Fig. 2.

Mapk10 and Mab21l1 are expressed in Ret^+/+ but not Ret^k−/k− intestines. Representative comparison of gene expression in Ret^+/+ versus Ret^k−/k− embryos by RNA in situ hybridization: Mapk10 (A, B, E, and F) and Mab21l1 (C, D, G, and H). Both genes are expressed in the myenteric layer of the Ret^+/+ intestine (A and C), but expression is lost in the Ret^k−/k− intestine (B and D). We see expression throughout the myenteric plexus of the Ret^+/+ stomach for both Mapk10 (E) and Mab21l1 (G) but only a small number of Mapk10- or Mab21l1-expressing cells in the equivalent region of the Ret^k−/k− stomach (arrows in F and H).