SIX1, also known as homeobox protein SIX1, is a member of the SIX gene family. It encodes protein that is characterized by a divergent DNA-binding homeodomain and an upstream SIX domain, which may be involved both in determining DNA-binding specificity and in mediating protein-protein interactions. It has been shown to play roles in vertebrate and insect development or has been implicated in maintenance of the differentiated state of tissues. Recombinant human SIX1 protein, fused to His-tag at N-terminus, was expressed in E.coli.