The complete sequence of the human locus for NgCAM-related cell adhesion molecule reveals a novel alternative exon in chick and man and conserved genomic organization for the L1 subfamily.

NrCAM is one member of the L1 subfamily of cell surface recognition molecules implicated in nervous system development and function. Here we report the complete sequence of the human NRCAM locus. The gene comprises 34 exons and shows extensive conservation of exon/intron structure compared to L1, suggesting a common evolutionary ancestor. By human–chick sequence comparison we identified exons not previously found in mammalian NRCAM mRNAs. One of these encodes a premature stop codon that would give rise to an isoform of NRCAM lacking ankyrin-binding capacity. The availability of the complete sequence will allow an investigation of the potential role of these splice variants, and examination of the regulatory elements controlling NRCAM expression as well as the relationship of NRCAM to disorders involving 7q.