Cloning and characterization of a gene coding for a protein (KAP) associated with the kinetoplast of epimastigotes and amastigotes of Trypanosoma cruzi.

We have cloned and characterized a gene of Trypanosoma cruzi which encodes a protein, KAP (kinetoplasts-associated protein), expressed in the kinetoplasts of epimastigotes and amastigotes, the replicative stages of the parasite, but not in kinetoplasts of trypomastigotes. The single-copy gene is transcribed into a 3900-nt polyadenylated mRNA. Its trans-splicing acceptor site is preceded by a run of 15 adenosine residues. An open reading frame of 1052 codons is followed by a 3′ untranslated region containing short sequences characteristic of rapidly degradable RNAs. The potential translation product of the KAP gene contains a central region composed of four blocks of repeats of a 9-amino-acid motif. Rabbit antibodies raised against three synthetic peptides containing KAP sequence recognized a 175-kDa protein in epimastigotes and amastigotes which appears by indirect immunofluorescence to be associated with their kinetoplasts. The antibodies do not recognize the kinetoplast of trypomastigotes. The amino terminus of KAP contains features compatible with mitochondrial topogenic sequences.