title: A vaccine grade of yeast Saccharomyces cerevisiae expressing mammalian myostatin.
abstract: BACKGROUND
  Yeast Saccharomyces cerevisiae is a widely-used system for protein expression. We previously showed that heat-killed whole recombinant yeast vaccine expressing mammalian myostatin can modulate myostatin function in mice, resulting in increase of body weight and muscle composition in these animals. Foreign DNA introduced into yeast cells can be lost soon unless cells are continuously cultured in selection media, which usually contain antibiotics. For cost and safety concerns, it is essential to optimize conditions to produce quality food and pharmaceutical products.
  
  
  RESULTS
  We developed a simple but effective method to engineer a yeast strain stably expressing mammalian myostatin. This method utilized high-copy-number integration of myostatin gene into the ribosomal DNA of Saccharomyces cerevisiae. In the final step, antibiotic selection marker was removed using the Cre-LoxP system to minimize any possible side-effects for animals. The resulting yeast strain can be maintained in rich culture media and stably express mammalian myostatin for two years. Oral administration of the recombinant yeast was able to induce immune response to myostatin and modulated the body weight of mice.
  
  
  CONCLUSIONS
  Establishment of such yeast strain is a step further toward transformation of yeast cells into edible vaccine to improve meat production in farm animals and treat human muscle-wasting diseases in the future.
authors.affiliation: College of Animal Science & Technology, Shaan'xi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, YangLing, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Sun
authors.forename: Ying
authors.initials: Y
authors.lastname: Xin
authors.forename: Lixia
authors.initials: L
authors.lastname: Ma
authors.forename: Youyou
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Kun
authors.initials: K
authors.lastname: Xu
authors.forename: Chonghua
authors.initials: C
authors.lastname: Ren
authors.forename: Cunfang
authors.initials: C
authors.lastname: Zhang
authors.forename: Zhilong
authors.initials: Z
authors.lastname: Chen
authors.forename: Hanjiang
authors.initials: H
authors.lastname: Yang
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002875:Chromosomes / Q000378:metabolism; D019426:Integrases / Q000235:genetics; D008297:Male; D051379:Mice; D055435:Myostatin / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D055435:Myostatin; D011994:Recombinant Proteins; D014614:Vaccines, Synthetic; C045073:Cre recombinase; D019426:Integrases