Transcription factor which binds a motif with the core sequence 5'-GTATCA-3' (PubMed:30890567). Plays a role in head morphogenesis (PubMed:11476572). May cooperate with the transcription factor vab-3 and phosphatase eya-1 to repress transcription factor ets-5 expression in non BAG neuronal cells (PubMed:30890567). Interacts with gmn-1. Expressed in the posterior gonad (PubMed:11476572). Expressed in some cells in the head that are probably neurons (PubMed:30890567). Not expressed in BAG neurons (PubMed:30890567). Expression starts during embryonic gastrulation and persists through to adults (PubMed:11476572). Expressed in neuronal precursor cells during embryogenesis (PubMed:11476572). Upon hatching, expression is also seen in sheath/spermatheca precursor cells and later in gonadal sheath cells (PubMed:11476572). Expressed in head hypodermal cells (hyp3, hyp4, hyp5 and hyp6) in larvae (PubMed:11476572). RNAi-mediated knockdown in hermaphrodite adults causes embryonic and larval lethality and head morphogenesis defects in L1 and L2 larval stages of offspring. Belongs to the SIX/Sine oculis homeobox family.