SELECTIVE EXPRESSION OF GLIONEXIN, A GLIAL GLYCOPROTEIN, IN INSECT MECHANORECEPTORS

The distribution of a glial cell-associated glycoprotein, glionexin (G X), on sensory receptors of the adult cricket Acheta domesticus is des cribed, using the monoclonal antibody 5B12 as an immunohistochemical p robe. GX was previously shown to be widely distributed in the embryo a nd to persist in the postembryonic to adult central nervous system. He re we demonstrate that it is restricted in the adult periphery to thre e subclasses of mechano-receptor sensilla: large socketed hair mechano receptors, their associated campaniform sensilla, and chordotonal orga ns. GX was not detected in photoreceptors, chemoreceptors, or other me chanoreceptors. The pattern of distribution differs significantly with in the three subclasses of mechanoreceptors. In the hair and campanifo rm receptors GX is restricted to the extracellular space among glial c ells clustered around the axon hillock region, but in chordotonal orga ns it surrounds the scolopidium at the tip of dendrites. The highly re stricted distribution of GX in the periphery suggests possible functio ns that include mechanical stability of the sensory apparatus and ioni c homeostasis in the respective neuronal spike-generating regions. The developmental modulation of GX expression is taken to imply multiple functions for the molecule during the life of the insect. (C) 1994 Joh n Wiley & Sons, Inc.