Homeobox protein SIX3 (SIX3)

Transcriptional regulator which can behave as both a transcriptional repressor and activator by binding a ATTA homeodomain core recognition sequence on those target genes. Throughout forebrain development represses WNT1 expression allowing zona limitans intrathalamica formation and thereby ensuring appropriate anterio-posterior patterning of the diencephalon and formation of the rostral diencephalon.

Acts as a direct upstream activator of SHH expression in the rostral diencephalon ventral midline and that subsequently SHH maintains its expression. Additionally, Six3 activity is required for the formation of the telencephalon.