UAS regulatory sequences drive expression of the the first 128 amino acid residues of Mef2 (which includes the MADS box and Mef2 domain) fused to the en repressor domain (amino acids 2-298). This is expected to result in a dominant-negative Mef2 protein.
39% of flies expressing Mef2Scer\UAS.T:en-Rep under the control of Scer\GAL4P0.5.Pdf are arrhythmic with respect to locomotor activity and the remainder have weaker rhythms than control flies.
Expression of Mef2Scer\UAS.T:en-Rep under the control of Scer\GAL4tim.Scer\UAS causes long locomotor activity rhythms, with a period of 25.4 +/- 0.7 hours. Half of the flies die within the first 5 days of the assay.