The structure and expression of the human neuroligin-3 gene

The neuroligins are a family of proteins that are thought to mediate cell t o cell interactions between neurons. During the sequencing at an Xq13 locus associated with a mental retardation syndrome in some studies, we discover ed a portion of the human orthologue of the rat neuroligin-3 gene. We now r eport the structure and the expression of that gene. The gene spans approxi mately 30 kb and contains eight exons. Unlike the rat gene, it codes for at least two mRNAs and at least one of which is expressed outside the CNS, In terestingly, the putative promoter for the gene overlaps the last exon of t he neighboring HOPA gene and is located less than 1 kb from an OPA element in which a polymorphism associated with mental retardation is found. These findings suggest a possible role for the neuroligin gene in mental retardat ion and that the role of the gene in humans may differ from its role in rat s. (C) 2000 Elsevier Science B.V. All rights reserved.