Involved in the transcriptional regulation of genes required for mesoderm differentiation, including itself. Indispensable for the formation of the notochord and the tail structure. Functions together with tbx16/spadetail in development of trunk and tail mesoderm. Functions by itself early in development to repress medial floor plate and promote notochord fate but at later times, functions together with tbx16/spadetail to promote medial floor plate formation. Acts in a parallel pathway to, but cooperates with, non-canonical wnt-signaling during tail formation. Required for the morphogenesis of Kupffer's vesicle and regulates left-right asymmetry. Monomer. Binds DNA as a monomer. First expressed at the dorsal side of the blastula embryo. Expressed in the germ ring, shield and chordamesoderm during gastrulation and is restricted to the notochord and tailbud during somitogenesis (at protein level). In the embryo, first expressed at the doming stage (4.2 hours). Highest expression is found between 5.2 and 9.5 hours (epiboly) after which levels gradually decrease, with expression becoming absent by 48 hours. By mesoderm-inducing factor activin A. Loss of notochord cells and posterior structures. Disrupts left-right development.