Yan Yan, Zhang Yuanying, Huaxia Yifeng, Wang Xiuling, Yao Pengbo, Guo Xingqi, Xu Baohua
State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, PR China.
State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, PR China; School of Basic Medical Sciences, Taishan Medical University, Taian, Shandong 271000, PR China.
Comp Biochem Physiol B Biochem Mol Biol. 2014 Jun-Jul;172-173:39-48. doi: 10.1016/j.cbpb.2014.04.004. Epub 2014 Apr 16.
Thioredoxin peroxidases (Tpxs), members of the antioxidant protein family, play critical roles in resisting oxidative stress. In this work, a novel 1-Cys thioredoxin peroxidase gene was isolated from Apis cerana cerana and was named AccTpx5. The open reading frame (ORF) of AccTpx5 is 663bp in length and encodes a 220-amino acid protein with a predicted molecular mass and isoelectric point of 24,921kDa and 5.45, respectively. Promoter sequence analysis of AccTpx5 revealed the presence of putative transcription factor binding sites related to early development and stress responses. Additionally, real-time quantitative PCR (Q-PCR) analysis indicated that AccTpx5 was primarily present in some developmental stages, with the highest expression levels in the first-instar larvae. The expression level of AccTpx5 was up-regulated under various abiotic stresses, including 4°C, 42°C, HgCl2, H2O2, phoxim and acaricide treatments. Conversely, it was down-regulated by UV and pyriproxyfen treatments. Moreover, H2O2 concentration dramatically increased under a variety of stressful conditions. Finally, the purified recombinant AccTpx5 protein protected the supercoiled form of plasmid DNA from damage in the thiol-dependent mixed-function oxidation (MFO) system. These results suggest that AccTpx5 most likely plays an essential role in antioxidant defence.
硫氧还蛋白过氧化物酶（Tpxs）是抗氧化蛋白家族成员，在抵抗氧化应激中发挥关键作用。在本研究中，从中华蜜蜂中分离出一个新的1-半胱氨酸硫氧还蛋白过氧化物酶基因，并将其命名为AccTpx5。AccTpx5的开放阅读框（ORF）长度为663bp，编码一个220个氨基酸的蛋白质，预测分子量和等电点分别为24,921kDa和5.45。AccTpx5的启动子序列分析显示存在与早期发育和应激反应相关的假定转录因子结合位点。此外，实时定量PCR（Q-PCR）分析表明，AccTpx5主要存在于某些发育阶段，在一龄幼虫中表达水平最高。在包括4°C、42°C、HgCl2、H2O2、辛硫磷和杀螨剂处理在内的各种非生物胁迫下，AccTpx5的表达水平上调。相反，紫外线和吡丙醚处理使其下调。此外，在各种应激条件下，H2O2浓度显著增加。最后，纯化的重组AccTpx5蛋白在硫醇依赖性混合功能氧化（MFO）系统中保护质粒DNA的超螺旋形式免受损伤。这些结果表明，AccTpx5很可能在抗氧化防御中起重要作用。
