• Journal of Microbiology and Biotechnology
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• v.3 no.2
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• pp.65-72
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• 1993

A heterologous gene expression and secretion system using a methylotrophic yeast, Hansenula polymorpha was developed for the production of anticoagulant hirudin. Hirudin gene was expressed under the control of a strong and inducible methanol oxidase (MOX or AOX) promoter. The mating factor a pre-pro leader sequence of Saccharomyces cerevisiae was employed for hirudin to be secreted into the extracellular medium. Hirudin expression cassette was introduced into three strains of H. polymorpha, A16, HPBl and DLl which have different genetic backgrounds. This expression cassette was stably integrated into the host chromosomal DNA. Biologically active and mature hirudin was efficiently expressed and secreted into the extracellular medium. About 19 mg/L of hirudin was found in the culture supernatant in the case of a two-copy integrant of the strain HPBl under suboptimal culture conditions.

• Journal of Microbiology and Biotechnology
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• v.1 no.4
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• pp.266-273
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• 1991

Hirudin, a 65-amino acid protein isolated from the salivary gland of the bloodsucking leech, Hirudo medicinalis, is a potent thrombin-specific inhibitor and blocks the thrombin-mediated conversion of fibrinogen to fibrin in clot formation. We have studied the gene expression and secretion of hirudin in yeast. Saccharomyces cerevisiae. A gene coding for hirudin was synthesized based on the amino acid sequence and cloned into a yeast expression vector $YEG{\alpha}-1$ containing the ${\alpha}-mating$ factor pre-pro leader sequence and galactose-inducible promoter, GALl0. Recombinant S. cerevisiae was found to secrete biologically active hirudin into the extracellular medium. The secreted recombinant hirudin was recovered from the culture medium and purified with ultrafiltration and reverse phase high performance liquid chromatography. Approximately 1 mg of hirudin per liter was produced under suboptimal culture conditions and brought to about 90% purity in two steps of purification.

• Microbiology and Biotechnology Letters
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• v.22 no.5
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• pp.477-484
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• 1994

Using a methylotrophic yeast Hansenula polymorpha, a heterologous gene expression and secretion system was developed for the production of hEGF(human Epidermal Growth Factor) which has been shown to promote epithelial cell proliferation and to inhibit gastric acid secretion. The hEGF gene was chemically synthesized according to the preferred codon usage in H. polymor- pha and expressed under the control of the strong and inducible methanol oxidase(MOX) promoter. The mating factor $\alpha$ pre-pro leader sequence of Saccharomyces cerevisiae was employed for hEGF to be secreted into the extracellular medium. This expression cassette was stably integrated into the host chromosomal DNA. Mature hEGF was efficiently expressed and secreted into the extracel- lular medium. About 24 mg/l of hEGF was detected in the cuture supernatant of a transformant with pA-EGF3 under the suboptimal culture conditions.

• Mycobiology
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• v.45 no.4
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• pp.362-369
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• 2017

We assessed the regulation of cryparin, a class II hydrophobin, using three representative mitogen-activated protein kinase (MAPK) pathways in Cryphonectria parasitica. Mutation of the CpSlt2 gene, an ortholog of yeast SLT2 in the cell wall integrity (CWI) pathway, resulted in a dramatic decrease in cryparin production. Similarly, a mutant of the CpBck1 gene, a MAP kinase kinase kinase gene in the CWI pathway, showed decreased cryparin production. Additionally, mutation of the cpmk1 gene, an ortholog of yeast HOG1, showed decreased cryparin production. However, mutation of the cpmk2 gene, an ortholog of yeast Kss1/Fus3, showed increased cryparin production. The easy-wet phenotype and accumulation of the cryparin transcript in corresponding mutants were consistent with the cryparin production results. In silico analysis of the promoter region of the cryparin gene revealed the presence of binding motifs related to downstream transcription factors of CWI, HOG1, and pheromone responsive pathways including MADS-box- and Ste12-binding domains. Real-time reverse transcriptase PCR analyses indicated that both CpRlm1, an ortholog of yeast RLM1 in the CWI pathway, and cpst12, an ortholog of yeast STE12 in the mating pathway, showed significantly reduced transcription levels in the mutant strains showing lower cryparin production in C. prasitica. However, the transcription of CpMcm1, an ortholog of yeast MCM1, did not correlate with that of the mutant strains showing downregulation of cryparin. These results indicate that three representative MAPK pathways played a role in regulating cryparin production. However, regulation varied depending on the MAPK pathways: the CWI and HOG1 pathways were stimulatory, whereas the pheromone-responsive MAPK was repressive.

• Journal of Life Science
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• v.12 no.4
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• pp.496-503
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• 2002

To develop a yeast strain of Pichia pastoris producing an antibacterial peptide, we have attempted the expression and secretion of an insect defensin. The nucleotide sequences corresponding to mature defensin were chemically synthesized by 6 oligomers, assembled in vitro and the synthesized gene was identified by nucleotide sequencing. The prepro sequence of yeast mating factor $\alpha$1 and the defensin gene were recombined into a Pichia expression vector, pPIC9K. The resulting plasmid, pPIDE, was transformed into P. pastoris GSl15 and transformants selected on histidine-deficient minimal plates were tested for antibacterial activity against Micrococcus luteus. Four strains with different antibacterial activity were selected for further analysis. Southern hybridization and RT-PCR verified the defensin gene was maintained and transcribed in a host. Four strains were cultivated in YPD broth for 96 hours to compare cell growth and antibacterial activity, They showed no difference in cell growth, however, each strain showed different antibacterial activity pattern with culture time. The maximal activity was about 550 AU/ $m\ell$.

• Biomolecules & Therapeutics
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• v.4 no.4
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• pp.297-300
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• 1996

LBD-001, a recombinant human interferon $\gamma$ produced by genetically engineered yeast as a host system, was administered intraperitoneally to Sprague-Dawley male rats from premating to mating period at least for 60 days and to female rats from at least for 2 weeks before mating to early gestation period (from day 0 to 7 of gestation) at dose levels of $0.35\times10^6, 0.39\times10^6, and 1.38\times10^6$ I.U./kg/day. In the positive control group, ethynylestradiol ($EE_2$; 40 $\mu\textrm{g}$/kg/day) was subcutaneously administered only to female rats during the early gestation period. Effects of the test agents on reproductive performances of the male or female rats and embryonic development were as followings; (1) No significant changes by the treatment of LBD-001 were observed in general behaviors, body weight, food and water consumption, and necropsy of parent animals. However, significant decreases of body weight, food consumption, and water consumption were observed in ($EE_2$ -treated female rats. (2) Mating performances and fertility of parent animals were not significantly affected by the treatment of LBD-001. In ($EE_2$ -treated females, however, the fertility was completely inhibited. (3) No changes in resorption rate and external abnormality of F1 fetuses were observed by the treatment of LBD-001. The results show that LBD-001 at the dose of $1.38\times10^6$ I.U./kg/day or less does not affect general toxicity and reproductive function of parent animals and embryonic development of F1 fetuses.

• Parasites, Hosts and Diseases
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• v.44 no.4 s.140
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• pp.303-312
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• 2006

Interactions between GRA proteins of dense granules in Toxoplasma gondii and host cell proteins were analyzed by yeast two-hybrid technique. The cMyc-GRA fusion proteins expressed from pGBKT7 plasmid in Y187 yeast were bound to host cell proteins from pGADT7-Rec-HeLa cDNA library transformed to AH109 yeast by mating method. By the selection procedures, a total of 939 colonies of the SD/-AHLT culture, 348 colonies of the $X-\alpha-gal$ positive and PCR, 157 colonies of the $X-\beta-gal$ assay were chosen for sequencing the cDNA and finally 90 colonies containing ORF were selected to analyze the interactions. GRA proteins interacted with a variety of host cell proteins such as enzymes, structural and functional proteins of organellar proteins of broad spectrum. Several specific bindings of each GRA protein to host proteins were discussed presumptively the role of GRA proteins after secreting into the parasitophorous vacuoles (PV) and the PV membrane in the parasitism of this parasite.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.196-200
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• 1999

A recombinant human $\alpha_{s1}$-casein was expressed as a secretory product in the yeast Saccharomyces cerevisiae. Three different leader sequences derived from the mating factor $\alpha$l (MF$\alpha$l), inulinase, and human $\alpha_{s1}$-casein were used to direct the secretion of human $\alpha_{s1}$-casein into the extracellular medium. Among the three leader sequences tested, the native leader sequence of human $\alpha_{s1}$-casein was found to be the most efficient in the secretory expression of human $\alpha_{s1}$-casein, which implies that the native leader sequence of human $\alpha_{s1}$-casein might be used very efficiently for the secretory production of other heterologous proteins in yeast. The recombinant human $\alpha_{s1}$-casein was proteolytically cleaved as the culture proceeded. Therefore, an attempt was made to produce human $\alpha_{s1}$-casein using a S. cerevisiae mutant in which the YAP3 gene encoding yeast aspartic protease 3 (YAP3) was disrupted. After 72 h of culture, most of the human $\alpha_{s1}$-casein secreted by the wild type was cleaved, whereas more than 70% of the human $\alpha_{s1}$-casein secreted by yap3-disruptant remained intact. The results suggest that YAP3 might be involved in the internal cleavage of human $\alpha_{s1}$-casein expressed in yeast

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.576-581
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• 2005

Phytase improves the bioavailability of phytate phosphorus in plant foods to humans and animals, and reduces the phosphorus pollution of animal waste. We have engineered the cell surface of the yeast. Saccharomyces cerevisiae, by anchoring active fungal phytase on its cell wall, in order to apply it as a dietary supplement containing bioconversional functions in animal foods and a whole cell bio-catalyst for the treatment of waste. The phytase gene (phyA) of Aspergillus niger with a signal peptide of rice amylase 1A (Ramy1A) was fused with the gene encoding the C-terminal half (320 amino acid residues from the C-terminus) of yeast ${\alpha}-agglutinin$, a protein which is involved in mating and is covalently anchored to the cell wall. The resulting fusion construct was introduced into S. cerevisiae and expressed under the control of the constitutive glyceraldehydes-3-phosphate dehydrogenase (GPD) promoter. Phytase plate assay revealed that the surface-engineered cell exhibited a catalytically active opaque zone which was restricted to the margin of the colony. Additionally, the phytase activity was detected in the cell fraction, but was not detected in the culture medium when it was grown in liquid. These results indicate that the phytase was successfully anchored to the cell surface of yeast and was displayed as its active form. The amount of recombinant phytase on the surface of yeast cells was estimated to be 16,000 molecules per cell.

• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.604-612
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• 1996

To improve the fermentation characteristics of the haploid starch-fermenting recombinant yeast strain K114/YIpMS$\Delta$R(LEU2/URA3) secreting both $\alpha$-amylase and glucoamylase was rare-mated with polyploid industrial yeast Saccharomyces sp. K35. The K35 strain had good fermentation-characteristics such as ethanol-tolerance, high temperature and sugar-tolerance, and high fermentation rate. Among the resulting 66 hybrids, the best strain RH51 was selected. The RH51 exhibited amylolytic activity of K114/YIpMS$\Delta$R(LEU2/URA3) as well as ethanol and sugar tolerance of K35. The optimum temperature of hybrid RH51 for starch fermentation was 34$\circ$C which was same as that of K35 but different from that (30$\circ$C) of K114/YIpMS$\Delta$R(LEU2/URA3). The optimum pH was 5.0. The optimum size of inoculum was 2% as the pellet (w/v) of yeast cells. The hybrid strain RH51 produced 7.0% ethanol (w/v) from 20% (w/v) soluble starch while K35 formed almost no ethanol, 0.3% (w/v). RH51 strain produced 7.5% (w/v) ethanol after 8 days in a 2.5 l fermenter containing 800 ml of 20% (w/v) soluble starch. The residual starch content in the fermentation medium was 1.68% (w/v), and therefore almost all the starch was fermented completely.