Functional characterization reveals a diverse array of metazoan fatty acid biosynthesis genes
Functional characterization reveals a diverse array of metazoan fatty acid biosynthesis genes
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DOI：
10.1111/mec.16808
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发表时间：
2022-12-21
影响因子：
4.9
通讯作者：
De Troch, Marleen
中科院分区：
文献类型：
--
作者：
Boyen, Jens;Ribes-Navarro, Alberto;De Troch, Marleen
长链（>= C-20）多不饱和脂肪酸（LC-PUFA）是大多数动物（包括人类）生理上重要的脂肪酸。虽然大多数LC-PUFA的产生发生在水生初级生产者如微藻中，但最近的研究表明某些群体（主要是海洋）无脊椎动物具有内源性LC-PUFA生物合成和/或从饮食前体生物转化的能力。迄今为止，LC-PUFA生物合成的遗传途径和机制在许多无脊椎动物中仍然未知，特别是在非模式物种中。然而，目前可用的许多基因组和转录组资源可以有助于我们了解后生动物的LC-PUFA生物合成能力。在我们以前生成的底栖harpacticoid桡足类Platychelipus littoralis的转录组中，我们检测到一个甲基末端去饱和酶，一个前端去饱和酶和七个延长酶，负责LC-PUFA生物合成的关键酶的表达。为了证明它们的功能，我们使用酵母中的异源表达来表征其中的八个。所述棉贪夜蛾甲基末端去饱和酶具有Δ 15/17/19去饱和活性，使得能够分别从18：2 n-6、20：4 n-6和22：5 n-6生物合成α-亚麻酸、二十碳五烯酸和二十二碳六烯酸（DHA）。其前端去饱和酶具有Delta 4去饱和活性，从22：5 n-3到DHA，这意味着P. littoralis具有多种途径来产生这种生理上重要的脂肪酸。所有研究的P. littoralis延伸酶对饱和和不饱和脂肪酸具有不同程度的延伸活性，产生长度高达30个碳的脂族烃链。我们的调查揭示了桡足类中脂肪酸生物合成基因的功能多样性，这突出了需要仔细研究初级消费者在为上层营养水平提供必需营养素方面的作用。
Long-chain (>= C-20) polyunsaturated fatty acids (LC-PUFAs) are physiologically important fatty acids for most animals, including humans. Although most LC-PUFA production occurs in aquatic primary producers such as microalgae, recent research indicates the ability of certain groups of (mainly marine) invertebrates for endogenous LC-PUFA biosynthesis and/or bioconversion from dietary precursors. The genetic pathways for and mechanisms behind LC-PUFA biosynthesis remain unknown in many invertebrates to date, especially in non-model species. However, the numerous genomic and transcriptomic resources currently available can contribute to our knowledge of the LC-PUFA biosynthetic capabilities of metazoans. Within our previously generated transcriptome of the benthic harpacticoid copepod Platychelipus littoralis, we detected expression of one methyl-end desaturase, one front-end desaturase, and seven elongases, key enzymes responsible for LC-PUFA biosynthesis. To demonstrate their functionality, we characterized eight of them using heterologous expression in yeast. The P. littoralis methyl-end desaturase has Delta 15/17/19 desaturation activity, enabling biosynthesis of alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid (DHA) from 18:2 n-6, 20:4 n-6 and 22:5 n-6, respectively. Its front-end desaturase has Delta 4 desaturation activity from 22:5 n-3 to DHA, implying that P. littoralis has multiple pathways to produce this physiologically important fatty acid. All studied P. littoralis elongases possess varying degrees of elongation activity for saturated and unsaturated fatty acids, producing aliphatic hydrocarbon chains with lengths of up to 30 carbons. Our investigation revealed a functionally diverse range of fatty acid biosynthesis genes in copepods, which highlights the need to scrutinize the role that primary consumers could perform in providing essential nutrients to upper trophic levels.