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. Author manuscript; available in PMC: 2016 Jun 1.
Published in final edited form as: Curr Opin Genet Dev. 2015 Mar 25;32:119–128. doi: 10.1016/j.gde.2015.02.008

Figure 1. Schematic representation of cardio-pharyngeal development in Ciona intestinalis.

Figure 1

(A) Schematic showing the trunk ventral cell progeny with divisions and migrations (green and blue arrows), from initial tail bud stage (8 hpf) to metamorphosing juvenile (45 hpf). Trunk ventral cells (TVC, green), STVC (secondary TVC, yellow), first heart precursors (FHP, red), atrial siphon muscle founder cells (ASMF, light blue), second heart precursors (SHP, orange), inner and outer ASM precursors (ASMPs, dark blue and violet, respectively), heart (red/orange). The first longitudinal muscle (LoM) derives from the ASM ring. The left side only is presented, linked nuclei indicate sister cells, dashed lines represent the midline. (B) Fluorescent in situ hybridization of key markers of the TVC progeny from 12.5 hpf to 22 hpf. The B7.5 lineage (red) is marked with Mesp>NLS::lacZ revealed by anti β-galactosidase immunostaining. Scale bar, 10 µm. (C) Summary of the ontogenetic interactions of the B7.5 cardiopharyngeal lineage. The TVC are transcriptionally primed pluripotent progenitors (1). Heart (e.g. Gata4/5/6, Hand) and ASM (e.g. Hand-r, Tbx1/10) transcriptional regulatory programs are segregated through cross-antagonisms coupled to asymmetric divisions (2). A myogenic program associated with Mrf is deployed downstream of Ebf, which also promotes Notch-mediated lateral inhibition of Mrf and maintenance of a pool of stem cell-like muscle progenitors (3). Same color code as above.