Figure 9
From: Time-dependent patterning of the mesoderm and endoderm by Nodal signals in zebrafish
Cell fate specification is accelerated when Nodal levels are increased. Embryos were injected with sqt mRNA at the 1–4 cell stage and treated with DMSO (A1-C1) or SB-431542 at various time points (A2-C7). Sqt induces ubiquitous expression of gsc and sox17 (B1, C1) but not flh (A1). (A2-C2) SB-431542 treatment at MBT blocks expression of each of these markers. flh is strongly expressed in embryos treated at 3.7 h (A3), but fades at later time points (A4-7). gsc expression is first detected in embryos treated at 3.7 h (B3), and expands at later time points (B4-7). sox17 expressing cells are first detected when embryos are treated at 4.3 h (C4), and expands at later time points (C5-7). Animal pole views at 10 h.