Schwarz, J., Spies, J.-P., & Bringmann, H.


Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.




Sleep-like states are characterized by massively reduced behavioural activity. Little is known about genetic control of sleep-like behaviour. It is also not clear how general activity levels during wake-like behaviour influence activity levels during sleep-like behaviour. Mutations that increase wake-like activity are generally believed to also increase activity during sleep-like behaviour and mutations that decrease wake-like activity are believed to have decreased activity during sleep-like behaviour. We studied sleep-like behaviour during lethargus in larvae of Caenorhabditis elegans. We looked through a small set of known mutants with altered activity levels. As expected, mutants with increased activity levels typically showed less sleep-like behaviour. Among these hyperactive mutants was a gain-of-function mutant of the conserved heterotrimeric G protein subunit Galphaq gene egl-30. We found, however, that an unusual semidominant hypoactive mutant of egl-30 also had reduced sleep-like behaviour. While movement was severely reduced and impaired in the semidominant egl-30 mutant, sleep-like behaviour was severely reduced: the semidominant egl-30 mutant lacked prolonged periods of complete immobility, reduced spontaneous neural activity less, and reduced responsiveness to stimulation less. egl-30 is a well-known regulator of behaviour. Our results suggest that egl-30 controls not only general activity levels, but also differences between wake-like and sleep-like behaviour.


… “every 30 minutes using a 495nm LED (CoolLED) coupled to the fluorescence port of the microscope. LED”…

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