Hematological and neurological expressed 1 protein （HN1） is a small protein which is extremely preserved 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. HN1 is also expressed in several tissues during embryonic development as well as in regions of the adult brain which display high plasticity.
