scholarly journals New Strategies for Efficient Expression of Heterologous Sugar Transporters in Saccharomyces cerevisiae

Author(s):  
Marilia M. Knychala ◽  
Angela A. dos Santos ◽  
Leonardo G. Kretzer ◽  
Fernanda Gelsleichter ◽  
Maria José Leandro ◽  
...  

: In our previous work we had developed an hxt-null Saccharomyces cerevisiae strain displaying high xylose reductase, xylitol dehydrogenase and xylulokinase activities that proved to be useful as a chassis strain to study new xylose transporters, as SsXUT1 from Scheffersomyces stipitis. Spathaspora passalidarum and Spathaspora arborariae have in their genomes genes with high sequence similarity (78-80%) to SsXUT1. To characterize these putative transporter genes (SpXUT1 and SaXUT1, respectively) they were expressed in the same chassis strain as SsXUT1. Surprisingly, the cloned genes could not restore the ability to grow in several monosaccharides tested, although the strains expressing the SsXUT1 and SpXUT1 permeases, after growth on maltose, showed the presence of 14C-glucose and 14C-xylose transport activity. An important feature of these permeases is that SsXUT1 lacks lysine residues in its N-terminal domain with high-confidence ubiquitinylation potential, and has only one at the C-terminal domain, while the SpXUT1 transporter had several of such residues at its C-terminal domain. When the SpXUT1 gene was cloned in a truncated version lacking such lysine residues, the permease allowed grow on glucose or xylose, and even promoted xylose fermentation by the hxt-null strain. In another approach, we deleted two arrestins known to be involved in sugar transporter ubiquitinylation and endocytosis (ROD1 and ROG3), but only the rog3Δ strain allowed modest growth on these sugars. Taken together, these results suggest that to allow efficient sugar transporter expression in S. cerevisiae the lysines involved in transporter endocytosis should be removed from the sequence of the permease.

2022 ◽  
Vol 8 (1) ◽  
pp. 84
Author(s):  
Marilia M. Knychala ◽  
Angela A. dos Santos ◽  
Leonardo G. Kretzer ◽  
Fernanda Gelsleichter ◽  
Maria José Leandro ◽  
...  

In previous work, we developed a Saccharomyces cerevisiae strain (DLG-K1) lacking the main monosaccharide transporters (hxt-null) and displaying high xylose reductase, xylitol dehydrogenase and xylulokinase activities. This strain proved to be a useful chassis strain to study new glucose/xylose transporters, as SsXUT1 from Scheffersomyces stipitis. Proteins with high amino acid sequence similarity (78–80%) to SsXUT1 were identified from Spathaspora passalidarum and Spathaspora arborariae genomes. The characterization of these putative transporter genes (SpXUT1 and SaXUT1, respectively) was performed in the same chassis strain. Surprisingly, the cloned genes could not restore the ability to grow in several monosaccharides tested (including glucose and xylose), but after being grown in maltose, the uptake of 14C-glucose and 14C-xylose was detected. While SsXUT1 lacks lysine residues with high ubiquitinylation potential in its N-terminal domain and displays only one in its C-terminal domain, both SpXUT1 and SaXUT1 transporters have several such residues in their C-terminal domains. A truncated version of SpXUT1 gene, deprived of the respective 3′-end, was cloned in DLG-K1 and allowed growth and fermentation in glucose or xylose. In another approach, two arrestins known to be involved in the ubiquitinylation and endocytosis of sugar transporters (ROD1 and ROG3) were knocked out, but only the rog3 mutant allowed a significant improvement of growth and fermentation in glucose when either of the XUT permeases were expressed. Therefore, for the efficient heterologous expression of monosaccharide (e.g., glucose/xylose) transporters in S. cerevisiae, we propose either the removal of lysines involved in ubiquitinylation and endocytosis or the use of chassis strains hampered in the specific mechanism of membrane protein turnover.


2004 ◽  
Vol 15 (2) ◽  
pp. 665-677 ◽  
Author(s):  
Franco J. Vizeacoumar ◽  
Juan C. Torres-Guzman ◽  
David Bouard ◽  
John D. Aitchison ◽  
Richard A. Rachubinski

The peroxin Pex23p of the yeast Yarrowia lipolytica exhibits high sequence similarity to the hypothetical proteins Ylr324p, Ygr004p, and Ybr168p encoded by the Saccharomyces cerevisiae genome. Ylr324p, Ygr004p, and Ybr168p are integral to the peroxisomal membrane and act to control peroxisome number and size. Synthesis of Ylr324p and Ybr168p, but not of Ygr004p, is induced during incubation of cells in oleic acid-containing medium, the metabolism of which requires intact peroxisomes. Cells deleted for YLR324w exhibit increased numbers of peroxisomes, whereas cells deleted for YGR004w or YBR168w exhibit enlarged peroxisomes. Ylr324p and Ybr168p cannot functionally substitute for one another or for Ygr004p, whereas Ygr004p shows partial functional redundancy with Ylr324p and Ybr168p. Ylr324p, Ygr004p, and Ybr168p interact within themselves and with Pex28p and Pex29p, which have been shown also to regulate peroxisome size and number. Systematic deletion of genes demonstrated that PEX28 and PEX29 function upstream of YLR324w, YGR004w, and YBR168w in the regulation of peroxisome proliferation. Our data suggest a role for Ylr324p, Ygr004p, and Ybr168p—now designated Pex30p, Pex31p, and Pex32p, respectively—together with Pex28p and Pex29p in controlling peroxisome size and proliferation in Saccharomyces cerevisiae.


Author(s):  
Mayanka Awasthi ◽  
Sahil Gulati ◽  
Debi P. Sarkar ◽  
Swasti Tiwari ◽  
Suneel Kateriya ◽  
...  

Abstract COVID-19 novel coronavirus disease caused by SARS-CoV-2 causes severe lethal respiratory illness in humans and has recently developed into a worldwide pandemic. The lack of effective treatment strategy and vaccines against SARS-CoV-2 poses a threat to human health. Extremely high infection rate and multi-organ secondary infection within a short time period makes this virus more deadly and challenging for therapeutic interventions. Despite of high sequence similarity and utilization of common host-cell receptor, human angiotensin-converting enzyme-2 (ACE2) for virus entry, SARS-CoV-2 is much infectious than SARS-CoV. Structure-based sequence comparison of the N-terminal domain (NTD) of spike protein of MERS-CoV, SARS-CoV and SARS-CoV-2 illustrate three short stretches of amino acid motifs in SARS-CoV-2 , which appears to be the reminiscent of MERS-CoV sialoside binding pockets. These key differences with SARS-CoV and similarity with MERS-CoV, suggest an evolutionary adaptation of SARS-CoV-2 spike protein reciprocal interaction with host surface sialosides.


1996 ◽  
Vol 16 (8) ◽  
pp. 4349-4356 ◽  
Author(s):  
M Braunstein ◽  
R E Sobel ◽  
C D Allis ◽  
B M Turner ◽  
J R Broach

Heterochromatin in metazoans induces transcriptional silencing, as exemplified by position effect variegation in Drosophila melanogaster and X-chromosome inactivation in mammals. Heterochromatic DNA is packaged in nucleosomes that are distinct in their acetylation pattern from those present in euchromatin, although the role these differences play in the structure of heterochromatin or in the effects of heterochromatin on transcriptional activity is unclear. Here we report that, as observed in the facultative heterochromatin of the inactive X chromosome in female mammalian cells, histones H3 and H4 in chromatin spanning the transcriptionally silenced mating-type cassettes of the yeast Saccharomyces cerevisiae are hypoacetylated relative to histones H3 and H4 of transcriptionally active regions of the genome. By immunoprecipitation of chromatin fragments with antibodies specific for H4 acetylated at particular lysine residues, we found that only three of the four lysine residues in the amino-terminal domain of histone H4 spanning the silent cassettes are hypoacetylated. Lysine 12 shows significant acetylation levels. This is identical to the pattern of histone H4 acetylation observed in centric heterochromatin of D. melanogaster. These two observations provide additional evidence that the silent cassettes are encompassed in the yeast equivalent of metazoan heterochromatin. Further, mutational analysis of the amino-terminal domain of histone H4 in S. cerevisiae demonstrated that this observed pattern of histone H4 acetylation is required for transcriptional silencing. This result, in conjunction with prior mutational analyses of yeast histones H3 and H4, indicates that the particular pattern of nucleosome acetylation found in heterochromatin is required for its effects on transcription and is not simply a side effect of heterochromatin formation.


2003 ◽  
Vol 14 (10) ◽  
pp. 4089-4102 ◽  
Author(s):  
Yuen Yi C. Tam ◽  
Juan C. Torres-Guzman ◽  
Franco J. Vizeacoumar ◽  
Jennifer J. Smith ◽  
Marcello Marelli ◽  
...  

Transcriptome profiling identified the gene PEX25 encoding Pex25p, a peroxisomal membrane peroxin required for the regulation of peroxisome size and maintenance in Saccharomyces cerevisiae. Pex25p is related to a protein of unknown function encoded by the open reading frame, YOR193w, of the S. cerevisiae genome. Yor193p is a peripheral peroxisomal membrane protein that exhibits high sequence similarity not only to Pex25p but also to the peroxisomal membrane peroxin Pex11p. Unlike Pex25p and Pex11p, Yor193p is constitutively expressed in wild-type cells grown in oleic acid-containing medium, the metabolism of which requires intact peroxisomes. Cells deleted for the YOR193w gene show a few enlarged peroxisomes. Peroxisomes are greatly enlarged in cells harboring double deletions of the YOR193w and PEX25 genes, the YOR193w and PEX11 genes, and the PEX25 and PEX11 genes. Yeast two-hybrid analyses showed that Yor193p interacts with Pex25p and itself, Pex25p interacts with Yor193p and itself, and Pex11p interacts only with itself. Overexpression of YOR193w, PEX25, or PEX11 led to peroxisome proliferation and the formation of small peroxisomes. Our data suggest a role for Yor193p, renamed Pex27p, in controlling peroxisome size and number in S. cerevisiae.


Fermentation ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 72
Author(s):  
Adriane Mouro ◽  
Angela A. dos Santos ◽  
Denis D. Agnolo ◽  
Gabriela F. Gubert ◽  
Elba P. S. Bon ◽  
...  

In recent years, many novel xylose-fermenting yeasts belonging to the new genus Spathaspora have been isolated from the gut of wood-feeding insects and/or wood-decaying substrates. We have cloned and expressed, in Saccharomyces cerevisiae, a Spathaspora arborariae xylose reductase gene (SaXYL1) that accepts both NADH and NADPH as co-substrates, as well as a Spathaspora passalidarum NADPH-dependent xylose reductase (SpXYL1.1 gene) and the SpXYL2.2 gene encoding for a NAD+-dependent xylitol dehydrogenase. These enzymes were co-expressed in a S. cerevisiae strain over-expressing the native XKS1 gene encoding xylulokinase, as well as being deleted in the alkaline phosphatase encoded by the PHO13 gene. The S. cerevisiae strains expressing the Spathaspora enzymes consumed xylose, and xylitol was the major fermentation product. Higher specific growth rates, xylose consumption and xylitol volumetric productivities were obtained by the co-expression of the SaXYL1 and SpXYL2.2 genes, when compared with the co-expression of the NADPH-dependent SpXYL1.1 xylose reductase. During glucose-xylose co-fermentation by the strain with co-expression of the SaXYL1 and SpXYL2.2 genes, both ethanol and xylitol were produced efficiently. Our results open up the possibility of using the advantageous Saccharomyces yeasts for xylitol production, a commodity with wide commercial applications in pharmaceuticals, nutraceuticals, food and beverage industries.


2003 ◽  
Vol 161 (2) ◽  
pp. 321-332 ◽  
Author(s):  
Franco J. Vizeacoumar ◽  
Juan C. Torres-Guzman ◽  
Yuen Yi C. Tam ◽  
John D. Aitchison ◽  
Richard A. Rachubinski

The peroxin Pex24p of the yeast Yarrowia lipolytica exhibits high sequence similarity to two hypothetical proteins, Yhr150p and Ydr479p, encoded by the Saccharomyces cerevisiae genome. Like YlPex24p, both Yhr150p and Ydr479p have been shown to be integral to the peroxisomal membrane, but unlike YlPex24p, their levels of synthesis are not increased upon a shift of cells from glucose- to oleic acid–containing medium. Peroxisomes of cells deleted for either or both of the YHR150w and YDR479c genes are increased in number, exhibit extensive clustering, are smaller in area than peroxisomes of wild-type cells, and often exhibit membrane thickening between adjacent peroxisomes in a cluster. Peroxisomes isolated from cells deleted for both genes have a decreased buoyant density compared with peroxisomes isolated from wild-type cells and still exhibit clustering and peroxisomal membrane thickening. Overexpression of the genes PEX25 or VPS1, but not the gene PEX11, restored the wild-type phenotype to cells deleted for one or both of the YHR150w and YDR479c genes. Together, our data suggest a role for Yhr150p and Ydr479p, together with Pex25p and Vps1p, in regulating peroxisome number, size, and distribution in S. cerevisiae. Because of their role in peroxisome dynamics, YHR150w and YDR479c have been designated as PEX28 and PEX29, respectively, and their encoded peroxins as Pex28p and Pex29p.


2019 ◽  
Vol 26 (36) ◽  
pp. 6544-6563
Author(s):  
Victoria Lucia Alonso ◽  
Luis Emilio Tavernelli ◽  
Alejandro Pezza ◽  
Pamela Cribb ◽  
Carla Ritagliati ◽  
...  

Bromodomains recognize and bind acetyl-lysine residues present in histone and non-histone proteins in a specific manner. In the last decade they have raised as attractive targets for drug discovery because the miss-regulation of human bromodomains was discovered to be involved in the development of a large spectrum of diseases. However, targeting eukaryotic pathogens bromodomains continues to be almost unexplored. We and others have reported the essentiality of diverse bromodomain- containing proteins in protozoa, offering a new opportunity for the development of antiparasitic drugs, especially for Trypansoma cruzi, the causative agent of Chagas’ disease. Mammalian bromodomains were classified in eight groups based on sequence similarity but parasitic bromodomains are very divergent proteins and are hard to assign them to any of these groups, suggesting that selective inhibitors can be obtained. In this review, we describe the importance of lysine acetylation and bromodomains in T. cruzi as well as the current knowledge on mammalian bromodomains. Also, we summarize the myriad of small-molecules under study to treat different pathologies and which of them have been tested in trypanosomatids and other protozoa. All the information available led us to propose that T. cruzi bromodomains should be considered as important potential targets and the search for smallmolecules to inhibit them should be empowered.


Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Mohamed Ramadan ◽  
Muna Alariqi ◽  
Yizan Ma ◽  
Yanlong Li ◽  
Zhenping Liu ◽  
...  

Abstract Background Upland cotton (Gossypium hirsutum), harboring a complex allotetraploid genome, consists of A and D sub-genomes. Every gene has multiple copies with high sequence similarity that makes genetic, genomic and functional analyses extremely challenging. The recent accessibility of CRISPR/Cas9 tool provides the ability to modify targeted locus efficiently in various complicated plant genomes. However, current cotton transformation method targeting one gene requires a complicated, long and laborious regeneration process. Hence, optimizing strategy that targeting multiple genes is of great value in cotton functional genomics and genetic engineering. Results To target multiple genes in a single experiment, 112 plant development-related genes were knocked out via optimized CRISPR/Cas9 system. We optimized the key steps of pooled sgRNAs assembly method by which 116 sgRNAs pooled together into 4 groups (each group consisted of 29 sgRNAs). Each group of sgRNAs was compiled in one PCR reaction which subsequently went through one round of vector construction, transformation, sgRNAs identification and also one round of genetic transformation. Through the genetic transformation mediated Agrobacterium, we successfully generated more than 800 plants. For mutants identification, Next Generation Sequencing technology has been used and results showed that all generated plants were positive and all targeted genes were covered. Interestingly, among all the transgenic plants, 85% harbored a single sgRNA insertion, 9% two insertions, 3% three different sgRNAs insertions, 2.5% mutated sgRNAs. These plants with different targeted sgRNAs exhibited numerous combinations of phenotypes in plant flowering tissues. Conclusion All targeted genes were successfully edited with high specificity. Our pooled sgRNAs assembly offers a simple, fast and efficient method/strategy to target multiple genes in one time and surely accelerated the study of genes function in cotton.


Author(s):  
Angélique Buton ◽  
Louis-Marie Bobay

Abstract Homologous recombination is a key pathway found in nearly all bacterial taxa. The recombination complex allows bacteria to repair DNA double strand breaks but also promotes adaption through the exchange of DNA between cells. In Proteobacteria, this process is mediated by the RecBCD complex, which relies on the recognition of a DNA motif named Chi to initiate recombination. The Chi motif has been characterized in Escherichia coli and analogous sequences have been found in several other species from diverse families, suggesting that this mode of action is widespread across bacteria. However, the sequences of Chi-like motifs are known for only five bacterial species: E. coli, Haemophilus influenzae, Bacillus subtilis, Lactococcus lactis and Staphylococcus aureus. In this study we detected putative Chi motifs in a large dataset of Proteobacteria and we identified four additional motifs sharing high sequence similarity and similar properties to the Chi motif of E. coli in 85 species of Proteobacteria. Most Chi motifs were detected in Enterobacteriaceae and this motif appears well conserved in this family. However, we did not detect Chi motifs for the majority of Proteobacteria, suggesting that different motifs are used in these species. Altogether these results substantially expand our knowledge on the evolution of Chi motifs and on the recombination process in bacteria.


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