The TGF-β signaling pathway is one of the major intercellular communication pathways involved in the
development of multicellular animals. Components of this signaling pathway are present in all Metazoa and it is involved
in establishing dorso-ventral axis in Bilateria. Here, we study the TGF-β signaling pathway structure and its expression
during the embryonic development of a sponge Halisarca dujardini.