A genetically encoded bioluminescent indicator for the sodium channel activity in living cells

We have developed a genetically encoded bioluminescent indicator for the Na(+) channel, in which Na(+)-sensitive Gaussia luciferase is fused with the voltage-gated Na(+) channel. This indicator is capable of detecting Na(+) flow through the pores of Na(+) channels. Because of high sensitivity and low background in luminescence assays, the absence of toxicity, and a wide linear dynamic range, this luciferase can be used to generate a novel, genetically encoded Na(+) channel indicator. It may provide a high-throughput screening system for drug discovery against Na(+) channels, which should be useful in controlling lethal cardiac arrhythmias, epileptic seizures, and intolerable pain associated with terminal stages of cancer. It may also offer a system for monitoring the Na(+) channel activity in living cells, which may be useful in illuminating neuronal activity in vivo.