Expression and function of nr4a2, lmx1b, and pitx3in zebrafish dopaminergic and noradrenergic neuronal development

Abstract

Our data indicate a conserved evolutionary role of Nr4a2 proteins in specification of the neurotransmitter phenotype, albeit it appears to be only one of several regulatory modules of dopaminergic differentiation, as most ventral diencephalic dopaminergic neurons do not express nr4a2 genes in zebrafish. For zebrafish lmx1b genes, which are not expressed in mature dopaminergic neurons, our data suggest a role in diencephalic precursor populations contributing to the ascending dopaminergic systems. A di-mesencephalic longitudinal domain of lmx1b expression may be the basis for the expansion and posterior shift of ventral di-/mesencephalic dopaminergic populations with ascending projections during evolution.