Anaylsis of the effects of inhibitor and activator systems (smad?s proteins) of TGF-ß on neural tube closure

The families of TGF-ßs (TGF-ß1, TGF-ß2, TGF-ß3) which their role on development of neural tube is still uncertain are multifunctional growth factors such as embryonic development, differentiation, proliferation, regulation and repairing of nervous system. The signaling pathway of TGF-ßs are controlling both Smad 1/2/3, which is activator, and Smad 6 and Smad 7, which are inhibitor, proteins. In the literature, the roles of both the members of TGF-ßs (TGF-ß1, TGF-ß2 and TGF-ß3) and Smad proteins during neural tube closure were not evaluate together. Therefore, we aim to evaluate of TGF-ß1, TGF-ß2, TGF-ß3, Smad 1/2/3, Smad 6 and Smad 7 proteins in during 24., 30. 48. and 72. hours of neural tube development stage of chick embryos using both and immunoblotting techniques.Both immunohistochemical and immunoblotting results demonstrated that, in early stage of chick development (24. and 30. hours) syntheses of TGF-ß1-2-3 were started, especially TGF-ß3 was more than the others and their syntheses were decreased 48. and 72. hours of development, in addition, synthesis of activator protein of Smad 1/2/3 was detected at 24. hours, its synthesis was increased 30. hours and decreased 48. and 72. hours of development. The syntheses of inhibitor proteins of Smad 6 and Smad 7 which were started 24. hour, increased 30. hours and decreased 48. and 72. hours of development were also detected.In conclusion, in early neurulation, we considered that the members of TGF-ßs are play a role and especially the activation of TGF-ß3 is more than the others TGF-ßs. In addition, the secretions of TGF-ßs were controlling different Smad proteins, in early stage of development, while three type of TGF-ßs and Smad 1/2/3 were actively secreted, expressions of TGF-ß1, TGF-ß2 and Smad 1/2/3 were decreased with neural tube closure. After all result, we suggested that the development of neural tube and closure are control with different TGF-ß and Smad proteins.