Genomic organization of Trypanosoma cruzi tRNA genes

An often neglected class of genes in large-scale genome analyses is the non-protein-coding genes. In particular, due to the incompleteness of the genome assembly, it had not been possible to determine the genomic organization of the tRNA genes in Trypanosoma cruzi --a eukaryotic unicellular pathogen causative of disabling human Chagas disease--. Here, we analyzed the genic content and distribution of tRNA genes in the nuclear genome of different strains compared with the genome organization of other related trypanosomatids. We found synteny in most of the tDNAs clusters between T. cruzi and Trypanosoma brucei, demonstrating the importance of the genome location of these Pol III transcribed genes. The vast majority of the isoacceptor species are encoded by two genes, except for tDNASeC, which is present as a tandem of 11 copies in the core compartment, associated with well-positioned nucleosomes. Finally, we describe a group of tRNA genes located at chromatin folding domain boundaries, possibly acting as chromatin insulators in T. cruzi.