Further Development 12.8: Stretching the zebrafish epiblast cells generates mesoderm

Stretching the zebrafish epiblast cells generates mesoderm. (A) During epiboly, cells at the border undergo structural changes and involute. As they do, mesodermal genes (red, dashed outline) are activated. (B) When the cortical cytoskeleton is prevented from contracting, the animal cap cells remain ectodermal and do not involute. (C) However, if these cells are pulled by a magnetic field, the mesodermal genes become expressed. (D,E) Circumpolar views of B and C, respectively, visualize expression of the mesodermal gene no tail (the zebrafish homologue of the brachyury gene). (D) no tail expression is blocked by the lack of involution. (E) no tail expression induced by stretching and subsequent involution.

FIGURE Stretching the zebrafish epiblast cells generates mesoderm. (A) During epiboly, cells at the border undergo structural changes and involute. As they do, mesodermal genes (red, dashed outline) are activated. (B) When the cortical cytoskeleton is prevented from contracting, the animal cap cells remain ectodermal and do not involute. (C) However, if these cells are pulled by a magnetic field, the mesodermal genes become expressed. (D,E) Circumpolar views of B and C, respectively, visualize expression of the mesodermal gene no tail (the zebrafish homologue of the brachyury gene). (D) no tail expression is blocked by the lack of involution. (E) no tail expression induced by stretching and subsequent involution. (A–C after S. Piccolo. 2013. Nature 504: 223–225.)

D and E from T. Brunet. et al. 2013. Nat Commun 4: 2821/CC BY 3.0