Yoshinobu Kaneko

Osaka University, Ibaraki, Osaka-fu, Japan

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Publications (52)121.2 Total impact

  • Article: Increased transcription of RPL40A and RPL40B is important for the improvement of RNA production in Saccharomyces cerevisiae.
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    ABSTRACT: Yeast (Saccharomyces cerevisiae) RNA is an important source of 5'-ribonucleotides that is used in both the food and pharmaceutical industries. Efficient transcription of rDNA is very important to construct yeast strains with high RNA content. The gene RRN10, which encodes, a component of the upstream activation factor, is essential to promote high-level transcription of rDNA. In our previous study, we isolated SupE strain as a dominant suppressor, which showed the ability to restore the severe growth defects and reduced RNA content caused by disruption of the RRN10 gene. SupE strain has multiple mutations which we designated collectively as SUPE. Further analysis on SUPE mutation indicated that RPL40A was responsible for suppression of defect caused by rrn10 disruption. However, there were no base changes in this gene as compared with the parental Δrrn10 strain, thus suggesting that an additional copy of RPL40A suppress the defects caused by Δrrn10 disruption, and that, in SupE strain, these defects are suppressed by increased transcription of RPL40A whose copy is doubled. When multiple copies of RPL40A were combined with SUPE mutation on an RRN10(+) background, the resultant SupE strain had significantly higher RNA content than wild-type strain. In addition, increased transcription of RPL40B also showed significant effect to restore the growth defect and reduced RNA content caused by Δrrn10 disruption. We propose a model to explain how SUPE mutation increases the transcription of ribosomal protein genes such as RPL40A and RPL40B in SupE strain, resulting in an increase in RNA content.
    Journal of Bioscience and Bioengineering 05/2013; · 1.79 Impact Factor
  • Article: Disruption of multiple genes whose deletion causes lactic-acid resistance improves lactic-acid resistance and productivity in Saccharomyces cerevisiae.
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    ABSTRACT: To create strains that have high productivity of lactic acid without neutralization, a genome-wide screening for strains showing hyper-resistance to 6% l-lactic acid (pH 2.6) was performed using the gene deletion collection of Saccharomyces cerevisiae. We identified 94 genes whose disruption led to resistance to 6% lactic acid in rich medium. We also found that multiple combinations of Δdse2, Δscw11, Δeaf3, and/or Δsed1 disruption led to enhanced resistance to lactic acid depending upon their combinations. In particular, the quadruple disruptant Δdse2Δscw11Δeaf3Δsed1 grew well in 6% lactic acid with the shortest lag phase. We then introduced an exogenous lactate dehydrogenase gene (LDH) into those single and multiple disruptants to evaluate their productivity of lactic acid. It was found that the quadruple disruptant displaying highest lactic-acid resistance showed a 27% increase of lactic-acid productivity as compared with the LDH-harboring wild-type strain. These observations suggest that disruption of multiple genes whose deletion leads to lactic-acid resistance is an effective way to enhance resistance to lactic acid, leading to high lactic-acid productivity without neutralization.
    Journal of Bioscience and Bioengineering 01/2013; · 1.79 Impact Factor
  • Article: Functionally redundant protein phosphatase genes PTP2 and MSG5 co-regulate the calcium signaling pathway in Saccharomyces cerevisiae upon exposure to high extracellular calcium concentration.
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    ABSTRACT: Reversible phosphorylation is one of the key post-translational modifications for the regulation of many essential cellular processes. We have previously reported that the disruption of two protein phosphatase (PPase) genes, PTP2 and MSG5, causes calcium sensitivity indicating that functional redundancy exists between the two PPases in response to high extracellular calcium. In this paper, we found that the inactivation of calcineurin by the disruption of the calcineurin regulatory subunit, CNB1 or treatment with a calcineurin inhibitor, FK506, can suppress the calcium-sensitive phenotype of the ptp2Δmsg5Δ double disruptant. In the wake of a calcium-induced, calcineurin-driven signaling pathway activation, the calcium sensitivity of the ptp2Δmsg5Δ double disruptant can be suppressed by regulating the SLT2 pathway through the disruption of the major kinases in the SLT2 signal cascade that include BCK1, MKK1 and SLT2. Also, we show that PTP2 and MSG5 are key regulatory PPases that prevent over-activation of the calcium-induced signaling cascade under the parallel control of the SLT2 and calcineurin pathways.
    Journal of Bioscience and Bioengineering 10/2012; · 1.79 Impact Factor
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    Article: Enhanced bio-ethanol production from cellulosic materials by semi-simultaneous saccharification and fermentation using high temperature resistant Saccharomyces cerevisiae TJ14.
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    ABSTRACT: The capability of multi-stress-tolerant Saccharomyces cerevisiae diploid strain TJ14 for the production of cellulosic bio-ethanol by semi-simultaneous saccharification and fermentation (SSSF) technology was evaluated under high-temperature conditions. At 39°C, the TJ14 produced 45 g/l ethanol by SSSF of 100 g (w/v)/l cellulose - a significantly higher concentration than reported in prevailing literature.
    Journal of Bioscience and Bioengineering 08/2012; · 1.79 Impact Factor
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    Article: Enhanced bioethanol production from cellulosic materials by semi-simultaneous saccharification and fermentation using high temperature resistant Saccharomyces cerevisiae TJ14
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    ABSTRACT: The capability of multi-stress-tolerant yeast Saccharomyces cerevisiae diploid strain TJ14 for the production of cellulosic bio-ethanol by semi-simultaneous saccharification and fermentation technology was evaluated under high-temperature conditions. At 39oC, the TJ14 produced 45g/l ethanol by SSSF of 100 g (w/v)/l cellulose–a significantly higher concentration than reported in prevailing literature.
    Journal of Bioscience and Bioengineering 07/2012; · 1.79 Impact Factor
  • Article: Increased transcription of NOP15, involved in ribosome biogenesis in Saccharomyces cerevisiae, enhances the production yield of RNA as a source of nucleotide seasoning.
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    ABSTRACT: Yeast RNA is a good source of nucleotide seasoning, and more than half of yeast RNA consists of ribosomal RNA (rRNA). Previously, we reported the development of a Saccharomyces cerevisiae strain displaying a 1.4- to 2.3-times higher RNA content than the wild-type strain through the isolation of dominant suppressors (designated SupA to SupG strains) from a Δrrn10 disruptant showing decreased rRNA transcription. In the present study, the cloning of one of the genes responsible for the suppression was attempted using a genomic library from the SupD strain. NOP15, a gene involved in ribosome biogenesis, was found to be responsible for suppressing the growth defect of the Δrrn10 disruptant. The isolated NOP15 allele (designated NOP15(T-279C)) possessed a single T to C substitution at nucleotide position-279 of NOP15. The transcription level of NOP15(T-279C) in the originally isolated SupD strain was 2-fold higher than that in the Δrrn10 disruptant. Furthermore, a dose-dependent relationship between the transcription level of NOP15 and total amount of RNA in the Δrrn10 disruptant was observed: the enhanced transcription due to the NOP15(T-279C) allele is involved in the suppression mechanisms in the SupD strain. Introduction of the NOP15(T-279C) allele into the wild-type strain increased the total RNA content by 1.4-fold. These results indicate that the transcription level of NOP15 is an important determinant of the productivity of RNA and that its increased transcription provides an effective approach to obtain higher RNA yields in yeast.
    Journal of Bioscience and Bioengineering 05/2012; 114(1):17-22. · 1.79 Impact Factor
  • Article: Characterization and gene expression profiles of thermotolerant Saccharomyces cerevisiae isolates from Thai fruits.
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    ABSTRACT: For industrial applications, fermentation of ethanol at high temperature offers advantages such as reduction in cooling costs, reduced risk of microbial contamination and higher efficiency of fermentation processes including saccharification and continuous ethanol stripping. Three thermotolerant Saccharomyces cerevisiae isolates (C3723, C3751 and C3867) from Thai fruits were capable of growing and producing 38 g/L ethanol up to 41°C. Based on genetic analyses, these isolates were prototrophic and homothallic, with dominant homothallic and thermotolerant phenotypes. After short-term (30 min) and long-term (12 h) exposure at 37°C, expression levels increased for the heat stress-response genes HSP26, SSA4, HSP82, and HSP104 encoding the heat shock proteins small HSP, HSP70, HSP90 and the HSP100 family, respectively. In isolates C3723 and C3867, expression was significantly higher than that in reference isolates W303 and TISTR5606 for TPS1 encoding trehalose-6-phosphate synthase, NTH1 encoding neutral trehalase and GSY1 encoding glycogen synthase. The results suggested that continuous high expression of heat stress-response genes was important for the long-term, heat stress tolerance of these thermotolerant isolates.
    Journal of Bioscience and Bioengineering 05/2012; 114(2):144-9. · 1.79 Impact Factor
  • Article: Large-scale genome reorganization in Saccharomyces cerevisiae through combinatorial loss of mini-chromosomes.
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    ABSTRACT: A highly efficient technique, termed PCR-mediated chromosome splitting (PCS), was used to create cells containing a variety of genomic constitutions in a haploid strain of Saccharomyces cerevisiae. Using PCS, we constructed two haploid strains, ZN92 and SH6484, that carry multiple mini-chromosomes. In strain ZN92, chromosomes IV and XI were split into 16 derivative chromosomes, seven of which had no known essential genes. Strain SH6484 was constructed to have 14 mini-chromosomes carrying only non-essential genes by splitting chromosomes I, II, III, VIII, XI, XIII, XIV, XV, and XVI. Both strains were cultured under defined nutrient conditions and analyzed for combinatorial loss of mini-chromosomes. During culture, cells with various combinations of mini-chromosomes arose, indicating that genomic reorganization could be achieved by splitting chromosomes to generate mini-chromosomes followed by their combinatorial loss. We found that although non-essential mini-chromosomes were lost in various combinations in ZN92, one mini-chromosome (18kb) that harbored 12 genes was not lost. This finding suggests that the loss of some combination of these 12 non-essential genes might result in synthetic lethality. We also found examples of genome-wide amplifications induced by mini-chromosome loss. In SH6484, the mitochondrial genome, as well as the copy number of genomic regions not contained in the mini-chromosomes, was specifically amplified. We conclude that PCS allows for genomic reorganization, in terms of both combinations of mini-chromosomes and gene dosage, and we suggest that PCS could be useful for the efficient production of desired compounds by generating yeast strains with optimized genomic constitutions.
    Journal of Bioscience and Bioengineering 02/2012; 113(6):675-82. · 1.79 Impact Factor
  • Article: Lactic-acid stress causes vacuolar fragmentation and impairs intracellular amino-acid homeostasis in Saccharomyces cerevisiae.
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    ABSTRACT: To gain more insight into adaptation response to lactic-acid stress in yeast, a genome-wide screening for genes whose disruption caused hypersensitivity to 4.0% l-lactic acid (pH 2.8) was performed using the gene deletion collection of Saccharomyces cerevisiae. We identified 107 genes that contributed significantly to the ability of yeast cells to adapt lactic-acid stress. More than 30% of the genes identified in this screening were newly identified to be involved in mechanisms for adaptation response to lactic acid. We found that protein urmylation by Uba4 and N-terminal acetylation by Nat3 were involved in lactic acid adaptation mechanisms. Functional categorization of the genes followed by microscopic analysis revealed that a variety of cellular functions were involved in adaptation response to lactic acid and function associated with vacuolar transport played important roles in adaptation response to lactic acid. We also found that vacuole fragmented immediately upon exposure to lactic- and hydrochloric-acid stress. In addition, our analysis revealed that lactic-acid stress significantly reduced the amount of intracellular amino acids. Amino acid supplementation recovered the adaptation deficiency to lactic acid, suggesting that intracellular amino-acid homeostasis plays important roles in adaptation response to lactic-acid stress. These data suggest that enhancing vacuolar integrity, as well as maintaining intracellular amino-acid homeostasis may be an efficient approach to confer resistance to lactic-acid stress.
    Journal of Bioscience and Bioengineering 12/2011; 113(4):421-30. · 1.79 Impact Factor
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    Article: Superior thermotolerance of Saccharomyces cerevisiae for efficient bioethanol fermentation can be achieved by overexpression of RSP5 ubiquitin ligase.
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    ABSTRACT: The simultaneous saccharification and fermentation process requires thermo-tolerant yeast to facilitate the enzymatic hydrolysis of cellulose. In this paper, we describe a Htg(+) strain that exhibits confluent growth at high temperature (41°C) and resistance to heat shock, ethanol, osmotic, oxidative and DNA damage stresses. HTG6, one of the six genes responsible for the thermotolerant phenotype was identified to be the gene RSP5 encoding a ubiquitin ligase. The RSP5 allele of the Htg(+) strain, designated RSP5-C, possessed five, one and two base changes in the promoter, open reading frame and terminator region, respectively. The base changes in the promoter region of the RSP5-C allele were found to be responsible for the thermotolerant phenotype by strongly increasing transcription of the RSP5 gene and consequently causing a rise in the ubiquitination of cell proteins. Overexpression of the RSP5-BY allele present in the htg6 host strain (Htg(-)) conferred thermotolerance at 41°C, to this strain as in the case of RSP5-C allele. We also discovered that an Htg(+) strain overexpressing the RSP5-C allele exhibits a more robust Htg(+) phenotype against higher temperature (43°C). The data presented here also suggest that overexpression of RSP5 could be applied to raise the upper limit of thermotolerance in S. cerevisiae strain used for industrial bioethanol production.
    Biotechnology advances 09/2011; 30(6):1289-300. · 8.25 Impact Factor
  • Article: Highly efficient bioethanol production by a Saccharomyces cerevisiae strain with multiple stress tolerance to high temperature, acid and ethanol.
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    ABSTRACT: Use of super strains exhibiting tolerance to high temperature, acidity and ethanol is a promising way to make ethanol production economically feasible. We describe here the breeding and performance of such a multiple-tolerant strain of Saccharomyces cerevisiae generated by a spore-to-cell hybridization technique without recombinant DNA technology. A heterothallic strain showing a high-temperature (41°C) tolerant (Htg(+)) phenotype, a derivative from a strain isolated from nature, was crossed with a homothallic strain displaying high-ethanol productivity (Hep(+)), a stock culture at the Thailand Institute of Scientific and Technological Research. The resultant hybrid TJ14 displayed ability to rapidly utilize glucose, and produced ethanol (46.6g/l) from 10% glucose fermentation medium at high temperature (41°C). Not only ethanol productivity at 41°C but also acid tolerance (Acd(+)) was improved in TJ14 as compared with its parental strains, enabling TJ14 to grow in liquid medium even at pH 3. TJ14 maintained high ethanol productivity (46.0g/l) from 10% glucose when fermentation was done under multiple-stress conditions (41°C and pH 3.5). Furthermore, when TJ14 was subjected to a repeated-batch fermentation scheme, the growth and ethanol production of TJ14 were maintained at excellent levels over ten cycles of fermentation. Thus, the multiple-stress (Htg(+) Hep(+) Acd(+)) resistant strain TJ14 should be useful for cost-effective bioethanol production under high-temperature and acidic conditions.
    New Biotechnology 07/2011; 29(3):379-86. · 2.76 Impact Factor
  • Article: Construction of a Saccharomyces cerevisiae strain with a high level of RNA.
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    ABSTRACT: A strategy has been developed for creating Saccharomyces cerevisiae strains with a high RNA content by following a three-step breeding procedure. In the first step, an S. cerevisiae disruptant of the RRN10 gene, one of the components of the UAF (upstream activation factor) complex of rRNA transcription, was constructed and showed severely slow growth. In the second step, seven suppressors were isolated that restored the slow growth of the Δrrn10 disruptant. Genetic analysis revealed that each of the seven suppressors that were isolated appeared to have dominant and multiple mutations. The specific growth rate of those suppressors was increased approximately two-fold as compared with the Δrrn10 parental strain. The absolute RNA content showed that the suppressors had an RNA content 32-56% higher than that of the Δrrn10 parental strain. In the last step, the RRN10 wild-type gene was integrated into chromosome V of each of the original suppressors. The total RNA content of the integrants was also 1.4- to 2.3-fold higher than the wild-type strain. In conclusion, since yeast RNA is the source of 5'-IMP and 5'-GMP that enhance the delicious taste in certain types of food, like soups and sauces, the strategy taken in this study provides effective approach to breed S. cerevisiae strains producing a higher content of RNA that will contribute to yeast food biotechnology.
    Journal of Bioscience and Bioengineering 05/2011; 112(1):1-7. · 1.79 Impact Factor
  • Article: Genetic interactions of ribosome maturation factors Yvh1 and Mrt4 influence mRNA decay, glycogen accumulation, and the expression of early meiotic genes in Saccharomyces cerevisiae.
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    ABSTRACT: The Saccharomyces cerevisiae Yvh1, a dual-specificity protein phosphatase involved in glycogen accumulation and sporulation, is required for normal vegetative growth. To further elucidate the role of Yvh1, we generated dominant mutants suppressing the slow growth caused by YVH1 disruption. One of the mutant alleles, designated as SVH1-1 (suppressor of Δyvh1 deletion), was identical to MRT4 (mRNA turnover) that contained a single-base substitution causing an amino acid change from Gly(68) to Asp. Mrt4(G68D) restored the deficiencies in growth and rRNA biogenesis that occurs in absence of Yvh1. Here, we report that the interaction between Mrt4 and Yvh1 is also essential for normal glycogen accumulation and mRNA decay as well as the induction of sporulation genes IME2, SPO13 and HOP1. The Mrt4(G68D) could restore the plethora of phenotypes we observed in absence of Yvh1. We found that Yvh1 is not essential for wild-type induction of the transcriptional regulator of these genes, IME1, suggesting that either translation or post-translational modification to activate Ime1 has been compromised. Since a defect in ribosome biogenesis in general can be related to other various defects, the ribosome biogenesis defect caused by absence of Yvh1 might be an indirect cause of observed phenotypes.
    Journal of biochemistry 04/2011; 150(1):103-11. · 1.95 Impact Factor
  • Article: CDC19 encoding pyruvate kinase is important for high-temperature tolerance in Saccharomyces cerevisiae.
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    ABSTRACT: Use of thermotolerant strains is a promising way to reduce the cost of maintaining optimum temperatures in the fermentation process. Here we investigated genetically a Saccharomyces cerevisiae strain showing a high-temperature (41°C) growth (Htg(+)) phenotype and the result suggested that the Htg(+) phenotype of this Htg(+) strain is dominant and under the control of most probably six genes, designated HTG1 to HTG6. As compared with a Htg(-) strain, the Htg(+) strain showed a higher survival rate after exposure to heat shock at 48°C. Moreover, the Htg(+) strain exhibited a significantly high content of trehalose when cultured at high temperature and stronger resistance to Congo Red, an agent that interferes with cell wall construction. These results suggest that a strengthened cell wall in combination with increased trehalose accumulation can support growth at high temperature. The gene CDC19, encoding pyruvate kinase, was cloned as the HTG2 gene. The CDC19 allele from the Htg(+) strain possessed five base changes in its upstream region, and two base changes resulting in silent mutations in its coding region. Interestingly, the latter base changes are probably responsible for the increased pyruvate kinase activity of the Htg(+) strain. The possible mechanism leading to this increased activity and to the Htg(+) phenotype, which may lead to the activation of energy metabolism to maintain cellular homeostasis, is discussed.
    New Biotechnology 03/2011; 29(2):166-76. · 2.76 Impact Factor
  • Article: Saccharomyces cerevisiae protein phosphatase Ppz1 and protein kinases Sat4 and Hal5 are involved in the control of subcellular localization of Gln3 by likely regulating its phosphorylation state.
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    ABSTRACT: A Saccharomyces cerevisiae mutant lacking PPZ1, encoding a serine/threonine protein phosphatase (PPase), is caffeine-sensitive. To clarify the function of Ppz1 in resistance to caffeine, we attempted systematically to identify protein kinase (PKase) whose disruption lead to suppression of caffeine sensitive phenotype of the ∆ppz1 disruptant since disruption of PPZ1 might cause caffeine sensitivity by increasing its phosphorylated substrates and we presumed that disruption of genes for PKase sharing the substrate with Ppz1 could restore the resistance through bypassing necessity for dephosphorylation of substrates. Among the 102 viable pkase disruptions, disruption of either SAT4 or HAL5 suppressed the caffeine sensitivity phenotype and increased expression of ENA1, encoding a P-type ATPase of the ∆ppz1 disruptant. Because increased expression of ENA1 in the ∆ppz1 disruptant was found to be suppressed by disruption of GLN3, localization and phosphorylation of Gln3 in the ∆ppz1 disruptant was compared to that in the ∆ppz1∆sat4 and ∆ppz1∆hal5 double disruptants. Gln3 was found to accumulate in the nucleus in the ∆ppz1 disruptant, and this nuclear localization was abolished by disruption of either SAT4 or HAL5. Interestingly, the level of Gln3 phosphorylation in the ∆ppz1∆sat4 and ∆ppz1∆hal5 disruptants decreased relative to wild type independent of caffeine. From these observations, we conclude that Ppz1 controls Gln3 localization by regulating its phosphorylation state in combination with Sat4 and Hal5.
    Journal of Bioscience and Bioengineering 01/2011; 111(3):249-54. · 1.79 Impact Factor
  • Article: Ethanol production from biomass by repetitive solid-state fed-batch fermentation with continuous recovery of ethanol.
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    ABSTRACT: To save cost and input energy for bioethanol production, a consolidated continuous solid-state fermentation system composed of a rotating drum reactor, a humidifier, and a condenser was developed. Biomass, saccharifying enzymes, yeast, and a minimum amount of water are introduced into the system. Ethanol produced by simultaneous saccharification and fermentation is continuously recovered as vapor from the headspace of the reactor, while the humidifier compensates for the water loss. From raw corn starch as a biomass model, 95 +/- 3, 226 +/- 9, 458 +/- 26, and 509 +/- 64 g l(-1) of ethanol solutions were recovered continuously when the ethanol content in reactor was controlled at 10-20, 30-50, 50-70 and 75-85 g kg-mixture(-1), respectively. The residue showed a lesser volume and higher solid content than that obtained by conventional liquid fermentation. The cost and energy for intensive waste water treatment are decreased, and the continuous fermentation enabled the sustainability of enzyme activity and yeast in the system.
    Applied Microbiology and Biotechnology 09/2010; 88(1):87-94. · 3.42 Impact Factor
  • Article: Deciphering cellular functions of protein phosphatases by comparison of gene expression profiles in Saccharomyces cerevisiae.
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    ABSTRACT: Expression profiles of protein phosphatase (PPase) disruptants were analyzed by use of Pearson's correlation coefficient to find profiles that correlated with those of 316 Reference Gene (RG) disruptants harboring deletions in genes with known functions. Twenty-six Deltappase disruptants exhibited either a positive or negative correlation with 94 RG disruptants when the p value for Pearson's correlation coefficient was >0.2. Some of the predictions that arose from this analysis were tested experimentally and several new Delta ppase phenotypes were found. Notably, Delta sit4 and Delta siw14 disruptants exhibited hygromycin B sensitivity, Delta sit4 and Delta ptc1 disruptants grew slowly on glycerol medium, the Delta ptc1 disruptant was found to be sensitive to calcofluor white and congo red, while the Delta ppg1 disruptant was found to be sensitive to congo red. Because on-going analysis of expression profiles of Saccharomyces cerevisiae disruptants is rapidly generating new data, we suggest that the approach used in the present study to explore PPase function is also applicable to other genes.
    Journal of Bioscience and Bioengineering 05/2010; 109(5):433-41. · 1.79 Impact Factor
  • Article: Identification of protein kinase disruptions as suppressors of the calcium sensitivity of S. cerevisiae Deltaptp2 Deltamsg5 protein phosphatase double disruptant.
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    ABSTRACT: The double disruptant of the S. cerevisiae protein phosphatase (PPase) genes, PTP2 (phosphotyrosine-specific PPase) and MSG5 (phosphotyrosine and phosphothreonine/serine-PPase) causes calcium-sensitive growth (Cas). Previous study using Fluorescent-activated cell sorting (FACS) analysis showed that this growth defect with calcium occurs at G1-S transition in the cell cycle. We discovered that six non-essential protein kinase (PKase) disruptions (Deltabck1, Deltamkk1, Deltaslt2/Deltampk1, Deltamck1, Deltassk2 and Deltayak1) suppressed the Cas-phenotype of the Deltaptp2 Deltamsg5 double disruptant. Bck1p, Mkk1p and Slt2p are components of the mitogen-activated protein kinase (MAPK) cascade of cell wall integrity pathway (Slt2 pathway), and Mck1p is its down regulator. Ssk2p is the MAPK kinase kinase of the high-osmolarity glycerol (HOG) pathway, while Yak1p is a negative regulator for the cAMP-dependent PKA pathway. FACS analysis revealed that only the disruption of Deltassk2 and Deltayak1 but not Deltabck1, Deltamkk1, Deltaslt2 and Deltamck1 was able to suppress the delayed G1-S transition, suggesting that suppression of the growth defect is not always accompanied by suppression of the G1-S transition delay. The discovery of these PKases as suppressors revealed that in addition to the previously anticipated Slt2 pathway, HOG, Yak1p and Mck1p regulatory pathways may also be involved in the calcium sensitivity of the Deltaptp2 Deltamsg5 double disruptant.
    Archives of Microbiology 03/2010; 192(3):157-65. · 1.43 Impact Factor
  • Article: Yeast protein phosphatases Ptp2p and Msg5p are involved in G1-S transition, CLN2 transcription, and vacuole morphogenesis.
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    ABSTRACT: We previously reported that double disruption of protein phosphatase (PPase) genes PTP2 (phosphotyrosine-specific PPase) and MSG5 (phosphotyrosine and phosphothreonine/serine-PPase) causes Ca(2+) sensitive growth, whereas the single disruptions do not. This finding suggests that Ptp2p and Msg5p are involved in Ca(2+)-induced stress response in a redundant manner. To gain insight into the molecular mechanism causing calcium sensitivity of the ptp2 msg5 double disruptant, we performed fluorescence-activated cell sorting analysis and found a delayed G1 phase. This delayed G1 was consistent with the defect in bud emergence, and reduced CLN2 transcription upon addition of CaCl(2). We also found that Slt2p is hyper-phosphorylated in the Deltaptp2 Deltamsg5 double disruptant and that the vacuole of the Deltaptp2 Deltamsg5 double disruptant is fragmented even in the absence of Ca(2+). These findings suggest that both Ptp2p and Msg5p are involved in the G1 to S transition and vacuole morphogenesis possibly through their regulation of Slt2 pathway.
    Archives of Microbiology 09/2009; 191(9):721-33. · 1.43 Impact Factor
  • Article: Advances in molecular methods to alter chromosomes and genome in the yeast Saccharomyces cerevisiae.
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    ABSTRACT: A fundamental issue in biotechnology is how to breed useful strains of microorganisms for efficient production of valuable biomaterials. On-going and more recent developments in gene manipulation technologies and chromosomal and genomic modifications in particular have facilitated important contributions in this area. "Chromosome manipulation technology" as an outgrowth of "gene manipulation technology" may provide opportunities for creating novel strains of organisms with a variety of genomic constitutions. A simple and rapid chromosome splitting technology called "PCR-mediated chromosome splitting" (PCS) that we recently developed has made it possible to manipulate chromosomes and genomes on a large scale in an industrially important microorganism, Saccharomyces cerevisiae. This paper focuses on recent advances in molecular methods for altering chromosomes and genome in S. cerevisiae featuring chromosome splitting technology. These advances in introducing large-scale genomic modifications are expected to accelerate the breeding of novel strains for biotechnological purposes, and to reveal functions of presently uncharacterized chromosomal regions in S. cerevisiae and other organisms.
    Applied Microbiology and Biotechnology 09/2009; 84(6):1045-52. · 3.42 Impact Factor