This protein is expressed exclusively in posterior mesoderm and ectoderm of early embryos suggesting a possible role in organization of anteroposterior axis. Expressed ubiquitously throughout the embryo at early stages. By mid-gastrula (stage 11), expression is concentrated in the mesoderm and ectoderm surrounding the yolk plug, being strongest in posterior dorsal mesoderm. At stage 13, also expressed at a low level in the pre-cement gland. At mid to late tailbud stages, highly localized in mesoderm and ectoderm derivatives in the extreme posterior of the tail. Expressed zygotically shortly after the midblastula transition (MBT). Expression remains constant till gastrulation then rapidly and transiently increases to peak during neurulation. Expression disappears by tailbud stages. By growth factors such as FGF and TFG-beta. By Wnt-signaling and BMP-signaling.