Expression Of Forkhead Box C2 Transcription Factor In Mouse Embryo Developing

Mouse forkhead box c2 (Foxc2), a member of the winged helix transcription factors super family with DNA-binding domains, is evolutionarily highly conserved and located on No.8 chromosome with the length of 2323bp. It is characterized by an independent DNA-binding domain. Isolation of the mouse and human mesenchyme fork head-2 genes reveals conservation of their gene and protein structures, and the human FOXC2 proteins has a conserved DNA-binding domain of 100 amino acids being 94% homology with mouse Foxc2. Many studies have shown that FOXC2 mutation is related with many human genetic diseases. It has been known that FOXC2 transcription factor is closely associated with Lymphoedema-Distichiasis syndrome (LD). Severe cases of this syndrome also have developmental anomalies of heart and axial skeleton, such as Fallot's tetrad, cleft palate. Some other studies have found that SNPs of this gene is related to obesity, lipid metabolism and insulin resistance. Otherwise, Foxc2 deficient mice died embryonically and perinatally, and show many kinds of congenital defects according with humans', including LD, interrupted aortic arch, cranium and vertebral column defects, developmental abnormalities of eyes and kidney and so on. Therefore, the study of the expression mode of Foxc2 proteins in mouse embryos may provide references to the mechanism actions of FOXC gene in human embryos and etiopathogenisis of some developmental defects.The current study analyzed the effect of Foxc2 gene on genesis and development of mouse tissues and organs using immunohistochemistry, which established the theoretical foundation to further understand the association between this gene and congenital developmental defect. The results showed that Foxc2 was expressed extensively in cephalic mesoderm-derived tissues: 1. Foxc2 was expressed early in the endodermis and surrounding mesenchyme of saccus lymphaticus. Its expression was seeing in the endodermis of collecting lymphatic vessel, but not in lymphatic capillary with the further differentiation of lymphatic vessels. 2. Foxc2 was expressed early in the endomembrane of cardiac ventricle and atrium. The expression in cardiac ventricle was decreasing later, it was only existing in the valve of cardiac ventricle at E17.5. But the expression in cardiac atrium was still. Foxc2 was strongly expressed in whole vessel wall of almost all the arteries also, it could be observed in the endothelial cell nucleus of some large vein too. 3. Foxc2 protein was expressed extensively in bones, not only in the vertebral body but also in other bones of embryo. 4. Foxc2 was expressed in the mesenchyme surrounding of the optic cup and lens early in the genesis of eye. Later, it was expressed in the iris, cornea and the location of vitreous body vascular. Foxc2 was localized only in the epithelium of blephara and anterior epithelium of cornea with the completely differentiation of eyes. 5. The strong brown-yellow positive stain of Foxc2 expression could be seeing in the mesenchyme of kidney and the endothelium of renal capsule and periphery of glomerulus later. Otherwise, Foxc2 was also expressed in the interrenal adventitia. 6. Foxc2 was expressed in the bony labyrinth and its mesenchyme, primary palate, palate and mesenchyme under the tongue epithelium. In addition, Foxc2 was expressed in many mesenchyme of the embryo, including brain and tractus alimentarius.The results of this studies suggested that the effect of Foxc2 on reforming of aorta, development and forming of vertebral column and development of other organs could not be substituted.