Fig.5.
Tbx20 overexpression rescues the cardiac defects present in tbx20 mutant embryos. (A) Diagram of the inducible activity of the tbx20-GR (glucocorticoid receptor) fusion protein. The addition of DXS (dexamethasone) is required for the translocation of the tbx20-GR protein into the nucleus. (B–D) Dorsal views of myl7 expression at the 16-somite stage in wild type embryos (B), tbx20 mutants (C) and tbx20 mutants injected with tbx20-GR mRNA (D). The cardiomyocyte production defects in tbx20 mutant embryos are substantially rescued by the injection of tbx20-GR mRNA. (E) Schematic representation of the hsp70l:Tbx20 transgene used for tbx20 overexpression. (F–H) Dorsal views of myl7 expression at the 16-somite stage in wild type (F), tbx20 mutant (G) and Tbx20−/−; Tg(hsp70l:Tbx20) embryos (H). (I–K) Frontal views of myl7 expression at 48hpf in wild type (I), tbx20 mutant (J) and Tbx20−/−;Tg(hsp70l:Tbx20) embryos (K). Overexpression of Tbx20 successfully restored cardiomyocyte production in tbx20 mutant embryos.