Co-Induction of Tetrahydrobiopterin and Catecholamine Syntheses in V-l-OVerexpressing PC12D Cells

Abstract

The regulation of the gene expression of the catecholamine-synthesizing enzymes is highly important in the determination of the phenotypes of catecholaminergic neurons in the developmental stage. V-l is a novel protein that may regulate the gene expression of the catecholamine-synthesizing enzymes. V-l was originally identified in the rat cerebellum as one of the proteins the expression of which was transiently increased during the initial stage of postnatal development (1,2). Although the V-l protein is likely to be an adapter protein consisting of the cdclO/SWI6 motif, also known as the ankyrin repeat (1), no protein has been identified yet as one interacting with V-l protein. V-l protein is expressed in chromaffin cells and catecholaminergic neurons (3), and three catecholamine biosynthetic enzymes, i.e. tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase, and dopamine β-hydroxylase, were up-regulated in cloned PCI 2D cells which overexpress V-l (3).