Hematological and neurological expressed 1 protein, also known as HN1, is a small protein that is highly conserved among species. HN1 expression is upregulated in regenerating neural tissues, including the axotomized adult rodent facial motor nerve and dedifferentiating retinal pigment epithelial cells of the Japanese newt. It is also expressed in numerous tissues during embryonic development as well as in regions of the adult brain that exhibit high plasticity. Recombinant human HN1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.