Tyrosine hydroxylase (TH) catalyzes the conversion Of L-tyrosine to 3,4-dihydroxy-L-phenylaianine, which is the first and rate-limiting step in catecholamine biosynthesis. In the present study, we report that treatment with the histone deacetylase (HDAC) inhibitors, trichostatin A (TSA) or sodium butyrate, prominently induces the TH promoter activity in both non-neuronal and neuronal cell lines. By analyzing a series of deletional reporter constructs, we also determined that the proximal 151 bp region of the TH promoter is largely responsible for TSA-mediated activation. Finally, we found that mutation of the Sp1 or CRE site, residing in the proximal area, abolishes TSA-mediated activation. strongly suggesting that the Sp1 and CRE sites may mediate TH promoter activation by inhibition of HDAC. In summary, our results provide a novel regulatory frame in which modulation of chromatin structure by histone deacetylase may contribute to transcriptional regulation of the TH via the Sp1 and/or CRE site. (C) 2003 Elsevier Inc. All rights reserved.