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Published October 1988 | public
Journal Article

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

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 subunit(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.

Additional Information

© 1988 Cell Press. Received 6 February 1988, Revised 30 July 1988. We wish to thank Dr. R. Llinas for his support during this project; D. Krafte, T. Snutch, A. Coldin, J. Leonard, and R. J. Leonard for sharing their expertise; and J. Campanelli and A. Kamb for their interest and insightful comments and suggestions. This research was supported by USPHS grant GM26976 To B. R., GM10991 to N. D., and GM29836 to H. A. L. J. H. H. is a fellow of the American Cancer Society.

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023