Cell Growth & Differentiation, Vol 6, Issue 6 623-629, Copyright © 1995 by American Association of Cancer Research

ARTICLES

Repression of Myc-Ras cotransformation by Mad is mediated by multiple protein-protein interactions

PJ Koskinen, DE Ayer and RN Eisenman
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98104, USA.

Mad is a bHLH/Zip protein that, as a heterodimer with Max, can repress Myc-induced transcriptional transactivation. Expression of Mad is induced upon terminal differentiation of several cell types, where it has been postulated to down-regulate Myc-induced genes that drive cell proliferation. Here we show that Mad also blocks transformation of primary rat embryo fibroblasts by c-Myc and the activated c-Ha-Ras oncoproteins. Mad mutants lacking either the basic region, the leucine zipper, or an intact NH2-terminal protein interaction domain fail to inhibit Myc-Ras cotransformation. These results indicate that the repression of cotransformation requires DNA-binding and is mediated by multiple protein-protein interactions involving both Max and mSin3, a putative mammalian corepressor protein. With increasing amounts of the cotransfected myc gene, the numbers of transformed foci are reduced and the ability of Mad to inhibit focus formation is attenuated. Moreover, cell lines derived from such foci constitutively express both Myc and Mad proteins. Whereas Bcl-2 can significantly increase the numbers of transformed foci by enhancing the survival of myc-ras-transfected cells, it does not counteract the repressive effects of Mad on transformation, suggesting that Mad affects the growth properties rather than the viability of cells. Taken together, our results demonstrate that Mad is capable of antagonizing the biological effects of Myc and thereby suggest that Mad could function as a tumor suppressor gene.

This article has been cited by other articles:

				K. Jiang, N. Hein, K. Eckert, J. Luscher-Firzlaff, and B. Luscher Regulation of the MAD1 promoter by G-CSF Nucleic Acids Res., March 1, 2008; 36(5): 1517 - 1531. [Abstract] [Full Text] [PDF]

				L. W. M. Loo, J. Secombe, J. T. Little, L.-S. Carlos, C. Yost, P.-F. Cheng, E. M. Flynn, B. A. Edgar, and R. N. Eisenman The Transcriptional Repressor dMnt Is a Regulator of Growth in Drosophila melanogaster Mol. Cell. Biol., August 15, 2005; 25(16): 7078 - 7091. [Abstract] [Full Text] [PDF]

				S. M. Cowley, R. S. Kang, J. V. Frangioni, J. J. Yada, A. M. DeGrand, I. Radhakrishnan, and R. N. Eisenman Functional Analysis of the Mad1-mSin3A Repressor-Corepressor Interaction Reveals Determinants of Specificity, Affinity, and Transcriptional Response Mol. Cell. Biol., April 1, 2004; 24(7): 2698 - 2709. [Abstract] [Full Text] [PDF]

				T. A. Baudino and J. L. Cleveland The Max Network Gone Mad Mol. Cell. Biol., February 1, 2001; 21(3): 691 - 702. [Full Text]

				C. Quéva, G. A. McArthur, B. M. Iritani, and R. N. Eisenman Targeted Deletion of the S-Phase-Specific Myc Antagonist Mad3 Sensitizes Neuronal and Lymphoid Cells to Radiation-Induced Apoptosis Mol. Cell. Biol., February 1, 2001; 21(3): 703 - 712. [Abstract] [Full Text]

				A. Hasegawa, M. Yasukawa, I. Sakai, and S. Fujita Transcriptional Down-Regulation of CXC Chemokine Receptor 4 Induced by Impaired Association of Transcription Regulator YY1 with c-Myc in Human Herpesvirus 6-Infected Cells J. Immunol., January 15, 2001; 166(2): 1125 - 1131. [Abstract] [Full Text] [PDF]

				A. N. Billin, A. L. Eilers, K. L. Coulter, J. S. Logan, and D. E. Ayer MondoA, a Novel Basic Helix-Loop-Helix-Leucine Zipper Transcriptional Activator That Constitutes a Positive Branch of a Max-Like Network Mol. Cell. Biol., December 1, 2000; 20(23): 8845 - 8854. [Abstract] [Full Text]

				G. Barrera-Hernandez, C. M. Cultraro, S. Pianetti, and S. Segal Mad1 Function Is Regulated through Elements within the Carboxy Terminus Mol. Cell. Biol., June 15, 2000; 20(12): 4253 - 4264. [Abstract] [Full Text]

				S. Gehring, S. Rottmann, A. R. Menkel, J. Mertsching, A. Krippner-Heidenreich, and B. Luscher Inhibition of Proliferation and Apoptosis by the Transcriptional Repressor Mad1. REPRESSION OF Fas-INDUCED CASPASE-8 ACTIVATION J. Biol. Chem., March 31, 2000; 275(14): 10413 - 10420. [Abstract] [Full Text] [PDF]

				H. Shen-Li, R. C. O'Hagan, H. Hou Jr., J. W. Horner II, H.-W. Lee, and R. A. DePinho Essential role for Max in early embryonic growth and development Genes & Dev., January 1, 2000; 14(1): 17 - 22. [Abstract] [Full Text]

				A. N. Billin, A. L. Eilers, C. Queva, and D. E. Ayer Mlx, a Novel Max-like BHLHZip Protein That Interacts with the Max Network of Transcription Factors J. Biol. Chem., December 17, 1999; 274(51): 36344 - 36350. [Abstract] [Full Text] [PDF]

				C. Quéva, G. A. McArthur, L. S. Ramos, and R. N. Eisenman Dwarfism and Dysregulated Proliferation in Mice Overexpressing the MYC Antagonist MAD1 Cell Growth Differ., December 1, 1999; 10(12): 785 - 796. [Abstract] [Full Text]

				A. L. Eilers, A. N. Billin, J. Liu, and D. E. Ayer A 13-Amino Acid Amphipathic alpha -Helix Is Required for the Functional Interaction between the Transcriptional Repressor Mad1 and mSin3A J. Biol. Chem., November 12, 1999; 274(46): 32750 - 32756. [Abstract] [Full Text] [PDF]

				F. Bahram, S. Wu, F. Oberg, B. Luscher, and L.-G. Larsson Posttranslational Regulation of Myc Function in Response to Phorbol Ester/Interferon-gamma -Induced Differentiation of v-Myc-Transformed U-937 Monoblasts Blood, June 1, 1999; 93(11): 3900 - 3912. [Abstract] [Full Text] [PDF]

				T. C. Lee and E. B. Ziff Mxi1 Is a Repressor of the c-myc Promoter and Reverses Activation by USF J. Biol. Chem., January 8, 1999; 274(2): 595 - 606. [Abstract] [Full Text] [PDF]

				S G Kennedy, A J Wagner, S D Conzen, J Jordan, A Bellacosa, P N Tsichlis, and N Hay The PI 3-kinase/Akt signaling pathway delivers an anti-apoptotic signal. Genes & Dev., March 15, 1997; 11(6): 701 - 713. [Abstract] [PDF]

				N. Schreiber-Agus, D. Stein, K. Chen, J. S. Goltz, L. Stevens, and R. A. DePinho Drosophila Myc is oncogenic in mammalian cells and plays a role in the diminutive phenotype PNAS, February 18, 1997; 94(4): 1235 - 1240. [Abstract] [Full Text] [PDF]

				P J Hurlin, C Queva, and R N Eisenman Mnt, a novel Max-interacting protein is coexpressed with Myc in proliferating cells and mediates repression at Myc binding sites. Genes & Dev., January 1, 1997; 11(1): 44 - 58. [Abstract] [PDF]