Gene Cloning, Protein Expression and Functional Analysis of a type 3 Metallothionein with Bioaccumulation Potential from Sonneratia alba
Dewei Niu 1, 2,  
Shuaiguang Li 1, 2,  
Shanze Yi 1, 2,  
Lianghua Shen 1, 2,  
Meiyan Huang 1, 2,  
Renchao Zhou 3,  
Feng Wang 1, 2  
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Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China
Guangdong Provincial Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, China
State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510530, China
Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd, MDC 19, Tampa, FL 33612, USA
Online publish date: 2018-05-24
Publish date: 2018-05-30
Submission date: 2017-04-04
Final revision date: 2017-05-30
Acceptance date: 2017-07-11
Pol. J. Environ. Stud. 2018;27(5):2203–2212
Sonneratia alba (S. alba) is a mangrove species grown in brackish water of tropical and subtropical regions. Due to its unique environment, it has evolved various mechanisms for modulating salt and metal levels. In order to find the genes connected with bioaccumulation of metals, the root transcriptome annotation of Sonneratia alba was analyzed and a new metallothionein (MT) gene was cloned. Sequence analysis found that the new MT gene belongs to type 3 MT, which is mostly expressed in roots. A simple and efficient method was used to express the type 3 MT of S. alba (SaMT3) by transforming the recombinant expression vector pET15b-SaMT3 into Escherichia coli (E. coli) Rosetta-gami and induction with the optimal conditions of 500 μM Isopropyl β-D-1-thiogalactopyranoside (IPTG) at 24ºC for 12 h. OD600 of E. coli cells expressing His fused SaMT3 protein after treated with 500 μM Cu2+ or 500 μM Pb2+ for 12 h can reach 1.01 or 0.98, while OD600 of control cells expressing His-tag can reach only 0.81 or 0.75. Both control cells and the cells expressing SaMT3 accumulated metals. Cells expressing SaMT3, however, accumulated more Pb2+ and Cu2+ (more than two times) than control cells. In vivo, real-time PCR showed that the SaMT3 transcript was induced significantly when stimulated with 250 μM, 500 μM, or 1,000 μM Cu2+ or Pb2+ for 24 h and 48 h. Taken together, the expression of SaMT3 can increase Cu2+ and Pb2+ resistance and binding capacity of E. coli.
Feng Wang   
Jinan university, Huangpu Road NO.601, 510632 Guangzhou, China