title: Trypanosoma cruzi: suppression of tuzin gene expression by its 5'-UTR and spliced leader addition site.
abstract: Teixeira, S. M. R., Kirchhoff, L. V., and Donelson, J. E. 1999. Trypanosoma cruzi: Suppression of tuzin gene expression by its 5'-UTR and spliced leader addition site. Experimental Parasitology 93, 143-151. The genome of the protozoan parasite Trypanosoma cruzi contains a tandemly repeated array of two alternating genes, one encoding amastin and the other encoding tuzin. Amastin is an abundant amastigote surface protein, whereas tuzin is thought to be a rare protein whose location and function are unknown. The 137-nucleotide 5' untranslated region (5'-UTR) of the tuzin mRNA has a 22-codon open translation reading frame containing 3 methionine codons followed by a stop codon that overlaps the methionine start codon of the tuzin coding region. A fragment containing the tuzin 5'-UTR and upstream intergenic region was placed in front of a luciferase reporter gene in a plasmid for transient transfection assays of luciferase activity. By mutating the three upstream ATGs in the tuzin 5'-UTR and replacing the tuzin spliced leader (SL) acceptor site with that of the amastin gene, we found that the 22-codon reading frame and the tuzin SL acceptor site combine to substantially reduce expression of the luciferase gene. These results indicate that expression of the multicopy tuzin gene is posttranscriptionally suppressed by both inefficient RNA processing and poor translation initiation, resulting in a low level of tuzin.
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City 52242, USA.
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: D020121:5' Untranslated Regions / Q000502:physiology*; D000818:Animals; D015153:Blotting, Western; D014355:Chagas Disease / Q000276:immunology; D016384:Consensus Sequence; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D007106:Immune Sera / Q000276:immunology; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics; D005810:Multigene Family; D016366:Open Reading Frames / Q000235:genetics; D010957:Plasmids; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D015800:Protozoan Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000737:chemistry; D020038:RNA, Spliced Leader / Q000502:physiology*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D014162:Transfection; D014349:Trypanosoma cruzi / Q000235:genetics* / Q000378:metabolism
chemical_list: D020121:5' Untranslated Regions; D007106:Immune Sera; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; D012333:RNA, Messenger; D020038:RNA, Spliced Leader; D011994:Recombinant Proteins; C088681:amastin protein, Trypanosoma cruzi; C095638:tuzin protein, Trypanosoma cruzi; D008156:Luciferases