THE DROSOPHILA EASILY SHOCKED GENE - A MUTATION IN A PHOSPHOLIPID SYNTHETIC PATHWAY CAUSES SEIZURE, NEURONAL FAILURE, AND PARALYSIS

We have characterized easily shocked (eas), a Drosophila ''bang-sensit ive'' paralytic mutant. Electrophysiological recordings from flight mu scles in the giant fiber pathway of adult eas flies reveal that induct ion of paralysis with electrical stimulation results in a brief seizur e, followed by a failure of the muscles to respond to giant fiber stim ulation. Molecular cloning, germline transformation, and biochemical e xperiments show that eas mutants are defective in the gene for ethanol amine kinase, which is required for a pathway of phosphatidylethanolam ine synthesis. Assays of phospholipid composition reveal that total ph osphatidylethanolamine is decreased in eas mutants. The data suggest t hat eas bang sensitivity is due to an excitability defect caused by al tered membrane phospholipid composition.