Figure 1.

Illustration of mitomiR origin and functioning site in the cell. Some mature miRNAs are imported into mitochondria after the pre-miRNA originated from the nucleus are processed by DICER. The other mitomiRs may be originated from mitochondrial genome-derived mRNA molecules. All mitomiRs can exert post-transcriptional modification in the mitochondria. Imported miRNAs may also target and function at nuclear-encoded mRNAs localized on the mitochondrial surface. However, the mechanisms underlying mitomiRs biogenesis and action site are still poorly understood.