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Fig. 6. Migrating LEM is necessary for normal gastrulation movement and elongation of AM. (A) and (B) Dorsal views of BCR-injected embryos at St. 12.5. The white brackets indicate the diameter of the blastopore. (C) and (D) Expression of Xnot, an AM marker, in a Std.-MO (control) (C) or xFN-MO (D) -injected embryo. The black and gray brackets in (D) indicate the widened and shortened notochord. (E) Quantification of embryos showing gastrulation defects (G.D.). Almost all control embryos were normal (n=39), whereas the BCR-FN morphants (n=30) showed a higher frequency of G.D. If the size of the yolk plug was bigger than a third of the diameter of the embryo, we categorized the sample as severely defective. (F) Quantification of the length and width of Xnot staining. Compared with controls (n=8), the BCR-FN morphants (n=7) showed a widened and shortened notochord. Error bars indicate s.d. **P<0.01. (G) Morphants at a late stage (St. 31). Scale bar: 1 mm. (H) Quantification of the A–P length of the late morphants. The dorsal axis extension was moderately reduced in the BCR-FN morphants (n=31), compared with the Std.-MO-injected embryos (n=21). Error bars indicate s.d. **P<0.01. |