title: [Expression of truncated fragment of human OPG in CHO-DHFR- cells and its bioactivity characterization].
abstract: OBJECTIVE
  To obtain high level expression of recombinant human truncated osteoprotegerin (TOPG) with higher bioactivity in CHO-DHFR(-) cells.
  
  
  METHODS
  The recombinant vector pcDNA3.1/DHFR-TOPG was constructed and transfected into CHO-DHFR(-) cells by the directions of LipofectAMINE 2000 for stable expression. The stable expression cell strains were screened by selective medium IMDM with 50 mL/L FCS, then serially passed in methotraxate (MTX) for gene amplification. The expression were analyzed by ELISA and RT-PCR. At last, the bioactivity analysis was performed in vitro.
  
  
  RESULTS
  The expression level of recombinant truncated human OPG was up to 6 mg/L x 72 h, and it had significant suppression effect on the formation of OLC (P<0.05).
  
  
  CONCLUSIONS
  Recombinant truncated human OPG has high expression and bioactivity. The results make it possible for further studying and clinical implying of OPG.
authors.affiliation: Key Laboratory of Hormones & Development of Ministry of Health, Metabolic Disease Hospital and Endocrinology Institute of Tianjin Medical University, Tianjin 300070, China. kanbh606@sohu.com
authors.forename: Bo-hong
authors.initials: BH
authors.lastname: Kang
authors.forename: Xiao-yi
authors.initials: XY
authors.lastname: Zang
authors.forename: Lan-ying
authors.initials: LY
authors.lastname: Li
authors.forename: Kong-yin
authors.initials: KY
authors.lastname: Zhao
mesh_terms: D000818:Animals; D016466:CHO Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D051379:Mice; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects; D053244:Osteoprotegerin / Q000737:chemistry*; D010446:Peptide Fragments / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013762:Tetrahydrofolate Dehydrogenase / Q000172:deficiency*
chemical_list: D018076:DNA, Complementary; D053244:Osteoprotegerin; D010446:Peptide Fragments; D012333:RNA, Messenger; D013762:Tetrahydrofolate Dehydrogenase