title: [Soluble expression, purification and bioactivity of hemangiopoietin protein].
abstract: OBJECTIVE
  To prepare a soluble hemangiopoietin(HAPO) protein and to construct pET22b(+) expression vector, to obtain pure recombinant HAPO protein and to measure its bioactivity.
  
  
  METHODS
  HAPO cDNA was amplified using RT-PCR method from a commercial human fetal liver cDNA library. The resulting product was cloned into pET22b(+) vector and transformed into E.coli BL21(DE3). The recombinant protein was isolated and purified by Ni(2+)-NTA chelating resin and the chromatographies of SP Sepharose FF. The adhesion of human umbilical vein endothelial cells (HUVEC) were measured by adhesion assay.
  
  
  RESULTS
  HAPO gene with a reading frame of 897 bp was successfully cloned from human fetal liver cDNA library, the expressed pET22b(+)-HAPO fused protein existed in a soluble form, with the yield above 10% total bacterial protein and its purity achieved above 80%. The activity assay showed that the treatment of HAPO enhanced total adherence of HUVEC in a concentration-dependent manner.
  
  
  CONCLUSIONS
  HAPO protein can be expressed in a soluble form. HAPO may facilitate the homing of hematopoietic stem/progenitor cells in vitro.
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Hospital of Blood Diseases, CAMS and PUMC, Tianjin 300020, China. libin_fdm@yahoo.com.cn
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.forename: Xiao-jing
authors.initials: XJ
authors.lastname: Wang
authors.forename: Yong-jun
authors.initials: YJ
authors.lastname: Liu
authors.forename: Zhong-chao
authors.initials: ZC
authors.lastname: Han
authors.forename: Tian-xiang
authors.initials: TX
authors.lastname: Pang
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D016133:Polymerase Chain Reaction; D011509:Proteoglycans / Q000096:biosynthesis* / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D012995:Solubility; D000099158:Proteoglycan 4
chemical_list: D011509:Proteoglycans; C419197:PRG4 protein, human; D000099158:Proteoglycan 4