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Su L, Wang X, Wang J, Luh F, Yen Y. Impact of N221S missense mutation in human ribonucleotide reductase small subunit b on mitochondrial DNA depletion syndrome. Sci Rep 2023; 13:19899. [PMID: 37964013 PMCID: PMC10645729 DOI: 10.1038/s41598-023-47284-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 11/11/2023] [Indexed: 11/16/2023] Open
Abstract
The impact of N221S mutation in hRRM2B gene, which encodes the small subunit of human ribonucleotide reductase (RNR), on RNR activity and the pathogenesis of mitochondrial DNA depletion syndrome (MDDS) was investigated. Our results demonstrate that N221 mutations significantly reduce RNR activity, suggesting its role in the development of MDDS. We proposed an allosteric regulation pathway involving a chain of three phenylalanine residues on the αE helix of RNR small subunit β. This pathway connects the C-terminal loop of β2, transfers the activation signal from the large catalytic subunit α to β active site, and controls access of oxygen for radical generation. N221 is near this pathway and likely plays a role in regulating RNR activity. Mutagenesis studies on residues involved in the phenylalanine chain and the regulation pathway were conducted to confirm our proposed mechanism. We also performed molecular dynamic simulation and protein contact network analysis to support our findings. This study sheds new light on RNR small subunit regulation and provides insight on the pathogenesis of MDDS.
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Affiliation(s)
- Leila Su
- Sino-American Cancer Foundation, Covina, CA, 91722, USA
| | - Xin Wang
- Sino-American Cancer Foundation, Covina, CA, 91722, USA
| | - Jianghai Wang
- Sino-American Cancer Foundation, Covina, CA, 91722, USA
| | - Frank Luh
- Sino-American Cancer Foundation, Covina, CA, 91722, USA
| | - Yun Yen
- Ph.D. Program for Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, 250 Wu-Hsing Street, Taipei, 110301, Taiwan.
- Center for Cancer Translational Research, Tzu Chi University, Hualien, 970374, Taiwan.
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Wang H, Han Y, Li S, Chen Y, Chen Y, Wang J, Zhang Y, Zhang Y, Wang J, Xia Y, Yuan J. Mitochondrial DNA Depletion Syndrome and Its Associated Cardiac Disease. Front Cardiovasc Med 2022; 8:808115. [PMID: 35237671 PMCID: PMC8882844 DOI: 10.3389/fcvm.2021.808115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/23/2021] [Indexed: 12/06/2022] Open
Abstract
Mitochondria is a ubiquitous, energy-supplying (ATP-based) organelle found in nearly all eukaryotes. It acts as a “power plant” by producing ATP through oxidative phosphorylation, providing energy for the cell. The bioenergetic functions of mitochondria are regulated by nuclear genes (nDNA). Mitochondrial DNA (mtDNA) and respiratory enzymes lose normal structure and function when nuclear genes encoding the related mitochondrial factors are impaired, resulting in deficiency in energy production. Massive generation of reactive oxygen species and calcium overload are common causes of mitochondrial diseases. The mitochondrial depletion syndrome (MDS) is associated with the mutations of mitochondrial genes in the nucleus. It is a heterogeneous group of progressive disorders characterized by the low mtDNA copy number. TK2, FBXL4, TYPM, and AGK are genes known to be related to MDS. More recent studies identified new mutation loci associated with this disease. Herein, we first summarize the structure and function of mitochondria, and then discuss the characteristics of various types of MDS and its association with cardiac diseases.
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Affiliation(s)
- Haiying Wang
- Department of Physiology, Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yijun Han
- Clinical Medical College, Jining Medical University, Jining, China
| | - Shenwei Li
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yunan Chen
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yafen Chen
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Jing Wang
- Dongying Fifth People's Hospital, Dongying, China
| | - Yuqing Zhang
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yawen Zhang
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Jingsuo Wang
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yong Xia
- Key Laboratory of Precision Oncology of Shandong Higher Education, Institute of Precision Medicine, Jining Medical University, Jining, China
- Yong Xia
| | - Jinxiang Yuan
- The Collaborative Innovation Center, Jining Medical University, Jining, China
- *Correspondence: Jinxiang Yuan
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Tseng YT, Li SW, HuangFu WC, Yen Y, Liu IH. The single nucleotide variant at c.662A>G in human RRM2B is a loss-of-function mutation. Mol Genet Genomic Med 2020; 8:e1497. [PMID: 32931159 PMCID: PMC7667293 DOI: 10.1002/mgg3.1497] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 08/14/2020] [Accepted: 08/21/2020] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Mitochondrial DNA maintenance defects (MDMDs) is one of the critical pediatric dysfunction. One of the recent report indicated that a severe patient of MDMDs carries the NP_056528.2:p.Asn221Ser (N221S) variation in the RRM2B gene (NM_015713.5). However, there is no direct evidence demonstrating the nature of the N221S variation. MATERIALS AND METHODS This study aimed to utilize zebrafish and morpholino oligomer (MO) knockdown technique to provide direct evidence for the nature of the N221S variation in the RRM2B. RESULTS The results showed that two distinct MOs were both able to perturb the expression of rrm2b in zebrafish and dose-dependently induced morphological defects. Furthermore, co-injection of human wild-type RRM2B mRNA with MO-e4i4 successfully rescued the developmental defects, whereas co-injection of RRM2B/N221S mRNA with MO-e4i4 did not rescue the developmental defects. CONCLUSION In conclusion, the functional assay in this study provided the direct evidence proving that the N221S variation is a loss-of-function mutation and plausibly related to the pathogenic developmental defects found in the infants of previous clinical reports.
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Affiliation(s)
- Yen-Tzu Tseng
- Department of Animal Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Shang-Wei Li
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.,Ph.D. Program for Cancer Molecular Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Wei-Chun HuangFu
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.,Ph.D. Program for Cancer Molecular Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Yun Yen
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.,Ph.D. Program for Cancer Molecular Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.,TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan.,Cancer Center, Taipei Municipal WanFang Hospital, Taipei, Taiwan
| | - I-Hsuan Liu
- Department of Animal Science and Technology, National Taiwan University, Taipei, Taiwan.,Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan.,School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan
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