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Gao K, Cheng M, Zuo X, Lin J, Hoogewijs K, Murphy MP, Fu XD, Zhang X. Active RNA interference in mitochondria. Cell Res 2020; 31:219-228. [PMID: 32807841 DOI: 10.1038/s41422-020-00394-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 07/24/2020] [Indexed: 02/06/2023] Open
Abstract
RNA interference (RNAi) has been thought to be a gene-silencing pathway present in most eukaryotic cells to safeguard the genome against retrotransposition. Small interfering RNAs (siRNAs) have also become a powerful tool for studying gene functions. Given the endosymbiotic hypothesis that mitochondria originated from prokaryotes, mitochondria have been generally assumed to lack active RNAi; however, certain bacteria have Argonaute homologs and various reports suggest the presence of specific microRNAs and nuclear genome (nDNA)-encoded Ago2 in the mitochondria. Here we report that transfected siRNAs are not only able to enter the matrix of mitochondria, but also function there to specifically silence targeted mitochondrial transcripts. The mitoRNAi effect is readily detectable at the mRNA level, but only recordable on relatively unstable proteins, such as the mtDNA-encoded complex IV subunits. We also apply mitoRNAi to directly determine the postulated crosstalk between individual respiratory chain complexes, and our result suggests that the controversial observations previously made in patient-derived cells might result from differential adaptation in different cell lines. Our findings bring a new tool to study mitochondrial biology.
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Affiliation(s)
- Kuanxing Gao
- State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072, China.,Key Laboratory for RNA Biology, Institute of Biophysics, Chinese Academy of Science, Beijing, 100101, China
| | - Man Cheng
- Key Laboratory for RNA Biology, Institute of Biophysics, Chinese Academy of Science, Beijing, 100101, China
| | - Xinxin Zuo
- State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072, China
| | - Jinzhong Lin
- State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200433, China
| | - Kurt Hoogewijs
- Department of Organic and Macromolecular Chemistry, University of Ghent, Ghent, 9000, Belgium
| | - Michael P Murphy
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 1TN, UK.,Department of Medicine, University of Cambridge, Cambridge, CB2 1TN, UK
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA, 92093-0651, USA.
| | - Xiaorong Zhang
- Key Laboratory for RNA Biology, Institute of Biophysics, Chinese Academy of Science, Beijing, 100101, China.
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Advances in methods for reducing mitochondrial DNA disease by replacing or manipulating the mitochondrial genome. Essays Biochem 2018; 62:455-465. [PMID: 29950320 PMCID: PMC6056713 DOI: 10.1042/ebc20170113] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/23/2018] [Accepted: 05/03/2018] [Indexed: 11/25/2022]
Abstract
Mitochondrial DNA (mtDNA) is a multi-copy genome whose cell copy number varies depending on tissue type. Mutations in mtDNA can cause a wide spectrum of diseases. Mutated mtDNA is often found as a subset of the total mtDNA population in a cell or tissue, a situation known as heteroplasmy. As mitochondrial dysfunction only presents after a certain level of heteroplasmy has been acquired, ways to artificially reduce or replace the mutated species have been attempted. This review addresses recent approaches and advances in this field, focusing on the prevention of pathogenic mtDNA transfer via mitochondrial donation techniques such as maternal spindle transfer and pronuclear transfer in which mutated mtDNA in the oocyte or fertilized embryo is substituted with normal copies of the mitochondrial genome. This review also discusses the molecular targeting and cleavage of pathogenic mtDNA to shift heteroplasmy using antigenomic therapy and genome engineering techniques including Zinc-finger nucleases and transcription activator-like effector nucleases. Finally, it considers CRISPR technology and the unique difficulties that mitochondrial genome editing presents.
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Murphy MP. Chemical biology of mitochondria. Interface Focus 2017. [DOI: 10.1098/rsfs.2017.0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
On 26–28 September 2016, the Theo Murphy (no relation) international scientific meeting on ‘Chemical biology approaches to assessing and modulating mitochondria’ was held at the Kavli Royal Society Centre, Chicheley Hall, Buckinghamshire, UK. Mike Murphy organized the meeting and it was enabled through the Royal Society scientific programme. The purpose of the conference was to bring together biologists, chemists and clinicians to discuss how to apply chemical biology to mitochondria to capitalize on the many new opportunities arising from the recent developments in mitochondrial biology.
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