p300 and ATF-2 are components of the DRF complex, which regulates retinoic acid- and E1A-mediated transcription of the c-jun gene in F9 cells
- Hiroaki Kawasaki1,2,3,4,
- Jun Song1,
- Richard Eckner5,
- Hideyo Ugai1,
- Robert Chiu6,
- Kazunari Taira2,3,4,
- Yang Shi7,
- Nic Jones8, and
- Kazunari K. Yokoyama1,9
- 1Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN), Tsukuba 305, Japan; 2National Institute for Advanced Interdisciplinary Research and 3National Institute of Bioscience and Human Technology, Agency of Industrial Science & Technology, MITI, Tsukuba 305, Japan; 4Institute of Applied Biochemistry, University of Tsukuba, Tsukuba 305, Japan; 5Institute for Molecular Biology, University of Zurich, Zurich, Switzerland; 6Department of Surgery/Oncology, University of California, Los Angeles, School of Medicine and Jonsson Comprehensive Cancer Center, Los Angeles, California 90024 USA; 7Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115 USA; 8Laboratory of Gene Regulation, Imperial Cancer Research Fund, London WC2A 3PX, UK
Abstract
Transcriptional activation of the c-jun gene is a critical event in the differentiation of F9 cells. In our previous studies we characterized an element [differentiation response element (DRE)] in the c-jun promoter that is both necessary and sufficient to confer the capacity for differentiation-dependent up-regulation. This element binds the differentiation regulatory factor (DRF) complex, of which one component is the adenovirus E1A-associated protein p300. We have now identified activation transcription factor-2 (ATF-2) as a DNA-binding subunit of the DRF complex. p300 and ATF-2 interact with each other in vivo and in vitro. The bromodomain and the C/H2 domain of p300 mediate the binding to ATF-2, which in turn requires a proline-rich region between amino acids 112 and 350 for its interaction with p300. The phosphorylation of the serine residue at position 121 of ATF-2 appears to be induced by protein kinase Cα (PKCα) after treatment of cells with retinoic acid (RA) or induction with E1A. In cotransfection assays, wild-type ATF-2 enhanced the transcription of an E2/tk–luciferase construct, in conjunction with p300–E2. However, a mutant form of ATF-2 with a mutation at position 121 (pCMVATF–2Ser121–Ala) did not. These results suggest that ATF-2 and p300 cooperate in the control of transcription by forming a protein complex that is responsive to differentiation-inducing signals, such as RA or E1A, and moreover, that the phosphorylation of ATF-2 by PKCα is probably a signaling event in the pathway that leads to the transactivation of the c-jun gene in F9 cells.
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Footnotes
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↵9 Corresponding author.
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E-MAIL kazunari{at}rtc.riken.go.jp; FAX 81-298-36-9120.
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- Received September 15, 1997.
- Accepted November 14, 1997.
- Cold Spring Harbor Laboratory Press
