J. R. Oncogenic capacity of the E2F1 gene. Proc Natl Acad Sci U S A. 1994 Dec 20;91(26):12823–12827. doi: 10.1073/pnas.91.26.12823. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Johnson D. G., Schwarz J. K., Cress W. D., Nevins J. R. Expression of transcription factor E2F1 induces quiescent cells to enter S phase. Nature. 1993 Sep 23;365(6444):349–352. doi: 10.1038/365349a0. [DOI] [PubMed] [Google Scholar]
- Kaelin W. G., Jr, Krek W., Sellers W. R., DeCaprio J. A., Ajchenbaum F., Fuchs C. S., Chittenden T., Li Y., Farnham P. J., Blanar M. A. Expression cloning of a cDNA encoding a retinoblastoma-binding protein with E2F-like properties. Cell. 1992 Jul 24;70(2):351–364. doi: 10.1016/0092-8674(92)90108-o. [DOI] [PubMed] [Google Scholar]
- Kwok R. P., Lundblad J. R., Chrivia J. C., Richards J. P., Bächinger H. P., Brennan R. G., Roberts S. G., Green M. R., Goodman R. H. Nuclear protein CBP is a coactivator for the transcription factor CREB. Nature. 1994 Jul 21;370(6486):223–226. doi: 10.1038/370223a0. [DOI] [PubMed] [Google Scholar]
- La Thangue N. B. DRTF1/E2F: an expanding family of heterodimeric transcription factors implicated in cell-cycle control. Trends Biochem Sci. 1994 Mar;19(3):108–114. doi: 10.1016/0968-0004(94)90202-x. [DOI] [PubMed] [Google Scholar]
- Lam E. W., La Thangue N. B. DP and E2F proteins: coordinating transcription with cell cycle progression. Curr Opin Cell Biol. 1994 Dec;6(6):859–866. doi: 10.1016/0955-0674(94)90057-4. [DOI] [PubMed] [Google Scholar]
- Lundblad J. R., Kwok R. P., Laurance M. E., Harter M. L., Goodman R. H. Adenoviral E1A-associated protein p300 as a functional homologue of the transcriptional co-activator CBP. Nature. 1995 Mar 2;374(6517):85–88. doi: 10.1038/374085a0. [DOI] [PubMed] [Google Scholar]
- Martin K., Trouche D., Hagemeier C., Sørensen T. S., La Thangue N. B., Kouzarides T. Stimulation of E2F1/DP1 transcriptional activity by MDM2 oncoprotein. Nature. 1995 Jun 22;375(6533):691–694. doi: 10.1038/375691a0. [DOI] [PubMed] [Google Scholar]
- Means A. L., Slansky J. E., McMahon S. L., Knuth M. W., Farnham P. J. The HIP1 binding site is required for growth regulation of the dihydrofolate reductase gene promoter. Mol Cell Biol. 1992 Mar;12(3):1054–1063. doi: 10.1128/mcb.12.3.1054. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mudryj M., Hiebert S. W., Nevins J. R. A role for the adenovirus inducible E2F transcription factor in a proliferation dependent signal transduction pathway. EMBO J. 1990 Jul;9(7):2179–2184. doi: 10.1002/j.1460-2075.1990.tb07387.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nevins J. R. E2F: a link between the Rb tumor suppressor protein and viral oncoproteins. Science. 1992 Oct 16;258(5081):424–429. doi: 10.1126/science.1411535. [DOI] [PubMed] [Google Scholar]
- Qin X. Q., Chittenden T., Livingston D. M., Kaelin W. G., Jr Identification of a growth suppression domain within the retinoblastoma gene product. Genes Dev. 1992 Jun;6(6):953–964. doi: 10.1101/gad.6.6.953. [DOI] [PubMed] [Google Scholar]
- Qin X. Q., Livingston D. M., Ewen M., Sellers W. R., Arany Z., Kaelin W. G., Jr The transcription factor E2F-1 is a downstream target of RB action. Mol Cell Biol. 1995 Feb;15(2):742–755. doi: 10.1128/mcb.15.2.742. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Singh P., Wong S. H., Hong W. Overexpression of E2F-1 in rat embryo fibroblasts leads to neoplastic transformation. EMBO J. 1994 Jul 15;13(14):3329–3338. doi: 10.1002/j.1460-2075.1994.tb06635.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Trouche D., Kouzarides T. E2F1 and E1A(12S) have a homologous activation domain regulated by RB and CBP. Proc Natl Acad Sci U S A. 1996 Feb 20;93(4):1439–1442. doi: 10.1073/pnas.93.4.1439. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wang H. G., Moran E., Yaciuk P. E1A promotes association between p300 and pRB in multimeric complexes required for normal biological activity. J Virol. 1995 Dec;69(12):7917–7924. doi: 10.1128/jvi.69.12.7917-7924.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wang H. G., Rikitake Y., Carter M. C., Yaciuk P., Abraham S. E., Zerler B., Moran E. Identification of specific adenovirus E1A N-terminal residues critical to the binding of cellular proteins and to the control of cell growth. J Virol. 1993 Jan;67(1):476–488. doi: 10.1128/jvi.67.1.476-488.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weintraub S. J., Chow K. N., Luo R. X., Zhang S. H., He S., Dean D. C. Mechanism of active transcriptional repression by the retinoblastoma protein. Nature. 1995 Jun 29;375(6534):812–815. doi: 10.1038/375812a0. [DOI] [PubMed] [Google Scholar]
- Wong H. K., Ziff E. B. Complementary functions of E1a conserved region 1 cooperate with conserved region 3 to activate adenovirus serotype 5 early promoters. J Virol. 1994 Aug;68(8):4910–4920. doi: 10.1128/jvi.68.8.4910-4920.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wu C. L., Zukerberg L. R., Ngwu C., Harlow E., Lees J. A. In vivo association of E2F and DP family proteins. Mol Cell Biol. 1995 May;15(5):2536–2546. doi: 10.1128/mcb.15.5.2536. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Xiao Z. X., Chen J., Levine A. J., Modjtahedi N., Xing J., Sellers W. R., Livingston D. M. Interaction between the retinoblastoma protein and the oncoprotein MDM2. Nature. 1995 Jun 22;375(6533):694–698. doi: 10.1038/375694a0. [DOI] [PubMed] [Google Scholar]
- Zhu L., van den Heuvel S., Helin K., Fattaey A., Ewen M., Livingston D., Dyson N., Harlow E. Inhibition of cell proliferation by p107, a relative of the retinoblastoma protein. Genes Dev. 1993 Jul;7(7A):1111–1125. doi: 10.1101/gad.7.7a.1111. [DOI] [PubMed] [Google Scholar]