Blockade of ion channel expression in Xenopus oocytes with complementary DNA probes to Na+ and K+ channel mRNAs.
Ionic currents were recorded from Xenopus oocytes injected with RNA isolated from chick or mouse brain. Three currents were studied: a rapid tetrodotoxin-sensitive Na+ current (Ina), an early outward K+ current sensitive to 4-aminopyridine (IA), and an inward current activated by the excitatory amino acid receptor agonist kainate. Oligonucleotides (60-80 bases long) complementary to rat brain Na+ channel sequences were prehybridized to chick brain RNA. These DNA sequences, upon injection into oocytes, specifically inhibited expression of INa relative to IA and the kainate-induced current in a dose-dependent manner. By contrast, prehybridization of oligonucleotides complementary to sequences either from the Drosophila Shaker locus (which codes for an early K+ current in Drosophila muscle) or from a homologous clone from mouse brain did not block the expression of the early outward K+ current induced in the oocytes by mRNA from chick or mouse brain. This method provides a convenient means for testing the functional role of cloned DNA species.
Lotan
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I
Department of Pharmacology, Howard Hughes Medical Institute, Columbia University, New York, New York 10032.
Volterra
A
A
Dash
P
P
Siegelbaum
S A
SA
Goelet
P
P
D000818:Animals; D001483:Base Sequence; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology; D004247:DNA / Q000235:genetics / Q000494:pharmacology; D015342:DNA Probes; D004330:Drosophila / Q000235:genetics; D004553:Electric Conductivity; D005260:Female; D005809:Genes, Regulator / Q000502:physiology; D007608:Kainic Acid / Q000494:pharmacology; D008969:Molecular Sequence Data; D009865:Oocytes / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000187:drug effects* / Q000502:physiology; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics* / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects* / Q000502:physiology; D014981:Xenopus / Q000502:physiology*
D015342:DNA Probes; D015221:Potassium Channels; D012333:RNA, Messenger; D015222:Sodium Channels; D004247:DNA; D012964:Sodium; D011188:Potassium; D007608:Kainic Acid