MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Sanya 572000, China.
Genes (Basel). 2024 Mar 15;15(3):365. doi: 10.3390/genes15030365.
Fatty acid desaturases (Fads), as key enzymes in the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFAs), catalyze the desaturation between defined carbons of fatty acyl chains and control the degree of unsaturation of fatty acids. In the present study, two Fads genes, designated and , were identified from the genome of the dwarf surf clam (Mollusca, Mactridae), and their spatiotemporal expression was examined. MulFadsA and MulFadsB contained the corresponding conserved functional domains and clustered closely with their respective orthologs from other mollusks. Both genes were expressed in the developmental stages and all tested adult tissues of , with exhibiting significantly higher expression levels in adult tissues than . Subsequently, the effects of dietary microalgae on expressions in the dwarf surf clam were investigated by feeding clams with two types of unialgal diets varying in fatty acid content, i.e., (Cp) and (Ph). The results show that the expressions of were significantly upregulated among adult tissues in the Cp group compared with those in the Ph group. In addition, we observed the desaturation activity of MulFadsA via heterologous expression in yeasts, revealing Δ5 desaturation activity toward PUFA substrates. Taken together, these results provide a novel perspective on LC-PUFA biosynthesis, expanding our understanding of fatty acid synthesis in marine mollusks.
脂肪酸去饱和酶（Fads）作为长链多不饱和脂肪酸（LC-PUFAs）生物合成中的关键酶，催化脂肪酸酰链定义碳之间的去饱和反应，控制脂肪酸的不饱和程度。本研究从矮滨螺（Mollusca，Mactridae）基因组中鉴定出两个 Fads 基因，分别命名为和，并检测了它们的时空表达。MulFadsA 和 MulFadsB 含有相应的保守功能结构域，并与其他软体动物的相应直系同源物紧密聚类。这两个基因在 的发育阶段和所有测试的成年组织中均有表达，而 在成年组织中的表达水平明显高于 。随后，通过用两种脂肪酸含量不同的单胞藻饲料（即 （Cp）和 （Ph））喂养蛤，研究了饮食微藻对矮滨螺 表达的影响。结果表明，与 Ph 组相比，Cp 组成年组织中 的表达在各组织中均显著上调。此外，我们通过在酵母中异源表达观察到 MulFadsA 的去饱和活性，表明其对 PUFA 底物具有 Δ5 去饱和活性。总之，这些结果为 LC-PUFA 生物合成提供了新的视角，扩展了我们对海洋软体动物脂肪酸合成的理解。
