Sun Yingning, Jin Zhao, Zhang Xinyang, Cui Tingting, Zhang Wenjian, Shao Shuli, Li Hui, Wang Ning
College of Animal Science and Technology, Northeast Agricultural University, Harbin, China.
College of Life Science and Agriculture Forestry, Qiqihar University, Qiqihar, China.
Front Physiol. 2020 Jun 10;11:610. doi: 10.3389/fphys.2020.00610. eCollection 2020.
Kruppel-like transcription factor 7 (KLF7) is a negative regulator of adipogenesis, however, its precise mechanism is poorly understood. Our previous KLF7 ChIP-seq analysis showed that one of the KLF7 binding peaks was present upstream of GATA binding protein 3 () in chicken preadipocytes. In the present study, we identified as a target of KLF7. Overexpression analysis showed KLF7 markedly enhanced the endogenous expression of in the immortalized chicken preadipcyte cell line (ICP2), and the luciferase reporter assay showed that KLF7 overexpression increased the reporter gene activity of the cloned upstream region (-5285/-4336 relative to the translation initiation codon ATG) of in ICP2 and DF1 cells, and mutation of the putative KLF7 binding site abolished the promotive effect of KLF7 overexpression on the reporter gene activity of the cloned upstream region. ChIP-qPCR further demonstrated that KLF7 directly bound to the upstream region. Gene expression analysis showed that mRNA expression in abdominal adipose tissue was significantly higher in lean chicken line than in the fat line at 2, 3, and 6 weeks of age. In addition, mRNA expression markedly decreased during the preadipocyte differentiation. Furthermore, a functional study showed that GATA3 overexpression inhibited the differentiation of the ICP2 cells. Taken together, our results demonstrated that KLF7 inhibits chicken adipogenesis, at least in part through direct upregulation of .
Kruppel样转录因子7(KLF7)是脂肪生成的负调节因子,然而,其确切机制尚不清楚。我们之前的KLF7染色质免疫沉淀测序(ChIP-seq)分析表明,在鸡前脂肪细胞中,一个KLF7结合峰位于GATA结合蛋白3(GATA3)上游。在本研究中,我们鉴定出GATA3是KLF7的一个靶标。过表达分析表明,KLF7显著增强了永生化鸡前脂肪细胞系(ICP2)中GATA3的内源性表达,荧光素酶报告基因测定表明,KLF7过表达增加了ICP2和DF1细胞中克隆的GATA3上游区域(相对于翻译起始密码子ATG为-5285/-4336)的报告基因活性,并且假定的KLF7结合位点的突变消除了KLF7过表达对克隆的GATA3上游区域报告基因活性的促进作用。ChIP-qPCR进一步证明KLF7直接与GATA3上游区域结合。基因表达分析表明,在2、3和6周龄时,瘦肉型鸡品系腹部脂肪组织中的GATA3 mRNA表达显著高于脂肪型鸡品系。此外,在前脂肪细胞分化过程中,GATA3 mRNA表达明显下降。此外,一项功能研究表明,GATA3过表达抑制了ICP2细胞的分化。综上所述,我们的结果表明KLF7至少部分通过直接上调GATA3来抑制鸡的脂肪生成。