FIG. 2.

Mutated Pept2 allele is a null allele, and no compensatory upregulation is found in related genes. (A) Northern blot analysis with RNA isolated from the kidneys of wild-type (+/+) and Pept2 knockout (−/−) mice. The 4-kb fragment corresponding to the PEPT2 mRNA was not detectable in the RNA from the Pept2 knockout mice. The blot was stripped and rehybridized with a glyceraldehyde-3-phosphate dehydrogenase probe as a loading and quality control (1.2-kb fragment). (B) Western blot analysis showing the absence of the PEPT2 protein in the kidney. The 100-kDa protein corresponding to the PEPT2 protein was not detectable in the knockout mice. The blot was probed with an antibody directed against actin as a quality and quantity control (42-kDa fragment). (C) Western blot analysis showing no increase in the PEPT1 protein level in the kidney. No differences were detected in the intensity of the 75-kDa band, which corresponds to the PEPT1 protein. The blot was probed with an antibody directed against actin as a quality and quantity control (42-kDa fragment). (D) Northern blot analysis showing no increase in the PHT1 mRNA level in the kidney. No differences were detected in the intensity of the 2.9-kb band which corresponds to the PHT1 RNA. The blot was striped and rehybridized with a glyceraldehyde-3-phosphate dehydrogenase probe as a loading and quality control (1.2-kb fragment). (E) Tissue overview after LacZ staining of kidney from adult Pept2^−/− mice and slices (F). Bar, 80 μm.