PDF(Pubmed)
Abstract：
Metallothioneins (MTs) are non-enzymatic metal-binding proteins widely found in animals, plants, and microorganisms and are regulated by metal-responsive transcription factor 1 (MTF1). MT and MTF1 play crucial roles in detoxification, antioxidation, and anti-apoptosis. Therefore, they are key factors allowing organisms to endure the toxicity of heavy metal pollution. Phascolosoma esculenta is a marine invertebrate that inhabits intertidal zones and has a high tolerance to heavy metal stress. In this study, we cloned and identified MT and MTF1 genes from P. esculenta (designated as PeMT and PeMTF1). PeMT and PeMTF1 were widely expressed in all tissues and highly expressed in the intestine. When exposed to 16.8, 33.6, and 84 mg/L of zinc ions, the expression levels of PeMT and PeMTF1 in the intestine increased first and then decreased, peaking at 12 and 6 h, respectively, indicating that both PeMT and PeMTF1 rapidly responded to Zn stress. The recombinant pGEX-6p-1-MT protein enhanced the Zn tolerance of Escherichia coli and showed a dose-dependent ABTS free radical scavenging ability. After RNA interference (RNAi) with PeMT and 24 h of Zn stress, the oxidative stress indices (MDA content, SOD activity, and GSH content) and the apoptosis indices (Caspase 3, Caspase 8, and Caspase 9 activities) were significantly increased, implying that PeMT plays an important role in Zn detoxification, antioxidation, and anti-apoptosis. Moreover, the expression level of PeMT in the intestine was significantly decreased after RNAi with PeMTF1 and 24 h of Zn stress, which preliminarily proved that PeMTF1 has a regulatory effect on PeMT. Our data suggest that PeMT and PeMTF1 play important roles in the resistance of P. esculenta to Zn stress and are the key factors allowing P. esculenta to endure the toxicity of Zn.
摘要：
金属硫蛋白（MT）是广泛存在于动物中的非酶金属结合蛋白，植物,和微生物，并受金属响应性转录因子1(MTF1)调控。MT和MTF1在解毒中起着至关重要的作用，抗氧化，和抗凋亡。因此,它们是使生物承受重金属污染毒性的关键因素。esculenta是一种海洋无脊椎动物，栖息在潮间带，对重金属胁迫具有很高的耐受性。在这项研究中,我们从P.esculenta(命名为PeMT和PeMTF1)中克隆并鉴定了MT和MTF1基因。PeMT和PeMTF1在所有组织中广泛表达，在肠道中高度表达。当暴露于16.8、33.6和84mg/L的锌离子时，肠组织中PeMT和PeMTF1的表达水平先升高后降低,在12和6小时达到峰值，分别,表明PeMT和PeMTF1均对Zn胁迫反应迅速。重组pGEX-6p-1-MT蛋白增强了大肠杆菌的锌耐受性，并表现出剂量依赖性的ABTS自由基清除能力。用PeMT进行RNA干扰（RNAi）和Zn胁迫24小时后，氧化应激指标(MDA含量，SOD活性,和GSH含量）和凋亡指数（Caspase3，Caspase8和Caspase9活性）显着增加，这意味着PEMT在锌解毒中起着重要作用，抗氧化，和抗凋亡。此外，用PeMTF1RNAi和Zn胁迫24h后，肠道中PeMT的表达水平显着降低，初步证明了PeMTF1对PeMT具有调节作用。我们的数据表明，PeMT和PeMTF1在P.esculenta对Zn胁迫的抗性中起着重要作用，并且是使P.esculenta承受Zn毒性的关键因素。
