The polarized distribution of poly(A+)-mRNA-induced functional ion channels in the Xenopus oocyte plasma membrane is prevented by anticytoskeletal drugs

Peter, Andreas B.; Schittny, Johannes C.; Niggli, Verena; Reuter, Harald; Sigel, Erwin (1991). The polarized distribution of poly(A+)-mRNA-induced functional ion channels in the Xenopus oocyte plasma membrane is prevented by anticytoskeletal drugs. Journal of cell biology, 114(3), pp. 455-464. Rockefeller Institute Press

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Foreign mRNA was expressed in Xenopus laevis oocytes. Newly expressed ion currents localized in defined plasma membrane areas were measured using the two-electrode voltage clamp technique in combination with a specially designed chamber, that exposed only part of the surface on the oocytes to channel agonists or inhibitors. Newly expressed currents were found to be unequally distributed in the surface membrane of the oocyte. This asymmetry was most pronounced during the early phase of expression, when channels could almost exclusively be detected in the animal hemisphere of the oocyte. 4 d after injection of the mRNA, or later, channels could be found at a threefold higher density at the animal than at the vegetal pole area. The pattern of distribution was observed to be similar with various ion channels expressed from crude tissue mRNA and from cRNAs coding for rat GABAA receptor channel subunits. Electron microscopical analysis revealed very similar microvilli patterns at both oocyte pole areas. Thus, the asymmetric current distribution is not due to asymmetric surface structure. Upon incubation during the expression period in either colchicine or cytochalasin D, the current density was found to be equal in both pole areas. The inactive control substance beta-lumicolchicine had no effect on the asymmetry of distribution. Colchicine was without effect on the amplitude of the expressed whole cell current. Our measurements reveal a pathway for plasma membrane protein expression endogenous to the Xenopus oocyte, that may contribute to the formation and maintenance of polarity of this highly organized cell.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Pharmacology 04 Faculty of Medicine > Service Sector > Institute of Pathology 04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy > Functional Anatomy
UniBE Contributor:	Schittny, Johannes, Niggli, Verena, Reuter, Harald, Sigel, Erwin
Subjects:	600 Technology > 610 Medicine & health 500 Science > 570 Life sciences; biology
ISSN:	0021-9525
Publisher:	Rockefeller Institute Press
Language:	English
Submitter:	Johannes Schittny
Date Deposited:	18 Aug 2014 13:43
Last Modified:	05 Dec 2022 14:33
PubMed ID:	1713591
URI:	https://boris.unibe.ch/id/eprint/50168