目的三结构域家族33(Trim33)在调控成骨细胞分化的过程中起到了非常重要的作用,而在脂肪细胞分化过程中的作用却鲜有报道。文中以Trim33为对象探讨其对脂肪细胞分化的影响。方法以转染Trim33-pcDNA3.1过表达质粒的骨髓基质细胞ST2细胞...目的三结构域家族33(Trim33)在调控成骨细胞分化的过程中起到了非常重要的作用,而在脂肪细胞分化过程中的作用却鲜有报道。文中以Trim33为对象探讨其对脂肪细胞分化的影响。方法以转染Trim33-pcDNA3.1过表达质粒的骨髓基质细胞ST2细胞作为实验组,以转染pc DNA3.1质粒的骨髓基质细胞ST2细胞作为对照组,将2组细胞进行成脂诱导分化后,利用油红O染色、qRT-PCR及Western blot技术分析2组细胞CCAAT增强子结合蛋白(C/EBP)α、成脂相关因子过氧化物酶体增殖物激活受体(PPAR)γ、脂肪细胞表征因子FABP4、脂肪因子adipsin等脂肪特异性基因表达的变化。结果与对照组相比,实验组Trim33表达水平显著上升(1.00±0.31 vs 88.51±14.31,P<0.01)。成脂诱导5 d后,经油红O染色,转染Trim33-pcDNA3.1过表达质粒,实验组较对照组细胞脂滴数量明显增多。A520结果与染色一致,实验组的A值明显高于对照组(0.69±0.03 vs 0.34±0.03,P<0.01)。与对照组比较,实验组PPARγ、C/EBPα、FABP4、adipsin mRNA相对表达[(1.00±0.19) vs (1.79±0.21)、(1.00±0.12) vs (2.28±0.24)、(1.00±0.01) vs (10.30±1.38)、(1.00±0.16) vs (12.50±1.96)]均明显增加(P<0.05)。实验组较对照组成脂特异性基因Trim33、PPARγ、C/EBPα、FABP4的蛋白表达上调。结论 Trim33能促进骨髓基质细胞脂堆积并增强脂肪特异性基因的表达。展开更多
Tripartite motif 33(TRIM33), a member of the transcription intermediate factor 1(TIF1) family of transcription cofactors,mediates transforming growth factor-beta(TGF-β) signaling through its PHD-Bromo cassette in mes...Tripartite motif 33(TRIM33), a member of the transcription intermediate factor 1(TIF1) family of transcription cofactors,mediates transforming growth factor-beta(TGF-β) signaling through its PHD-Bromo cassette in mesendoderm differentiation during early mouse embryonic development. However, the role of the TRIM33 RING domain in embryonic differentiation is less clear. Here, we report that TRIM33 mediates Wnt signaling by directly regulating the expression of a specific subset of Wnt target genes, and this action is independent of its RING domain. We show that TRIM33 interacts with β-catenin, a central player in Wnt signaling in mouse embryonic stem cells(mESCs). In contrast to previous reports in cancer cell lines, the RING domain does not appear to function as the E3 ligase for β-catenin, since neither knockout nor overexpression of TRIM33 had an effect on β-catenin protein levels in mESCs. Furthermore, we show that although TRIM33 seems to be dispensable for Wnt signaling through a reporter assay, loss of TRIM33 significantly impairs the expression of a subset of Wnt target genes, including Mixl1,in a Wnt signaling-dependent manner. Together, our results indicate that TRIM33 regulates Wnt signaling independent of the E3 ligase activity of its RING domain for β-catenin in mESCs.展开更多
文摘目的三结构域家族33(Trim33)在调控成骨细胞分化的过程中起到了非常重要的作用,而在脂肪细胞分化过程中的作用却鲜有报道。文中以Trim33为对象探讨其对脂肪细胞分化的影响。方法以转染Trim33-pcDNA3.1过表达质粒的骨髓基质细胞ST2细胞作为实验组,以转染pc DNA3.1质粒的骨髓基质细胞ST2细胞作为对照组,将2组细胞进行成脂诱导分化后,利用油红O染色、qRT-PCR及Western blot技术分析2组细胞CCAAT增强子结合蛋白(C/EBP)α、成脂相关因子过氧化物酶体增殖物激活受体(PPAR)γ、脂肪细胞表征因子FABP4、脂肪因子adipsin等脂肪特异性基因表达的变化。结果与对照组相比,实验组Trim33表达水平显著上升(1.00±0.31 vs 88.51±14.31,P<0.01)。成脂诱导5 d后,经油红O染色,转染Trim33-pcDNA3.1过表达质粒,实验组较对照组细胞脂滴数量明显增多。A520结果与染色一致,实验组的A值明显高于对照组(0.69±0.03 vs 0.34±0.03,P<0.01)。与对照组比较,实验组PPARγ、C/EBPα、FABP4、adipsin mRNA相对表达[(1.00±0.19) vs (1.79±0.21)、(1.00±0.12) vs (2.28±0.24)、(1.00±0.01) vs (10.30±1.38)、(1.00±0.16) vs (12.50±1.96)]均明显增加(P<0.05)。实验组较对照组成脂特异性基因Trim33、PPARγ、C/EBPα、FABP4的蛋白表达上调。结论 Trim33能促进骨髓基质细胞脂堆积并增强脂肪特异性基因的表达。
基金supported by the National Natural Science Foundation of China (20141300584, 20151301548 to Qiaoran Xi)the THU-PKU Center for Life Sciences
文摘Tripartite motif 33(TRIM33), a member of the transcription intermediate factor 1(TIF1) family of transcription cofactors,mediates transforming growth factor-beta(TGF-β) signaling through its PHD-Bromo cassette in mesendoderm differentiation during early mouse embryonic development. However, the role of the TRIM33 RING domain in embryonic differentiation is less clear. Here, we report that TRIM33 mediates Wnt signaling by directly regulating the expression of a specific subset of Wnt target genes, and this action is independent of its RING domain. We show that TRIM33 interacts with β-catenin, a central player in Wnt signaling in mouse embryonic stem cells(mESCs). In contrast to previous reports in cancer cell lines, the RING domain does not appear to function as the E3 ligase for β-catenin, since neither knockout nor overexpression of TRIM33 had an effect on β-catenin protein levels in mESCs. Furthermore, we show that although TRIM33 seems to be dispensable for Wnt signaling through a reporter assay, loss of TRIM33 significantly impairs the expression of a subset of Wnt target genes, including Mixl1,in a Wnt signaling-dependent manner. Together, our results indicate that TRIM33 regulates Wnt signaling independent of the E3 ligase activity of its RING domain for β-catenin in mESCs.
