Wnt3

Wnt3 is a secreted Wnt ligand linked to canonical Wnt/β-catenin signaling, a pathway that controls embryonic development and adult homeostasis^[1]. Mechanistically, Wnt3 activity supports TCF/LEF-dependent transcription and connects ligand-receptor signaling to cell fate regulation^[1]. In mouse embryos, Wnt3 expression precedes gastrulation and becomes restricted to the posterior epiblast, visceral endoderm, primitive streak, and mesoderm^[2]. Wnt3-null embryos fail to form a primitive streak, mesoderm, or node, establishing Wnt3 as a core regulator of vertebrate axis formation^[2]. In limb development, ectodermal Wnt3/β-catenin signaling establishes and maintains the apical ectodermal ridge, linking Wnt3 to limb morphogenesis^[3]. Human evidence further connects homozygous WNT3 mutation with tetra-amelia, supporting its early requirement in limb, craniofacial, and urogenital development^[4]. Compared with Wnt3a, Wnt3 shows distinct activity in spinal cord neural precursors: Wnt3 transiently increases proliferation and enhances neurogenesis, whereas Wnt3a sustains proliferation^[5]. For experimental applications, Wnt3/Wnt3a pathway studies can use canonical Wnt agonists, antagonists, or GSK-3β inhibitors to interrogate β-catenin-dependent proliferation, neurogenesis, and neurite outgrowth^[1][5].