Figure 2. Double conditional knockout of Smyd2 and Pkd1 delayed renal cyst formation.

(A) Representative kidneys from Pkd1^fl/fl:Smyd2^+/+:Ksp-Cre (Smyd2^+/+) and Pkd1^fl/fl:Smyd2^fl/fl:Ksp-Cre (Smyd^fl/fl) neonates. Scale bars: 2 mm. (B) Percent cystic area relative to total kidney section area was significantly decreased in P7 kidneys from Pkd1^fl/fl:Smyd2^fl/fl:Ksp-Cre versus Pkd1^fl/fl:Smyd2^+/+:Ksp-Cre neonates. Data reflect all sections quantified for each condition (n = 12 in Smyd2^+/+ group and n = 14 in Smyd2^fl/fl group). (C) KW/BW ratios were reduced in P7 Pkd1^fl/fl:Smyd2^fl/fl:Ksp-Cre versus Pkd1^fl/fl:Smyd2^+/+:Ksp-Cre neonates. (D) BUN levels were significantly decreased in P7 serum from Pkd1^fl/fl:Smyd2^fl/fl:Ksp-Cre neonates compared with Pkd1^fl/fl:Smyd2^+/+:Ksp-Cre neonates. (E) Pkd1^fl/fl:Smyd2^fl/fl:Ksp-Cre mice lived to a mean age of 22.2 days (n = 16), whereas Pkd1^fl/fl:Smyd2^+/+:Ksp-Cre mice died of PKD at a mean age of 16.3 days (n = 20). P < 0.01. (F) Western blot analysis of SMYD2 expression in P7 kidneys from Pkd1^fl/fl:Smyd2^+/+:Ksp-Cre (Smyd2^+/+) and Pkd1^fl/fl:Smyd2^fl/fl:Ksp-Cre (Smyd^fl/fl) neonates. (G) Cell proliferation was decreased in P7 kidneys from Pkd1^fl/fl:Smyd2^fl/fl:Ksp-Cre neonates versus those from Pkd1^fl/fl:Smyd2^+/+:Ksp-Cre neonates, as detected with Ki67 staining. The percentage of Ki67-positive nuclei in cyst-lining epithelial cells was calculated from an average of 1,000 nuclei per mouse kidney section. Scale bars: 100 μm. (H) Knockout of Smyd2 induced cyst-lining epithelial cell death in kidneys from P7 Pkd1^fl/fl:Smyd2^fl/fl:Ksp-Cre neonates, while apoptosis was rare in kidneys from Pkd1^fl/fl:Smyd2^+/+:Ksp-Cre neonates, as detected by TUNEL assay. Scale bars: 100 μm. The images in G and H are also shown in Supplemental Figure 1, A and B.