1
|
Vučković A, Freyer C, Wredenberg A, Hillen HS. The molecular machinery for maturation of primary mtDNA transcripts. Hum Mol Genet 2024; 33:R19-R25. [PMID: 38779769 PMCID: PMC11112384 DOI: 10.1093/hmg/ddae023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 01/31/2024] [Accepted: 02/08/2024] [Indexed: 05/25/2024] Open
Abstract
Human mitochondria harbour a circular, polyploid genome (mtDNA) encoding 11 messenger RNAs (mRNAs), two ribosomal RNAs (rRNAs) and 22 transfer RNAs (tRNAs). Mitochondrial transcription produces long, polycistronic transcripts that span almost the entire length of the genome, and hence contain all three types of RNAs. The primary transcripts then undergo a number of processing and maturation steps, which constitute key regulatory points of mitochondrial gene expression. The first step of mitochondrial RNA processing consists of the separation of primary transcripts into individual, functional RNA molecules and can occur by two distinct pathways. Both are carried out by dedicated molecular machineries that substantially differ from RNA processing enzymes found elsewhere. As a result, the underlying molecular mechanisms remain poorly understood. Over the last years, genetic, biochemical and structural studies have identified key players involved in both RNA processing pathways and provided the first insights into the underlying mechanisms. Here, we review our current understanding of RNA processing in mammalian mitochondria and provide an outlook on open questions in the field.
Collapse
MESH Headings
- Humans
- DNA, Mitochondrial/genetics
- RNA Processing, Post-Transcriptional
- Mitochondria/genetics
- Mitochondria/metabolism
- RNA, Mitochondrial/genetics
- RNA, Mitochondrial/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Animals
- Transcription, Genetic
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
Collapse
Affiliation(s)
- Ana Vučković
- Department of Cellular Biochemistry, University Medical Center Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
- Research Group Structure and Function of Molecular Machines, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Christoph Freyer
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Anna Steckséns gata 47, 171 64 Solna, Sweden
| | - Anna Wredenberg
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Anna Steckséns gata 47, 171 64 Solna, Sweden
| | - Hauke S Hillen
- Department of Cellular Biochemistry, University Medical Center Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
- Research Group Structure and Function of Molecular Machines, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Robert-Koch-Straße 40, 37073 Göttingen, Germany
- Research Group Structure and Function of Molecular Machines, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig-Weg 11, Goettingen 37077, Germany
| |
Collapse
|
2
|
Shino A, Otsu M, Imai K, Fukuzawa K, Morishita EC. Probing RNA-Small Molecule Interactions Using Biophysical and Computational Approaches. ACS Chem Biol 2023; 18:2368-2376. [PMID: 37856793 PMCID: PMC10662358 DOI: 10.1021/acschembio.3c00287] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/30/2023] [Indexed: 10/21/2023]
Abstract
Interest in small molecules that target RNA is flourishing, and the expectation set on them to treat diseases with unmet medical needs is high. However, several challenges remain, including difficulties in selecting suitable tools and establishing workflows for their discovery. In this context, we optimized experimental and computational approaches that were previously employed for the protein targets. Here, we demonstrate that a fluorescence-based assay can be effectively used to screen small molecule libraries for their ability to bind and stabilize an RNA stem-loop. Our screen identified several fluoroquinolones that bind to the target stem-loop. We further probed their interactions with the target using biolayer interferometry, isothermal titration calorimetry (ITC), and nuclear magnetic resonance spectroscopy. The results of these biophysical assays suggest that the fluoroquinolones bind the target in a similar manner. Armed with this knowledge, we built models for the complexes of the fluoroquinolones and the RNA target. Then, we performed fragment molecular orbital (FMO) calculations to dissect the interactions between the fluoroquinolones and the RNA. We found that the binding free energies obtained from the ITC experiments correlated strongly with the interaction energies calculated by FMO. Finally, we designed fluoroquinolone analogues and performed FMO calculations to predict their binding free energies. Taken together, the results of this study support the importance of conducting orthogonal assays in binding confirmation and compound selection and demonstrate the usefulness of FMO calculations in the rational design of RNA-targeted small molecules.
Collapse
Affiliation(s)
- Amiu Shino
- Basic
Research Division, Veritas In Silico Inc., Shinagawa, Tokyo 141-0031, Japan
| | - Maina Otsu
- Basic
Research Division, Veritas In Silico Inc., Shinagawa, Tokyo 141-0031, Japan
| | - Koji Imai
- Basic
Research Division, Veritas In Silico Inc., Shinagawa, Tokyo 141-0031, Japan
| | - Kaori Fukuzawa
- Graduate
School of Pharmaceutical Sciences, Osaka
University, Suita, Osaka 565-0871, Japan
- School
of Pharmacy and Pharmaceutical Sciences, Hoshi University, Shinagawa, Tokyo 142-8501, Japan
| | | |
Collapse
|
3
|
Takase N, Otsu M, Hirakata S, Ishizu H, Siomi MC, Kawai G. T-hairpin structure found in the RNA element involved in piRNA biogenesis. RNA (NEW YORK, N.Y.) 2022; 28:541-550. [PMID: 34987083 PMCID: PMC8925976 DOI: 10.1261/rna.078967.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
PIWI-interacting RNAs (piRNAs) repress transposons to protect the germline genome from DNA damage caused by transposon transposition. In Drosophila, the Traffic jam (Tj) mRNA is consumed to produce piRNA in its 3'-UTR. A cis element located within the 3'-UTR, Tj-cis, is necessary for piRNA biogenesis. In this study, we analyzed the structure of the Tj-cis RNA, a 100-nt RNA corresponding to the Tj-cis element, by the SHAPE and NMR analyses and found that a stable hairpin structure formed in the 5' half of the Tj-cis RNA. The tertiary structure of the 16-nt stable hairpin was analyzed by NMR, and a novel stem-loop structure, the T-hairpin, was found. In the T-hairpin, four uridine residues are exposed to the solvent, suggesting that this stem-loop is the target of Yb protein, a Tudor domain-containing piRNA biogenesis factor. The piRNA biogenesis assay showed that both the T-hairpin and the 3' half are required for the function of the Tj-cis element, suggesting that both the T-hairpin and the 3' half are recognized by Yb protein.
Collapse
Affiliation(s)
- Naomi Takase
- Department of Life Science, Graduate School of Advanced Engineering, Chiba Institute of Technology, Chiba 275-0016, Japan
| | - Maina Otsu
- Department of Life Science, Graduate School of Advanced Engineering, Chiba Institute of Technology, Chiba 275-0016, Japan
| | - Shigeki Hirakata
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
| | - Hirotsugu Ishizu
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
- Department of Molecular Biology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Mikiko C Siomi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
| | - Gota Kawai
- Department of Life Science, Graduate School of Advanced Engineering, Chiba Institute of Technology, Chiba 275-0016, Japan
| |
Collapse
|