Research Article

CRYPTOCHROME Is a Blue-Light Sensor That Regulates Neuronal Firing Rate

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Science  03 Mar 2011:
DOI: 10.1126/science.1199702


Light-responsive neural activity in central brain neurons is generally conveyed through opsin-based signaling from external photoreceptors. Large lateral ventral arousal neurons (l-LNv) in Drosophila melanogaster increase action potential firing within seconds in response to light in the absence of all opsin-based photoreceptors. Light-evoked changes in membrane resting potential occur in approximately 100 milliseconds. The light response is selective for blue wavelengths, corresponding to the spectral sensitivity of CRYPTOCHROME (CRY). cry-null lines are light unresponsive, but restored CRY expression in the l-LNv rescues responsiveness. Furthermore, expression of CRY in neurons that are normally unresponsive to light confers responsiveness. The CRY-mediated light response requires a flavin redox-based mechanism and depends on potassium channel conductance, but is independent of the classical circadian CRY-TIMELESS interaction.