Characterization of kinetoplast DNA minicircles in Trypanosoma rangeli.

Kinetoplast DNA, the mitochondrial DNA of kinetoplastid protozoans, is a network of interlocked minicircles and maxicircles. We analyzed the sequence organization of minicircle DNAs in the El Tocuyo strain and the San Augustin clone B6 of Trypanosoma rangeli. The frequencies of different minicircle types, as defined by the number of 136-bp conserved regions (CRs), are different in the two strains. About half of the 1.7-kb T. rangeli El Tocuyo minicircles have 1 CR and most of the others have 2. In contrast, most of the 1.6-kb T. rangeli San Augustin minicircles have 2 CRs, while some have four. The CR contains a replication origin at one end and is conserved both within and between the two strains. Comparisons of the T. rangeli El Tocuyo and T. rangeli San Augustin minicircle CRs with minicircle CRs of other kinetoplastid species reveal that they are most similar to those of Trypanosoma cruzi.