Figure 4. Kidney cysts in double transgenics can be found throughout all segments of the nephron.

(A–D) H&E staining of adult kidneys demonstrates numerous cystic dilatations in the cortex and outer medulla in Six2-cre^tg/+, Wnt9b^tg/+ double transgenics and a normal kidney architecture in Wnt9b^tg/+ controls. (E–H) Cysts were derived from proximal tubules (LTL-positive) and distal loop of Henle (THP-positive). DBA-positive and Aquaporin 2- positive collecting duct cysts were also identified in smaller number. Since Six2-cre is not expressed in the collecting duct, these cysts are produced through signaling from neighboring cells or secondary to dilatation of more proximal segments.