Related Experiment Videos
Multiple Shaker potassium channels in a primitive metazoan
T Jegla1, N Grigoriev, W J Gallin
1Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Summary
Two Shaker potassium channel genes were found in jellyfish, indicating this gene family existed before complex nervous systems evolved. This discovery sheds light on the early evolution of ion channels in animals.
Area of Science:
- Neuroscience
- Evolutionary Biology
- Molecular Biology
Background:
- Voltage-gated potassium channels (Kv channels) are crucial for nervous system function.
- Four Kv channel gene subfamilies (Shaker, Shal, Shab, Shaw) diversify modern animal nervous systems.
- No Kv channel data existed for ancient diploblastic metazoans before this study.
Purpose of the Study:
- Investigate Kv channel diversity in early-diverging animals.
- Determine the ancestral K+ channel repertoire in the first nervous systems.
- Compare Kv channels in diploblasts and triploblasts to understand evolutionary origins.
Main Methods:
- Isolation of two Shaker subfamily cDNA clones (jShak1, jShak2) from the jellyfish Polyorchis penicillatus.
- Expression of isolated clones in Xenopus oocytes.
- Electrophysiological characterization of expressed currents.
Main Results:
- Identified two distinct Shaker subfamily genes in a cnidarian (jellyfish).
- Expressed currents (jShak1, jShak2) showed functional similarities to Drosophila Shaker currents.
- Demonstrated multiple Shaker genes predate the major animal radiation event.
Conclusions:
- The Shaker K+ channel subfamily was established with functional identity before the first major metazoan radiation.
- Multiple Shaker genes have been independently selected for across diverse metazoans.
- This finding provides insights into the fundamental set of K+ channels present in early nervous systems.