Putative Neuronal Cell Adhesion Molecule (PUNC)

Mouse Punc is a transmembrane protein that belongs to the immunoglobulin (Ig) superfamily. With a domain configuration of 4 Ig domains and 2 fibronectin type III repeats, Punc represents a novel subclass within the Ig superfamily. Sequence comparisons revealed that Punc is related to Ig superfamily members that are either associated with axons or function in axon guidance. Punc is highly expressed in the nervous system and limb buds of the developing mouse embryo. At midgestation, expression levels of Punc decrease sharply. Strong expression throughout the central nervous system at embryonic day 9.5 (E9.5) to E10.5 was followed by a gradual decrease until expression became virtually extinct at E15.5 except in brain and inner ear. In neonatal mice, expression was strongest in the anterior domain of the cerebellum.