Matsumoto M, Imagawa M, Aoki Y
Environmental Health Sciences Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-0053, Japan.
Biochem J. 1999 Mar 15;338 ( Pt 3)(Pt 3):599-605.
3,3',4,4',5-Pentachlorobiphenyl (PenCB), one of the most toxic co-planar polychlorinated biphenyl congeners, specifically induces class Pi glutathione S-transferase (GSTP1) as well as cytochrome P-450 1A1 in primary cultured rat liver parenchymal cells [Aoki, Matsumoto and Suzuki (1993) FEBS Lett. 333, 114-118]. However, the 5'-flanking sequence of the GSTP1 gene does not contain a xenobiotic responsive element, to which arylhydrocarbon receptor binds. Using a chloramphenicol acetyltransferase assay we demonstrate here that the enhancer termed GSTP1 enhancer I (GPEI) is necessary for the stimulation by PenCB of GSTP1 gene expression in primary cultured rat liver parenchymal cells. GPEI is already known to contain a dyad of PMA responsive element-like elements oriented palindromically. It is suggested that a novel signal transduction pathway activated by PenCB contributes to the stimulation of GSTP1 expression.
3,3',4,4',5-五氯联苯(PenCB)是毒性最强的共平面多氯联苯同系物之一,它能在原代培养的大鼠肝实质细胞中特异性诱导Pi类谷胱甘肽S-转移酶(GSTP1)以及细胞色素P-450 1A1的产生[Aoki、Matsumoto和Suzuki(1993年),《欧洲生物化学学会联合会快报》333卷,第114 - 118页]。然而,GSTP1基因的5'侧翼序列并不包含芳烃受体结合的外源性反应元件。在此,我们通过氯霉素乙酰转移酶分析证明,名为GSTP1增强子I(GPEI)的增强子对于PenCB刺激原代培养的大鼠肝实质细胞中GSTP1基因表达是必需的。已知GPEI含有一对呈回文排列的佛波酯反应元件样元件。有人提出,由PenCB激活的一条新的信号转导途径有助于刺激GSTP1的表达。