DCX and prion disease: Doublecortin (Dcx), a neuroblast and immature neuron marker, was significantly up-regulated at end-stage compared with onset in wild-type mice (Fig. 5C), while the mature neuron marker, Neuronal Nuclei (NeuN), was decreased in wild-type and Neil3 KO mice at onset and end-stage of prion disease, due to severe neuronal loss (Fig. 5D).