Leignel Vincent, Marchand Justine, Moreau Brigitte, Chénais Benoît
Université du Maine, EA3265, Laboratoire de Biologie et Génétique Evolutive, Le Mans, F-72085, France.
Comp Biochem Physiol C Toxicol Pharmacol. 2008 Jul;148(1):6-13. doi: 10.1016/j.cbpc.2008.02.005. Epub 2008 Mar 4.
Hydrothermal vent conditions can alter DNA and hydrothermal organisms may develop detoxification mechanisms and/or genetic adaptations. Hydrothermal vent animals notably synthesize a high quantity of metallothioneins (MT). Recent studies have revealed that the levels of MT within hydrothermal crustacean tissues are higher than those found in other vent animals. To improve our understanding of the environmental impacts exerted on the vent organisms, we characterized the metallothioneins (cDNA and Mt genes) of several members of the Bythograeidae (Bythograea thermydron, Cyanagraea praedator and Segonzacia mesatlantica) which is the only endemic hydrothermal crab family. In comparison, the isolation of metallothionein cDNA was also carried out in several coastal crab families. The results showed that the hydrothermal crabs possess Mt composed of three exons and two introns presenting conserved splicing signals. The cDNA sequences isolated from distinct crabs showed multiple substitutions. In spite of the unique environmental conditions, the protein sequence analysis revealed no specific amino acid residue for the MT of the three hydrothermal crabs. However, gene expression analysis performed by real-time PCR based on S. mesatlantica (hydrothermal crab) compared to Pachygrapsus marmoratus (coastal crab) confirmed the higher metallothionein induction in hydrothermal crabs suggested by others authors.
热液喷口环境条件会改变DNA，热液生物可能会形成解毒机制和/或遗传适应性。热液喷口动物尤其会合成大量金属硫蛋白（MT）。最近的研究表明，热液甲壳类动物组织中的MT水平高于其他喷口动物。为了更好地理解对喷口生物施加的环境影响，我们对拜氏蟹科（拜氏热蟹、捕食蓝蟹和大西洋中脊蟹）的几个成员的金属硫蛋白（cDNA和Mt基因）进行了表征，拜氏蟹科是唯一的地方性热液蟹科。相比之下，还在几个沿海蟹科中进行了金属硫蛋白cDNA的分离。结果表明，热液蟹的Mt由三个外显子和两个内含子组成，具有保守的剪接信号。从不同螃蟹中分离出的cDNA序列显示出多个替换。尽管环境条件独特，但蛋白质序列分析显示，这三种热液蟹的MT没有特定的氨基酸残基。然而，基于大西洋中脊蟹（热液蟹）与斑纹厚蟹（沿海蟹）进行的实时PCR基因表达分析证实了其他作者提出的热液蟹中金属硫蛋白诱导水平较高的观点。
