title: Human β-defensin-2 production from S. cerevisiae using the repressible MET17 promoter.
abstract: BACKGROUND
  Baker's yeast Saccharomyces cerevisiae is a proven host for the commercial production of recombinant biopharmaceutical proteins. For the manufacture of heterologous proteins with activities deleterious to the host it can be desirable to minimise production during the growth phase and induce production late in the exponential phase. Protein expression by regulated promoter systems offers the possibility of improving productivity in this way by separating the recombinant protein production phase from the yeast growth phase. Commonly used inducible promoters do not always offer convenient solutions for industrial scale biopharmaceutical production with engineered yeast systems.
  
  
  RESULTS
  Here we show improved secretion of the antimicrobial protein, human β-defensin-2, (hBD2), using the S. cerevisiae MET17 promoter by repressing expression during the growth phase. In shake flask culture, a higher final concentration of human β-defensin-2 was obtained using the repressible MET17 promoter system than when using the strong constitutive promoter from proteinase B (PRB1) in a yeast strain developed for high-level commercial production of recombinant proteins. Furthermore, this was achieved in under half the time using the MET17 promoter compared to the PRB1 promoter. Cell density, plasmid copy-number, transcript level and protein concentration in the culture supernatant were used to study the effects of different initial methionine concentrations in the culture media for the production of human β-defensin-2 secreted from S. cerevisiae.
  
  
  CONCLUSIONS
  The repressible S. cerevisiae MET17 promoter was more efficient than a strong constitutive promoter for the production of human β-defensin-2 from S. cerevisiae in small-scale culture and offers advantages for the commercial production of this and other heterologous proteins which are deleterious to the host organism. Furthermore, the MET17 promoter activity can be modulated by methionine alone, which has a safety profile applicable to biopharmaceutical manufacturing.
authors.affiliation: Novozymes Biopharma UK Limited, Castle Court, 59 Castle Boulevard, Nottingham, NG7 1FD, UK.|Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, Aalborg East, 9220, Aalborg, Denmark.
authors.forename: Thea S B
authors.initials: TS
authors.lastname: Møller
authors.affiliation: Novozymes Biopharma UK Limited, Castle Court, 59 Castle Boulevard, Nottingham, NG7 1FD, UK.
authors.forename: Joanna
authors.initials: J
authors.lastname: Hay
authors.affiliation: Novozymes Biopharma UK Limited, Castle Court, 59 Castle Boulevard, Nottingham, NG7 1FD, UK.
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: Saxton
authors.affiliation: Novozymes Biopharma UK Limited, Castle Court, 59 Castle Boulevard, Nottingham, NG7 1FD, UK.
authors.forename: Karen
authors.initials: K
authors.lastname: Bunting
authors.affiliation: Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, Aalborg East, 9220, Aalborg, Denmark.
authors.forename: Evamaria I
authors.initials: EI
authors.lastname: Petersen
authors.affiliation: Novozymes Biopharma UK Limited, Castle Court, 59 Castle Boulevard, Nottingham, NG7 1FD, UK.
authors.forename: Søren
authors.initials: S
authors.lastname: Kjærulff
authors.affiliation: Novozymes Biopharma UK Limited, Castle Court, 59 Castle Boulevard, Nottingham, NG7 1FD, UK. chrisfinnis@hotmail.com.
authors.forename: Christopher J A
authors.initials: CJ
authors.lastname: Finnis
mesh_terms: D003470:Culture Media / Q000737:chemistry; D003547:Cysteine Synthase / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D006801:Humans; D008715:Methionine / Q000494:pharmacology; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D012697:Serine Endopeptidases / Q000235:genetics; D023083:beta-Defensins / Q000096:biosynthesis* / Q000235:genetics*
chemical_list: D003470:Culture Media; C106641:DEFB4A protein, human; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D023083:beta-Defensins; D008715:Methionine; D003547:Cysteine Synthase; C103381:MET17 protein, S cerevisiae; D012697:Serine Endopeptidases; C023302:yeast proteinase B
keywords: Human β-defensin-2; MET17 promoter; Saccharomyces cerevisiae; Yeast