Kinetoplast DNA minicircles of trypanosomatids encode for a protein product

The major constituent of the trypanosomal kinetoplast DNA network are several thousand duplex DNA minicircles whose biological function is still unknown. The coding capacity and expression of these DNA minicircles, was studied in the trypanosomatid Crithidia fasciculata. Kinetoplast DNA minicircle fragments inserted into bacterial plasmid vectors were expressed in the bacterial cell. Sera elicited in rabbits, by immunization with the translational products of kinetoplast DNA minicircles in E. coli, reacted specifically with Crithidia fasciculata cellular antigens. It is inferred that kinetoplast DNA minicircles contain long open reading frames of nucleotides which are expressed in the trypanosomatid cell.