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Evidence for the involvement of more than one mRNA species in controlling the inactivation process of rat and rabbit brain Na channels expressed in Xenopus oocytes

Krafte, Douglas S. and Snutch, Terry P. and Leonard, John P. and Davidson, Norman and Lester, Henry A. (1988) Evidence for the involvement of more than one mRNA species in controlling the inactivation process of rat and rabbit brain Na channels expressed in Xenopus oocytes. Journal of Neuroscience, 8 (8). pp. 2859-2868. ISSN 0270-6474. PMCID PMC6569391. doi:10.1523/jneurosci.08-08-02859.1988. https://resolver.caltech.edu/CaltechAUTHORS:20191104-094627196

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Abstract

The properties of rat and rabbit brain sodium (Na) channels expressed in Xenopus oocytes following either unfractionated or high-molecular- weight mRNA injections were compared to assess the relative contribution of different size messages to channel function. RNA was size-fractionated on a sucrose gradient and a high-molecular-weight fraction (7–10 kilobase) encoding the α-subunit gave rise to functional voltage-dependent Na channels in the oocyte membrane. Single- channel conductance, mean open time, and time to first opening were all similar to the values for channels following injection of unfractionated RNA. In contrast, inactivation properties were markedly different; Na currents from high-molecular-weight RNA inactivated with a several-fold smaller macroscopic inactivation rate and showed a steady-state voltage dependence that was shifted in the depolarizing direction by at least 10 mV relative to that for unfractionated RNA. Single-channel recording revealed that the kinetic difference arose from a greater probability for high-molecular-weight RNA induced channels to reopen during a depolarizing voltage step. Pooling all gradient fractions and injecting this RNA into oocytes led to the appearance of Na channels with inactivation properties indistinguishable from those following injection of unfractionated RNA. These results suggest that mRNA species not present in the high- molecular-weight fraction can influence the inactivation process of rat brain Na channels expressed in Xenopus oocytes. This mRNA may encode β-subunits or other proteins that are involved in posttranslational processing of voltage-dependent Na channels.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1523/jneurosci.08-08-02859.1988DOIArticle
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6569391PubMed CentralArticle
ORCID:
AuthorORCID
Lester, Henry A.0000-0002-5470-5255
Additional Information:© 1988 Society for Neuroscience. Received July 21, 1987; revised Jan. 15, 1988; accepted Jan. 18, 1988. We wish to thank M. Fearey for technical assistance, F. Shon for assistance with the computer programs, and W. A. Catterall for the gift of a-scorpion toxin. This work was supported by NS-11756, GM-10991, an NRSA individual fellowship (D.S.K.), and fellowships from the American Heart Association Greater Los Angeles Affiliate (T.P.S. and J.P.L.).
Funders:
Funding AgencyGrant Number
NIHNS-11756
NIHGM-10991
American Heart Association, Greater Los Angeles AffiliateUNSPECIFIED
NIH Predoctoral FellowshipUNSPECIFIED
Issue or Number:8
PubMed Central ID:PMC6569391
DOI:10.1523/jneurosci.08-08-02859.1988
Record Number:CaltechAUTHORS:20191104-094627196
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20191104-094627196
Official Citation:Evidence for the involvement of more than one mRNA species in controlling the inactivation process of rat and rabbit brain Na channels expressed in Xenopus oocytes. DS Krafte, TP Snutch, JP Leonard, N Davidson, HA Lester. Journal of Neuroscience 1 August 1988, 8 (8) 2859-2868; DOI: 10.1523/JNEUROSCI.08-08-02859.1988
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:99645
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:04 Nov 2019 18:29
Last Modified:16 Nov 2021 17:48

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