Figure 4.

Visceral defects in FgfR2-IIIc^+/Δ mice. (A) Comparison of whole lungs at postnatal day 1 (P1) showing the development of a single right lobe in hemizygotes compared with four distinct lobes in the wild type. (B–G) Transverse sections through the right lobes stained with hematoxylin–eosin showing partial lobe separation in the mutant right lung (indicated by arrowheads in C), as well as the development of fewer bronchioles lined with ciliated cells and fewer branched alveolar structures (D and E). (B and C, bars = 4 mm.) In mutants, lung mesenchyme is more compact and often congested with red blood cells (F and G). (H) Dissected exorbital lacrimal glands with their surrounding mesenchyme still attached to the eye and stained with the dye carmalum to reveal branching, show a clear lack of gland development in hemizygotes. (I) Comparison of kidneys at P2 reveals severe growth retardation in hemizygotes which does not seem to affect the adrenal glands lying above each kidney. (J and K) Saggital hematoxylin–eosin (H&E)-stained sections through E14.5 embryonic kidneys show the presence of fewer developing nephrons in the cortical region of hemizygotes. (L and M) H&E-stained transverse section of P2 kidneys, showing fewer and degenerating glomeruli (arrowheads), dilated proximal and distal tubules, and more undifferentiated mesenchyme in hemizygotes.