UASt regulatory sequences drive expression of an inverted repeat.
Expression via P{GAL4-tim.E}27 or P{cry-GAL4.Z}17 (in the presence of Dcr-2Scer\UAS.cDa) results in robust reduction in the the number of flies showing rhythmic behaviour in constant darkness, a concomitant reduction in the 'rhythmic strength' value of flies classified as rhythmic, and a prolonged period.