Neuroligin 3 is expressed in a wide range of glia during development

In Drosophila, Gliotactin is necessary for the development of the glial sheath which protects the peripheral nerves from exposure to hemolymph. Gliotactin belongs to a family of transmembrane serine-esterase like proteins which are important for the formation of cellular junctions. Evolutionary analysis of other members of this family of proteins showed that neuroligins were most closely related to Gliotactin. Using a reverse genetic approach we have isolated the vertebrate homolog of Gliotactin which corresponds to Neuroligin 3. Using RT-PCR and immunostaining we have shown that Neuroligins 2 and 3 are expressed in dorsal root ganglia, and in cultured Schwann cells. Neuroligin 3 is expressed in the olfactory ensheathing glia of the olfactory epithelium. In addition, Neuroligin 1 and/or Neuroligin 3 are expressed in astrocytes in developing mouse spinal cord and retina. The glial expression of the neuroligins, close evolutionary relationship, and interactions with related proteins suggests that these proteins may function in glial wrapping of peripheral axons in vertebrates. This work is supported by RHNI, HHMI and BCHRF.