MAPT and tauopathy: To explore the genetic interaction between Stg and Tau, we used the well-established fly tauopathy model GMR-hTau2N4R (hereafter GMR-hTau), which is based on the expression of the longest hTau isoform (2N4R) under the control of the glass multimer reporter (GMR) regulatory sequences, which drive transcription in all cell types posterior to the morphogenetic furrow in the developing eye (Hay et al., 1994; Jackson et al., 2002).