Targeted attenuation of electrical activity in Drosophila using a genetically modified K+ channel

We describe here a general technique for the graded inhibition of cellular excitability in vivo. Inhibition is accomplished by expressing a geneticall y modified Shaker K+ channel (termed the EKO channel) in targeted cells. Un like native K+ channels, the EKO channel strongly shunts depolarizing curre nt: activating at potentials near E-K and not inactivating. Selective targe ting of the channel to neurons, muscles, and photoreceptors in Drosophila u sing the Gal4-UAS system results in physiological and behavioral effects co nsistent with attenuated excitability in the targeted cells, often with los s of neuronal function at higher transgene dosages. By permitting the incre mental reduction of electrical activity, the EKO technique can be used to a ddress a wide range of questions regarding neuronal function.