RESUMO
BACKGROUND: The Trypanosomatidae family possesses one of the most unusual DNAs found in nature: the kinetoplast genome. It consists of a few dozen maxicircles that encode for some subunits of mitochondrial enzymes and rRNAs in a cryptic pattern and thousands of minicircles that encode for the guide RNAs (gRNAs), all catenated and constituting a dense network. The complexity of kinetoplast genome based on its intricate DNA structure is well known; however, only a small number of proteins associated with kinetoplast DNA (kDNA) have been described, and the majority are related with the replication process. METHODS: We describe the protein profile obtained using formaldehyde as a cross-linking agent to obtain the kinetoplast DNA-protein complex, and Southwestern assay to identify the kDNA binding proteins present in the complex. RESULTS: We identified seven proteins eluted from the kDNA complex fixed by formaldehyde. Polyclonal antiserum developed against the kDNA-protein complex recognized only four proteins in crude extracts of epimastigote stage, suggesting immunogenic differences among these proteins and/or their availability in the kinetoplast genome. Southwestern assay using minicircle fragments showed nine kDNA binding proteins in crude extracts of Trypanosoma cruzi epimastigote. CONCLUSIONS: We describe several proteins associated with the kDNA. Some could be involved in the essential process for parasite life and also could be a good target for drug or vaccine development. The results contribute to understanding the organization of the kinetoplast genome.
