Transcription factor that is involved in the regulation of cell proliferation, apoptosis and embryonic development. Depending on context, functions as transcriptional repressor or activator. Required for the normal formation of pre-placodal ectoderm. First detected in gastrula. Prominently expressed in all neurogenic cephalic placodes and in lateral line primordia from neurula to tadpole stages. Weakly expressed in muscle later in development. Belongs to the SIX/Sine oculis homeobox family.