Figure 6.

Impaired Notch signaling in Regulator of G protein signaling 6 (RGS6)^−/−/Ca²⁺/calmodulin‐dependent protein kinase II (CaMKII)^VV embryos. A, quantitative polymerase chain reaction indicated that expression of the Notch receptor (Notch1), Notch ligand (Jagged [Jag] 1), and the Notch downstream target genes Hey1 and Hey2 were decreased in RGS6^−/−/CaMKII^VV yolk sacs, embryos, and hearts relative to RGS6^−/−/CaMKII^MM embryos. In contrast, Hey1L was only decreased in embryos and heart in double mutants N=3, *P<0.05, **P<0.01 RGS6^−/−/CaMKII^VV vs RGS6^−/−/CaMKII^MM. B, Western blot analysis indicated that Notch1 intracellular domain (N1ICD) expression was reduced in RGS6^−/−/CaMKII^VV embryos compared with RGS6^−/−/CaMKII^MM embryos. C, Immunohistochemistry using N1ICD antibody showed decreased expression levels of N1ICD levels in the heart endothelial layer of RGS6^−/−/CaMKII^VV embryos compared with RGS6^−/−/CaMKII^MM embryos as Notch intracellular domain (red) co‐localizes with platelet endothelial cell adhesion molecule 1 (PECAM1) (green). Scale bars=50 μm. DAPI indicates 4′,6‐diamidino‐2‐phenylindole.