Liu Xiaojun, Liu Zhenming, Jin Can, Li Haoran, Li Jia-Le
Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai, People's Republic of China.
National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, People's Republic of China.
Biotechnol Appl Biochem. 2019 Jan;66(1):14-20. doi: 10.1002/bab.1690. Epub 2018 Sep 25.
Matrix proteins play important roles in molluscan shell biomineralization, which helps in the understanding of mechanisms associated with pearl formation. In this study, we characterized the gene encoding a novel shell-matrix protein, hic24, in Hyriopsis cumingii and investigated its structure and function. The full cDNA sequence of hic24 is 756 bp, with an open reading frame of 654 bp encoding 217 amino acids, including a signal peptide of 18 amino acids. Sequence analysis revealed that the protein is ∼23.5 kDa, and that Gly accounted for 11.5% of the total amino acid content. Secondary structure prediction indicated a structure comprised predominantly by β-folds. Quantitative real-time polymerase chain reaction and in situ hybridization indicated that hic24 is expressed in the dorsal epithelial cells of the mantle, indicating hic24 as a nacreous-layer matrix protein. Additionally, hic24 expression patterns during pearl biomineralization showed that hic24 regulates the growth of the later nacreous layer. After attenuating hic24 expression by RNA interference in the mantle, we observed that hic24 plays a role in biomineralization of the shell nacre by inhibiting calcium carbonate nucleation.
基质蛋白在软体动物贝壳生物矿化过程中发挥着重要作用，这有助于理解与珍珠形成相关的机制。在本研究中，我们对三角帆蚌中一种编码新型贝壳基质蛋白hic24的基因进行了表征，并研究了其结构和功能。hic24的完整cDNA序列为756 bp，开放阅读框为654 bp，编码217个氨基酸，包括一个18个氨基酸的信号肽。序列分析表明，该蛋白分子量约为23.5 kDa，甘氨酸占总氨基酸含量的11.5%。二级结构预测表明其结构主要由β折叠组成。定量实时聚合酶链反应和原位杂交表明，hic24在外套膜的背侧上皮细胞中表达，表明hic24是一种珍珠层基质蛋白。此外，hic24在珍珠生物矿化过程中的表达模式表明，hic24调节后期珍珠层的生长。通过RNA干扰减弱外套膜中hic24的表达后，我们观察到hic24通过抑制碳酸钙成核作用在贝壳珍珠层的生物矿化中发挥作用。
