Neuron
Volume 1, Issue 8, October 1988, Pages 649-658
Journal home page for Neuron

Article
At least two mRNA species contribute to the properties of rat brain A-type potassium channel expressed in xenopus oocytes

https://doi.org/10.1016/0896-6273(88)90164-XGet rights and content

Abstract

Fast transient K+ channels (A channels) of the type operating in the subthreshold region for Na+ action potential generation were expressed in Kenopus oocytes injected with rat brain poly(A) RNA. Sucrose gradient fractionation of the RNA separates mRNAs encoding A-currents (6–7 kb) from mRNAs encoding other voltage-dependent K+ channels. A-currents expressed with fractionated mRNA differ in kineticsAnd pharmacology from A-currents expressed with total mRNA. The original properties of the A-currents can be reconstituted when small mRNAs (2–4 kb) are added to the large mRNA fraction. Thus the properties of the A-currents expressed with total poly(A) RNA depend on the presence of more than one mRNA species. mRNA(s) present in the large RNA fraction must encode channel subunits since they express an A-current by themselves. The small mRNA(s) may encode a second jsubunit(s) or a factor, such as an enzymatic activity that modulates the properties of the channels, which could play a role in generating A-channel functional diversity.

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