During their life cycle Trypanosoma cruzi parasites multiply as extracellular epimastigotes in the reduviid bug and as intracellular amastigotes in the mammalian host. The genome of T. cruzi contains a cluster of tandemly arrayed, alternating genes encoding proteins called amastin and tuzin. Amastin is an abundant protein on the surface of amastigotes and its mRNA constitutes 1-2% of the total mRNA at this stage. Tuzin is a less abundant protein of unknown cellular location. The amastin/tuzin gene cluster is constitutively transcribed in epimastigotes and amastigotes, but the steady state level of amastin mRNA is 85-fold higher in amastigotes than in epimastigotes. The 3' untranslated region of the amastin gene is involved in this differential expression. Tuzin mRNA levels do not differ substantively in the two life stages. We propose to elucidate the posttranscriptional events that enhance expression of the amastin genes in amastigotes and maintain a relatively constant level of expression of the tuzin genes in both amastigotes and epimastigotes. A combination of linker replacements and protein binding assays will be used in these studies. In addition, we plan to utilize the sequence of the amastin 3' untranslated region and downstream intergenic region to differentially express in amastigotes specific proteins that will be used to (i) develop a more sensitive detection assay for amastigotes in T. cruzi- infected animals, (ii) examine whether animals already infected with T. cruzi are less susceptible to challenge by T. cruzi than are uninfected animals, (iii) determine the cellular location of tuzin, and (iv) induce amastigotes to undergo programmed cell death. Finally, we will assess whether amastin and/or tuzin can serve a target antigens for an improved diagnostic test for T. cruzi infection.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI040591-04
Application #
6137206
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Program Officer
Fairfield, Alexandra
Project Start
1997-01-01
Project End
2001-12-31
Budget Start
2000-01-01
Budget End
2000-12-31
Support Year
4
Fiscal Year
2000
Total Cost
$191,045
Indirect Cost
Name
University of Iowa
Department
Biochemistry
Type
Schools of Medicine
DUNS #
062761671
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Lazaryan, Aleksandr; Lobashevsky, Elena; Mulenga, Joseph et al. (2006) Human leukocyte antigen B58 supertype and human immunodeficiency virus type 1 infection in native Africans. J Virol 80:6056-60
Barrett, Brian; LaCount, Douglas J; Donelson, John E (2004) Trypanosoma brucei: a first-generation CRE-loxP site-specific recombination system. Exp Parasitol 106:37-44
DaRocha, Wanderson D; Otsu, Keiko; Teixeira, Santuza M R et al. (2004) Tests of cytoplasmic RNA interference (RNAi) and construction of a tetracycline-inducible T7 promoter system in Trypanosoma cruzi. Mol Biochem Parasitol 133:175-86
Yao, Chaoqun; Leidal, Kevin G; Brittingham, Andrew et al. (2002) Biosynthesis of the major surface protease GP63 of Leishmania chagasi. Mol Biochem Parasitol 121:119-28
LaCount, Douglas J; Barrett, Brian; Donelson, John E (2002) Trypanosoma brucei FLA1 is required for flagellum attachment and cytokinesis. J Biol Chem 277:17580-8
LaCount, D J; El-Sayed, N M; Kaul, S et al. (2001) Analysis of a donor gene region for a variant surface glycoprotein and its expression site in African trypanosomes. Nucleic Acids Res 29:2012-9
Recinos, R F; Kirchhoff, L V; Donelson, J E (2001) Cell cycle expression of histone genes in Trypanosoma cruzi. Mol Biochem Parasitol 113:215-22
Tang, J; Myracle, A D; Allen, S et al. (2001) Novel alleles at the lymphotoxin alpha (LTalpha) locus mark extended HLA haplotypes in native Africans. Hum Immunol 62:269-78
Coughlin, B C; Teixeira, S M; Kirchhoff, L V et al. (2000) Amastin mRNA abundance in Trypanosoma cruzi is controlled by a 3'-untranslated region position-dependent cis-element and an untranslated region-binding protein. J Biol Chem 275:12051-60
Grandgenett, P M; Coughlin, B C; Kirchhoff, L V et al. (2000) Differential expression of GP63 genes in Trypanosoma cruzi. Mol Biochem Parasitol 110:409-15

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