Okamura Masashi, Kudo Hiromi, Wakabayashi Ken-ichi, Tanaka Toshiya, Nonaka Aya, Uchida Aoi, Tsutsumi Shuichi, Sakakibara Iori, Naito Makoto, Osborne Timothy F, Hamakubo Takao, Ito Sadayoshi, Aburatani Hiroyuki, Yanagisawa Masashi, Kodama Tatsuhiko, Sakai Juro
Laboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8904, Japan.
Proc Natl Acad Sci U S A. 2009 Apr 7;106(14):5819-24. doi: 10.1073/pnas.0901676106. Epub 2009 Mar 23.
Wnt signaling through beta-catenin and TCF maintains preadipocytes in an un-differentiated proliferative state; however, the molecular pathway has not been completely defined. By integrating gene expression microarray, chromatin immunoprecipitation-chip, and cell-based experimental approaches, we show that Wnt/beta-catenin signaling activates the expression of COUP-TFII which recruits the SMRT corepressor complex to the first introns located downstream from the first exons of both PPARgamma1 and gamma2 mRNAs. This maintains the local chromatin in a hypoacetylated state and represses PPARgamma gene expression to inhibit adipogenesis. Our experiments define the COUP-TFII/SMRT complex as a previously unappreciated component of the linear pathway that directly links Wnt/beta-catenin signaling to repression of PPARgamma gene expression and the inhibition of adipogenesis.
通过β-连环蛋白和TCF的Wnt信号传导使前脂肪细胞维持在未分化的增殖状态;然而,该分子途径尚未完全明确。通过整合基因表达微阵列、染色质免疫沉淀芯片和基于细胞的实验方法,我们发现Wnt/β-连环蛋白信号传导激活COUP-TFII的表达,COUP-TFII招募SMRT共抑制复合物至PPARγ1和γ2 mRNA首个外显子下游的首个内含子。这使局部染色质维持在低乙酰化状态并抑制PPARγ基因表达以抑制脂肪生成。我们的实验将COUP-TFII/SMRT复合物定义为线性途径中一个先前未被认识的组分,该组分直接将Wnt/β-连环蛋白信号传导与PPARγ基因表达的抑制及脂肪生成的抑制联系起来。