Submitted on February 6, 2008
Accepted on March 27, 2008
An Androgen-Inducible Proximal Tubule-Specific Cre-Recombinase Transgenic Model
Huiping Li1, Xiyou Zhou2, Deborah R Davis1, Di Xu3, and Curt D. Sigmund4*
1 Internal Medicine, University of Iowa, Iowa City, Iowa, United States
2 Molecular Biology, University of Iowa, Iowa City, Iowa, United States
3 Genetics, University of Iowa, Iowa City, Iowa, United States
4 Departments of Medicine and Physiology & Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States
* To whom correspondence should be addressed. E-mail: curt-sigmund{at}uiowa.edu.
To facilitate the study of renal proximal tubules, we generated a transgenic mouse strain expressing an improved Cre-recombinase (iCre) under the control of the kidney androgen regulated protein (KAP) promoter. The transgene was expressed in the kidney of male mice but not in female mice. Treatment of female transgenic mice with androgen induced robust expression of the transgene in the kidney. We confirmed the presence of Cre-recombinase activity and the cell-specificity by breeding the KAP2-iCRE mice with ROSA26 reporter mice. X-gal staining of kidney sections from male double transgenic mice showed robust staining in the epithelial cells of renal proximal tubules. 
-galactosidase staining in female mice became evident in proximal tubules after administration of androgen. This model of inducible Cre-recombinase in the renal proximal tubule should provide a novel useful tool for studying the physiological significance of genes expressed in the renal proximal tubule. This has advantages of other current models where cre-recombinase expression is constitutive, not inducible.
