title: Proteomic analysis of Toxoplasma gondii KI-1 tachyzoites.
abstract: We studied on the proteomic characteristics of Toxoplasma gondii KI-1 tachyzoites which were originally isolated from a Korean patient, and compared with those of the well-known virulent RH strain using 2-dimensional electrophoresis (2-DE), mass spectrometry, and quantitative real-time PCR. Two-dimensional separation of the total proteins isolated from KI-1 tachyzoites revealed up to 150 spots, of which 121 were consistent with those of RH tachyzoites. Of the remaining 29 spots, 14 showed greater than 5-fold difference in density between the KI-1 and RH tachyzoites at a pH of 5.0-8.0. Among the 14 spots, 5 from the KI-1 isolate and 7 from the RH strain were identified using MALDI-TOF mass spectrometry and database searches. The spots from the KI-1 tachyzoites were dense granule proteins (GRA 2, 3, 6, and 7), hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGRPTase), and uracil phosphoribosyltransferase (UPRTase). The spots from the RH strain were surface antigen 1 (SAG 1), L-lactate dehydrogenase (LDH), actin, chorismate synthase, peroximal catalase, hexokinase, bifunctional dihydrofolate reductase-thymidylate synthase (DHTR-TS), and nucleoside-triphosphatases (NTPases). Quantitative real-time PCR supported our mass spectrometric results by showing the elevated expression of the genes encoding GRA 2, 3, and 6 and UPRTase in the KI-1 tachyzoites and those encoding GRA 7, SAG 1, NTPase, and chorismate synthase in the RH tachyzoites. These observations demonstrate that the protein compositions of KI-1 and RH tachyzoites are similar but differential protein expression is involved in virulence.
authors.affiliation: Department of Ophthalmology, Chungnam National University School of Medicine, Daejeon 301-747, Korea.
authors.forename: Si-Hwan
authors.initials: SH
authors.lastname: Choi
authors.forename: Tae Yun
authors.initials: TY
authors.lastname: Kim
authors.forename: Sung Goo
authors.initials: SG
authors.lastname: Park
authors.forename: Guang-Ho
authors.initials: GH
authors.lastname: Cha
authors.forename: Dae-Whan
authors.initials: DW
authors.lastname: Shin
authors.forename: Jong-Yil
authors.initials: JY
authors.lastname: Chai
authors.forename: Young-Ha
authors.initials: YH
authors.lastname: Lee
mesh_terms: D015180:Electrophoresis, Gel, Two-Dimensional; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008969:Molecular Sequence Data; D040901:Proteomics; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D014122:Toxoplasma / Q000737:chemistry / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D014123:Toxoplasmosis / Q000469:parasitology
chemical_list: D015800:Protozoan Proteins