The mitochondrial genome encodes abundant small noncoding RNAs

Abstract

Small noncoding RNAs identified thus far are all encoded by the nuclear genome. Here, we report that the murine and human mitochondrial genomes encode thousands of small noncoding RNAs, which are predominantly derived from the sense transcripts of the mitochondrial genes (host genes), and we termed these small RNAs mitochondrial genome-encoded small RNAs (mitosRNAs). DICER inactivation affected, but did not completely abolish mitosRNA production. MitosRNAs appear to be products of currently unidentified mitochondrial ribonucleases. Overexpression of mitosRNAs enhanced expression levels of their host genes in vitro, and dysregulated mitosRNA expression was generally associated with aberrant mitochondrial gene expression in vivo. Our data demonstrate that in addition to 37 known mitochondrial genes, the mammalian mitochondrial genome also encodes abundant mitosRNAs, which may play an important regulatory role in the control of mitochondrial gene expression in the cell.

Mitoepigenetics: The different shades of grey

“…The studies suggested the presence of unique class of small RNAs in the human mitochondria (Mercer et al, 2011;Ro et al, 2013). Apart from this, a subset of the nuclear encoded microRNAs have been shown to localize to the mitochondria (Das et al, 2012).…”

A Novel Class of Somatic Small RNAs Similar to Germ Cell Pachytene PIWI-interacting Small RNAs

“…Two biological replicates of FACS-purified Sertoli cells from control, Dicer cKO, and Drosha cKO testes (n ϭ 2) were sequenced using the Ion Torrent Personal Genome Machine (PGM) (Invitrogen) as described (17,18). Briefly, sncRNAs were isolated using the mirVana miRNA isolation kit (Invitrogen), and cDNA libraries were generated using the Ion Total RNA-Seq kit v2 (Invitrogen).…”

Identification and Characterization of MicroRNAs in Small Brown Planthopper (Laodephax striatellus) by Next-Generation Sequencing

“…This suggests that the mitochondrial genome encodes mitosRNAs in animals. However, the mapped L. striatellus sRNAs had peaks at 22 nt (unique reads) and 23 nt (redundant reads) (Figure S1), which was different from the peak at 30 nt observed in the human and mouse genomes [38]. Thus, it can be concluded that different mechanisms may be used to produce mitosRNAs in different species [38].…”