Neurofibromatosis type 2 (NF2) is a complex nervous system disorder characterized by the development of schwannomas (especially vestibular), meningiomas, ependymomas and juvenile lens opacities. Mutation in the NF2 gene, which encodes for the schwannomin protein (SCH), a member of the band 4.1 superfamily of genes, predisposes carriers to these central nervous system tumors. We have isolated a mouse cDNA from a brain library which contains the complete open reading frame of the mouse homologue of the NF2 gene. This cDNA encodes for a 596 amino acid protein with 98% identity to the human SCH. Cross species hybridization experiments predict that the NF2 gene is highly conserved in other vertebrates. Northern analysis detects a 4.5 kb transcript in mouse brain, kidney, cardiac muscle, skin and lung suggesting ubiquitous expression. The predicted secondary structure of SCH, which is shared by all members of the band 4.1 superfamily, includes a highly conserved amino-terminal domain which is believed to bind to proteins in the plasma membrane and a large highly charged alpha-helix domain proposed to associate with the cytoskeleton. The NF2 gene is the first example of a tumor suppressor gene whose protein product appears to act as a membrane cytoskeleton-linker. These results show that the NF2 gene is highly conserved and suggests that the analysis of the mouse NF2 gene might yield insights into the function of the human gene.