Figure 8
From: Mesodermal origin of median fin mesenchyme and tail muscle in amphibian larvae
Descendants from blastomere C4 form fin mesenchyme in Xenopus laevis.
A, Schematic of the experiment. At the 32-cell stage one C4 blastomere was labelled by microinjection of ruby-dextran. At stage 40 the labelling can be found in somites, in the posterior part of the intestine, in the blood and in the fin. The squares indicate the areas displayed in B,C,F,G. The vertical line indicates the cutting planes in D and E. B,B’C,C’, Groups of labelled cells migrate from the somites to the dorsal (B,B’) and ventral fin (C,C’). Squares in B and C indicate the regions displayed in B’ and C‘ at higher magnification. D, Transversal section through posterior trunk with labelled somite (som) and fin mesenchymal cells (arrows); overlay of dextran-fluorescence and phase-contrast image. E, Transversal vibratome section through posterior trunk with labelled somite (som) and with a labelled fin mesenchyme cell (arrow). DAB-peroxidase staining using the biotin-residues of the ruby-dextran tracer. F–G, Fin mesenchyme cells (arrows) at higher magnification; F, dextran fluorescence; G, after DAB-peroxidase staining. Abbreviations: A, animal; V, vegetal; DA, dorsoanterior; VP, ventroposterior; An, anterior; D, dorsal; Po, posterior; V, ventral; epi; epidermis; som, somite; Number of cases: 65
