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Fig. 2. Developmental expression of a-SM actin expression. (A) Schematic representation of the developmental distribution of a-SM
actin. From stage 37/38 to stage 46, a-SM actin is detected in the heart. From stage 40 and on, a-SM actin expression is predominently
expressed in vascular and visceral SM cells. (B) At stage 23, no labeling is detected in the lateral plate (arrowheads). (C) By stage 37/38,
a faint labeling is observed in the heart anlage (h), just beneath the pharyngial cavity (ph). (D) Stage-41 embryo displaying an a-SM actin
immunoreactivity confined to the outer layer of the endoderm, where the first intestinal loop starts to differentiate. Two sections in the
anterior (E) and posterior (F) regions of an embryo at stage 43 present a staining delineating the differentiating endoderm. (G) At the same
stage heart is also labeled (arrowhead). (H) Enlargement of the heart area shown in (G); staining is restricted to the atrium (a) whereas
ventricule (v) remains negative. (I,J) Stage-47 embryo where labeling is detected in the outer coat of the gut loops in anterior (I) and more
posterior (J) regions. (K) Detail of a stage-47 embryo stained with the a-SM actin antibody, aorta (ao), lung (lu) and intestine (in) present
a strong immunoreactivity whereas liver (li), notochord (n) and somites (s) do not. Magnification: B, D-G and I-J ´40; C, H and K ´80. |
