title: Dictyostelium discoideum as an expression host for the circumsporozoite protein of Plasmodium falciparum.
abstract: We have used the cellular slime mold, Dictyostelium discoideum (Dd), to express the Plasmodium falciparum circumsporozoite protein (CS), a potential component of a subunit vaccine against malaria. This was accomplished via an expression vector based on the discoidin I-encoding gene promoter, in which we linked a sequence coding for a Dd leader peptide to the almost complete CS coding region (pEDII-CS). CS production at both the mRNA and protein levels is induced by starving cells in a simple phosphate buffer. Variation in pH or cell density does not seem to influence CS synthesis. CS-producing cells can be grown either on their normal substrate, bacteria, or on a semi-synthetic media, without affecting CS accumulation level. The CS produced in Dd seems similar to the natural parasite protein as judged by its size and epitope recognition by a panel of monoclonal antibodies. We constructed a second expression vector in which the CS is under the control of a Dd ras promoter. CS accumulation can then be induced by external addition of cAMP. Such a tightly regulated promoter may allow expression of proteins potentially toxic to the cell. Thus, Dd could be a useful eukaryotic system to produce recombinant proteins, in particular from human or animal parasites like P. falciparum.
authors.affiliation: Institute of Biochemistry, University of Lausanne, Epalinges, Switzerland.
authors.forename: N
authors.initials: N
authors.lastname: Fasel
authors.forename: C
authors.initials: C
authors.lastname: Begdadi-Rais
authors.forename: M
authors.initials: M
authors.lastname: Bernard
authors.forename: C
authors.initials: C
authors.lastname: Bron
authors.forename: G
authors.initials: G
authors.lastname: Corradin
authors.forename: C D
authors.initials: CD
authors.lastname: Reymond
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics*; D015153:Blotting, Western; D003001:Cloning, Molecular; D004023:Dictyostelium / Q000235:genetics*; D000070821:Discoidins; D005656:Fungal Proteins / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D011905:Genes, ras / Q000235:genetics; D037102:Lectins; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D000953:Antigens, Protozoan; D000070821:Discoidins; D005656:Fungal Proteins; D037102:Lectins; D015800:Protozoan Proteins; D011994:Recombinant Proteins; C041595:circumsporozoite protein, Protozoan