The FRT cassette present in TI{TI}tkvGFP.FRT.Q199D-mCh has been excised, removing the GFP-tagged wild-type tkv coding sequence and allowing expression of the mutated mCherry-tagged tkv coding sequence that remains; this mutated sequence carries a Q199D point mutation (this results in a constitutively active protein).
tkvQ199D-mCherry clones induced on the nub expression domain results in severe wing disc and adult wing malformation.