Eskitis Institute for Drug Discovery, Griffith University, Nathan Brisbane 4111, Queensland, Australia.
The University of Queensland Diamantina Institute, Translational Research Institute, Woolloongabba Brisbane 4102, Queensland, Australia.
Sci Rep. 2017 Aug 14;7(1):8109. doi: 10.1038/s41598-017-05451-5.
Development of neural progenitors depends upon the coordination of appropriate intrinsic responses to extrinsic signalling pathways. Here we show the deubiquitylating enzyme, Usp9x regulates components of both intrinsic and extrinsic fate determinants. Nestin-cre mediated ablation of Usp9x from embryonic neural progenitors in vivo resulted in a transient disruption of cell adhesion and apical-basal polarity and, an increased number and ectopic localisation of intermediate neural progenitors. In contrast to other adhesion and polarity proteins, levels of β-catenin protein, especially S33/S37/T41 phospho-β-catenin, were markedly increased in Usp9x embryonic cortices. Loss of Usp9x altered composition of the β-catenin destruction complex possibly impeding degradation of S33/S37/T41 phospho-β-catenin. Pathway analysis of transcriptomic data identified Wnt signalling as significantly affected in Usp9x embryonic brains. Depletion of Usp9x in cultured human neural progenitors resulted in Wnt-reporter activation. Usp9x also regulated components of the Notch signalling pathway. Usp9x co-localized and associated with both Itch and Numb in embryonic neocortices. Loss of Usp9x led to decreased Itch and Numb levels, and a concomitant increase in levels of the Notch intracellular domain as well as, increased expression of the Notch target gene Hes5. Therefore Usp9x modulates and potentially coordinates multiple fate determinants in neural progenitors.
神经祖细胞的发育依赖于适当的内在反应与外在信号通路的协调。在这里，我们发现去泛素化酶 Usp9x 调节内在和外在命运决定因素的组成部分。在体内，通过 Nestin-cre 介导的 Usp9x 敲除，胚胎神经祖细胞的细胞黏附和顶端-基底极性短暂受到破坏，中间神经祖细胞的数量增加，并异位定位。与其他黏附和极性蛋白不同，Usp9x 胚胎皮质中β-连环蛋白蛋白，特别是 S33/S37/T41 磷酸化-β-连环蛋白的水平显著增加。Usp9x 的缺失改变了 β-连环蛋白破坏复合物的组成，可能阻碍 S33/S37/T41 磷酸化-β-连环蛋白的降解。转录组数据分析的通路分析表明，Wnt 信号在 Usp9x 胚胎脑中受到显著影响。在培养的人神经祖细胞中耗尽 Usp9x 导致 Wnt 报告基因激活。Usp9x 还调节 Notch 信号通路的组成部分。Usp9x 在胚胎新皮质中与 Itch 和 Numb 共定位和相关。Usp9x 的缺失导致 Itch 和 Numb 水平降低，同时 Notch 细胞内结构域水平增加，以及 Notch 靶基因 Hes5 的表达增加。因此，Usp9x 调节并可能协调神经祖细胞中的多种命运决定因素。
