The choroid plexus is recombined early embryonically in the Cux2-Cre line, but not in the Nestin-Cre or Dlx5/6-Cre lines. A, Representative images of recombination in Nestin-Cre;Ai9, Dlx5/6-Cre;Ai9, and Cux2-Cre;Ai9 adult animals. The choroid plexus is completely recombined in Cux2-Cre;Ai9 animals, very sparsely recombined in Nestin-Cre;Ai9 animals, and not recombined in Dlx5/6-Cre;Ai9 animals. B, Representative images of choroid plexus recombination in Cux2-Cre;Ai9 embryos. The choroid plexus is completely recombined in Cux2-Cre;Ai9 embryos, including in the dorsal telencephalic midline from which the choroid plexus derives, as early as E10.5. ChP, Choroid plexus; DTM, dorsal telencephalic midline. Scale bar, 100 μm.