The NF-E2-related factor 2 (Nrf2), an ubiquitous, evolutionarily conserved transcription factor, acts as a major sensor of oxidative stress in cells. In the present study, a Nrf2 homolog was newly identified in the thick shell mussel Mytilus coruscus. Accordingly, its functional role in antioxidant defense in response to acute benzo(a)pyrene (Bap) exposure was assessed. The newly identified McNrf2 affiliated to traditional Nrf2 family through Blast, multiple alignment and phylogenetic analysis. After acute exposure to Bap, antioxidants including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathine reductase (GR) were significantly induced in gills and digestive glands at both mRNA and enzymatic levels, and the expression of McNrf2 mRNA was also up-regulated. The analysis of correlating the expression of McNrf2 and the mRNA levels of these antioxidant genes showed positive ties, indicating that Nrf2 was needed for protracted induction of such genes. Further, the recombinant McNrf2 was produced through pET-32a prokaryotic system. After 50 μg/L Bap exposure, ROS generation and LPO level in gills of Nrf2 over-expressed mussels significantly decreased compared to Nrf2 wild-type mussels, as well as reduced ROS production in digestive glands. Collectively, these results show that Nrf2 pathway can provide protection from oxidative stress triggered by Bap in the thick shell mussel.

NF-E2相关因子2（Nrf2）是一种普遍存在的，进化上保守的转录因子，是细胞中氧化应激的主要传感器。在本研究中，在厚壳贻贝Mytilus coruscus中新发现了Nrf2同源物。因此，评估了其在响应急性苯并（a）py（Bap）暴露时在抗氧化防御中的功能作用。通过Blast，多重比对和系统发育分析，新鉴定的Mc Nrf2属于传统Nrf2家族。急性暴露于Bap的后，抗氧化剂，包括超氧化物歧化酶（SOD），过氧化氢酶（CAT），谷胱甘肽过氧化物酶（GPx的）和谷胱甘肽还原酶（GR）中在mRNA和酶活两级鳃和消化腺被显著诱导，并且表达了McNrf2 mRNA也上调。Mc Nrf2的表达与这些抗氧化剂基因的mRNA水平相关的分析显示出正相关，表明Nrf2是长期诱导此类基因所需要的。此外，通过pET-32a原核系统产生了重组Mc Nrf2。暴露于50μg/ L的Bap后，与Nrf2野生型贻贝相比，Nrf2过表达的贻贝g中的ROS生成和LPO水平显着降低，并且消化腺中的ROS产量降低。总而言之，这些结果表明，Nrf2途径可以提供保护，防止厚壳贻贝中Bap触发氧化应激。