Expression of TGF-βs 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-beta 1, TGF-beta 2, TGF-beta 3) have been described. In the, nervous system, the presence of TGF-beta 1 has remained undetectable in other structures than meninges and choroids plexus, while TGF-beta 2 and TGF-beta 3 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-beta 1 and TGF-beta 3 are expressed in neural crest cells. In addition, we demonstrate the existence of interbalance between TGF-beta 1 and TGF-beta 3 with possible functional implications, which, together with the expression of TGF-beta 1 in the CNS, represents one of the most important contributions of this work.