Involved in the transcriptional regulation of genes required for mesoderm differentiation. In the developing embryo, expressed in the mesenchyme founder cells, vegetal plate of the mesenchyme blastula, extending tip of the invaginating archenteron and, later, in the secondary mesenchyme cells. First detected in the swimming blastula, maximally expressed in the gastrula. Levels decrease in the prism larval stage and are barely detectable by the pluteus larval stage.