title: Amastin mRNA abundance in Trypanosoma cruzi is controlled by a 3'-untranslated region position-dependent cis-element and an untranslated region-binding protein.
abstract: The genome of Trypanosoma cruzi contains tandem arrays of alternating genes encoding amastin and tuzin. Amastin is a surface glycoprotein abundantly expressed on the intracellular mammalian amastigote form of the protozoan parasite, and tuzin is a G-like protein. We demonstrated previously that the amastin-tuzin gene cluster is polycistronically transcribed to an equal extent in all parasite life cycle stages. The steady state level of amastin mRNA, however, is 68-fold more abundant in amastigotes than in epimastigotes. Here we show that the half-life of amastin mRNA is 7 times longer in amastigotes than in epimastigotes. Linker replacement experiments demonstrate that the middle one-third of the 630-nucleotide 3'-untranslated region (UTR) is responsible for the amastin mRNA up-regulation. This positive effect is dependent on the distance of the 3'-UTR segment from the stop codon and the polyadenylation site as well as on its orientation. A protein or protein complex more abundant in amastigotes than in epimastigotes binds to this minimally defined 3'-UTR segment and may be involved in its regulatory function.
authors.affiliation: Department of Biochemistry, University of Iowa, Iowa City 52242, USA.
authors.forename: B C
authors.initials: BC
authors.lastname: Coughlin
authors.forename: S M
authors.initials: SM
authors.lastname: Teixeira
authors.forename: L V
authors.initials: LV
authors.lastname: Kirchhoff
authors.forename: J E
authors.initials: JE
authors.lastname: Donelson
mesh_terms: D020413:3' Untranslated Regions / Q000502:physiology*; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003609:Dactinomycin / Q000494:pharmacology; D004742:Enhancer Elements, Genetic / Q000502:physiology*; D006207:Half-Life; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D015800:Protozoan Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D013816:Thermodynamics; D014349:Trypanosoma cruzi / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D020413:3' Untranslated Regions; D008562:Membrane Glycoproteins; D011500:Protein Synthesis Inhibitors; D015800:Protozoan Proteins; D012333:RNA, Messenger; C088681:amastin protein, Trypanosoma cruzi; D003609:Dactinomycin