Cell-specific, developmentally and hormonally regulated expression of the rabbit uteroglobin transgene and the endogenous mouse uteroglobin gene in transgenic mice.

We have generated a transgenic mouse line by introducing the rabbit uteroglobin gene with 4 kb of 5'-flanking DNA and 1 kb of 3'-flanking DNA into the mouse germ line via microinjection into fertilized oocytes. Expression of the rabbit uteroglobin transgene was examined and compared with the endogenous mouse uteroglobin gene. Both genes are expressed in the lung, male genital tract and uterus. In the lung, mRNA expression is enhanced by glucocorticoids and restricted to the Clara cells that line terminal and respiratory bronchioli. During embryonic lung development, transcripts are first detected at day 17. Expression in the uterus is restricted to the glandular epithelium and can be induced by sequential treatment with estrogens and progesterone. In the uterus of these pseudopregnant mice the level of rabbit uteroglobin transcripts is higher than that of the mouse endogenous uteroglobin transcripts. In the male genital tract, expression of both genes is restricted to the epithelial layers of the vesicular gland, vas deferens and epididymis. Our results indicate that the rabbit uteroglobin gene together with 4 kb of 5'-flanking DNA and 1 kb of 3'-flanking DNA contains the information required for cell type-specific, developmentally, and hormonally regulated expression.