PDF(Pubmed)
Abstract：
Carotenoids play important roles in living organisms. However, animals cannot synthesize carotenoids by themselves, and they must absorb and accumulate carotenoids from their diets in which some key genes are involved. In present study, a gene named StAR-like-3 was characterized in the noble scallop Chlamys nobilis, and its function was identified using golden scallops with higher carotenoids content and brown scallops with less carotenoids content by immunohistochemistry, carotenoid binding assay and RNAi. Results showed that the StAR-like-3 encodes a 54.7 kDa transmembrane protein (named as StAR3) of 481 amino acids containing a MENTAL domain and a START (Steroidogenic acute regulatory protein-related lipid transfer) domain, and its expression level in hemocytes and intestine of golden scallops were significantly higher than those of brown ones. Subsequently, the StAR3 protein was detected in the intestinal epithelial cells of golden scallops, and recombinant StAR3 could bind lutein conjugated to protein G and antibody to form a yellow complex, suggesting it is a carotenoid binding protein involving in carotenoids accumulation in golden scallops. Furthermore, total carotenoids content of hemolymph in golden scallops was significantly decreased when the expression of StAR-like-3 suppressed, suggesting this gene plays an important role in transport of carotenoids. Conclusion, the present results indicated that the StAR-like-3 is a key gene responsible for the carotenoids accumulation in the scallop.
摘要：
类胡萝卜素在生物体中起重要作用。然而,动物不能自己合成类胡萝卜素，他们必须从饮食中吸收和积累类胡萝卜素，其中涉及一些关键基因。在目前的研究中,一种名为StAR-like-3的基因在高贵的扇贝Chlamysnobilis中表征，用类胡萝卜素含量较高的金扇贝和类胡萝卜素含量较低的棕色扇贝通过免疫组织化学鉴定其功能，类胡萝卜素结合测定和RNAi。结果表明，StAR-like-3编码481个氨基酸的54.7kDa跨膜蛋白（命名为StAR3），其中包含一个MENTAL域和一个START（类固醇性急性调节蛋白相关脂质转移）域，金扇贝在血细胞和肠道中的表达水平明显高于棕色扇贝。随后，在金扇贝的肠上皮细胞中检测到StAR3蛋白，重组StAR3能与G蛋白和抗体结合形成黄色复合物，这表明它是一种类胡萝卜素结合蛋白，参与类胡萝卜素在黄金扇贝中的积累。此外，当StAR-like-3的表达被抑制时，金扇贝中血淋巴的总类胡萝卜素含量显着降低，这表明该基因在类胡萝卜素的转运中起着重要作用。结论,本结果表明，StAR样3是扇贝中类胡萝卜素积累的关键基因。
