Expression of ventral diencephalon-enriched genes in zebrafish.

Dopaminergic (DA) neurons in the vertebrate di- and mesencephalon play essential roles in movement control, endocrine modulation and many other important physiological activities. To identify genes that may regulate the specification and differentiation of diencephalic DA neurons in zebrafish, the spatial and temporal expression pattern of a set of genes was investigated. In situ hybridization analysis revealed that expression of DNA binding inhibitor 3 (Id3), early B cell factor 2 (Ebf2), Ebf3, Iroquois related homeobox 1 (Irx1), Kruppel-like factor 7 (Klf7), mab-21-like 1 (Mab21l1), fatty acid binding protein 7 (Fabp7) and stathmin-like 4 (Stmn4), were enriched in the diencephalon of zebrafish. Among these genes, Id3 was expressed specifically in a subset of DA neurons in the ventral diencephalon, with co-expression of neurogenin1 (Ngn1). Alteration of expression levels of Id3 inhibited maturation of developing DA neurons. Taken together, our study provides genetic characteristics of DA neurons in the diencephalon of zebrafish.