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Figure 4. Inhibition of cardiogenesis by SOX7 and SOX18 morpholinos: Fertilized eggs were injected at animal and vegetal sites with a total of 30 ng of morpholino and examined at stage ∼30. A: A schematic of a stage-30 embryo showing the location of the cardiogenic region (rrow (image from Nieuwkoop and Faber, 1967). In situ hybridization using antisense RNAs directed against either MHCα (B) or Nkx2.5 (E,F). Both the SOX7 morpholino (MO7) (B,E) and the SOX18 morpholino (MO18) (C,E) reduced the size and intensity of the MHCα and Nkx2.5 staining domains. A combination of both morpholinos (15+15 ng/embryo) (D,F) produced a more complete suppression of MHCα and Nkx2.5 staining (see also Table 1). Rescue studies: To confirm the specificity of the morpholino effects, MO7+MO18-injected embryos were injected with RNAs (0.5 ng/embryo) encoding either altSOX7-GFP (G,K), SOX7GGG-GFP (H,L), SOX18β-GFP (J,M), or mtSOX18β δC-VP16 (18VP16) (J); at stage 30 the embryos were stained in situ for MHCα (G) or Nkx2.5 (K). SOX7, SOX18, and mtSOX18β δC-VP16 rescued the effects of the combined morpholinos, whereas SOX7GGG-GFP did not. |
