Zhu Xuechen, Min Zheying, Tan Renbo, Tao Qinghua
The MOE Key Laboratory of Protein Sciences, Tsinghua University School of Life Sciences, Beijing 10084, China.
The MOE Key Laboratory of Protein Sciences, Tsinghua University School of Life Sciences, Beijing 10084, China.
Mech Dev. 2015 Nov;138 Pt 3:305-12. doi: 10.1016/j.mod.2015.08.008. Epub 2015 Sep 3.
The NF2 gene product Merlin is a FERM-domain protein possessing a broad tumor-suppressing function. NF2/Merlin has been implicated in regulating multiple signaling pathways critical for cell growth and survival. However, it remains unknown whether NF2/Merlin regulates Wnt/β-catenin signaling during vertebrate embryogenesis. Here we demonstrate that NF2/Merlin is required for body pattern formation in the Xenopus laevis embryo. Depletion of the maternal NF2/Merlin enhances organizer gene expression dependent on the presence of β-catenin, and causes dorsanteriorized development; Morpholino antisense oligo-mediated knockdown of the zygotic NF2/Merlin shifts posterior genes anteriorwards and reduces the anterior development. We further demonstrate that targeted depletion of NF2 in the presumptive dorsal tissues increases the levels of nuclear β-catenin in the neural epithelial cells. Biochemical analyses reveal that NF2 depletion promotes the production of active β-catenin and concurrently decreases the level of N-terminally phosphorylated β-catenin under the stimulation of the endogenous Wnt signaling. Our findings suggest that NF2/Merlin negatively regulates the Wnt/β-catenin signaling activity during the pattern formation in early X. laevis embryos.
NF2基因产物Merlin是一种具有广泛肿瘤抑制功能的FERM结构域蛋白。NF2/Merlin参与调节对细胞生长和存活至关重要的多种信号通路。然而，在脊椎动物胚胎发育过程中，NF2/Merlin是否调节Wnt/β-连环蛋白信号通路仍不清楚。在此，我们证明NF2/Merlin是非洲爪蟾胚胎身体模式形成所必需的。母体NF2/Merlin的缺失增强了依赖于β-连环蛋白存在的组织者基因表达，并导致背前部发育；吗啉代反义寡核苷酸介导的合子NF2/Merlin敲低使后部基因向前移位并减少前部发育。我们进一步证明，在假定的背侧组织中靶向敲低NF2会增加神经上皮细胞核β-连环蛋白的水平。生化分析表明，在体内Wnt信号的刺激下，NF2的缺失促进了活性β-连环蛋白的产生，同时降低了N端磷酸化β-连环蛋白的水平。我们的研究结果表明，NF2/Merlin在早期非洲爪蟾胚胎的模式形成过程中对Wnt/β-连环蛋白信号活性起负调节作用。
