Completely functional double-barreled chloride channel expressed from a single Torpedo cDNA.
We have performed an electrophysiological analysis of the recently cloned Torpedo marmorata Cl- channel. Functional expression of Cl- channels in oocytes of Xenopus laevis previously injected with cRNA yielded an outward-rectifying current activated by hyperpolarization. Replacement of Cl- with other anions significantly reduced or inhibited the current. Single-channel recordings from cell-attached patches exhibited burst-like Cl- channel activity with rapid fluctuations between three equally spaced substates (0 pS, 9 pS, and 18 pS). The properties of the cloned Cl- channel were almost identical to those of the reconstituted native T. californica Cl- channel and were in full agreement with the predictions of the double-barreled channel model [Hanke, W. & Miller, C. (1983) J. Gen. Physiol. 82, 25-45]. Our results imply that the cloned cDNA codes for the completely functional Torpedo electroplax Cl- channel.
Bauer
C K
CK
Physiologisches Institut, Universität Hamburg, Federal Republic of Germany.
Steinmeyer
K
K
Schwarz
J R
JR
Jentsch
T J
TJ
D000818:Animals; D018118:Chloride Channels; D002712:Chlorides / Q000378:metabolism; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D004553:Electric Conductivity; D004594:Electrophysiology; D005260:Female; D015640:Ion Channel Gating; D007473:Ion Channels / Q000502:physiology*; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D008954:Models, Biological; D009865:Oocytes / Q000502:physiology; D011336:Probability; D014101:Torpedo; D014982:Xenopus laevis
D018118:Chloride Channels; D002712:Chlorides; D007473:Ion Channels; D008565:Membrane Proteins; D004247:DNA