Regulation of human metallothionein-III gene expression by p300 and SP-1

Abstract

Metallothionein (MT) gene family consists of several members (MT I, II, III) that are tightly regulated during development. Human MT I and MT II are expressed in many tissues, including the brain, whereas human MT III is expressed mainly in the central nervous system. Human MTs are thought to play roles both in the intracellular regulation of the essential trace elements (zinc or copper) and in the protection from of a variety of stress conditions. Human MT I and MT II expression are regulated by metals like as zinc or cadmium. However the transcriptional regulation mechanism of human MT III is still obscure, although human MT III is expressed in the brain and the prostatic cancer regions. In this study, the objectives of the present study was to investigated the transcription factor of strength and specificity of human MT-III promoter region, and designed sever point mutations of nuclear factor binding site form nucleotide -1243 to +72 to a luciferase reporter gene. The luciferase activity of human MT-III promoter was increased in the human neuroblastoma cell line, SH-SY5Y, after the treatment of Trichostatin A (TSA) or cotransfected with the p300, which contains acetyltransferase activity. The activity of human MT-III promoter was dramatically increased after the cotransfection of p300 and TSA compared with p300 alone. Furthermore, the activity of human MT-III promoter was significantly increased in the cotransfection of SP-1 (stimulation protein-1). These results suggested that the regulation of human MT-III gene expression related to SP-1 transcriptional activity by p300 binding protein-mediated acetylation.