MicroRNAs Involved in the Regulation of LC-PUFA Biosynthesis in Teleosts: miR-33 Enhances LC-PUFA Biosynthesis in Siganus canaliculatus by Targeting insig1 which in Turn Upregulates srebp1
MicroRNAs Involved in the Regulation of LC-PUFA Biosynthesis in Teleosts: miR-33 Enhances LC-PUFA Biosynthesis in Siganus canaliculatus by Targeting insig1 which in Turn Upregulates srebp1
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参与调节硬骨鱼 LC-PUFA 生物合成的 MicroRNA：miR-33 通过靶向 insig1 增强 Siganus canaliculatus 的 LC-PUFA 生物合成，insig1 进而上调 srebp1
DOI：
10.1007/s10126-019-09895-w
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发表时间：
2019
影响因子：
3
通讯作者：
Li Yuan You
中科院分区：
文献类型：
--
作者：
Sun Jun Jun;Zheng Li Guo;Chen Cui Ying;Zhang Jin Ying;Hong Cui;Zhang Qing Hao;Ma Hong Yu;Monroig Oscar;Tocher Douglas R;Wang Shu Qi;Li Yuan You
转录后调控机制在LC-PUFA生物合成的调控中起重要作用。我们前期的研究发现，miR-33可以增加长鳍蓝子鱼脂肪酰去饱和酶（fads 2）的表达，但具体机制尚不清楚。在此，我们证实miR-33可以靶向胰岛素诱导基因1（insig 1）的3′UTR，导致其在兔鱼肝细胞系（SCHL）中的蛋白水平下调。在体外过表达miR-33抑制了insig 1的mRNA水平，并增加了Δ6Δ5 fads 2和elovl 5以及srebp 1的mRNA水平。在SCHL细胞中，蛋白水解激活的固醇调节元件结合蛋白-1（Srebp 1）被Insig 1阻断，Insig 1的过表达降低成熟Srebp 1水平，而Insig 1的抑制导致相反的效果。Srebp 1可增强Δ6Δ5 fads 2和elovl 5的启动子活性，其表达水平随srebp 1的敲低而降低。miR-33的过表达还导致18：3 n-3至18：4 n-3和20：5 n-3至22：5 n-3的更高转化，其分别通过Δ6Δ5 Fads 2和Elovl 5与去饱和和延伸相关。结果表明，miR-33调控兔鱼LC-PUFA生物合成的机制是通过靶向insig 1增强srebp 1的表达。这些发现为研究miRNAs参与硬骨鱼类LC-PUFA生物合成的调控机制提供了新的思路。
Post-transcriptional regulatory mechanisms play important roles in the regulation of LC-PUFA biosynthesis. Our previous study revealed that miR-33 could increase the expression of fatty acyl desaturases (fads2) in the rabbitfish Siganus canaliculatus, but the specific mechanism is unknown. Here, we confirmed that miR-33 could target the 3′UTR of insulin-induced gene 1 (insig1), resulting in downregulation of its protein level in the rabbitfish hepatocyte line (SCHL). In vitro overexpression of miR-33 inhibited the mRNA level of insig1 and increased the mRNA levels of Δ6Δ5 fads2 and elovl5, as well as srebp1. In SCHL cells, proteolytic activation of sterol-regulatory-element-binding protein-1 (Srebp1) was blocked by Insig1, with overexpression of insig1 decreasing mature Srebp1 level, while inhibition of insig1 led to the opposite effect. Srebp1 could enhance the promoter activity of Δ6Δ5 fads2 and elovl5, whose expression levels decreased with knockdown of srebp1 in SCHL. Overexpression of miR-33 also resulted in a higher conversion of 18:3n-3 to 18:4n-3 and 20:5n-3 to 22:5n-3, linked to desaturation and elongation via Δ6Δ5 Fads2 and Elovl5, respectively. The results suggested that the mechanism by which miR-33 regulates LC-PUFA biosynthesis in rabbitfish is through enhancing the expression of srebp1 by targeting insig1. The findings here provide more insight to the mechanism of miRNAs involvement in the regulation of LC-PUFA biosynthesis in teleosts.