Fig. 6

FOXL2 and SOX9 expression in WT embryos. (a,b) Localization by immunofluorescence confocal microscopy shows FOXL2 (a) and SOX9 (b) in green, and nuclei in red at 9.5. Both are expressed in the head mesenchyme. (a1,b1) Magnification of the regions shown in a and b. Dotted lines in a1 and b1 highlight respectively FOXL2 and SOX9 positive cells, located in the same region of consecutive sections. (c-e) Alcian blue staining (c), FOXL2 and SOX9 immunofluorescence in consecutive sections of a 14.5 dpc embryo (d,e). (d) FOXL2 positive cells are present within the vertebral bodies (dotted lines) and in the intervertebral mesenchyme (white arrow). (e) By contrast, SOX9 is localized only within the vertebral bodies (dotted lines); Scale bars: (a,b) 10X = 300 um, (a1,b1,c,d,e) 40X = 75 um, (a1,b1) 63X = 47,6 um. vb, vertebral bodies; im, intervertebral mesenchyme