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Figure 10. Differential gene expression at early gastrula stages and during laterality. A,A': A GFP reporter expresses in the dorsal lip when the pitx3 binding site in the lhx1 promoter is intact (A), but is down-regulated when mutated (split exposure image in A'; both fluorescence images exposed 19 sec). B–D: Vegetal view of embryos injected with control-morpholino (CMO) display wild-type gene expression patterns. B'–D': But pitx3-morpholino (P3MO) affects gene expression during the beginning of gastrulation. Dorsal lip is oriented to the top. Note the lateral depression of lateral lhx1 and t (arrows in B' and D', respectively) and expansion of gsc expression in P3MO embryos and knockdown embryos (compare C and C', arrows). E–G: Genes participating in the laterality signal cascade are normally expressed in left lateral plate mesoderm (arrows). E'–G': In morphants where pitx3 is knocked down, expression of xnr5 downstream targets xnr1, lefty, and pitx2 is decreased or absent in the left lateral plate mesoderm (arrows). |
