Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Fudan University, Shanghai, 200011, China; NHC Key Lab of Reproduction (Shanghai Institute of Planned Parenthood Research), Institute of Reproduction and Development, Fudan University, Shanghai, 200032, China.
Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Fudan University, Shanghai, 200011, China.
J Genet Genomics. 2020 Jun 20;47(6):301-310. doi: 10.1016/j.jgg.2020.06.003. Epub 2020 Jun 27.
Wnt signaling pathways, including the canonical Wnt/β-catenin pathway, planar cell polarity pathway, and Wnt/Ca signaling pathway, play important roles in neural development during embryonic stages. The DVL genes encode the hub proteins for Wnt signaling pathways. The mutations in DVL2 and DVL3 were identified from patients with neural tube defects (NTDs), but their functions in the pathogenesis of human neural diseases remain elusive. Here, we sequenced the coding regions of three DVL genes in 176 stillborn or miscarried fetuses with NTDs or Dandy-Walker malformation (DWM) and 480 adult controls from a Han Chinese population. Four rare mutations were identified: DVL1 p.R558H, DVL1 p.R606C, DVL2 p.R633W, and DVL3 p.R222Q. To assess the effect of these mutations on NTDs and DWM, various functional analyses such as luciferase reporter assay, stress fiber formation, and in vivo teratogenic assay were performed. The results showed that the DVL2 p.R633W mutation destabilized DVL2 protein and upregulated activities for all three Wnt signalings (Wnt/β-catenin signaling, Wnt/planar cell polarity signaling, and Wnt/Ca signaling) in mammalian cells. In contrast, DVL1 mutants (DVL1 p.R558H and DVL1 p.R606C) decreased canonical Wnt/β-catenin signaling but increased the activity of Wnt/Ca signaling, and DVL3 p.R222Q only decreased the activity of Wnt/Ca signaling. We also found that only the DVL2 p.R633W mutant displayed more severe teratogenicity in zebrafish embryos than wild-type DVL2. Our study demonstrates that these four rare DVL mutations, especially DVL2 p.R633W, may contribute to human neural diseases such as NTDs and DWM by obstructing Wnt signaling pathways.
Wnt 信号通路，包括经典的 Wnt/β-连环蛋白通路、平面细胞极性通路和 Wnt/Ca 信号通路，在胚胎发育阶段的神经发育中发挥重要作用。DVL 基因编码 Wnt 信号通路的枢纽蛋白。DVL2 和 DVL3 的突变已在神经管缺陷（NTD）患者中被鉴定出来，但它们在人类神经疾病发病机制中的作用仍不清楚。在这里，我们对 176 例无脑儿或流产胎儿的 DVL 三个基因的编码区进行了测序，这些胎儿患有 NTD 或 Dandy-Walker 畸形（DWM），并对来自汉族的 480 名成年对照组进行了测序。鉴定出了四个罕见的突变：DVL1 p.R558H、DVL1 p.R606C、DVL2 p.R633W 和 DVL3 p.R222Q。为了评估这些突变对 NTD 和 DWM 的影响，进行了各种功能分析，如荧光素酶报告基因分析、应力纤维形成和体内致畸试验。结果表明，DVL2 p.R633W 突变使 DVL2 蛋白不稳定，并上调了哺乳动物细胞中所有三种 Wnt 信号通路（Wnt/β-连环蛋白信号通路、Wnt/平面细胞极性信号通路和 Wnt/Ca 信号通路）的活性。相比之下，DVL1 突变体（DVL1 p.R558H 和 DVL1 p.R606C）降低了经典的 Wnt/β-连环蛋白信号通路，但增加了 Wnt/Ca 信号通路的活性，而 DVL3 p.R222Q 仅降低了 Wnt/Ca 信号通路的活性。我们还发现，只有 DVL2 p.R633W 突变体在斑马鱼胚胎中表现出比野生型 DVL2 更严重的致畸性。我们的研究表明，这四个罕见的 DVL 突变，特别是 DVL2 p.R633W，可能通过阻断 Wnt 信号通路导致人类神经疾病，如 NTD 和 DWM。
