CHROMOSOMAL MAPPING OF THE HUMAN M6 GENES

M6 is a neuronal membrane glycoprotein that may have an important role in neural development. This molecule was initially defined by a monoc lonal antibody that affected the survival of cultured cerebellar neuro ns and the outgrowth of neurites. The nature of the antigen was discov ered by expression cDNA cloning using this monoclonal antibody. Two di stinct murine M6 cDNAs (designated M6a and M6b) whose deduced amino ac id sequences were remarkably similar to that of the myelin proteolipid protein were previously isolated. We have isolated partial human cDNA and genomic clones encoding M6a and M6b and have characterized them b y restriction mapping, Southern hybridization with cDNA probes, and se quence analysis. We have localized these genes within the human genome by FISH (fluorescence in situ hybridization). The human M6a gene is l ocated at 4q34, and the M6b gene is located at Xp22.2. A number of hum an neurological disorders have been mapped to the Xp22 region, includi ng Aicardi syndrome (MIR;I 304050), Rett syndrome (MIM 312750), X-link ed Charcot-Marie-Tooth neuropathy (MIM 302801), and X-linked mental re tardation syndromes (MRX1, MIM 309530). This raises the possibility th at a defect in the M6b gene is responsible for one of these neurologic al disorders. (C) 1996 Academic Press, Inc.