Developing a set of strong intronic promoters for robust metabolic engineering in oleaginous Rhodotorula (Rhodosporidium) yeast species

Microbial Cell Factories

Research

Yanbin Liu¹  Chong Mei John Koh¹  Sihui Amy Yap¹  Lianghui Ji² 

[1] Biomaterials and Biocatalysts Group, Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, 117604, Singapore, Singapore;Biomaterials and Biocatalysts Group, Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, 117604, Singapore, Singapore;School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore, Singapore;

关键词: Rhodosporidium/Rhodotorula;    Metabolic engineering;    Oleaginous yeast;    Promoter;    Lipid;   

DOI  :  10.1186/s12934-016-0600-x

 received in 2016-07-26, accepted in 2016-11-19,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundRed yeast species in the Rhodotorula/Rhodosporidium genus are outstanding producers of triacylglyceride and cell biomass. Metabolic engineering is expected to further enhance the productivity and versatility of these hosts for the production of biobased chemicals and fuels. Promoters with strong activity during oil-accumulation stage are critical tools for metabolic engineering of these oleaginous yeasts.ResultsThe upstream DNA sequences of 6 genes involved in lipid biosynthesis or accumulation in Rhodotorula toruloides were studied by luciferase reporter assay. The promoter of perilipin/lipid droplet protein 1 gene (LDP1) displayed much stronger activity (4–11 folds) than that of glyceraldehyde-3-phosphate dehydrogenase gene (GPD1), one of the strongest promoters known in yeasts. Depending on the stage of cultivation, promoter of acetyl-CoA carboxylase gene (ACC1) and fatty acid synthase β subunit gene (FAS1) exhibited intermediate strength, displaying 50–160 and 20–90% levels of GPD1 promoter, respectively. Interestingly, introns significantly modulated promoter strength at high frequency. The incorporation of intron 1 and 2 of LDP1 (LDP1in promoter) enhanced its promoter activity by 1.6–3.0 folds. Similarly, the strength of ACC1 promoter was enhanced by 1.5–3.2 folds if containing intron 1. The intron 1 sequences of ACL1 and FAS1 also played significant regulatory roles. When driven by the intronic promoters of ACC1 and LDP1 (ACC1in and LDP1in promoter, respectively), the reporter gene expression were up-regulated by nitrogen starvation, independent of de novo oil biosynthesis and accumulation. As a proof of principle, overexpression of the endogenous acyl-CoA-dependent diacylglycerol acyltransferase 1 gene (DGA1) by LDP1in promoter was significantly more efficient than GPD1 promoter in enhancing lipid accumulation.ConclusionIntronic sequences play an important role in regulating gene expression in R. toruloides. Three intronic promoters, LDP1in, ACC1in and FAS1in, are excellent promoters for metabolic engineering in the oleaginous and carotenogenic yeast, R. toruloides.

【 授权许可】

CC BY   
© The Author(s) 2016