The RMCE cassette of the TI{CRIMIC.TG4.0}wittyCR60298-TG4.0 insertion has been replaced with a TI{FFL.0} cassette that is in gene-trap (GT) orientation relative to witty. This is expected to truncate the witty protein and to result in the expression of a separate mCherry protein under the control of endogenous witty regulatory sequences.