Neurons in the monoaminergic nuclei of the rat and human central nervous system express FAI/dlk

The gene DLK I encodes a member of the epidermal growth factor (EGF) superfamily, delta-like (dlk). When exposed in vivo to the action of an unknown protease, this type I membrane protein generates a soluble peptide referred to as Fetal antigen I (FA I). By acting in juxtacrine as well as paracrine/autocrine manners, both forms have been shown to be active in the differentiation/proliferation process of various cell types. In adults, FAl/dIk has been demonstrated mainly within (neuro) endocrine tissues. In this study we investigated the presence of FAI/dIk in other parts of the developing and adult rat and human CNS. Using immunocytochemistry and in situ hybridization vie found that in both species FAI/dIk was expressed in neurons of the Edinger-Westphal's nucleus as well as in substantia nigra, ventral tegmental area (VTA), locus coeruleus and in certain parts of the raphe nuclei. NeuroReport 12:3959-3963 (C) 2001 Lippincott Williams & Wilkins.