Acts as a transcriptional repressor. May be involved in DNA damage-inducible cell cycle arrests (checkpoints) (By similarity). At early cleavage stages, localized within the animal half of the embryo. At gastrulation, expression expands over the whole embryo excluding the future endodermal cells of the blastopore. During neurulation, expressed in the prospective eye field and in the neural crest cells. Strongly enriched in the eye vesicles at stage 26. From stage 29 onwards, expressed predominantly in the eye, the branchial arches and the vagal ganglion. At stage 38, expressed throughout the head with strongest expression in the head mesenchyme and the eye lens. Both isoform 1 and isoform 2 are expressed both maternally and zygotically. Present in all embryonic stages including early cleavage stages, with levels decreasing during gastrulation. Expression is then up-regulated at stage 25 and persists until stage 45.