Fig. 4

Ripply1 terminates tbx6 and mesp-b expression in the pre-somitic mesoderm. (A-D) Control and Ripply1 MO-injected embryos at the 12-somite stage labeled for tbx6 (A, mRNA; B, protein), and mesp-ba (C) and mesp-bb mRNA (D). All markers are upregulated in the absence of Ripply1. MF20 (B, red) labels slow muscle progenitors. (E-G) Tg(hsp70l:ripply1^myc) embryos and non-transgenic sibling 0.5h (E) and 1h (F,G) post heat shock. Transgenics lose expression of Tbx6 protein (E) and mesp-ba mRNA (G), tbx6 mRNA is only slightly reduced (F). (H-J) Tg(hsp70l:mesp-ba^myc) embryos and non-transgenic siblings 1h post heat shock. Ubiquitous expression of Mesp-ba leads to upregulation of ripply1 mRNA in wild type and tbx6 mutants (H,I). mesp-ba mRNA is not ubiquitously upregulated after Tg(hsp70l:mesp-ba^myc): levels are low in the paraxial mesoderm, endogenous mesp-ba expression (arrowheads) is downregulated (J). (K) Control and Mesp-b MO-injected embryos labeled for mesp-ba mRNA. Scale bars: 100µm.