Kinetoplast DNA, the mitochondrial DNA of trypanosomatids, is a remarkable DNA structure that contains, in the species Crithidia fasciculata, 5000 topologically linked duplex DNA minicircles. Their replication initiates at two conserved sequences, a dodecamer, known as the universal minicircle sequence (UMS), and a hexamer, which are located at the replication origins of the minicircle L and H ...

It is well known that several antitrypanosomatid drugs accumulate in the parasite's mitochondrion, where they often bind to the organellar DNA, the kinetoplast. To what extent this property relates to the mode of action of these compounds has remained largely unquantified. Here we show that single point mutations that remove the dependence of laboratory strains of the sleeping sickness parasite...

Guide RNAs (gRNAs) for the editing of sites 1-8 of COIII mRNA and an "unexpected" partially edited COIII mRNA are encoded in the variable regions of specific kinetoplast DNA minicircles. The gRNAs can form 37 and 44 nucleotide perfect hybrids (allowing for G-U base pairs) with edited mRNAs. The gRNAs were detected on Northern blots and shown to have unique 5' ends situated close to the beginnin...

Kinetoplastid parasites cause lethal diseases in humans and animals. The kinetoplast itself contains the mitochondrial genome, comprising a huge, complex DNA network that is also an important drug target. Isometamidium, for example, is a key veterinary drug that accumulates in the kinetoplast in African trypanosomes. Kinetoplast independence and isometamidium resistance are observed where certa...

Kinetoplastid protozoa such as trypanosomes and Leishmania are important because they cause human disease. These parasites are named after one of their most unusual features, a mitochondrial DNA known as kinetoplast DNA (kDNA). Unlike all other DNA in nature, kDNA comprises a giant network of interlocked DNA rings with a topology resembling that of medieval chain mail. The replication of the kD...

Kinetoplast DNA (kDNA), a unique mitochondrial structure common to trypanosomatid parasites, contains thousands of DNA minicircles that are densely packed and can be topologically linked into a chain mail-like network. Experimental data indicate that every minicircle in the network is, on average, singly linked to three other minicircles (i.e., has mean valence 3) before replication and to six ...

Kinetoplast DNA is a network of interlocked minicircles and maxicircles. In situ hybridization, using probes detected by digital fluorescence microscopy, has clarified the in vivo structure and replication mechanism of the network. The probe recognizes only nicked minicircles. Hybridization reveals prereplication kinetoplasts (with closed minicircles), donut-shaped replicating kinetoplasts (wit...

The structure of the kinetoplast DNA of Trypanosoma equiperdum has been studied and compared to the structure of the circular mitochondrial DNA extracted from a dyskinetoplastic strain of T. equiperdum. In T. equiperdum wild type, the kinetoplast DNA constitutes approximately 6% of the total cellular DNA and is composed of approximately 3,000 supercoiled minicircles of 6.4 x 10(5) daltons and a...

1. Replicating kinetoplast DNA networks from both Crithidia fasciculata and Leishmania tarentolae have an equilibrium density in ethidium bromide— CsQ which is less than that of covalently closed non-replicating networks. After a few hours of chase, these networks assume the covalently closed posi-. tion in the gradient. 2. Pulse-labeled minicircles isolated, from sonicated networks band in the...