Trypanosoma cruzi: a putative vacuolar ATP synthase subunit and a CAAX prenyl protease-encoding gene, as examples of gene identification in genome projects.

An international genome program has been initiated to increase the knowledge about the Trypanosoma cruzi genome and thereby find effective tools to treat Chagas' disease. We here report the molecular characterization of two novel genes found in the course of this project. Two of the open reading frames (ORF) identified in the sequencing of the third smallest chromosome of the CL Brener strain of T. cruzi were selected for further molecular characterization due to their similarity to genes with interesting functions in other organisms and their potential as targets to combat the parasite. The first ORF (402 bp) showed homology to a 14-kDa vacuolar ATP synthase subunit F from a variety of organisms, such as yeast, rat, bovine, human, and a number of prokaryotes. The second ORF (1188 bp) resembled a CAAX prenyl protease-encoding gene, identified in different organisms, including Homo sapiens, Saccharomyces cerevisiae, and Arabidopsis thaliana, as well as several prokaryotes. RT-PCR from T. cruzi total epimastigote RNA allowed us to isolate the complete transcripts of these genes. Furthermore, screening of an available normalized cDNA library derived from the same stage of the parasite confirmed that both genes are expressed at least in the epimastigote stage of T. cruzi. Comparison of the putative T. cruzi proteins to their counterparts in other organisms revealed significant protein sequence conservation over large evolutionary distances. Computer analysis revealed the presence of several motifs in both proteins, possibly related to the regulation and localization of these proteins in the parasite.