Zhejiang Mariculture Research Institute, Zhejiang Key Laboratory of Exploitation and Preservation of Coastal Bio-resource, Wenzhou Key Labroatory of Marine Biological Genetics and Breeding, Wenzhou 325005, China; Zhejiang Ocean University, Zhoushan 316022, China.
Zhejiang Mariculture Research Institute, Zhejiang Key Laboratory of Exploitation and Preservation of Coastal Bio-resource, Wenzhou Key Labroatory of Marine Biological Genetics and Breeding, Wenzhou 325005, China.
Gene. 2022 Dec 15;845:146865. doi: 10.1016/j.gene.2022.146865. Epub 2022 Sep 5.
Exposure to cadmium (Cd), a heavy metal, can cause strong and toxic side effects. Cd can enter the body of organisms in several ways, leading to various pathological reactions in the body. Tegillarca granosa is a kind of bivalve shellfish favored by people in the coastal areas of China. Bivalve shellfish can easily absorb heavy metal pollutants from water bodies while filter feeding. T. granosa is considered a hyper-accumulator of Cd, and the TgABCA3 gene is highly expressed in individuals with a high content of Cd-exposed blood clam. However, it is unclear whether TgABCA3 is involved in Cd ion transport in blood clam and the molecular mechanism for the mechanism of the Cd-induced responses for maintaining cell homeostasis. In this study, the complete cDNA of the TgABCA3 gene was analyzed to provide insights into the roles of TgABCA3 in resistance against Cd in blood clam. The complete sequence of TgABCA3 showed high identity to that of TgABCA3 from other bivalves and contained some classical motifs of ATP-binding cassette transport proteins. TgABCA3 expression in different tissues was measured using real-time quantitative polymerase chain reaction (qRT-PCR) and western blot analysis. The tissue-specific expression showed that TgABCA3 expression was highest in the gill tissue. The TgABCA3 expression in the gill tissue was silenced using the RNA interference technique. After TgABCA3 silencing, the TgABCA3 expression decreased, the Cd content increased, the oxygen consumption and ammonia excretion rates increased, and the ingestion rate decreased. These results showing that the extents of Cd accumulation and resulting toxic effects are related to expression levels and activity of TgABCA3 indicate that TgABCA3 has a protective function against Cd in the clam. This increase in Cd accumulation results in serious damage to the body, leading to the enhancement of its physiological metabolism. Therefore, the findings of the study demonstrated that TgABCA3 can participate in the transport of Cd ions in the blood clam through active transport and play a vital role in Cd detoxification.
镉（Cd）是一种重金属，接触它会导致强烈和有毒的副作用。Cd 可以通过几种方式进入生物体，导致体内发生各种病理反应。泥蚶是中国沿海地区人们喜爱的一种双壳贝类。双壳贝类在滤食过程中很容易从水体中吸收重金属污染物。泥蚶被认为是 Cd 的超积累者，在血蛤体内暴露于高浓度 Cd 的个体中，TgABCA3 基因高度表达。然而，尚不清楚 TgABCA3 是否参与血蛤中 Cd 离子的运输以及 Cd 诱导反应维持细胞内稳态的分子机制。在这项研究中，分析了 TgABCA3 基因的完整 cDNA，以深入了解 TgABCA3 在血蛤抵抗 Cd 中的作用。TgABCA3 的完整序列与其他双壳贝类的 TgABCA3 具有高度的同一性，并包含一些 ATP 结合盒转运蛋白的经典基序。使用实时定量聚合酶链反应（qRT-PCR）和 Western blot 分析测量不同组织中的 TgABCA3 表达。组织特异性表达显示，TgABCA3 在鳃组织中的表达最高。使用 RNA 干扰技术沉默鳃组织中的 TgABCA3 表达。沉默 TgABCA3 后，TgABCA3 表达下降，Cd 含量增加，耗氧率和氨排泄率增加，摄食率下降。这些结果表明，Cd 积累的程度和由此产生的毒性作用与 TgABCA3 的表达水平和活性有关，表明 TgABCA3 对蛤具有保护作用。这种 Cd 积累的增加会对身体造成严重损害，导致其生理代谢增强。因此，研究结果表明，TgABCA3 可以通过主动运输参与血蛤中 Cd 离子的运输，并在 Cd 解毒中发挥重要作用。
