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Published October 1, 1981 | public
Journal Article Open

Abnormal Action Potentials Associated with the Shaker Complex Locus of Drosophila


Intracellular recordings of action potentials were made from the cervical giant axon in Shaker (Sh) mutants and normal Drosophila. The mutants showed abnormally long delays in repolarization. The defect is not due to abnormal Ca2+ channels, because it persists in the presence of Co2+, a Ca2+-channel blocker. On the other hand, the K+-channel blocker 4-aminopyridine causes a similar effect in normal animals, suggesting that the Sh mutant may have abnormal K+ conductance. Gene-dosage analysis of Sh shows that the defect is not due to underproduction of an otherwise normal molecule; it may be due to an abnormal molecule produced by the mutated gene. Gel electrophoresis failed to detect an abnormal protein, suggesting that, if Sh codes for a nervous system protein, it is rare. Genetic analysis of the Sh locus indicates three regions. Mutations or chromosome breaks in the two flanking regions cause Sh mutant physiology; the central region shows a "haplolethal effect"--i.e., heterozygous females are lethal.

Additional Information

Copyright © 1981 by the National Academy of Sciences. Contributed by Seymour Benzer, July 20, 1981. We are grateful to S. Benzer for continual encouragement and support. We thank L. Kauvar, J. Reinitz, and S. Shotwell for discussion. Special thanks go to I. Duncan for cytogenetic determinations. T. Homyk, G. Lefevre, and J. Merriam kindly provided several stocks. This research was supported by National Science Foundation Grant PCM 7911771 to S. Benzer and the Pew Memorial Trust. M.A.T. was supported by a Muscular Dystrophy Association fellowship and National Institutes of Health Training Grant GM 7401-02. A.F. was supported by National Institutes of Health Fellowship F05 TWO2477 and a Gosney Foundation fellowship. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.


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