Figure 1.

Hif-2α deletion in the kidney occurs with high efficiency. (A) Shown is the mean mRNA expression level of Hif-2α exon 2 in kidney and liver extracts by real-time PCR analysis (n = 6). Exon 2 is flanked by loxP site and targeted for Cre-mediated recombination. Exon 2 expression levels were normalized to Hif-2α exon 8, which is not deleted. Bars represent mean values ± SEMs. (B) LacZ staining of kidney and liver tissue from a P3Pro mouse expressing the ROSA26R Cre-reporter transgene. Magnification, ×100 (top) and ×400 (bottom). (C) P3Pro-Cre is not expressed in biliary epithelial or Ito cells. Immunohistochemistry was performed in conjunction with X-gal staining on frozen liver tissue sections. LacZ expression did not colocalize with cytokeratin 19 (CK19), which is specific for biliary epithelial cells (left) nor did it overlap with staining for desmin, which is a histologic marker of Ito cells (right). Shown are LacZ-positive cells (blue) and CK19- or desmin-positive cells (brown) on the left or right, respectively. Wt refers to Cre-negative littermates. Arrows depict desmin-positive cells. Magnification, ×400. *P < .05; ns, not statistically significant.