A αTub84B promoter drives expression of wts that has been mutated to carry a T1083A amino acid substitution (non-phosphorylatable mutation, predicted to result in a non-functional protein), and which is tagged at the N-terminal end with Citrine and at the C-terminal end with mTFP1. mTFP1 and Citrine can act as a fluorescence resonance energy transfer (FRET) pair (donor and acceptor respectively), and changes in the quenching ratio (acceptor channel emissions/donor channel emissions) can be used to monitor conformational changes in the mutant wts protein in vivo. Generated by excision of the FRT cassette in wtsT1083A.αTub84B.FRT.CWT.