RNA degradation in yeast and human mitochondria

Abstract

Proper function of mitochondria requires that expression of mitochondrially encoded genes be maintained at the right level for the cell’s present conditions, and changed in response to stimuli. To that end the levels of mitochondrial RNAs must be kept under strict, dynamic control. Since yeast and human mitochondria have limited possibilities to regulate gene expression by altering the transcription initiation rate, posttranscriptional processes, including RNA degradation, are of great importance. In both organisms mitochondrial RNA degradation seems to mostly depend on the RNA helicase Suv3. Yeast Suv3 functions in cooperation with Dss1 ribonuclease by forming a two-subunit complex called the mitochondrial degradosome. The human ortholog of Suv3 (hSuv3, hSuv3p, SUPV3L1) is also indispensable for mitochondrial RNA decay but its ribonucleolitic partner has so far escaped identification. In this review we summarize the current knowledge about RNA degradation in human and yeast mitochondria.