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FIG. 4. Xcml overexpression blocks gastrulation movements. (A, B) Injection of Xcml mRNA in two dorso-vegetal blastomeres retards
gastrulation. (A) At the midgastrula stage, the blastopore of injected embryos is longer in the dorso-ventral direction as a result of
suppression of latero-medial movements and intercalation of cells on the dorsal side of embryo. (B) At the neurula stage, injected embryos
have short axis and open blastopore; arrowheads indicate the anterior and posterior ends of axial complexes. (C) Expression of early marker
genes in intact and Xcml RNA-injected embryos studied by whole-mount in situ hybridization. (C) Early gastrula (stage 10.5) embryos,
expression of dorsal markers chr (C) and gsc (D), and panmesodermal marker Xbra (E). (F) Neurula stage embryos. Expression patterns of
actin (F) and Xbra (G). Expression of Pax-6 (H) in defective embryos with an open blastopore identifies two reduced axial complexes in
lateral lips of the blastopore (right embryo, arrows), and in apparently normal injected embryos (middle, arrowheads) reveals shortening of
the neural tube compared to uninjected embryos (left). Expression of Xnot (I) indicates abnormal position of notochord in injected embryos.
Xcml Overexpression Blocks Gastrulation 489
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