A recombination-based mCherry-to-GFP switch transgene consisting of: the ato 5'Eye enhancer (a 2918 nt fragment located 7471 nt 5' to the ato start codon), the ato basal promoter (a 1058 nt
fragment located 58 nt 5' to the ato start codon), a FRT-mCherry-Tag:NLS(Unk)-hsp70 stop-FRT cassette, followed by a nuclear-localised GFP.