Fig. 7. Regulation of cell proliferation and gene expression by Gata3. Control wild-type or Gata3^+/- embryos (A,C,E) and Gata3^-/- embryos (B,D,F) were analyzed by immunohistochemistry with anti-phosphorylated-histone H3 and anti-E-cadherin antibodies (A,B) and by in situ hybridization with Ret (C,D) and Wnt11 (E,F) cRNA probes. (A,B) The number of mitotic cells (white arrows) and the cellularity (broken lines) of the nephric duct were significantly higher in Gata3^-/- compared with control embryos. Sections A,B were counterstained with DAPI (blue) (C,D) Ret expression was absent from Gata3^-/- hypercellular nephric ducts. Strong Ret expression is still present in the Gata3^-/- spinal cord (sc). (E,F) Expression of the Ret-regulated Wnt11 gene was completely lost in Gata3^-/- nephric ducts in contrast to control embryos. Broken lines in A,B,D,F demarcate the epithelial nephric duct, as defined by E-cadherin staining. da, dorsal aorta; ec, ectoderm; nd, nephric duct; sc, spinal cord.