Related Experiment Video
Updated: Aug 15, 2026
Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes
Published on: January 11, 2011
Mitosis-promoting factor-mediated suppression of a cloned delayed rectifier potassium channel expressed in Xenopus
A Brüggemann1, W Stühmer, L A Pardo
1Max-Planck-Institut für Experimentelle Medizin, Göttingen, Germany.
Abstract:
The cell cycle is the crucial process that leads to mitosis in all cell types. The dramatic redirectioning of many cellular processes during the cycle is known to involve ion channels, either changing their level of expression or their voltage dependence, as in the case of inward rectifiers. Here we describe the specific inhibition of heterologously expressed ionic channels at the onset of maturation in Xenopus oocytes. In cells expressing rat eag (R-eag) potassium channels, maturation induces a dramatic reduction in the current amplitude, which is almost complete in most cases. The key molecule in oocyte maturation, the mitosis-promoting factor (a complex of cyclin B and p34cdc2), is able to induce similar changes when injected into the oocytes.
Insights
Cell cycle maturation in Xenopus oocytes specifically inhibits rat eag (R-eag) potassium channels. This inhibition is mediated by the mitosis-promoting factor, highlighting ion channel regulation during cell division.
Area of Science:
- Cell Biology
- Molecular Biology
- Ion Channel Physiology
Background:
- The cell cycle, essential for cell division and mitosis, involves dynamic regulation of cellular processes.
- Ion channels are known to be modulated during the cell cycle through changes in expression or voltage dependence.
Purpose of the Study:
- To investigate the specific inhibition of heterologously expressed ionic channels during Xenopus oocyte maturation.
- To determine the role of the mitosis-promoting factor in regulating ion channel activity.
Main Methods:
- Heterologous expression of rat eag (R-eag) potassium channels in Xenopus oocytes.
- Electrophysiological recordings to measure current amplitude.
- Injection of mitosis-promoting factor (cyclin B and p34cdc2 complex) into oocytes.
Main Results:
- Maturation of Xenopus oocytes led to a significant reduction in R-eag potassium channel current amplitude.
- The observed current reduction was nearly complete in most oocytes.
- Injection of the mitosis-promoting factor mimicked the inhibitory effects seen during natural oocyte maturation.
Conclusions:
- The mitosis-promoting factor plays a key role in the specific inhibition of R-eag potassium channels during oocyte maturation.
- Ion channel regulation is a critical component of the cellular events leading to mitosis.
