Promoters for lipogenesis-specific downregulation in Yarrowia lipolytica

Abstract

<jats:title>Abstract</jats:title> <jats:p>Yarrowia lipolytica is a non-conventional yeast with potential applications in the biofuel and biochemical industries. It is an oleaginous yeast that accumulates lipids when it encounters nutrient limitation in the presence of excess carbon. Its molecular toolbox includes promoters for robust constitutive expression, regulated expression through the addition of media components and inducible expression during lipid accumulation. To date, no promoters have been identified that lead to downregulation at the transition from growth to lipid accumulation. We identified four native Y. lipolytica promoters that downregulate the expression of genes at this natural transition. Using the fatty acid desaturase genes FAD2 and OLE1 as reporter genes for these promoters, we correlated repression of desaturase transcript levels with a reduction of desaturated fatty acids at the transition to lipid accumulation. These promoters can restrict to the growth phase an essential or favorable activity that is undesirable during lipid accumulation under traditional fermentation conditions without media additions. This expression pattern results in lipogenesis phase-specific changes that could be useful in applications relating to optimizing lipid yield and composition.</jats:p>

Yarrowia lipolytica Strains and Their Biotechnological Applications: How Natural Biodiversity and Metabolic Engineering Could Contribute to Cell Factories Improvement

“…Very recently, a research team from Novogy Inc. (Cambridge, MA, USA) has identified four native Y. lipolytica promoters able to downregulate the expression of genes at the transition from growth phase to lipid accumulation one [ 238 ]. These promoters could be used to restrict to the growth phase the expression of native or heterologous genes which product would be undesirable during the lipid accumulation phase, with no need of medium change during fermentation.…”

“…These promoters could be used to restrict to the growth phase the expression of native or heterologous genes which product would be undesirable during the lipid accumulation phase, with no need of medium change during fermentation. This series of new promoters able to drive lipogenesis phase-specific changes in the expression pattern will constitute valuable tools for many projects aiming to optimize lipid yield and composition in Y. lipolytica [ 238 ].…”

Customized yeast cell factories for biopharmaceuticals: from cell engineering to process scale up

“…Robust promoters such as PICL1, PTEF1, PXPR2, PPOT1, PRPS7, and PPOX2 are widely used in Y. lipolytica [ 30 , 31 ]. Nevertheless, issues like promoter repression due to low pH and elevated glucose level, or presence of promoter activity only in the existence of fatty acid by-products frequently mark these promoters unsuited for commercial purposes [ 32 ]. The PEYK1 promoter identified from Y. lipolytica was found to be functional under varying erythrulose and erythritol levels of and has been anticipated to permit strict regulation and induction of protein [ 33 ].…”

“…In addition, five newly isolated promoters of Y. lipolytica were selected to study the consequence of gene repression due to fatty acid metabolism; and one of the selected promoters could downregulate FAD1 and OLE1 genes under depleted conditions of nitrogen. These findings provided prospective promoters that possibly will be applied for gene knock-down rather than knock-out experiments [ 32 ].…”

Metabolic engineering of oleaginous yeasts to enhance single cell oil production

“…The palmitoleic acid (C16:1) and C18:1 is formed by introducing double bond at the Δ9 position of alkyl chain catalyzed by OLE1 (YALI0C05951g; Probst et al, 2016;Kamineni, Chen, Chifamba & Tsakraklides, 2020). These FFAs are then transported to endoplasmic reticulum (ER) via cytosol for further utilization and conversion to TAGs (Arora et al, 2019).…”