Project description:Saccharomyces cerevisiae has been used as a secretion host for production of various products, including pharmaceuticals. However, few antibody molecules have been functionally expressed in S. cerevisiae due to the incompatible surface glycosylation. Our laboratory previously isolated a group of yeast mutant strains with different α-amylase secretory capacities, and these evolved strains have showed advantages for production of some heterologous proteins. However, it is not known whether these secretory strains are generally suitable for pharmaceutical protein production. Here, three non-glycosylated antibody fragments with different configurations (Ran-Fab fragment Ranibizumab, Pex-the scFv peptide Pexelizumab, and Nan-a single V-type domain) were successfully expressed and secreted in three background strains with different secretory capacities, including HA (wild type), MA (evolved strain), and LA (evolved strain). However, the secretion of Ran and Nan were positively correlated with the strains’ secretory capacity, while Pex was most efficiently secreted in the parental strain. Therefore, transcriptional analysis was performed to explore the fundamental changes triggered by the expression of the different pharmaceutical proteins in these selected yeast strains.
Project description:To better understand how yeast adapt and respond to sequential stressors, an industrial yeast strain, URM 6670 (also known as BT0510), which is highly flocculent, tolerant to ethanol, osmotic and heat shock stresses, was subjected to three different treatments: 1. osmotic stress followed by ethanol stress, 2. oxidative stress followed by ethanol stress, 3. glucose withdrawal followed by ethanol stress. Samples were collected before the first stress (control), after the first stress and after the second stress (ethanol). RNA was extracted and analyzed by RNAseq.
Project description:The modification of the The modification of the tolerance of xylose-fermenting yeast is an urgent issue for improving ethanol production. In this study, multiple genes involving in superoxide dismutase, glutathione biosynthesis, NADPH regeneration and acetic acid degradation were overexpressed using stress-induced promoters, which is selected from the transcriptome data. Stress-induced promoters were used to realize the feedback control of the tolerant genes, which can ultimately improve the tolerance and ethanol production. We reported the stress-induced promoters for overexpressing tolerant genes and increasing yeast tolerance in a feedback manner
Project description:Telomere chromatin structure is pivotal for maintaining genome stability by regulating the binding of telomere-associated proteins and inhibition of a DNA damage response. In yeast, the silent information regulator (Sir) proteins bind to terminal telomeric repeats and to subtelomeric X-elements resulting in histone deacetylation and transcriptional silencing. Herein, we show that sir2 mutant strains display a very specific loss of a nucleosome residing in the X-element. Most yeast telomeres contain an X-element and the nucleosome occupancy defect in sir2 mutants is remarkably consistent between different telomeres.
Project description:The yeast RNA binding protein PUB1 contains a prion-like domain (PrLD) and, when overexpressed, localizes into cytoplasmic liquid droplets and is toxic. However, truncated versions lacking the PrLD are either soluble or aggregating and do not significantly alter yeast growth. Analysis of the interactomes of WT and mutant PUB1 was analyzed to clarify the link between droplets formation and toxicity.