51. Physical and Functional Interactions among AP-2 Transcription Factors, p300/CREB-binding Protein, and CITED2
- Author
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Helen C. Hurst, José Bragança, Shoumo Bhattacharya, Jyrki J. Eloranta, J. Claire Ibbitt, and Simon D. Bamforth
- Subjects
Transcriptional Activation ,Mutant ,Biochemistry ,Mice ,Structure-Activity Relationship ,Transactivation ,Animals ,CREB-binding protein ,Molecular Biology ,Transcription factor ,Cellular localization ,Histone Acetyltransferases ,biology ,Nuclear Proteins ,DNA ,Cell Biology ,Precipitin Tests ,Molecular biology ,DNA-Binding Proteins ,Repressor Proteins ,Histone ,Transcription Factor AP-2 ,Trans-Activators ,biology.protein ,Ectopic expression ,Dimerization ,E1A-Associated p300 Protein ,Transcription Factors - Abstract
The transcriptional co-activators and histone acetyltransferases p300/CREB-binding protein (CBP) interact with CITED2, a transcription factor AP-2 (TFAP2) co-activator. p300/CBP, CITED2, and TFAP2A are essential for normal neural tube and cardiac development. Here we show that p300 and CBP co-activate TFAP2A in the presence of CITED2. TFAP2A transcriptional activity was modestly impaired in p300(+/-) and CBP(+/-) mouse embryonic fibroblasts; this was rescued by ectopic expression of p300/CBP. p300, TFAP2A, and endogenous CITED2 could be co-immunoprecipitated from transfected U2-OS cells indicating that they can interact physically in vivo. CITED2 interacted with the dimerization domain of TFAP2C, which is highly conserved in TFAP2A/B. In mammalian two-hybrid experiments, full-length p300 and TFAP2A interacted only when CITED2 was co-transfected. N-terminal residues of TFAP2A, containing the transactivation domain, are both necessary and sufficient for interaction with p300, and this interaction was independent of CITED2. Consistent with this, N-terminal residues of TFAP2A were required for p300- and CITED2-dependent co-activation. A histone acetyltransferase-deficient p300 mutant (D1399Y) did not co-activate TFAP2A and did not affect the expression or cellular localization of TFAP2A or CITED2. In mammalian two-hybrid experiments p300D1399Y failed to interact with TFAP2A, explaining, at least in part, its failure to function as a co-activator. Our results suggest a model wherein interactions among TFAP2A, CITED2, and p300/CBP are necessary for TFAP2A-mediated transcriptional activation and for normal neural tube and cardiac development.
- Published
- 2003
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