Thirteen copies of the lexAop regulatory sequence are fused upstream of a CD4-IFP2.0-T2A-HO1 cassette, which encodes a membrane-targeted monomeric fluorescent protein (CD4-IFP2.0) plus the heme oxygenase 1 (Hsap\HMOX1) which is required for IFP2.0 to fluoresce. The two open reading frames are separated by a self-cleaving 2A motif.