Cloning and functional expression of a plant voltage-dependent chloride channel.
Plant cell membrane anion channels participate in basic physiological functions, such as cell volume regulation and signal transduction. However, nothing is known about their molecular structure. Using a polymerase chain reaction strategy, we have cloned a tobacco cDNA (CIC-Nt1) encoding a 780-amino acid protein with several putative transmembrane domains. CIC-Nt1 displays 24 to 32% amino acid identity with members of the animal voltage-dependent chloride channel (CIC) family, whose archetype is CIC-0 from the Torpedo marmorata electric organ. Injection of CIC-Nt1 complementary RNA into Xenopus oocytes elicited slowly activating inward currents upon membrane hyperpolarization more negative than -120 mV. These currents were carried mainly by anions, modulated by extracellular anions, and totally blocked by 10 mM extracellular calcium. The identification of CIC-Nt1 extends the CIC family to higher plants and provides a molecular probe for the study of voltage-dependent anion channels in plants.
Lurin
C
C
Institut des Sciences Végétales, Centre National de la Recherche Scientifique (CNRS), Gif sur Yvette, France.
Geelen
D
D
Barbier-Brygoo
H
H
Guern
J
J
Maurel
C
C
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018118:Chloride Channels / Q000235:genetics*; D002712:Chlorides / Q000502:physiology; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000235:genetics; D015640:Ion Channel Gating / Q000502:physiology; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics; D010947:Plants, Toxic; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000235:genetics*; D014982:Xenopus laevis
D018118:Chloride Channels; D002712:Chlorides; D017931:DNA Primers; D018076:DNA, Complementary; D010940:Plant Proteins