Characterization of an Scl^−/− YS cell line. (A) Comparison of day 9.5 Scl^−/− (left) and wild-type (right) embryos. (B) Genotyping PCR of Scl^+/− progeny and derived cell lines, where 1, 9, 10, 11, YS1, and YS2 are homozygous null. (C) Morphology of YS1 (i) and RM26 (ii) cells. (D) Differentiation of cells on matrigel YS1 plated on matrigel (i) and RM26 plated on matrigel (ii). RM 26 is a murine mesenchymal stem cell line with known endothelial differential potential.⁷²