Expression of TGF-betas in the embryonic nervous system: analysis of interbalance between isoforms

Transforming growth factor-beta (TGF-beta) is a family of growth factors with essential and multiple roles during embryonic development. In mammals, three isoforms (TGF-beta1, TGF-beta2, TGF-beta3) have been described. In the nervous system, the presence of TGF-beta1 has remained undetectable in other structures than meninges and choroids plexus, while TGF-beta2 and TGF-beta3 were considered as the neural members of the family. In the present study, we have analysed the expression pattern of the three isoforms in the neural tube, brain, and spinal cord during development in both mouse and chicken. The data reveal specific patterns for each isoform. This work also shows that both TGF-beta1 and TGF-beta3 are expressed in neural crest cells. In addition, we demonstrate the existence of interbalance between TGF-beta1 and TGF-beta3 with possible functional implications, which, together with the expression of TGF-beta1 in the CNS, represents one of the most important contributions of this work.