A NOVEL PROTEIN CONTAINING CDC10 SWI6 MOTIFS REGULATES EXPRESSION OF MESSENGER-RNA ENCODING CATECHOLAMINE BIOSYNTHESIZING ENZYMES/

Catecholaminergic (dopaminergic, noradrenergic, and adrenergic) transm itter phenotypes require the cooperative actions of four biosynthetic enzymes: tyrosine hydroxylase, aromatic L-amino acid decarboxylase, do pamine beta-hydroxylase, and phenylethanolamine N-methyltransferase, M echanisms that control expression of these enzymes in a transmitter ph enotype-specific manner, however, are poorly understood. Here, we prov ide evidence that overexpression of a novel cdc10/SWI6 motif-containin g protein, V-1, elicits the coordinate up regulation of tyrosine hydro xylase, aromatic L-amino acid decarboxylase, and dopamine beta-hydroxy lase mRNAs in the neuronal cell line PC12D, and as a result, catechola mine levels are increased. Furthermore, V-1 is strongly expressed in t he cytoplasm of rat chromaffin cells of adrenal medulla, Thus, V-1 may act as a cytoplasmic protein/protein adapter and be involved in contr ol of the catecholaminergic phenotype expression via an intracellular pathway signaling to the nucleus.