The RMCE cassette of the TI{CRIMIC.TG4.1}CG3091CR60215-TG4.1 insertion has been replaced with a TI{FFL.1} cassette that is in gene-trap (GT) orientation relative to CG3091. This is expected to truncate the CG3091 protein and to result in the expression of a separate mCherry protein under the control of endogenous CG3091 regulatory sequences.