Mini-exon gene sequence polymorphism among Trypanosoma rangeli strains isolated from distinct geographical regions

Abstract

Trypanosoma rangeli can infect humans and the same domestic and wild animals and triatomine vectors infected by T. cruzi in Central and South America. This overlapping distribution complicates the epidemiology of Chagas disease because of the cross-reactivity between T. rangeli and T. cruzi antigens. We have studied T. rangeli strains isolated from different geographical regions using the mini-exon gene as a genetic marker. Two pairs of oligonucleotides directed to this gene were designed in order to detect specifically T. rangeli DNA by PCR assays. This assay was highly sensitive, able to amplify the target sequence using the equivalent DNA content of a single parasite as template, and demonstrated no cross-reactivity with T. cruzi DNA. T. rangeli SC-58 strain, isolated in southern Brazil, showed a distinct electrophoretic pattern from the other T. rangeli strains tested. Low stringency single specific primer-PCR (LSSP) assays were able to detect sequence polymorphisms at the mini-exon gene among T. rangeli strains. Sequence comparisons of this gene revealed that the SC-58 strain was genetically distinct from strains isolated in Central America and northern South America. In addition to insertion/deletion events, the presence of microsatellite repeats in the non-transcribed region of the gene contribute to the intra-species variability.

Molecular karyotype and chromosomal localization of genes encoding ß-tubulin, cysteine proteinase, hsp 70 and actin in Trypanosoma rangeli

“…Our results are in agreement with previous data based on DNA fingerprinting, RAPD and mini-exon gene sequences analysis that showed that T. rangeli populations from Southern Brazil are distinct from T. rangeli from Colombia, Venezuela and Honduras (Macedo et al 1993, Steindel et al 1994, Grisard et al 1999a, Stevens et al 1999.…”

“…A weak hybridization with this gene probe was observed in the compression zone of gels (above 1000 Kb) in T. rangeli SC 58, SC 61 and Pepita Gonzales strains, that may represent a small number of gene copies in a larger chromosome. This polymorphism observed among T. rangeli strains is in agreement with early reports from Macedo et al (1993) using DNA fingerprinting, Steindel et al (1994) using isoenzyme electrophoresis and RAPD, and Grisard et al (1999a) using the mini-exon gene sequence analysis.…”

Genetic diversity of Colombian sylvatic Trypanosoma cruzi isolates revealed by the ribosomal DNA

“…It is interesting that two groups of T. rangeli were previously described by Vallejo et al (1994) when amplifying the conserved region of minicircle molecules. Polymorphism among strains from distinct geografical origin was also evidenced using the mini-exon primary DNA sequence and low stringency single specific primer PCR (LSSP-PCR) profiles (Grisard et al 1999). Therefore, as different markers are examined the finding of polymorphism among T. rangeli isolates is becoming a common observation.…”

Detection of Trypanosoma cruzi and Trypanosoma rangeli infection in triatomine vectors by amplification of the histone H2A/SIRE and the sno-RNA-C11 genes

“…However, current PCR assays used for mixed infection detection show some disadvantages such as the amplification of bands of similar size both in T. cruzi and T. rangeli 27,28 , the amplification of polymorphic fragments 11,19 , and bias to T. cruzi in the case of mixed T. cruzi and T. rangeli infection 9,33,36 . Therefore, it is necessary to develop new techniques as better options to specifically identify each of these parasite species in mixed infections.…”