UPTAKE OF FLUORESCENT DYES ASSOCIATED WITH THE FUNCTIONAL EXPRESSION OF THE CYSTIC-FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR IN EPITHELIAL-CELLS

Specific mutations in the cystic fibrosis transmembrane conductance re gulator (CFTR), the most common autosomal recessive fatal genetic dise ase of Caucasians, result in the loss of epithelial cell adenosine 3', 5'-cyclic-monophosphate (cAMP)-stimulated Cl- conductance. We show tha t the influx of a fluorescent dye, dihydrorhodamine 6G (dR6G), is incr eased in cells expressing human CFTR after retrovirus- and adenovirus- mediated gene transfer. dR6G influx is stimulated by cAMP and is inhib ited by antagonists of cAMP action, Dye uptake is ATP-dependent and in hibited by Cl- removal or the addition of 10 mM SCN-. Increased staini ng is associated with functional activation of CFTR Cl- permeability, dR6G staining enables both the fluorescent assessment of CFTR function and the identification of successfully corrected cells after gene the rapy.