Ligand for members of the frizzled family of seven transmembrane receptors. Can activate or inhibit canonical Wnt signaling, depending on receptor context. Required during embryogenesis for extension of the primary anterior-posterior axis. Regulates convergent extension movements and hypaxial myogenesis during gastrulation via activation of non-canonical Wnt signaling (PubMed:22406073). Expressed both maternally and zygotically (Ref.1). Expressed in the germ ring at the blastoderm margin during the shield stage of gastrulation, expression is higher dorsally than ventrally (PubMed:22406073). Expressed at the posterior dorsal midline at the four-somite stage and in the pectoral fin bud 48 hours post-fertilization (PubMed:22406073). Zygotic expression begins during somitogenesis and is confined to the mesenchyme of the developing tailbud, the posterior 4-5 somites and the ventrolateral mesenchyme of the head (Ref.1). In later stages, expressed in the pharyngeal arch mesenchyme and pectoral finbuds (Ref.1). Not detected in mature chondrocytes (Ref.1). Palmitoleoylation is required for efficient binding to frizzled receptors. Depalmitoleoylation leads to Wnt signaling pathway inhibition. Morpholino knockdown results in convergent extension movement defects during gastrulation and an absence of myod1 expression in the majority of hypaxial muscle precursor cells. Belongs to the Wnt family.