Monitoring catecholamine differentiation in the embryonic brain and peripheral neurons using E. coli lacZ as a reporter gene.

An X-gal based histochemical assay was used to detect catecholamine (CA) cells in transgenic mouse embryos, in which the expression of the lacZ reporter was driven by the tissue-specific promoter of the rat tyrosine hydroxylase (TH) gene. As the first enzyme in the biosynthetic pathway for CA neurotransmitters, TH is a specific phenotypic marker for CA cells in the central and peripheral nervous systems of adult animals. During embryogenesis, TH expression appears permanently within CA-producing cells, and transiently within several other cell types. In this study we were able to monitor TH expression in transgenic mouse embryos by following the expression of the lacZ reporter in substantia nigral dopaminergic neurons in the central nervous system, the trigeminal (V) sensory ganglia, and dorsal root ganglia in the periphery. Our results demonstrate that the rat TH promoter-lacZ transgene provides an important experimental tool for monitoring catecholaminergic lineage cells during embryogenesis.