Transcriptional repressor with a role in dorsal axis formation and neural plate expansion; maintains an undifferentiated neural ectoderm after neural induction. Maternal expression is localized to the animal hemisphere of the cleavage embryo. In pre-gastrula embryos, zygotic expression begins in the presumptive neural ectoderm. During gastrulation, expression is confined to the superficial layer of cells in the dorsal blastopore lip (Spemann organizer). Also expressed at a lower level in the paraxial mesoderm but not in the notochord. Expression is subsequently lost until after neural tube closure when expression re-initiates in the tailtip within the entire neural tube and paraxial mesoderm, but not in the notochord. Expressed both maternally and zygotically. First expressed at stage II of oogenesis. Maternal expression levels are low and become further reduced after fertilization. Zygotic expression begins at the mid-blastula transition and peaks during the gastrula/neurula stages. A lower level of expression is then maintained during tailbud and later stages. Strongly by siamois, moderately by cer1 and weakly by wnt8 and nog.