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Fig. 2. Microscopic and histological assessment of physical defects in MLC2a-null
embryos. Whole embryo assessment of wild-type (A) and MLC2a-null (G) mouse
embryos at somite pairs 24. Note that the null mutant displays severe chest
edema. Paraffin wax-embedded serial sections of wild-type (B-F) and MLC2a-null
(H-L) mouse embryos were stained for nuclei and cytoplasm with Hematoxylin and
Eosin, respectively. White arrows point out the lack of mesenchymal cell
seeding in atrioventricular cushions of MLC2a mutant (K), in contrast to
normal mesenchymal cell seeding in atrioventricular cushions of wild-type
control (E). Black arrows in D and J indicate dilated ventricle. A, atria; OT,
outflow tract; RA, right ventricle; LA, left atria; RV, right ventricle; LV,
left ventricle; SV, sinus venosus.