C. elegans osm-3 gene mediating osmotic avoidance behaviour encodes a kinesin-like protein

In the nematode Caenorhabditis elegans, mutants in osm-3 gene are known to be defective in osmotic avoidance, chemotaxis and dauer formation behaviours. To study the molecular basis of these pleiotropic defects we have cloned the osm-3 gene by germline transformation of osm-3 (p802) mutants through microinjection of the wild type genomic DNA. Northern analysis reveals a 3.0 kb transcript corresponding to osm-3. DNA sequencing of the transforming 4.3 kb fragment revealed a kinesin heavy chain-like protein, which contains conserved ATPase and microtubule binding domains. Our results are consistent with the previous EM data on osm-3 (p802) mutants that show an accumulation of dense matrix material in the amphid sheath cytoplasm and a shortened distal segment of the amphid channel cilium. These data suggest a kinesin-like role of the osm-3 product in axonal transport.