1. Characterization of endogenous sodium channel gene expressed in Chinese hamster ovary cells.
- Author
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Lalik PH, Krafte DS, Volberg WA, and Ciccarelli RB
- Subjects
- Animals, Base Sequence, Blotting, Northern, CHO Cells, Cloning, Molecular methods, Cricetinae, Molecular Sequence Data, Oligodeoxyribonucleotides, Poly A genetics, Poly A isolation & purification, Polymerase Chain Reaction methods, RNA genetics, RNA isolation & purification, RNA, Messenger genetics, RNA, Messenger isolation & purification, Rats, Restriction Mapping, Sequence Homology, Nucleic Acid, Sodium Channels drug effects, Tetrodotoxin pharmacology, Brain physiology, DNA genetics, Sodium Channels genetics, Sodium Channels physiology
- Abstract
Chinese hamster ovary (CHO-K1) cells were observed to display transient inward Na+ currents of average amplitude (-92 +/- 20 pA), which activated at voltages more than -40 mV, and peak inward currents were observed at potentials equal to or more than +10 mV. Inward Na+ currents in these cells were eliminated after treatment with 500 or 50 nM tetrodotoxin (TTX), whereas 5 nM TTX resulted in 64 +/- 10% inhibition of Na+ current. Using DNA primers designed to bind to the rat brain IIA Na+ channel subtype, we amplified specific polymerase chain reaction (PCR) fragments from CHO-K1 poly-(A)+RNA. The cloning and sequencing of two of these fragments confirmed the presence of an endogenously expressed Na+ channel gene in these cells, which we have termed cho 1. Comparison of the DNA sequence of cho 1 PCR fragments with other known Na+ channel genes indicated a high degree of homology with rat brain Na+ channel subtypes. Northern blots using riboprobes generated from the cho 1 PCR fragments revealed the presence of a specific 9-kb mRNA in these cells. The molecular and electrophysiological data suggest that the cho 1 Na+ channel gene from CHO-K1 cells is closely related to brain-type Na+ channels.
- Published
- 1993
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