The DMX-R sequence of Ecol\lacZnuc.Dll.DMX is mutated from 'GACAATATTTGGGAAATTAAATCATTCCCGCGGACAGTTTTATAGTGCGGGCGTGGC' to 'GACAATATTTGGGAAAccAAATCATTCCCGCGGACAGTTTTATAGTGCGGGCGTGGC' (mutated residues in lower case.)