Fig. 5. The expression of Hesr1 and Hesr2 is unaffected in Tbx2-misexpressed, Notch2-KO or Notch2-activated hearts. Hesr1 and Hesr2 expression was examined in Tbx2-ME (A,B), Notch2-KO (D,E) and Notch2-ICD-ME (G,H) embryos (E9.0). (A,B) The expected expression patterns of Hesr1 (A) and Hesr2 (B) were observed in the Tbx2-ME hearts. A normal expression pattern for Hesr1 (D,G) and Hesr2 (E,H) was observed in Notch2-KO (E9.5) and Notch2-ICD-ME (E9.0) embryos. (C) Tbx2 was detectable throughout the entire heart in the Tbx2-ME embryo. (F,I) Notch2 expression was detectable using a probe directed against the Notch2-ICD (I), but not with a probe for the extracellular domain (ECD) of Notch2 (F). A, atrium; V, ventricle; LA, left atrium; LV, left ventricle.