Developmental Cell 17 Supplemental Data Cdx and Hox Genes Differentially Regulate Posterior Axial Growth in Mammalian Embryos

Figure S1. Characterization of Cdx expression during embryogenesis and impact of Cdx mutations on posterior axial elongation (A) Expression of Cdx2, Cdx4, and Hoxb8 (a “central ” or trunk Hox gene) revealed by in situ hybridization in posterior tissues in E8.5 to E12.5 wild type embryos. Expression of Cdx2 in the “posterior growth zone ” ends after E12.5, that of Cdx4 before E10.5, and that of Hoxb8 around E9.5. (B) Schematic representation of the axial extension phenotypes of Wt and Cdx mutant embryos around E10.5. Only Cdx2 mutants, or compound Cdx mutants carrying a mutated Cdx2 allele exhibit premature arrest of the embryonic body axis. The Cdx mutants studied most extensively in this work are the compound Cdx2+/-/Cdx4-/- embryos referred to as Cdx2/4 mutants. (C and D) Illustration of the decrease in size of the posterior tissues of the Cdx2/4 mutant embryo at the 7-somite stage, and measurement of the posterior embryonic part (including the PSM) between the last formed somite boundary and the posterior tip (black arrows) at the 4- to 14-somite stage. Length reduction in mutants is manifest from the 7-somite stage on. The size of the PSM between the last formed somite boundary and the posterior part of the node (dashe