Ricerc@Sapienza

Whole exome sequencing (WES) is currently the most practical approach for the investigation of coding variations in medical research. However, in several cases, it remains difficult to identify causative mutations and this could be due to different technical and biological reasons. Despite these limitations, exome experiments could provide other information that is generally filtered out, and that could at least partially explain negative results. The aim of this project is to analyse exome data focusing on biological information that is usually discarded and that could be helpful in the comprehension of molecular bases of genetic diseases: mitochondrial DNA and microRNAs variants. Mitochondria are eukaryotic semi-autonomous organelles of endosymbiotic origin and they constitute a dynamic network, which is intimately interconnected with other cell components: an intense crosstalk with the nucleus provides mitochondria with nuclear-encoded proteins as well as noncoding RNAs, which function as a guide molecules in RNA silencing required for mitochondrial homeostasis and function. Preliminary results suggest that at least a portion of miRNAs is efficiently captured by exome enrichment kits. Now we propose to evaluate the exome enrichment systems' capture efficiency of mitochondrial DNA sequences too. This analysis will be performed on a cohort of patients with different diseases and the results will be analyzed to improve our knowledge about the crosstalk between nuclear and mitochondrial genome and the role of these variants to explain the genetic variability. We will focus our attention on variants potentially altering nuclear-coded miRNAs' acting in the nucleus or in cytosol on genes encoding mitochondrial proteins. Finally, we will also analyze predicted nuclear-encoded miRNAs acting in mitochondria too. A list of selected mitochondrial and microRNA variants will be experimentally validated using functional assays to evaluate their biological effect on phenotype.