CLC chloride channels in Caenorhabditis elegans.
The genome of the nematode Caenorhabditis elegans encodes six putative chloride channels (CeCLC-1 through CeCLC-6) that represent all three known branches of the mammalian CLC gene family. Using promoter fragments to drive the expression of the green fluorescent protein, CeCLC-2, -3, and -4 expression was studied in transgenic C. elegans. CeCLC-4 was specifically expressed in the large H-shaped excretory cell, where it was co-expressed with CeCLC-3, which is also expressed in other cells, including neurons, muscles, and epithelial cells. Also, CeCLC-2 was expressed in several cells of the nervous system, intestinal cells, and vulval muscle cells. Similar to mammalian CLC proteins, only two nematode CLC channels elicited detectable plasma membrane currents in Xenopus oocytes. CeCLC-3 currents were inwardly rectifying and were activated by positive prepulses. Its complex gating behavior can be explained by two gates, at least one of which depends on extracellular anions. In this respect it resembles some mammalian chloride channels with which it also shares a preference of chloride over iodide. C. elegans thus provides new opportunities to understand common mechanisms underlying structure and function in CLC channels and will allow for a genetic dissection of chloride channels in this simple model organism.
Schriever
A M
AM
Zentrum für Molekulare Neurobiologie Hamburg (ZMNH), Hamburg University, Martinistrasse 85, D-20246 Hamburg, Germany.
Friedrich
T
T
Pusch
M
M
Jentsch
T J
TJ
D000818:Animals; D017173:Caenorhabditis elegans / Q000737:chemistry / Q000235:genetics*; D002460:Cell Line; D018118:Chloride Channels / Q000235:genetics*; D002712:Chlorides / Q000494:pharmacology; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004594:Electrophysiology; D005260:Female; D015870:Gene Expression; D017238:Genes, Helminth / Q000235:genetics; D049452:Green Fluorescent Proteins; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D009865:Oocytes; D010802:Phylogeny; D020033:Protein Isoforms / Q000235:genetics; D012326:RNA Splicing; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014981:Xenopus
D018118:Chloride Channels; D002712:Chlorides; D018076:DNA, Complementary; D008164:Luminescent Proteins; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins