title: Expression of human vascular endothelial growth factor receptor Flt-1 extracellular domain 1-3 loop cDNA in Pichia pastoris, purification of the expressed product and detection of its biological activity.
abstract: OBJECTIVE
  To express human vascular endothelial growth factor receptor Flt-1 extracellular domain 1-3 loop cDNA in Pichia. pastroris, and to purify the expressed product and detect its biological activity.
  
  
  METHODS
  By inserting human Flt-1 (1-3 loop) cDNA coding 316 amino acid residues into Pichia pastoris expression vector pPIC9K containing AOX1 promoter and the sequences of alpha secreting signal peptides, a recombinant expression plasmid pPIC9K/Flt-1 (1-3) was constructed and transformed to yeast host strain GS115, then His+ Muts phenotype transformant was screened out and cultured in flasks, and Flt-1 (1-3) was expressed under the induction of 1% methanol.
  
  
  RESULTS
  SDS-PAGE showed that after being induced with 1% methanol for 4d, the expressed product existed in supernatant in the form of soluble molecule and contained 60% of total protein expressed. Western blot showed good antigenicity and specificity of expressed product. After being purified by CM-Sepharose FF and Sephacryl S-100 chromatography, the purity of the expressed product reached above 90%. Biological assay proved that the expressed product could bind to hVEGF165 and inhibit the proliferation of HUVEC stimulated by hVEGF165.
  
  
  CONCLUSIONS
  Human vascular endothelial growth factor receptor Flt-1 extracellular domain 1-3 loop was successfully expressed. The study lays a foundation for further application of the expressed product in the treatment of vasoformation related diseases, such as tumor and diabetic retinopathy.
authors.affiliation: Institute of Molecular Immunology, First Military Medical University, Guangzhou 510515, China.
authors.forename: L
authors.initials: L
authors.lastname: Ma
authors.forename: X N
authors.initials: XN
authors.lastname: Wang
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Zhang
authors.forename: X M
authors.initials: XM
authors.lastname: Zhou
authors.forename: G F
authors.initials: GF
authors.lastname: Zeng
authors.forename: A J
authors.initials: AJ
authors.lastname: Chen
mesh_terms: D001483:Base Sequence; D015153:Blotting, Western; D002478:Cells, Cultured; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D010641:Phenotype; D010843:Pichia / Q000235:genetics*; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D040281:Vascular Endothelial Growth Factor Receptor-1
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D020794:Receptor Protein-Tyrosine Kinases; D040281:Vascular Endothelial Growth Factor Receptor-1