Extent of gata4 expression responds to Wnt/β-catenin signaling. (A-T) Wnt/β-catenin signaling regulates gata4 expression. (A-E) gata4 expression was restricted to the rostral ALPM in apc morphants (B) and in embryos injected with wnt3 RNA (C), was unaltered in wnt3 morphants (D), and was expanded caudally in dkk1-overexpressing embryos (E), compared with controls (A). (F-J) gata5 expression, (K-O) nkx2.5 expression, and (P-T) ttna expression were not affected. The embryos were co-stained with a myod probe to ensure the proper developmental stage. (U,V)Wnt signaling modulates gata4 expression at the transcriptional level. The expression of gfp in gata4::gfp transgenic fish was revealed by in situ hybridization using a gfp riboprobe. (W-Y1) Two-color fluorescent in situ hybridization showed that gata4 expression was partially depleted from the nkx2.5 expression domain and its lateral region in apc morphants (W1-Y1), compared with in controls (W-Y). Shown are dorsal views of 12-somite staged embryos with anterior to the left; only the right LPM is shown in W-Y1. Arrowheads indicate the posterior end of gata4 expression.
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