title: Molecular cloning and expression of Cucumisin (Cuc m 1), a subtilisin-like protease of Cucumis melo in Escherichia coli.
abstract: BACKGROUND
  Oral allergy syndrome resulted from plant-derived foods is frequent among adults. Allergy to melon (cucumis melo) is one of the most frequent fruit allergies in Iran. Three different major allergens have been found in Cucumis melo that Cuc m 1 (cucumisin) has been identified as the major allergen of melon. Cucumisin is an alkaline serine protease that it is found as a 78kDa protein in precursor form. The aim of this study was production of recombinant Cuc m 1 in Escherichia coli (E. coli) cells and characterization of its allergenicity property.
  
  
  METHODS
  Production of recombinant Cuc m 1 was carried out by cDNA cloning technique into the pET32b(+) vector using specific primers designed based on cucumisin nucleotide sequence available in Genebank database, cucumisin encoding gene and directional cloning method. Cloned plasmid into E. coli TOP10 was transformed into E. coli BL21 and expression of the protein was induced by IPTG. The recombinant protein was purified via Ni-NTA affinity chromatography using histidine tag in recombinant protein. IgE binding of this protein was assessed by IgE-immunoblotting, ELISA and inhibition ELISA.
  
  
  RESULTS
  The directional cloning was resulted in expression of a fusion Cuc m 1. Immunoblotting with sera of patients allergic to melon showed strong reactivity with purified protein band. Inhibition assays demonstrated that purified rCuc m 1 could be the same with natural form of Cuc m 1 in total extract.
  
  
  CONCLUSIONS
  In the present study, we have provided a functional recombinant cucumisin allergen, rCuc m 1 with 86kDa, which may be used as a standard allergen for clinical diagnosis and study of allergy to melon.
authors.affiliation: Bu-Ali Research Institute, Immunology Research Center, Iran.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Sankian
authors.forename: Farideh
authors.initials: F
authors.lastname: Talebi
authors.forename: Maliheh
authors.initials: M
authors.lastname: Moghadam
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Vahedi
authors.forename: Farahzad Jabbari
authors.initials: FJ
authors.lastname: Azad
authors.forename: Abol-Reza
authors.initials: AR
authors.lastname: Varasteh
mesh_terms: D003001:Cloning, Molecular; D028463:Cucumis melo / Q000201:enzymology* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D005512:Food Hypersensitivity / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D012697:Serine Endopeptidases / Q000235:genetics* / Q000378:metabolism*; D013381:Subtilisins / Q000378:metabolism
chemical_list: D007073:Immunoglobulin E; D012697:Serine Endopeptidases; D013381:Subtilisins; C041541:cucumisin