抄録
The Sec1/Munc-18 (SM) family members are essential factors that regulate docking/fusion of membrane-bound organelles in various eukaryotic cells, but their precise roles are still unclear. To elucidate the physiological roles of SM proteins in membrane traffic and organelle biogenesis in a multicellular organism, we have systematically isolated deletion mutations of all the SM genes (unc-18, vps-33.1, vps-33.2, vps-45, T07A9.10 and F43D9.3) on the C. elegans genome, using a TMP (trimethylpsolaren)/UV method. We found that the SM mutations result in various phenotypes, such as embryonic lethality, larval lethality, small brood size, and reduction of motility. To investigate which trafficking pathways are impaired in these mutants, transgenic analyses using fluorescent reporters were performed. vps-33.1 and vps-45 mutations caused the defects on both the fluid-phase and the receptor-mediated endocytosis pathways, and these endocytic defects were linked to abnormal morphologies of endosomes or lysosomes in the mutant cells. The mutation of the neuron-specific gene, unc-18, resulted in the defect of secretion of synaptic vesicles. These functional analyses of SM mutants revealed that SM proteins are key molecules regulating membrane traffic on both the exo-and the endocytic pathways in a multicellular organism. [J Physiol Sci. 2008;58 Suppl:S25]
