Genes for cysteine proteinases from Trypanosoma rangeli

PCR amplification of genomic DNA from the American trypanosome, Trypanosoma rangeli, using as primers oligonucleotides derived from the gene of cruzipain, the major cysteine proteinase (CP) from Trypanosoma cruzi, allowed the production of a probe which was used to obtain three clones encoding a CP with 70% overall identity with cruzipain. The genes are organized in tandem, with a monomere size of approximately 2 kbp, located on two chromosomes which, in some parasite isolates, have a high molecular mass (higher than 5.7 Mbp), and in others are much smaller (about 500 kbp). The low expression of this CP at the protein level correlates well with the low level of specific mRNA found in Northern blots.