1964bp of genomic sequences upstream of the Ir84a start codon is fused upstream of a membrane-targeted fusion protein containing the Tag:SS(Akh) signal peptide, the Tag:M(hCD4) transmembrane domain, a tandem fluorescent dimer composed of EGFP and GFP and an endoplasmic reticulum export signal from the Hsap\KCNJ2 gene.