Involved in specifying the paraxial, but not dorsal, mesoderm. May regulate the expression of T-box transcription factors required for mesoderm formation and differentiation (By similarity). Coexpression of ntl and spt is required for expression. Expression is first detected in the marginal zone of the blastoderm. Expression becomes more apparent at the germ-ring stage. In the early gastrula, expressed only in hypoblast cells of the germ ring. At mid-gastrula stage, expressed in ventrolateral mesoderm and is subsequently restricted to the segmental plate at late gastrula stage. At the segmentation period, expressed in the presomitic mesoderm including the tailbud. Expression is also detected in the adaxial cells in the vicinity of the presomitic mesoderm.