Characterization of microneme proteins of Toxoplasma gondii.
Three microneme proteins of Toxoplasma gondii have been characterized using 3 monoclonal antibodies and a recombinant protein specific antiserum. In all cases, apical labeling of tachyzoites and bradyzoites was observed by indirect immunofluorescence assay. Immunogold localization on ultrathin sections of bradyzoites or tachyzoites showed a specific labeling of micronemes. The following proteins were characterized using 2-dimensional gel electrophoresis and Western immunoblotting: Mic 1 (60 kDa, Pi 6.5), Mic 2 (120 kDa, Pi 5) and Mic 3 (90 kDa, Pi 6.75). The 90-kDa protein (Mic 3) is a heterodimer of two 38-kDa polypeptides (Pi 6.7 and 6.75 respectively) linked by disulfide bridges. Metabolic labeling and immunoprecipitation assays showed that at least one of the 38-kDa polypeptides was processed from a 40-kDa precursor. No processing was observed during the biosynthesis of the 120- and 60-kDa polypeptides.
Achbarou
A
A
Unité 42 INSERM, Villeneuve d'Ascq, France.
Mercereau-Puijalon
O
O
Autheman
J M
JM
Fortier
B
B
Camus
D
D
Dubremetz
J F
JF
D000818:Animals; D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan / Q000302:isolation & purification; D016253:Microscopy, Immunoelectron; D008970:Molecular Weight; D015388:Organelles / Q000276:immunology / Q000378:metabolism / Q000648:ultrastructure; D015800:Protozoan Proteins / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D014122:Toxoplasma / Q000276:immunology* / Q000378:metabolism / Q000648:ultrastructure
D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015800:Protozoan Proteins