The RMCE cassette of the TI{CRIMIC.TG4.1}Ca-βCR01554-TG4.1 insertion has been replaced with a TI{FFL.1} cassette that is in gene-trap (GT) orientation relative to Ca-β. This is expected to truncate the Ca-β protein and to result in the expression of a separate mCherry protein under the control of endogenous Ca-β regulatory sequences.