Utilizing the Caenorhabditis elegans genome database, we have characterized two novel four-domain voltage-gated ion channel (VGIC) genes. The C. elegans C11D2.6 and C27F2.3 gene products (called
nca-1 and
nca-2, respectively, for "novel ion channel alpha-1 subunit") are similar to that of other four-domain VGICs such as sodium and calcium channels although their pore regions reveal a unique ion selectivity motif. Our efforts to date have focused on characterizing the properties of the NCA-1 and NCA-2 gene products. We have determined the cellular expression patterns of
nca-1 and
nca-2 by using GFP-promoter fusion constructs. The
nca-1 transgene was found to be primarily expressed in phayngeal neurons, neurons of the nerve ring, motorneurons of the ventral nerve chord, and neurons in the tail, whereas the
nca-2 transgene was found to be expressed primarily in the neurons of the nerve ring. Gene knock-outs of
nca-1 and
nca-2 indicate that neither mutant strain shows any overt morphological phenotype. Efforts are underway to further characterize the phenotypes of these mutant strains. In addition, full length cDNAs of
nca-1 and
nca-2 have been isolated in order to determine the electrophysiological and pharmacological properties of the NCA-1 and NCA-2 channels. This work was funded by CIHR (Canada)