The transgene is composed of 2.3 kb of rat Ugb (Scgb1a1) promoter, a reverse tetracycline responsive transactivator gene (rt-TA), and 2 kb of human growth hormone sequences, which includes introns and a polyadenylation signal. Transgene expression was confirmed by RT-PCR analysis. The rat Scgb1a1 promoter is active in respiratory epithelial cells. (J:61736)