Transcription factor that plays an important role in the development of several organs, including kidney, skull and stomach. During kidney development, maintains cap mesenchyme multipotent nephron progenitor cells in an undifferentiated state by opposing the inductive signals emanating from the ureteric bud and cooperates with WNT9B to promote renewing progenitor cells proliferation. Acts through its interaction with TCF7L2 and OSR1 in a canonical Wnt signaling independent manner preventing transcription of differentiation genes in cap mesenchyme such as WNT4. Also acts independently of OSR1 to activate expression of many cap mesenchyme genes, including itself, GDNF and OSR1. During craniofacial development plays a role in growth and elongation of the cranial base through regulation of chondrocyte differentiation. During stomach organogenesis, controls pyloric sphincter formation and mucosal growth through regulation of a gene network including NKX2-5, BMPR1B, BMP4, SOX9 and GREM1. During branchial arch development, acts to mediate HOXA2 control over the insulin-like growth factor pathway. May also be involved in limb tendon and ligament development (By similarity). Plays a role in cell proliferation and migration. Interacts with TCF7L2; in a canonical Wnt signaling independent manner; prevents transcription of differentiation genes in cap mesenchyme. Interacts with OSR1; form a strong repressor complex with TCF7L2, TLE2 and TLE3 to prevent the activation of Wnt/beta-catenin target genes in the cap mesenchyme. Interacts with HOXA11, EYA1 and EYA3. Strongly expressed in skeletal muscle. Expressed in Wilms' tumor and in the cap mesenchyme of fetal kidney (at protein level). Found at 48 dpc in the anterior cranial base with detection concentrated in the sphenoid precursor. Expression is also detected in the pituitary gland. Belongs to the SIX/Sine oculis homeobox family.