The Dishevelled proteins transduce both canonical Wnt/β-catenin and non-canonical Wnt/planar cell polarity (PCP) signaling pathways to regulate many key developmental processes during embryogenesis. Here, we disrupt both canonical and non-canonical Wnt pathways by targeting the entire Dishevelled family of genes (Dvl1, Dvl2, and Dvl3) to investigate their functional roles in the early embryo. We identified several defects in anterior-posterior axis specification and mesoderm patterning in Dvl1^+/−; Dvl2^−/−; Dvl3^−/− embryos. Homozygous deletions in all three Dvl genes (Dvl TKO) resulted in defects in distal visceral endoderm migration and a complete failure to induce mesoderm formation. To identify potential mechanisms that lead to the defects in the developmental processes preceding gastrulation, we generated Dvl TKO mouse embryonic stem cells (mESCs) and compared the transcriptional profile of these cells with wild-type (WT) mESCs during germ lineage differentiation into 3D embryoid bodies (EBs). While the Dvl TKO mESCs displayed similar morphology, self-renewal properties, and minor transcriptional variation from WT mESCs, we identified major transcriptional dysregulation in the Dvl TKO EBs during differentiation in a number of genes involved in anterior-posterior pattern specification, gastrulation induction, mesenchyme morphogenesis, and mesoderm-derived tissue development. The absence of the Dvls leads to specific down-regulation of BMP signaling genes. Furthermore, exogenous activation of canonical Wnt, BMP, and Nodal signaling all fail to rescue the mesodermal defects in the Dvl TKO EBs. Moreover, endoderm differentiation was promoted in the absence of mesoderm in the Dvl TKO EBs, while the suppression of ectoderm differentiation was delayed. Overall, we demonstrate that the Dvls are dispensable for maintaining self-renewal in mESCs but are critical during differentiation to regulate key developmental signaling pathways to promote proper axis specification and mesoderm formation.

Disheveled 蛋白转导经典 Wnt/β-连环蛋白和非经典 Wnt/平面细胞极性 (PCP) 信号通路，以调节胚胎发生过程中的许多关键发育过程。在这里，我们通过靶向整个Disheveled基因家族（ Dvl1 、 Dvl2和Dvl3 ）来破坏经典和非经典 Wnt 通路，以研究它们在早期胚胎中的功能作用。我们在Dvl1 ^+/-中发现了前后轴规格和中胚层模式的几个缺陷； Dvl2 ^-/- ; Dvl3 ^−/−胚胎。所有三个Dvl基因 ( Dvl TKO) 的纯合缺失导致远端内脏内胚层迁移缺陷和诱导中胚层形成完全失败。为了确定导致原肠胚形成前发育过程缺陷的潜在机制，我们生成了Dvl TKO 小鼠胚胎干细胞 (mESC)，并将这些细胞与野生型( WT ) mESC 在胚系分化为 3D 胚状体期间的转录谱进行比较机构（EB）。虽然Dvl TKO mESC 表现出与WT mESC 相似的形态、自我更新特性和较小的转录变异，但我们在Dvl TKO EB 分化过程中发现了一些与前后模式规范、原肠胚形成诱导、间充质形态发生和中胚层衍生组织发育。 Dvls的缺失会导致 BMP 信号基因的特异性下调。此外，经典 Wnt、BMP 和 Nodal 信号传导的外源激活均无法挽救Dvl TKO EB 中的中胚层缺陷。此外，在Dvl TKO EB中缺乏中胚层的情况下，内胚层分化得到促进，而外胚层分化的抑制则被延迟。总的来说，我们证明Dvls对于维持 mESC 的自我更新是可有可无的，但在分化过程中对于调节关键发育信号通路以促进适当的轴规范和中胚层形成至关重要。