Isolation and characterization of the mouse ortholog of the Fukuyama-type congenital muscular dystrophy gene.

Fukuyama-type congenital muscular dystrophy (FCMD) is a severe autosomal-recessive muscular dystrophy accompanied by brain malformation. Previously, we identified the gene responsible for FCMD through positional cloning. Here we report the isolation of its murine ortholog, Fcmd. The predicted amino acid sequence of murine fukutin protein encoded by Fcmd is 90% identical to that of its human counterpart. Radiation hybrid mapping localized the gene to 2.02 cR telomeric to D4Mit272 on chromosome 4. Northern blot analysis revealed ubiquitous expression of Fcmd in adult mouse tissues. Through in situ hybridization, we observed a wide distribution of Fcmd expression throughout embryonic development, most predominantly in the central and peripheral nervous systems. We also detected high Fcmd expression in the ventricular zone of proliferating neurons at 13.5 days post-coitum. Brain malformation in FCMD patients is thought to result from defective neuronal migration. Our data suggest that neuronally expressed Fcmd is likely to be important in the development of normal brain structure.