title: Single argonaute protein from Toxoplasma gondii is involved in the double-stranded RNA induced gene silencing.
abstract: Here, we report the characterization of the argonaute protein from Toxoplasma gondii. This is the first report on the function of an argonaute protein with structural features overlapping between argonaute proteins of archaeal bacteria and eukaryotes. The full-length cDNA clone has an open reading frame of 1575 bp, which encodes a 524 amino acid protein with a calculated molecular weight of 58.5 kDa and an estimated isoelectric point of 9.4. This argonaute protein, called TgAgo, exhibits unique features: (i) TgAgo is smaller than reported argonaute proteins derived from higher eukaryotic organisms (i.e. Arabidopsis, human and nematodes) but has a similar size to those from archaeal bacteria (i.e. Pyrococcus furiosus and Archaeoglobus fulgidus); (ii) TgAgo contains a conserved PIWI domain and non-conserved PAZ domain; (iii) TgAgo is mainly localized in the cytoplasm; and (iv) despite its small size, TgAgo participates in the double-stranded RNA induced gene silencing. Using a transgenic parasite line, in which TgAgo expression is lowered, we showed that the expression of TgAgo is required for the double-stranded RNA induced gene silencing, RNA interference mechanism.
authors.affiliation: Chemistry and Biochemistry Department, University of Windsor, Windsor, Ont., Canada N9B 3P4.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Al Riyahi
authors.forename: Fatme
authors.initials: F
authors.lastname: Al-Anouti
authors.forename: Marwan
authors.initials: M
authors.lastname: Al-Rayes
authors.forename: Sirinart
authors.initials: S
authors.lastname: Ananvoranich
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D018076:DNA, Complementary / Q000235:genetics; D016054:DNA, Protozoan / Q000235:genetics; D020868:Gene Silencing; D017125:Genes, Protozoan; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D015800:Protozoan Proteins / Q000096:biosynthesis / Q000235:genetics*; D012330:RNA, Double-Stranded / Q000235:genetics; D016053:RNA, Protozoan / Q000235:genetics; D016415:Sequence Alignment; D014122:Toxoplasma / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D016054:DNA, Protozoan; D015800:Protozoan Proteins; D012330:RNA, Double-Stranded; D016053:RNA, Protozoan