Díaz-Viraqué Florencia, Ehrlich Ricardo, Robello Carlos
Laboratorio de Interacciones Hospedero-Patógeno-UBM, Institut Pasteur de Montevideo, Montevideo, Uruguay.
Departamento de Bioquímica, Facultad de Ciencias, Universidad de la República; Institut Pasteur de Montevideo, Montevideo, Uruguay.
Genome Biol Evol. 2025 May 30;17(6). doi: 10.1093/gbe/evaf108.
A frequently overlooked category of genes in large-scale genome analyses is the nonprotein-coding genes. Specifically, the genomic organization of tRNA genes in Trypanosoma cruzi-a unicellular eukaryotic pathogen responsible for causing the debilitating human disease Chagas disease-has largely remained uncharted due to the previous incompleteness of the genome assembly. By utilizing advanced genomic techniques and improved assembly methods, the quality of genome assemblies has significantly improved, making these studies feasible. Here, we analyzed the genic content and distribution of tRNA genes in the nuclear genome of various 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, highlighting the significance of the genomic location of these Pol III-transcribed genes. A vast majority of the isoacceptor species are encoded by two genes, except for tDNASeC, which comprises 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, potentially acting as chromatin insulators in T. cruzi.
在大规模基因组分析中，一类经常被忽视的基因是非蛋白质编码基因。具体而言，克氏锥虫（一种导致人类患使人衰弱的恰加斯病的单细胞真核病原体）中tRNA基因的基因组组织，由于之前基因组组装的不完整性，在很大程度上仍未被探索。通过利用先进的基因组技术和改进的组装方法，基因组组装的质量有了显著提高，使得这些研究成为可能。在这里，我们分析了不同菌株核基因组中tRNA基因的基因含量和分布，并与其他相关锥虫的基因组组织进行了比较。我们发现克氏锥虫和布氏锥虫的大多数tDNA簇存在同线性，突出了这些由RNA聚合酶III转录的基因的基因组位置的重要性。除了tDNASeC外，绝大多数同功受体种类由两个基因编码，tDNASeC在与定位良好的核小体相关的核心区域由11个串联拷贝组成。最后，我们描述了一组位于染色质折叠域边界的tRNA基因，它们可能在克氏锥虫中充当染色质绝缘子。
