Overexpression of cruzipain, the major cysteine proteinase of Trypanosoma cruzi, is associated with enhanced metacyclogenesis

• Type: Article in International Scientific Journal
• Date: 1997

Authors

tomas, am (Author) ICBAS; miles, ma (Author) Other; kelly, jm (Author) Other

Journal

Title: European Journal of Biochemistry

Vol. 244

Pages: 596-603

ISSN: 0014-2956

Publisher: Blackwell

Indexing

ISI Web of Knowledge

Scopus - 58 Citations

Other information

Authenticus ID: P-007-7GD

Abstract (EN): Cruzipain, the major cysteine proteinase of Trypanosoma cruzi has been proposed as a target for chemotherapy against Chagas' disease. To investigate the role of cruzipain we transfected T. cruzi epimastigotes with a recombinant cosmid containing approximately 20 tandemly repeated cruzipain genes. Transformed cells had multiple episomal copies of the vector and exhibited considerable overexpression of cruzipain activity. The upregulation was maintained throughout the parasite life-cycle, and electrophoretic detection techniques indicated that overexpression was correlated with correctly processed enzyme. Immunoelectron microscopy demonstrated that cruzipain had the same developmentally regulated subcellular localisation in transformed and non-transformed cells. In the insect epimastigote form, the enzyme was restricted to vesicles of the endosomal/lysosomal system, whereas in the intracellular forms it was also readily detectable on the cell surface. Phenotypic analysis of the transformed parasites showed that they had an enhanced ability to undergo metacyclogenesis and suggested an association between overexpression of cruzipain and increased resistance to the cysteine proteinase inhibitor Cbz-Phe-Phe-CHN2 (where Cbz is benzoyloxycarbonyl). The increased resistance, however, was less than might be expected if cruzipain was the primary target of the inhibitor. Transgenic parasites did not exhibit increased infectivity.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8