Cyclin-dependent kinase-9, as a novel component of p300/GATA-4 complex, is involved in differentiation of mouse ES cells into cardiac myocytes

Cyclin-dependent kinase-9, as a novel component of p300/GATA-4 complex, is involved in differentiation of mouse ES cells into cardiac myocytes

Shinji Kaichi1, Tomohide Takaya2, Tatsuya Morimoto3, Yoichi Sunagawa2, Teruhisa Kawamura2, Koh Ono3, Toru Kita3, Kyoko Hidaka4, Takayuki Morisaki4, Shiro Baba1, Toshio Heike1, Tatsutoshi Nakahata1, Koji Hasegawa2.

  1. Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
  2. Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto, Japan.
  3. Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
  4. Department of Bioscience, National Cardiovascular Center Research Institute, Osaka, Japan.

第71回日本循環器学会学術集会 (神戸), 2007/03/17 (ポスター).

Abstract

Differentiation of embryonic stem (ES) cells into cardiac myocytes requires activation of cardiac-specific gene program. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) govern gene expression patterns by being recruited to target genes through association with specific transcription factors. One of HATs, p300 serves as a coactivator of cardiac-specific transcription factors such as a zinc finger protein GATA-4. Treatment of ES cells with trichostatin A (TSA), a specific HDAC inhibitor, induces acetylation of GATA-4 and facilitates their differentiation into cardiac myocytes. Here, we show that cyclin-dependent kinase-9 (CDK9), a component of positive transcription elongation factor b which increases activity of RNA Pol II by hyperphosphorylation, is a novel component of p300/GATA-4 complex. CDK9 interacted not only with GATA-4 but also with p300. A dominant-negative form of CDK9 and CDK9 kinase inhibitor, 5,6-dichloro-1-h-ribofuranosyl-benzimidazole (DRB) inhibited p300-induced activation of GATA-4-dependent transcription as well as acetylation of GATA-4. We examined effects of DRB on myocardial differentiation by flow cytometry in an ES cell line, in which GFP is expressed under the control of the cardiac-specific NKX-2.5 promoter. Administration of DRB into mouse ES cells repressed TSA-induced expression of GFP controlled by the cardiac-specific NKX-2.5 promoter. These findings demonstrate that CDK9, as a novel component of p300/GATA-4 complex, is involved in the differentiation of mouse ES cells into cardiac myocytes.