Publications by authors named "Satoshi Harashima"

Polyploid (2n, 3n, and 4n) genomes are known to be unstable in Saccharomyces cerevisiae. Here, we attempted construction of super-polypoid strains (defined as having higher ploidy than tetraploidy) up to 32n by using the matα2-PBT method that we newly developed and investigated their genomic stability. It is known that cell size increases as ploidy increases up to tetraploid.

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Chromosome aneuploidy is a common phenomenon in industrial yeast. Aneuploidy is considered one of the strategies to enhance the industrial properties of Saccharomyces cerevisiae strains. However, the effects of chromosomal aneuploidy on the brewing properties of sake have not been extensively studied.

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How ploidy is determined in organisms is an important issue in bioscience. Polyploidy is believed to be relevant to useful traits of domesticated plants and microorganisms. As such, polyploidy is central to many applications in biotechnology.

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Nowadays, CRISPR (clustered regularly interspaced short palindromic repeats) and the CRISPR-associated protein (Cas9) system play a major role in genome editing. To target the desired sequence of the genome successfully, guide RNA (gRNA) is indispensable for the CRISPR/Cas9 system. To express gRNA, a plasmid expressing the gRNA sequence is typically constructed; however, construction of plasmids involves much time and labor.

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Previously, we identified 49 undeletable chromosomal regions harboring only non-essential genes in the genome of Saccharomyces cerevisiae. We proposed that there might be unknown synthetic lethal combinations of genes present in such undeletable regions of the genome. In this study, we chose four of the smallest undeletable chromosomal regions among the 49 and performed extensive further analyses to narrow down the gene-pairs responsible for lethality by replacing sub-regions in various combinations with a DNA module comprising the CgLEU2 marker.

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In our previous study, a novel genome engineering technology, PCR-mediated chromosome duplication (PCDup), was developed in Saccharomyces cerevisiae that enabled the duplication of any desired chromosomal region, resulting in a segmental aneuploid. From one round of transformation, PCDup can duplicate a single chromosomal region efficiently. However, simultaneous duplication of multiple chromosomal regions is not possible using PCDup technology, which is a serious drawback.

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Article Synopsis
  • Researchers developed two advanced genome editing techniques—CRISPR-PCD for chromosomal deletion and CRISPR-PCRep for chromosomal replacement—using the CRISPR/Cas9 system for enhanced efficiency.
  • These methods allow for the simultaneous manipulation of multiple chromosomal regions in a single transformation, overcoming limitations of previous techniques that could only target one region at a time.
  • Experimental results showed high success rates in deleting and replacing chromosomal regions, indicating these technologies could significantly streamline genetic analysis and the development of improved yeast strains for industrial use.
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The clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (CRISPR/Cas9) system is one of the most powerful tools for genome engineering. However, some of the steps are laborious, reducing its usability. In this study, we have developed a simplified method, called the guide RNA-transient expression system (gRNA-TES), to deliver gRNA in yeast.

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To achieve inorganic phosphate (Pi) homeostasis, cells must be able to sense intracellular and extracellular Pi concentrations. In the Pi signaling (PHO) pathway in Saccharomyces cerevisiae, high Pi represses genes involved in Pi uptake (e.g.

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Chromosome engineering is an important technology with applications in basic biology and biotechnology. Chromosome splitting technology called PCS (PCR-mediated Chromosome Splitting) has already been developed as a fundamental chromosome engineering technology in the budding yeast. However, the splitting efficiency of PCS technology is not high enough to achieve multiple splitting at a time.

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As yeast is commonly used for RNA production, it is industrially important to breed strains with high RNA contents. The upstream activating factor (UAF) plays an important role in transcription of ribosomal RNA (rRNA), a major constituent of intracellular RNA species. Here, we targeted the essential rRNA transcription regulator Rrn5 of Saccharomyces cerevisiae, a component of the UAF complex, and disrupted the genomic RRN5 gene using a helper plasmid carrying an RRN5 gene.

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Article Synopsis
  • High-temperature ethanol fermentation offers benefits like reduced cooling costs, lower bacterial contamination risks, and the ability to conduct simultaneous saccharification and fermentation.
  • Developing yeast strains that can tolerate high temperatures and various stresses (like ethanol and oxidative stress) is crucial for efficient fermentation.
  • The C3253, C3751, and C4377 Saccharomyces cerevisiae strains not only withstand high temperatures but also show better ethanol production compared to control strains, making them promising candidates for high-temperature fermentation processes.
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Article Synopsis
  • PCR-mediated chromosome splitting (PCS) allows for the division of chromosomes in yeast but is limited to splitting one site at a time due to low homologous recombination activity.
  • * The new CRISPR-PCS technology combines PCS with the CRISPR/Cas9 genome editing system, significantly boosting efficiency and enabling multiple chromosome splits simultaneously.
  • * This advancement is expected to enhance yeast strain breeding for industrial applications and improve the study of genome functions.
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Polylactic acid plastics are receiving increasing attention for the control of atmospheric CO2 emissions. Lactic acid, the building block for polylactic acid, is produced by fermentation technology from renewable carbon sources. The yeast Saccharomyces cerevisiae, harboring the lactate dehydrogenases gene (LDH), produces lactic acid at a large scale due to its strong acid resistance, to its simple nutritional requirements and to its ease of genetic engineering.

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To gain better understanding of the diversity and evolution of the gene regulation system in eukaryotes, the phosphate signal transduction (PHO) pathway in non-conventional yeasts has been studied in recent years. Here we characterized the PHO pathway of Hansenula polymorpha, which is genetically tractable and distantly related to Saccharomyces cerevisiae and Schizosaccharomyces pombe, in order to get more information for the diversity and evolution of the PHO pathway in yeasts. We generated several pho gene-deficient mutants based on the annotated draft genome of H.

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Saccharomyces cerevisiae strains from industrial and natural geographical environments are reported to show great variation in copy number of chromosomal regions. Such variation contributes to the mechanisms underlying adaptation to different environments. Here, we created and phenotypically analyzed segmentally haploidized strains, each harboring a deletion of one copy of approximately 100-300 kb of the left or right terminal region of 16 chromosomes in a diploid strain by using a PCR-mediated chromosomal deletion method.

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Segmental aneuploidy can play an important role in environmental adaptation. However, study of segmental aneuploids is severely hampered by the difficulty of creating them in a designed fashion. Here, we describe a PCR-mediated chromosome duplication (PCDup) technology that enables the generation of segmental aneuploidy at any desired chromosomal region in Saccharomyces cerevisiae.

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The GATA transcription activator Gln3 in the budding yeast (Saccharomyces cerevisiae) activates transcription of nitrogen catabolite repression (NCR)-sensitive genes. In cells grown in the presence of preferred nitrogen sources, Gln3 is phosphorylated in a TOR-dependent manner and localizes in the cytoplasm. In cells grown in non-preferred nitrogen medium or treated with rapamycin, Gln3 is dephosphorylated and is transported from the cytoplasm to the nucleus, thereby activating the transcription of NCR-sensitive genes.

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Chromosome engineering enables large-scale genome manipulation and can be used as a novel technology for breeding of yeasts. PCR-mediated chromosome splitting (PCS) offers a powerful tool for chromosome engineering by enabling a yeast chromosome to be split at any desired site. By applying PCS, a huge variety of chromosome combinations can be created and the best strain under specific conditions can be selected-a technology that we have called genome reorganization.

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The phosphorylation status of cellular proteins results from an equilibrium between the activities of protein kinases and protein phosphatases (PPases). Reversible protein phosphorylation is an important aspect of signal transduction that regulate many biological processes in eukaryotic cells. The Saccharomyces cerevisiae genome encodes 40 PPases, including seven members of the protein phosphatase 2C subfamily (PTC1 to PTC7).

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The Saccharomyces cerevisiae Siw14, a tyrosine phosphatase involved in the response to caffeine, participates in regulation of the phosphorylation and intracellular localization of Gln3, a GATA transcriptional activator of nitrogen catabolite repression-sensitive genes. In Δsiw14 cells, the phosphorylation level of Gln3 is decreased and the nuclear localization of Gln3 is stimulated by caffeine. However, the mechanism by which Siw14 controls the localization and function of Gln3 remains unclear, although the nuclear localization of Gln3 is known to be induced by activation of the type 2A phosphatases (PP2As) Pph21 and Pph22, and the type 2A-related phosphatase Sit4.

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Despite systematic approaches to mapping networks of genetic interactions in Saccharomyces cerevisiae, exploration of genetic interactions on a genome-wide scale has been limited. The S. cerevisiae haploid genome has 110 regions that are longer than 10 kb but harbor only non-essential genes.

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A key mechanism of signal transduction in eukaryotes is reversible protein phosphorylation, mediated through protein kinases and protein phosphatases (PPases). Modulation of signal transduction by this means regulates many biological processes. Saccharomyces cerevisiae has 40 PPases, including seven protein phosphatase 2C (PP2C PPase) genes (PTC1-PTC7).

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Improvement of the lactic acid resistance of the yeast Saccharomyces cerevisiae is important for the application of the yeast in industrial production of lactic acid from renewable resources. However, we still do not know the precise mechanisms of the lactic acid adaptation response in yeast and, consequently, lack effective approaches for improving its lactic acid tolerance. To enhance our understanding of the adaptation response, we screened for S.

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Yeast fatty acid synthase (Fas) comprises two subunits, α6 and β6, encoded by FAS2 and FAS1, respectively. To determine features of yeast Fas that control fatty acyl chain length, chimeric genes were constructed by combining FAS sequences from Saccharomyces cerevisiae (ScFAS) and Hansenula polymorpha (HpFAS), which mostly produces C16 and C18 fatty acids, respectively. The C16/C18 ratios decreased from 2.

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