title: Reliable high-throughput approach for screening of engineered constitutive promoters in the yeast Pichia pastoris.
abstract: OBJECTIVE
  To develop a reliable and sensitive high-throughput approach for the screening of engineered constitutive promoters in the yeast Pichia pastoris.
  
  
  RESULTS
  The yeast-enhanced green fluorescent protein (yEGFP) was used as the reporter to monitor the promoter strength. After eliminating the interfering components (yeast extract and tryptone) with fluorescence signal from the medium, a high-throughput screening approach was established and optimized to obtain a low standard deviation of cell density (6.9%) and fluorescence (7.4%) in 48-deep-well microplates. Then, 300 clones containing GAP promoter (P(GAP)) variants were screened, exhibiting a wide range in fluorescent intensity from about 8% to 218% of that obtained with P(GAP). Six representative clones with unique promoter sequence were picked for further characterization. A good correlation between yEGFP fluorescence in microplates and shake flasks was observed. Furthermore, the high correlation between fluorescence and transcript levels confirmed that expression was transcriptionally controlled.
  
  
  CONCLUSIONS
  We developed a reliable high-throughput screening approach that can be used to select engineered constitutive promoters of varying strengths.
  
  
  CONCLUSIONS
  This approach is expected to accelerate the selection of constitutive promoters in P. pastoris and can also be applied for the screening of other constitutive expression clones.
authors: State Key Laboratory of Bioreactor Engineering, East China University of Science & Technology, Shanghai, China.
authors: X
authors: X
authors: Qin
authors: J
authors: J
authors: Qian
authors: C
authors: C
authors: Xiao
authors: Y
authors: Y
authors: Zhuang
authors: S
authors: S
authors: Zhang
authors: J
authors: J
authors: Chu
mesh_terms: D015723:Gene Library; D049452:Green Fluorescent Proteins / Q000235:genetics; D016296:Mutagenesis; D010843:Pichia / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic
chemical_list: C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins