Shaking the Need to Sleep?

Science's STKE  03 May 2005:
Vol. 2005, Issue 282, pp. tw166
DOI: 10.1126/stke.2822005tw166

Some people require only 3 to 4 hours of sleep a night--far less than the 7 or 8 hours most individuals need for optimal performance. This ability to function well with little sleep may run in families, prompting Cirelli et al. to search for genetic mutations that affect sleep duration. A screen of 9000 mutant Drosophila lines uncovered a line of flies, which the authors called minisleep (mns), that slept only 4 to 5 hours each day, compared with the 9 to 15 hours a day that wild-type flies spend sleeping. The mns mutation affected sleep duration but not the frequency with which flies fell asleep and, unlike wild-type flies, the response of mns flies to complex stimuli was not impaired by sleep deprivation. The mns flies showed a shaking phenotype after exposure to anesthetics, suggesting a mutation in Shaker (Sh), which encodes a voltage-dependent potassium channel. The short-sleeping phenotype indeed mapped to the Sh locus, and sequence analysis revealed a point mutation resulting in substitution of isoleucine for a threonine in the Shaker S1 domain. Moreover, following outcrossing to eliminate genetic modifiers, other Shaker mutations were revealed to elicit the short-sleeping phenotype. The authors noted that the short-sleeping Shaker mutants also had a reduced life span. Thus--at least in flies--a point mutation in the Shaker channel appears to be sufficient to confer the ability to function well on markedly reduced amounts of sleep.

C. Cirelli, D. Bushey, S. Hill, R. Huber, R. Kreber, B. Ganetzky, G. Tononi, Reduced sleep in Drosophila Shaker mutants. Nature 434, 1087-1092 (2005). [PubMed]