Parasitic protozoans of the family Trypanosomatidae cause disease on a world wide scale in a variety of verterbrate, inverterbrate, and plant species. Trypanosoma cruzi, the etiologic agent of Chagas' disease, is a member of this family. Chagas disease is endemic throughout much of South and Central America afflicting over twenty million people. While the disease is essentially absent from North America, T. cruzi is indigenous to portions of the southwestern United States. T. cruzi has a complex life cycle involving obligatory developmental stages within the insect vector and the mammalian host. These stages include the non-dividing trypomastigotes (found in both the insect vector and the blood stream of the host) as well as the dividing epimastigotes (exclusively in the insect vector) and intracellular amastigotes. The only forms capable of invading vertebrate cells are the non-dividing trypomastigotes. An understanding of the genetic mechanisms involved in the control of the developmental cycle will undoubtedly add significantly to our understanding of the biology of this class of protozoan. To elucidate these genetic mechanisms we have chosen to study the expression of the polyubiquitin (PUB) and ubiquitin-fusion (FUS) genes of T. cruzi. These genes were chosen because many of the factors known to regulate their expression in other eukaryotic organisms are encountered by the parasite either as a consequence of their developmental life cycle or alterations in the growth conditions experienced during transmission. Our previous work has demonstrated that these genes are deferentially regulated in response to environmental stress or altered growth conditions. Further we have shown that at least two PUB genes are preceded by DNA sequences containing homologies to the heat shock elements found in other organisms. Before gene regulation can be understood at the molecular level, promoters and regulatory sequences must first be identified and characterized. Promoters have not been identified for any protein coding genes in trypanosomes therefore, we shall initially focus on the identification and characterization of the primary transcription products of the PUB and FUS genes. By mapping the 5' termini of the primary transcripts, regions containing potential promoters and/or regulatory regions will be identified. These regions will be further analyzed based on their protein binding characteristics.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI026578-01
Application #
3140351
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Project Start
1988-07-01
Project End
1991-06-30
Budget Start
1988-07-01
Budget End
1989-06-30
Support Year
1
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of Tennessee Health Science Center
Department
Type
Schools of Medicine
DUNS #
941884009
City
Memphis
State
TN
Country
United States
Zip Code
38163
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Hummel, H S; Gillespie, R D; Swindle, J (2000) Mutational analysis of 3' splice site selection during trans-splicing. J Biol Chem 275:35522-31
Chung, S H; Swindle, J (1997) Trypanosoma cruzi: circularization of linear DNA fragments prior to integration during generation of stable transformants. Mol Biochem Parasitol 89:321-5
Ajioka, J; Swindle, J (1996) The calmodulin-ubiquitin (CUB) genes of Trypanosoma cruzi are essential for parasite viability. Mol Biochem Parasitol 78:217-25
Chung, S H; Gillespie, R D; Swindle, J (1994) Analyzing expression of the calmodulin and ubiquitin-fusion genes of Trypanosoma cruzi using simultaneous, independent dual gene replacements. Mol Biochem Parasitol 63:95-107
Ajioka, J; Swindle, J (1993) The calmodulin-ubiquitin associated genes of Trypanosoma cruzi: their identification and transcription. Mol Biochem Parasitol 57:127-36
Hariharan, S; Ajioka, J; Swindle, J (1993) Stable transformation of Trypanosoma cruzi: inactivation of the PUB12.5 polyubiquitin gene by targeted gene disruption. Mol Biochem Parasitol 57:15-30
Gillespie, R D; Ajioka, J; Swindle, J (1993) Using simultaneous, tandem gene replacements to study expression of the multicopy ubiquitin-fusion (FUS) gene family of Trypanosoma cruzi. Mol Biochem Parasitol 60:281-92
Chung, S H; Swindle, J (1990) Linkage of the calmodulin and ubiquitin loci in Trypanosoma cruzi. Nucleic Acids Res 18:4561-9