DEEP DESCRIPTION OF MITOCHONDRIAL GUIDE RNA REPERTOIRES IN THE SIX MAIN LINEAGES OF TRYPANOSOMA CRUZI

RUSMAN, F; RAGONE, PG; TOMASINI, N; ACUÑA, L; FLORIDIA-YAPUR, N; DIOSQUE, P

Salta

Congreso; Joint LV Annual SAIB Meeting and XIV PABMB Congress; 2019

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The kinetoplastic (mitochondrial) DNA of Trypanosoma cruzi consists in two types of molecules: maxicircles and minicircles. Maxicircles encode typical mitochondrial products (rRNA and respiratory chain subunits), although some of the protein coding genes are encrypted. To generate functional mRNAs, it is required an intricate process of RNA editing that involves the insertion and elimination of uridine residues at specific messenger sites. Genetic information for editing is provided by guide RNAs (gRNAs) encoded by minicircles. Unfortunately, mRNA edition and gRNA repertoires are mostly unknown in T.cruzi. In the present work, we have inferred gRNAs on deep-sequenced minicircle hypervariable regions (mHVRs) and rebuilt edition cascades for nine T. cruzi strains belonging to the six main lineages (TcI-TcVI). A total of 6,743,029 gRNAs were detected. Inferred gRNAs were clustered according to sequence similarity to constitute gRNA classes. Results showed an extreme diversity of gRNA classes, highly frequent minicircles that apparently do not code gRNAs and very divergent gRNA repertoires among lineages and within some lineages. In addition, we observed variable gRNA class redundancy (different gRNA classes that edits the same mRNA region) among strains. It was also observed that some strains have upon four times more gRNA classes than others. In addition, we failed to rebuild complete cascades for components of the respiratory complex I in several strains. Finally, we observed that gRNA classes from different strains may potentially edit mRNAs from other lineages in the same way as they edit their self mRNAs. This is a requisite for suitability of biparental inheritance of minicircles in hybrids, a recently proposed hypothesis in T. cruzi. Different evolutionary mechanisms and biological process are discussed in order to explain differences among strains and lineages.