Plays a role in axon and dendrite arborization during cranial nerve development (PubMed:24044555). Also important for neural crest migration and early development of other anterior structures including eye, brain and cranial cartilage (PubMed:28104388). In developing neurons, accumulates in early growth cones and at branching points of axons and dendrites. Detected from early embryogenesis onwards (stages 11-35) (PubMed:24044555, PubMed:28104388). Expressed in the mesoderm during gastrulation (PubMed:24044555). Expressed in migrating neural crest cells, where it partially colocalizes with twist1 (PubMed:28104388). As development proceeds, shows marked expression in developing anterior structures including brain, pharyngeal arches, eye (including retina and lens), otic vesicle, heart, pronephros, liver and cranial ganglia (PubMed:24044555, PubMed:28104388). Morpholino knockdown severely impairs cranial nerve development, with shorter or missing cranial ganglia and reduced nerve arborization (PubMed:24044555). Neural crest migration is impaired, although neural crest induction is not significantly affected (PubMed:28104388). Brain size is reduced and cranial cartilage development is severely disrupted, leading to smaller head size (PubMed:28104388). Eyes are smaller and deformed, with coloboma formation and disrupted retinal lamination (PubMed:28104388). In eye, expression of the genes rax, pax6 and otx2 is reduced (PubMed:28104388). In brain, expression of the genes emx1, pax6, otx2, en2 and egr2 is reduced (PubMed:28104388). Tissues show increased apoptosis and reduced cell proliferation (PubMed:28104388). Belongs to the N4BP3 family.