Effects of Cu2+Stress on the Expression Pattern of MT2 Gene in Rainbow Trout in Aquaculture Waters
The aim of this study is to investigate the effect of copper ion stress in water on the expression pattern of MT2 gene in rainbow trout(Oncorhynchus mykiss),and to develop Metallothioneins as molecular markers for detecting heavy metal copper pollution in aquatic ecosystems.The CDS sequence of rainbow trout MT2 gene was obtained using TA cloning method,and the expression patterns of MT2 gene in different tissues of rainbow trout were detected.The MT2 gene expression dynamics at 1 d,2 d,3 d,4 d after Cu2+stress(75 μg/L,150 μg/L,300 μg/L)and 1 d and 2 d after stress recovery were detect-ed as well.The results showed that the CDS region of rainbow trout MT2 gene was 186 bp,encoding 62 amino acids,with a typical Cys-X(1～3)-Cys structure,which is an unstable hydrophilic protein.The MT2 gene sequence of rainbow trout showed the highest homology with that of Atlantic salmon and the highest expression was found in the liver,followed by the brain.The results of the stress test showed that MT2 gene showed a tendency to increase and then decrease in liver and gill,and a tendency to gradually increase in head kidney,spleen and brain with a certain dose-dependence,and intestinal MT2 gene was significantly suppressed at 2 d,3 d and 4 d of stress.After recovery from stress,the expression of MT2 gene in liver,head kidney,gill and brain of the treated group was still significantly elevated.In summary,rainbow trout MT2 gene can be in-duced to be expressed by Cu2+in different tissues,and it is hypothesized that MT2 gene may play an important role in rainbow trout's resistance to heavy metal toxicity.Moreover,the expression of MT2 gene is correlated with the concentration of copper ions,and it can be used as a molecular biomarker for detecting heavy metal copper contamination in the ecology of waters.
rainbow troutMT2copper ion stressgene cloningexpression pattern
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