Ligand for members of the frizzled family of seven transmembrane receptors. Acts in the canonical Wnt signaling pathway by promoting beta-catenin-dependent transcriptional activation (By similarity). Involved in neurogenesis. Performs a partially redundant function with wnt10b in the formation of the midbrain-hindbrain boundary (MHB) organizer. In the hindbrain, mediates lateral inhibition of boundary cell specification, probably via up-regulation of proneural and Delta gene expression in non-boundary cells; localized expression of wnt1 in boundary cells is maintained via rfng-mediated modulation of Notch activity. In the embryo, expressed in the developing central nervous system (CNS), with an expression pattern very similar to that of wnt10b. During somitogenesis, expressed strongly in hindbrain boundary and roof plate cells. First detected at around 8 hours post-fertilization (hpf) within the prospective midbrain-hindbrain boundary (MHB). By 10 hpf, expressed in two stripes that converge at the dorsal midline. During somitogenesis, this expression domain extends to the prospective epiphysis and the dorsal midline of the hindbrain; unlike wnt10b, wnt1 is not detected in the prospective cerebellum. The hindbrain domain bifurcates along the midline to form two dorsolateral columns with transverse bands of up-regulation at rhombomere boundaries; these are refined into stripes which are maintained at least until at least 48 hpf. At 30 hpf, expressed in the epiphysis, the dorsal midline of the optic tectum, the anterior half of the MHB constriction and in the hindbrain walls. Not detected in adults. Palmitoleoylation is required for efficient binding to frizzled receptors. Palmitoleoylation is necessary for proper trafficking to cell surface (By similarity). Depalmitoleoylated by NOTUM, leading to inhibit Wnt signaling pathway (By similarity). Morpholino knockdown results in broadening of hindbrain boundary marker expression. Belongs to the Wnt family.