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

  • Jun Jun Sun
  • Li Guo Zheng
  • Cui Ying Chen
  • Jin Ying Zhang
  • Cui Hong You
  • Qing Hao Zhang
  • Hong Yu Ma
  • Óscar Monroig
  • Douglas R. Tocher
  • Shu Qi WangEmail author
  • Yuan You LiEmail author
Original Article


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.


miR-33 insig1 srebp1 Δ6Δ5fads2 elovl5 LC-PUFA biosynthesis 


Funding Information

This work was financially supported by the National Key R&D Program of China (2018YFD0900400), National Natural Science Foundation of China (No. 31873040 and No. 31702357), Natural Science Foundation of Guangdong Province (2018A030313910), China Agriculture Research System (CARS-47) and Guangdong Agriculture Research System (Freshwater Fish).

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.


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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Guangdong Provincial Key Laboratory of Marine BiotechnologyShantou UniversityShantouChina
  2. 2.School of Marine SciencesSouth China Agricultural UniversityGuangzhouChina
  3. 3.Instituto de Acuicultura Torre de la SalConsejo Superior de Investigaciones Científicas (IATS-CSIC)CastellónSpain
  4. 4.Institute of Aquaculture, Faculty of Natural SciencesUniversity of StirlingStirlingUK

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