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Quantitative Comparison of cis-Regulatory Element (CRE) Activities in Transgenic Drosophila melanogaster
Published on: December 19, 2011
Daxx interacts with and modulates the activity of CREB
Yen-Sung Huang1, Che-Chang Chang, Tien-Chi Huang
1Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China.
Cell Cycle (Georgetown, Tex.)
|December 22, 2011
Summary
Daxx protein represses cAMP-responsive gene expression by binding to CREB and inhibiting its DNA binding. This interaction modulates CREB-mediated transcription, offering a new understanding of gene regulation.
Area of Science:
- Molecular Biology
- Gene Regulation
Background:
- cAMP-responsive gene expression is activated by phosphorylated CREB (cAMP response element-binding protein) recruiting CBP.
- Proteins interacting with CREB or CBP can modulate CREB-dependent transactivation.
Purpose of the Study:
- To investigate the role of Daxx in CREB-mediated transcription.
- To elucidate the mechanism by which Daxx affects cAMP-responsive gene expression.
Main Methods:
- Yeast two-hybrid screening to identify CREB-interacting proteins.
- shRNA-mediated depletion and overexpression of Daxx.
- In vitro and in vivo binding assays.
- Reporter gene assays.
- Electrophoresis mobility shift assays (EMSA).
- Chromatin immunoprecipitation (ChIP) experiments.
Main Results:
- Daxx was identified as a CREB-interacting protein.
- Daxx depletion decreased, while overexpression increased, cAMP/PKA-induced reporter activity and gene expression.
- Daxx's C-terminal domain binds to CREB's basic leucine zipper domain.
- Daxx binding to CREB repressed CRE-mediated reporter activity and attenuated CREB's DNA binding potential.
Conclusions:
- Daxx plays a novel repressive role in cAMP-responsive gene expression.
- Daxx inhibits CREB transcriptional activity by interfering with its DNA binding.
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