Fig. 4. The Ripply2-knockout mouse exhibits segmentation defects. (A-D) Ripply2^+/- and Ripply2^-/- embryos (n=3 at E10.5) were compared by external morphology (A,B) and by the Hematoxylin and Eosin staining of parasagittal sections of tail regions (C,D). Ripply2^-/- embryos display irregularly sized myotomes, and an unclear segmental border. (E-G) Skeletal preparations at E17.5 stained with Alizarin Red-Alcian Blue reveal that the Ripply2^-/- fetus harbors fewer pedicles of neural arches and lacks components of the proximal ribs (F; n=4), which is similar to the aberrant phenotype of the Psen1-null fetus (G; n=2).