GENE INTERACTIONS AFFECTING MECHANOSENSORY TRANSDUCTION IN CAENORHABDITIS-ELEGANS

GENETIC screening has identified a group of mec (mechanosensory) genes that are required for the function of a set of six touch-receptor neu rons in the nematode Caenorhabditis elegans1,2. Such genes potentially encode components of the mechanosensory apparatus. We have cloned one of these genes, mec-10, which is a member of the degenerin gene famil y (genes such as mec-4 and deg-1 (refs 3, 4) that can be mutated to ca use neurodegeneration). Because components of an amiloride-sensitive s odium channel (alpha, beta and gammarENaC) from rat6-8 share considera ble sequence similarity with the C. elegans genes, it is likely that d egenerins may function as channel proteins. Here we show that two dege nerin homologues (mec-4 and mec-10) are expressed in the same cells, a lthough each provides a unique function. Based on genetic data of muta tions affecting mec-10-induced degeneration, we propose that the produ cts of three genes (mec-4, mec-10 and mec-6) form a complex needed for mechanosensation, and that several other mec genes may be important i n regulating the putative channel complex.