The maternally expressed gene Tssc3 regulates the expression of MASH2 transcription factor in mouse trophoblast stem cells through the AKT-Sp1 signaling pathway.
The maternally expressed gene Tssc3 regulates the expression of MASH2 transcription factor in mouse trophoblast stem cells through the AKT-Sp1 signaling pathway.
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DOI：
10.1074/jbc.m112.388777
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发表时间：
2012-12-14
期刊：
影响因子：
--
通讯作者：
Wake N
中科院分区：
文献类型：
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作者：
Takao T;Asanoma K;Tsunematsu R;Kato K;Wake N
背景：Tssc3基因是一个母系表达的印迹基因。结果：TSSC 3通过磷酸化AKT和Sp1从细胞质到细胞核的转位来调节TS细胞中Mash2的转录。结论：TSSC 3决定TS细胞发育为滋养层祖细胞和/或迷路滋养层细胞的命运。TSSC 3通过AKT/Sp1/MASH 2信号通路调控TS细胞分化。Tssc 3是一个母系表达/父系沉默的印迹基因。最近的证据表明，TSSC 3的缺失导致小鼠胎盘过度生长。这些发现表明TSSC3基因作为胎盘生长的负调节因子发挥作用。本研究旨在探讨TSSC 3在小鼠滋养层干细胞分化中的作用及其信号通路。首先，我们测试了TS细胞中Tssc3的表达水平。TS细胞表达Tssc 3，在诱导分化后第1~4天表达量最高，第5天表达下调。TSSC 3在TS细胞中的过表达上调了小鼠滋养层分化的标志基因Gcm 1和Mash 2。在干细胞条件下培养的TS细胞中，通过siRNA下调TSSC 3增强了Pl1和Tpbpa的表达，表明TSSC 3对TS向滋养层祖细胞和/或迷路滋养层细胞的分化有贡献。TSSC 3通过与磷脂酰肌醇磷酸脂质结合激活PI3K/AKT途径，并增强含有E-box结构的启动子的活性，该E-box结构是Mash 2下游靶基因启动子的结合序列。PI3K抑制剂抑制TSSC 3诱导的启动子活性。TSSC 3通过PI3K/AKT途径诱导Sp1从细胞质向细胞核转位。核Sp1通过与共有Sp1结合基序结合来激活Mash2转录。这是首次报道TSSC 3通过TSSC 3/PI3K/AKT/MASH 2信号通路在TS向滋养层祖细胞和/或迷路滋养层细胞分化中起重要作用。
Background: Tssc3 is a maternally expressed imprinted gene. Results: TSSC3 regulates Mash2 transcription in TS cells through phosphorylation of AKT and Sp1 translocation from cytoplasm to nucleus. Conclusion: TSSC3 determines the fate of TS cells in terms of development into trophoblast progenitors and/or labyrinth trophoblasts. Significance: TSSC3 regulates TS cell differentiation through the AKT/Sp1/MASH2 signaling pathway. Tssc3 is a maternally expressed/paternally silenced imprinted gene. Recent evidence suggests that the loss of TSSC3 results in placental overgrowth in mice. These findings showed that the TSSC3 gene functions as a negative regulator of placental growth. In this study, we describe the function of TSSC3 and its signaling pathway in mouse trophoblast stem (TS) cell differentiation. First of all, we tested Tssc3 expression levels in TS cells. TS cells expressed Tssc3, and its expression level was the highest from day 1 to 4 but was down-regulated at day 5 after the induction of differentiation. Overexpression of TSSC3 in TS cells up-regulated Gcm1 and Mash2, which are marker genes of mouse trophoblast differentiation. Down-regulation of TSSC3 by siRNA enhanced Pl1 and Tpbpa expression in TS cells cultured under stem cell conditions, suggesting the contribution of TSSC3 to the differentiation from TS to trophoblast progenitors and/or labyrinth trophoblasts. TSSC3 activated the PI3K/AKT pathway through binding with phosphatidylinositol phosphate lipids and enhanced the activity of a promoter containing an E-box structure, which is the binding sequence of the Mash2 downstream target gene promoter. PI3K inhibitor suppressed the promoter activity induced by TSSC3. TSSC3 induced Sp1 translocation from cytoplasm to nucleus through the PI3K/AKT pathway. Nuclear Sp1 activated the Mash2 transcription by Sp1 binding with a consensus Sp1-binding motif. This is the first report describing that TSSC3 plays an important role in the differentiation from TS to trophoblast progenitors and/or labyrinth trophoblasts through the TSSC3/PI3K/AKT/MASH2 signaling pathway.