Human mitochondria hub of small RNAs: Analysis by deep Sequencing

We report here that human mitochondria contain small RNA including microRNA, piRNA, tRNA, rRNA, and RNA repeats. Mitochondria from human cells were purified and RNA isolated. Small RNAs were purified, library generated and analyzed by Illumina Hiseq 2000 system. The sequencing generated 19.5 and 17.7 million reads from HEK-293 and HeLa respectively. 91% and 97% sequences of HEK293 and HeLa respectively were annotated to various classes of small RNA. The total percentage of 4.21 and 2.58 sequences from HEK293 and HeLa respectively was found to be of miRNA. Further, we found only 1.2 % sequences from both the libraries aligned to mitochondrial genome. These results suggest that there is efficient transport of nuclear encoded small RNA to mitochondria. The small RNA in mitochondria may regulate critical cellular processes. Overall design: Analyzing the smallRNA in human mitochondria from two human cell lines (HEK-293 and HeLa).