School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka, 422-8526, Japan.
Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, 422-8526, Japan.
Transgenic Res. 2023 Oct;32(5):411-421. doi: 10.1007/s11248-023-00363-9. Epub 2023 Aug 24.
n-3 polyunsaturated fatty acids (n-3 PUFAs), including α-linolenic acid and eicosapentaenoic acid (EPA), are essential nutrients for vertebrates including humans. Vertebrates are n-3 PUFA-auxotrophic; hence, dietary intake of n-3 PUFAs is required for their normal physiology and development. Although fish meal and oil have been utilized as primary sources of n-3 PUFAs by humans and aquaculture, these traditional n-3 PUFA sources are expected to be exhausted because of the increasing consumption requirements of humans. Hence, it is necessary to establish alternative n-3 PUFA sources to reduce the gap between the supply and demand of n-3 PUFAs. Here, we investigated whether insects, which are considered as a novel source of essential nutrients, could store n-3 PUFAs by the forced expression of n-3 PUFA biosynthetic enzymes. We utilized Drosophila as an insect model to generate transgenic strains expressing Caenorhabditis elegans PUFA biosynthetic enzymes and examined their effects on the proportion of fatty acids. The ubiquitous expression of methyl-end desaturase FAT-1 prominently enhanced the proportions of α-linolenic acid, indicating that FAT-1 is useful for metabolic engineering to fortify α-linolenic acid in insect. Furthermore, the ubiquitous expression of nematode front-end desaturases (FAT-3 and FAT-4), PUFA elongase (ELO-1), and FAT-1 led to EPA bioproduction. Hence, nematode PUFA biosynthetic genes may serve as powerful genetic tools for enhancing the proportion of EPA in insects. This study represents the first step toward the establishment of n-3 PUFA-producing insects.
n-3 多不饱和脂肪酸（n-3 PUFAs），包括α-亚麻酸和二十碳五烯酸（EPA），是包括人类在内的脊椎动物的必需营养物质。脊椎动物是 n-3 PUFA-营养缺陷型的；因此，需要从饮食中摄入 n-3 PUFAs，以维持其正常的生理和发育。虽然鱼类饲料和油一直被人类和水产养殖用作 n-3 PUFAs 的主要来源，但由于人类消费需求的不断增加，这些传统的 n-3 PUFA 来源预计将枯竭。因此，有必要建立替代 n-3 PUFA 来源，以缩小 n-3 PUFA 的供需差距。在这里，我们研究了昆虫是否可以通过强制表达 n-3 PUFA 生物合成酶来储存 n-3 PUFAs。我们利用果蝇作为昆虫模型，生成表达秀丽隐杆线虫 PUFA 生物合成酶的转基因品系，并检查它们对脂肪酸比例的影响。甲基末端去饱和酶 FAT-1 的普遍表达显著提高了α-亚麻酸的比例，表明 FAT-1 可用于代谢工程，以强化昆虫中的α-亚麻酸。此外，线虫前端去饱和酶（FAT-3 和 FAT-4）、PUFA 延长酶（ELO-1）和 FAT-1 的普遍表达导致 EPA 的生物合成。因此，线虫 PUFA 生物合成基因可以作为增强昆虫中 EPA 比例的有力遗传工具。本研究代表了建立 n-3 PUFA 生产昆虫的第一步。
