Trypanosoma cruzi: structure and transcription of kinetoplast DNA maxicircles of cloned stocks.

Restriction endonuclease mapping of the Trypanosoma cruzi kinetoplast DNA maxicircle was performed in nine cloned stocks using maxicircle probes from T. brucei. Analysis of the maxicircle 13-15-kbp encoding region allowed cloned stocks to be divided into three groups: A, B, and C. Parasites from groups A and B had 3% sequence divergence while parasites from group C showed 16-17% sequence divergence with regard to parasites from groups A and B. Cross-hybridization experiments demonstrated that the 23-25-kbp maxicircle divergent region was similar in sequence in group A and B, but different in group C parasites. The high homology of the T. cruzi and T. brucei encoding regions allowed the use of T. brucei probes to detect T. cruzi transcripts, whose overall picture did not differ for parasites from any of the nine assayed clones.