UASt regulatory sequences drive expression of a mutated form of dco that carries the amino acid replacement K38R (producing a dominant negative protein) and in which the nuclear localization signal sequence has been mutated (from KRQK to NNQN). The protein is tagged at the C-terminal end with Tag:MYC and with the Tag:NLS(SV40-largeT) nuclear localisation signal.
The expression of dcoK38R.NLS-.UAS.Tag:MYC,Tag:NLS(SV40-largeT) under the control of Scer\GAL4tim.PE does not have a significant effect on the circadian rhythmicity and period, as compared to controls.