MitoWheel, visualizing the human mitochondrial genome

A mitochondrial disorder with ptosis and exercise intolerance without ophthalmoparesis secondary to m.5865 T > C variant

We describe a novel mitochondrial variant (m.5865 T > C) in a patient with decreased exercise endurance and juvenile onset slowly progressive bilateral ptosis without ophthamloparesis. The m.5865 T > C variant was seen in 82.9% of mtDNA molecules in skeletal muscle tissue and ~8% of mtDNA molecules in urine epithelium, but was not detected in blood leukocytes. The proband does not demonstrate any additional features often seen in individuals with a mitochondrial disorder (i.e., sensorineural hearing loss, type 2 diabetes, stroke-like episodes, muscle weakness, ophthalmoparesis, cardiomyopathy or cardiac arrhythmias). This case suggests that ptosis and exercise intolerance, without ophthalmoparesis, are the primary clinical features of the m.5865 T > C mtDNA variant.

An in silico argument for mitochondrial microRNA as a determinant of primary non function in liver transplantation

Mitochondria have their own genomic, transcriptomic and proteomic machinery but are unable to be autonomous, needing both nuclear and mitochondrial genomes. The aim of this work was to use computational biology to explore the involvement of Mitochondrial microRNAs (MitomiRs) and their interactions with the mitochondrial proteome in a clinical model of primary non function (PNF) of the donor after cardiac death (DCD) liver. Archival array data on the differential expression of miRNA in DCD PNF was re-analyzed using a number of publically available computational algorithms. 10 MitomiRs were identified of importance in DCD PNF, 7 with predicted interaction of their seed sequence with the mitochondrial transcriptome that included both coding, and non coding areas of the hypervariability region 1 (HVR1) and control region. Considering miRNA regulation of the nuclear encoded mitochondrial proteome, 7 hypothetical small proteins were identified with homolog function that ranged from co-factor for formation of ATP Synthase, REDOX balance and an importin/exportin protein. In silico, unconventional seed interactions, both non canonical and alternative seed sites, appear to be of greater importance in MitomiR regulation of the mitochondrial genome. Additionally, a number of novel small proteins of relevance in transplantation have been identified which need further characterization.

MitoTool: a web server for the analysis and retrieval of human mitochondrial DNA sequence variations

MitoTool, a web-based bioinformatics platform, is designed for deciphering human mitochondrial DNA (mtDNA) data in batch mode. The platform has advantages in (i) parsing diverse types of mtDNA data; (ii) automatically classifying haplogroup according to mtDNA sequences or variants; (iii) discovering possibly missing variants of the samples with claimed haplogroups status; (iv) estimating the evolutionary conservation index, protein coding effect and potential pathogenicity of certain substitutions; (v) performing statistical analysis for haplogroup distribution frequency between case and control groups. Furthermore, it offers an integrated database for retrieving five types of mitochondrion-related information. The MitoTool is freely accessed at http://www.mitotool.org.