1
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Huan MJ, Fu PP, Chen X, Wang ZX, Ma ZR, Cai SZ, Jiang Q, Wang Q. Identification of the central role of RNA polymerase mitochondrial for angiogenesis. Cell Commun Signal 2024; 22:343. [PMID: 38907279 PMCID: PMC11191269 DOI: 10.1186/s12964-024-01712-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 06/10/2024] [Indexed: 06/23/2024] Open
Abstract
Mitochondria are central to endothelial cell activation and angiogenesis, with the RNA polymerase mitochondrial (POLRMT) serving as a key protein in regulating mitochondrial transcription and oxidative phosphorylation. In our study, we examined the impact of POLRMT on angiogenesis and found that its silencing or knockout (KO) in human umbilical vein endothelial cells (HUVECs) and other endothelial cells resulted in robust anti-angiogenic effects, impeding cell proliferation, migration, and capillary tube formation. Depletion of POLRMT led to impaired mitochondrial function, characterized by mitochondrial depolarization, oxidative stress, lipid oxidation, DNA damage, and reduced ATP production, along with significant apoptosis activation. Conversely, overexpressing POLRMT promoted angiogenic activity in the endothelial cells. In vivo experiments demonstrated that endothelial knockdown of POLRMT, by intravitreous injection of endothelial specific POLRMT shRNA adeno-associated virus, inhibited retinal angiogenesis. In addition, inhibiting POLRMT with a first-in-class inhibitor IMT1 exerted significant anti-angiogenic impact in vitro and in vivo. Significantly elevated expression of POLRMT was observed in the retinal tissues of streptozotocin-induced diabetic retinopathy (DR) mice. POLRMT endothelial knockdown inhibited pathological retinal angiogenesis and mitigated retinal ganglion cell (RGC) degeneration in DR mice. At last, POLRMT expression exhibited a substantial increase in the retinal proliferative membrane tissues of human DR patients. These findings collectively establish the indispensable role of POLRMT in angiogenesis, both in vitro and in vivo.
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Affiliation(s)
- Meng-Jia Huan
- Department of Ophthalmology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, China
- The Affiliated Eye Hospital, Nanjing Medical University, Nanjing, 210029, China
| | - Ping-Ping Fu
- Department of Ophthalmology, Shanghai Eye Diseases Prevention & Treatment Center, Shanghai Eye Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Xia Chen
- Department of Anesthesiology, Children's hospital of Soochow University, Suzhou, 215025, China
| | - Zhao-Xia Wang
- Department of Endocrinology, Fengcheng Hospital of Fengxian Distric, Shanghai, China
| | - Zhou-Rui Ma
- Department of Burn and Plastic Surgery, Children's Hospital of Soochow University, Suzhou, China
| | - Shi-Zhong Cai
- Department of Child and Adolescent Healthcare, Children's Hospital of Soochow University, Suzhou, China.
- Key Laboratory of Congenital Structural Malformations of Suzhou City, Suzhou, China.
| | - Qin Jiang
- The Affiliated Eye Hospital, Nanjing Medical University, Nanjing, 210029, China.
| | - Qian Wang
- Department of Anesthesiology, Children's hospital of Soochow University, Suzhou, 215025, China.
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2
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Kong Y, Li X, Zhang H, Fu B, Jiang HY, Yang HL, Dai J. Targeting POLRMT by a first-in-class inhibitor IMT1 inhibits osteosarcoma cell growth in vitro and in vivo. Cell Death Dis 2024; 15:57. [PMID: 38228583 PMCID: PMC10791695 DOI: 10.1038/s41419-024-06444-9] [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: 09/18/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 01/18/2024]
Abstract
Osteosarcoma (OS) is a highly aggressive form of bone cancer that predominantly affects adolescents and young adults. In this study, we have undertaken an investigation into the potential anti-OS cell activity of IMT1 (inhibitor of mitochondrial transcription 1), a first-in-class inhibitor of RNA polymerase mitochondrial (POLRMT). IMT1 exhibited a profound inhibitory effect on cell survival, proliferation, cell cycle progression, and migration in primary and immortalized OS cells. Furthermore, this POLRMT inhibitor elicited apoptosis in the OS cells, without, however, inducing cytotoxicity in human osteoblasts or osteoblastic cells. IMT1 disrupted mitochondrial functions in OS cells, resulting in mitochondrial depolarization, oxidative injury, lipid peroxidation, and ATP reduction in OS cells. Silencing POLRMT using targeted shRNA closely mimicked the actions of IMT1 and exerted potent anti-OS cell activity. Importantly, IMT1's effectiveness was diminished in POLRMT-silenced OS cells. Subsequent investigations revealed that IMT1 suppressed the activation of the Akt-mammalian target of rapamycin (mTOR) cascade in OS cells. IMT1 treatment or POLRMT silencing in primary OS cells led to a significant reduction in Akt1-S6K-S6 phosphorylation. Conversely, it was enhanced upon POLRMT overexpression. The restoration of Akt-mTOR activation through the introduction of a constitutively active S473D mutant Akt1 (caAkt1) mitigated IMT1-induced cytotoxicity in OS cells. In vivo, oral administration of IMT1 robustly curtailed the growth of OS xenografts in nude mice. Furthermore, IMT1 suppressed POLRMT activity, impaired mitochondrial function, repressed Akt-mTOR activation, and induced apoptosis within xenograft tissues. Collectively, these findings underscore the potent growth-inhibitory effects attributed to IMT1 via targeted POLRMT inhibition. The utilization of this POLRMT inhibitor carries substantial therapeutic promise in the context of OS treatment.
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Affiliation(s)
- Yang Kong
- Department of Orthopedics, the First Affiliated Hospital of Soochow University, Suzhou, China
- Department of Orthopedics, The First People's Hospital of ChuZhou, ChuZhou, China
| | - Xiangrong Li
- Department of Pharmacy, Kongjiang Hospital of Yangpu District, Shanghai, China
| | - Huanle Zhang
- Department of Radiotherapy, Suzhou Ninth People's Hospital, Suzhou, China
| | - Bin Fu
- Department of Orthopedics, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Hua-Ye Jiang
- Department of Orthopedics, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Hui-Lin Yang
- Department of Orthopedics, the First Affiliated Hospital of Soochow University, Suzhou, China.
- Orthopedic Institute, Medical College, Soochow University, Suzhou, China.
| | - Jin Dai
- Department of Orthopedics, Suzhou Wujiang District Children's Hospital, Suzhou, China.
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3
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Platz KR, Rudisel EJ, Paluch KV, Laurin TR, Dittenhafer-Reed KE. Assessing the Role of Post-Translational Modifications of Mitochondrial RNA Polymerase. Int J Mol Sci 2023; 24:16050. [PMID: 38003238 PMCID: PMC10671485 DOI: 10.3390/ijms242216050] [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: 10/10/2023] [Revised: 11/02/2023] [Accepted: 11/02/2023] [Indexed: 11/26/2023] Open
Abstract
The mitochondrial proteome is subject to abundant post-translational modifications, including lysine acetylation and phosphorylation of serine, threonine, and tyrosine. The biological function of the majority of these protein modifications is unknown. Proteins required for the transcription and translation of mitochondrial DNA (mtDNA) are subject to modification. This suggests that reversible post-translational modifications may serve as a regulatory mechanism for mitochondrial gene transcription, akin to mechanisms controlling nuclear gene expression. We set out to determine whether acetylation or phosphorylation controls the function of mitochondrial RNA polymerase (POLRMT). Mass spectrometry was used to identify post-translational modifications on POLRMT. We analyzed three POLRMT modification sites (lysine 402, threonine 315, threonine 993) found in distinct structural regions. Amino acid point mutants that mimic the modified and unmodified forms of POLRMT were employed to measure the effect of acetylation or phosphorylation on the promoter binding ability of POLRMT in vitro. We found a slight decrease in binding affinity for the phosphomimic at threonine 315. We did not identify large changes in viability, mtDNA content, or mitochondrial transcript level upon overexpression of POLRMT modification mimics in HeLa cells. Our results suggest minimal biological impact of the POLRMT post-translational modifications studied in our system.
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4
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Jacobs HT. A century of mitochondrial research, 1922-2022. Enzymes 2023; 54:37-70. [PMID: 37945177 DOI: 10.1016/bs.enz.2023.07.002] [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] [Indexed: 11/12/2023]
Abstract
Although recognized earlier as subcellular entities by microscopists, mitochondria have been the subject of functional studies since 1922, when their biochemical similarities with bacteria were first noted. In this overview I trace the history of research on mitochondria from that time up to the present day, focussing on the major milestones of the overlapping eras of mitochondrial biochemistry, genetics, pathology and cell biology, and its explosion into new areas in the past 25 years. Nowadays, mitochondria are considered to be fully integrated into cell physiology, rather than serving specific functions in isolation.
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Affiliation(s)
- Howard T Jacobs
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland; Department of Environment and Genetics, La Trobe University, Melbourne, VIC, Australia.
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5
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Daglish SCD, Fennell EMJ, Graves LM. Targeting Mitochondrial DNA Transcription by POLRMT Inhibition or Depletion as a Potential Strategy for Cancer Treatment. Biomedicines 2023; 11:1598. [PMID: 37371693 PMCID: PMC10295849 DOI: 10.3390/biomedicines11061598] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/27/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Transcription of the mitochondrial genome is essential for the maintenance of oxidative phosphorylation (OXPHOS) and other functions directly related to this unique genome. Considerable evidence suggests that mitochondrial transcription is dysregulated in cancer and cancer metastasis and contributes significantly to cancer cell metabolism. Recently, inhibitors of the mitochondrial DNA-dependent RNA polymerase (POLRMT) were identified as potentially attractive new anti-cancer compounds. These molecules (IMT1, IMT1B) inactivate cancer cell metabolism through reduced transcription of mitochondrially-encoded OXPHOS subunits such as ND1-5 (Complex I) and COI-IV (Complex IV). Studies from our lab have discovered small molecule regulators of the mitochondrial matrix caseinolytic protease (ClpP) as probable inhibitors of mitochondrial transcription. These compounds activate ClpP proteolysis and lead to the rapid depletion of POLRMT and other matrix proteins, resulting in inhibition of mitochondrial transcription and growth arrest. Herein we present a comparison of POLRMT inhibition and ClpP activation, both conceptually and experimentally, and evaluate the results of these treatments on mitochondrial transcription, inhibition of OXPHOS, and ultimately cancer cell growth. We discuss the potential for targeting mitochondrial transcription as a cancer cell vulnerability.
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Affiliation(s)
| | | | - Lee M. Graves
- Department of Pharmacology and the Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (S.C.D.D.); (E.M.J.F.)
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6
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Guenther DC, Mori S, Matsuda S, Gilbert JA, Willoughby JLS, Hyde S, Bisbe A, Jiang Y, Agarwal S, Madaoui M, Janas MM, Charisse K, Maier MA, Egli M, Manoharan M. Role of a "Magic" Methyl: 2'-Deoxy-2'-α-F-2'-β- C-methyl Pyrimidine Nucleotides Modulate RNA Interference Activity through Synergy with 5'-Phosphate Mimics and Mitigation of Off-Target Effects. J Am Chem Soc 2022; 144:14517-14534. [PMID: 35921401 PMCID: PMC9389587 DOI: 10.1021/jacs.2c01679] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Although 2′-deoxy-2′-α-F-2′-β-C-methyl (2′-F/Me) uridine nucleoside derivatives
are a successful class of antiviral drugs, this modification had not
been studied in oligonucleotides. Herein, we demonstrate the facile
synthesis of 2′-F/Me-modified pyrimidine phosphoramidites and
their subsequent incorporation into oligonucleotides. Despite the
C3′-endo preorganization of the parent nucleoside,
a single incorporation into RNA or DNA resulted in significant thermal
destabilization of a duplex due to unfavorable enthalpy, likely resulting
from steric effects. When located at the terminus of an oligonucleotide,
the 2′-F/Me modification imparted more resistance to degradation
than the corresponding 2′-fluoro nucleotides. Small interfering
RNAs (siRNAs) modified at certain positions with 2′-F/Me had
similar or better silencing activity than the parent siRNAs when delivered
via a lipid nanoparticle formulation or as a triantennary N-acetylgalactosamine conjugate in cells and in mice. Modification
in the seed region of the antisense strand at position 6 or 7 resulted
in an activity equivalent to the parent in mice. Additionally, placement
of the antisense strand at position 7 mitigated seed-based off-target
effects in cell-based assays. When the 2′-F/Me modification
was combined with 5′-vinyl phosphonate, both E and Z isomers had silencing activity comparable
to the parent. In combination with other 2′-modifications such
as 2′-O-methyl, the Z isomer
is detrimental to silencing activity. Presumably, the equivalence
of 5′-vinyl phosphonate isomers in the context of 2′-F/Me
is driven by the steric and conformational features of the C-methyl-containing sugar ring. These data indicate that
2′-F/Me nucleotides are promising tools for nucleic acid-based
therapeutic applications to increase potency, duration, and safety.
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Affiliation(s)
- Dale C Guenther
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | - Shohei Mori
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | - Shigeo Matsuda
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | - Jason A Gilbert
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | | | - Sarah Hyde
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | - Anna Bisbe
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | - Yongfeng Jiang
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | - Saket Agarwal
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | - Mimouna Madaoui
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | - Maja M Janas
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | - Klaus Charisse
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | - Martin A Maier
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
| | - Martin Egli
- Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Muthiah Manoharan
- Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States
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7
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Singh M, Posse V, Peter B, Falkenberg M, Gustafsson C. Ribonucleotides embedded in template DNA impair mitochondrial RNA polymerase progression. Nucleic Acids Res 2022; 50:989-999. [PMID: 35018464 PMCID: PMC8789056 DOI: 10.1093/nar/gkab1251] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 11/30/2021] [Accepted: 12/07/2021] [Indexed: 11/12/2022] Open
Abstract
Human mitochondria lack ribonucleotide excision repair pathways, causing misincorporated ribonucleotides (rNMPs) to remain embedded in the mitochondrial genome. Previous studies have demonstrated that human mitochondrial DNA polymerase γ can bypass a single rNMP, but that longer stretches of rNMPs present an obstacle to mitochondrial DNA replication. Whether embedded rNMPs also affect mitochondrial transcription has not been addressed. Here we demonstrate that mitochondrial RNA polymerase elongation activity is affected by a single, embedded rNMP in the template strand. The effect is aggravated at stretches with two or more consecutive rNMPs in a row and cannot be overcome by addition of the mitochondrial transcription elongation factor TEFM. Our findings lead us to suggest that impaired transcription may be of functional relevance in genetic disorders associated with imbalanced nucleotide pools and higher levels of embedded rNMPs.
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Affiliation(s)
- Meenakshi Singh
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, SE-405 30, Sweden
| | - Viktor Posse
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, SE-405 30, Sweden
| | - Bradley Peter
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, SE-405 30, Sweden
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, SE-405 30, Sweden
| | - Claes M Gustafsson
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, SE-405 30, Sweden
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8
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Durand M, Nagot N, Nhu QBT, Vallo R, Thuy LLT, Duong HT, Thanh BN, Rapoud D, Quillet C, Tran HT, Michel L, Tuyet TNT, Hai OKT, Hai VV, Feelemyer J, Perre PV, Jarlais DD, Minh KP, Laureillard D, Molès JP. Mitochondrial Genotoxicity of Hepatitis C Treatment among People Who Inject Drugs. J Clin Med 2021; 10:jcm10214824. [PMID: 34768343 PMCID: PMC8584601 DOI: 10.3390/jcm10214824] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 12/12/2022] Open
Abstract
Antiviral nucleoside analogues (ANA) are newly used therapeutics acting against the hepatitis C virus (HCV). This class of drug is well known to exhibit toxicity on mitochondrial DNA (mtDNA). People who inject drugs (PWID) are particularly affected by HCV infection and cumulated mitotoxic drug exposure from HIV treatments (antiretrovirals, ARV) and other illicit drugs. This study aims to explore the impact of direct-acting antiviral (DAA) treatments on mtDNA among PWID. A total of 470 actively injecting heroin users were included. We used quantitative PCR on whole blood to determine the mitochondrial copy number per cell (MCN) and the proportion of mitochondrial DNA deletion (MDD). These parameters were assessed before and after DAA treatment. MDD was significantly increased after HCV treatment, while MCN did not differ. MDD was even greater when subjects were cotreated with ARV. In multivariate analysis, we identified that poly-exposure to DAA and daily heroin injection or regular consumption of methamphetamines were positively associated with high MCN loss while DAA and ARV treatments or methadone use were identified as risk factors for having mtDNA deletion. These observations deserve attention since they were previously associated with premature cell ageing or cell transformation and therefore call for a long-term follow-up.
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Affiliation(s)
- Mélusine Durand
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, EFS, University of Antilles, 34394 Montpellier, France; (N.N.); (R.V.); (D.R.); (C.Q.); (P.V.P.); (D.L.); (J.-P.M.)
- Correspondence: ; Tel.: +33-43435-9120
| | - Nicolas Nagot
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, EFS, University of Antilles, 34394 Montpellier, France; (N.N.); (R.V.); (D.R.); (C.Q.); (P.V.P.); (D.L.); (J.-P.M.)
| | - Quynh Bach Thi Nhu
- Faculty of Public Health, Hai Phong University of Medicine and Pharmacy, Haiphong 04212, Vietnam; (Q.B.T.N.); (L.L.T.T.); (H.T.D.); (B.N.T.); (H.T.T.); (K.P.M.)
| | - Roselyne Vallo
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, EFS, University of Antilles, 34394 Montpellier, France; (N.N.); (R.V.); (D.R.); (C.Q.); (P.V.P.); (D.L.); (J.-P.M.)
| | - Linh Le Thi Thuy
- Faculty of Public Health, Hai Phong University of Medicine and Pharmacy, Haiphong 04212, Vietnam; (Q.B.T.N.); (L.L.T.T.); (H.T.D.); (B.N.T.); (H.T.T.); (K.P.M.)
| | - Huong Thi Duong
- Faculty of Public Health, Hai Phong University of Medicine and Pharmacy, Haiphong 04212, Vietnam; (Q.B.T.N.); (L.L.T.T.); (H.T.D.); (B.N.T.); (H.T.T.); (K.P.M.)
| | - Binh Nguyen Thanh
- Faculty of Public Health, Hai Phong University of Medicine and Pharmacy, Haiphong 04212, Vietnam; (Q.B.T.N.); (L.L.T.T.); (H.T.D.); (B.N.T.); (H.T.T.); (K.P.M.)
| | - Delphine Rapoud
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, EFS, University of Antilles, 34394 Montpellier, France; (N.N.); (R.V.); (D.R.); (C.Q.); (P.V.P.); (D.L.); (J.-P.M.)
| | - Catherine Quillet
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, EFS, University of Antilles, 34394 Montpellier, France; (N.N.); (R.V.); (D.R.); (C.Q.); (P.V.P.); (D.L.); (J.-P.M.)
| | - Hong Thi Tran
- Faculty of Public Health, Hai Phong University of Medicine and Pharmacy, Haiphong 04212, Vietnam; (Q.B.T.N.); (L.L.T.T.); (H.T.D.); (B.N.T.); (H.T.T.); (K.P.M.)
| | - Laurent Michel
- CESP UMR1018, Paris Saclay, Pierre Nicole Center, French Red Cross, 75005 Paris, France;
| | - Thanh Nham Thi Tuyet
- Supporting Community Development Initiatives, Hanoi 11513, Vietnam; (T.N.T.T.); (O.K.T.H.)
| | - Oanh Khuat Thi Hai
- Supporting Community Development Initiatives, Hanoi 11513, Vietnam; (T.N.T.T.); (O.K.T.H.)
| | - Vinh Vu Hai
- Infectious & Tropical Diseases Department, Viet Tiep Hospital, Haiphong 04708, Vietnam;
| | - Jonathan Feelemyer
- School of Global Public Health, New York University, New York, NY 10003, USA; (J.F.); (D.D.J.)
| | - Philippe Vande Perre
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, EFS, University of Antilles, 34394 Montpellier, France; (N.N.); (R.V.); (D.R.); (C.Q.); (P.V.P.); (D.L.); (J.-P.M.)
| | - Don Des Jarlais
- School of Global Public Health, New York University, New York, NY 10003, USA; (J.F.); (D.D.J.)
| | - Khue Pham Minh
- Faculty of Public Health, Hai Phong University of Medicine and Pharmacy, Haiphong 04212, Vietnam; (Q.B.T.N.); (L.L.T.T.); (H.T.D.); (B.N.T.); (H.T.T.); (K.P.M.)
| | - Didier Laureillard
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, EFS, University of Antilles, 34394 Montpellier, France; (N.N.); (R.V.); (D.R.); (C.Q.); (P.V.P.); (D.L.); (J.-P.M.)
- Infectious & Tropical Diseases Department, Caremeau University Hospital, 30029 Nîmes, France
| | - Jean-Pierre Molès
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, EFS, University of Antilles, 34394 Montpellier, France; (N.N.); (R.V.); (D.R.); (C.Q.); (P.V.P.); (D.L.); (J.-P.M.)
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9
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Cazier AP, Blazeck J. Advances in promoter engineering: novel applications and predefined transcriptional control. Biotechnol J 2021; 16:e2100239. [PMID: 34351706 DOI: 10.1002/biot.202100239] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 11/08/2022]
Abstract
Synthetic biology continues to progress by relying on more robust tools for transcriptional control, of which promoters are the most fundamental component. Numerous studies have sought to characterize promoter function, determine principles to guide their engineering, and create promoters with stronger expression or tailored inducible control. In this review, we will summarize promoter architecture and highlight recent advances in the field, focusing on the novel applications of inducible promoter design and engineering towards metabolic engineering and cellular therapeutic development. Additionally, we will highlight how the expansion of new, machine learning techniques for modeling and engineering promoter sequences are enabling more accurate prediction of promoter characteristics. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Andrew P Cazier
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst St. NW, Atlanta, Georgia, 30332, USA
| | - John Blazeck
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst St. NW, Atlanta, Georgia, 30332, USA
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10
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Shin Y, Murakami KS. Watching the bacterial RNA polymerase transcription reaction by time-dependent soak-trigger-freeze X-ray crystallography. Enzymes 2021; 49:305-314. [PMID: 34696836 DOI: 10.1016/bs.enz.2021.06.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
RNA polymerase (RNAP) is the central enzyme of gene expression, which transcribes DNA to RNA. All cellular organisms synthesize RNA with highly conserved multi-subunit DNA-dependent RNAPs, except mitochondrial RNA transcription, which is carried out by a single-subunit RNAP. Over 60 years of extensive research has elucidated the structures and functions of cellular RNAPs. In this review, we introduce a brief structural feature of bacterial RNAP, the most well characterized model enzyme, and a novel experimental approach known as "Time-dependent soak-trigger-freeze X-ray crystallography" which can be used to observe the RNA synthesis reaction at atomic resolution in real time. This principle methodology can be used for elucidating fundamental mechanisms of cellular RNAP transcription.
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Affiliation(s)
- Yeonoh Shin
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Katsuhiko S Murakami
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Pennsylvania State University, University Park, PA, United States.
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11
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Long C, Romero ME, La Rocco D, Yu J. Dissecting nucleotide selectivity in viral RNA polymerases. Comput Struct Biotechnol J 2021; 19:3339-3348. [PMID: 34104356 PMCID: PMC8175102 DOI: 10.1016/j.csbj.2021.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/28/2021] [Accepted: 06/02/2021] [Indexed: 01/18/2023] Open
Abstract
Designing antiviral therapeutics is of great concern per current pandemics caused by novel coronavirus or SARS-CoV-2. The core polymerase enzyme in the viral replication/transcription machinery is generally conserved and serves well for drug target. In this work we briefly review structural biology and computational clues on representative single-subunit viral polymerases that are more or less connected with SARS-CoV-2 RNA dependent RNA polymerase (RdRp), in particular, to elucidate how nucleotide substrates and potential drug analogs are selected in the viral genome synthesis. To do that, we first survey two well studied RdRps from Polio virus and hepatitis C virus in regard to structural motifs and key residues that have been identified for the nucleotide selectivity. Then we focus on related structural and biochemical characteristics discovered for the SARS-CoV-2 RdRp. To further compare, we summarize what we have learned computationally from phage T7 RNA polymerase (RNAP) on its stepwise nucleotide selectivity, and extend discussion to a structurally similar human mitochondria RNAP, which deserves special attention as it cannot be adversely affected by antiviral treatments. We also include viral phi29 DNA polymerase for comparison, which has both helicase and proofreading activities on top of nucleotide selectivity for replication fidelity control. The helicase and proofreading functions are achieved by protein components in addition to RdRp in the coronavirus replication-transcription machine, with the proofreading strategy important for the fidelity control in synthesizing a comparatively large viral genome.
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Affiliation(s)
- Chunhong Long
- School of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | | | - Daniel La Rocco
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Jin Yu
- Department of Physics and Astronomy, Department of Chemistry, NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, CA 92697, USA
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12
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Chiu CF, Chang HY, Huang CY, Mau CZ, Kuo TT, Lee HC, Huang SY. Betulinic Acid Affects the Energy-Related Proteomic Profiling in Pancreatic Ductal Adenocarcinoma Cells. Molecules 2021; 26:molecules26092482. [PMID: 33923185 PMCID: PMC8123215 DOI: 10.3390/molecules26092482] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/21/2021] [Accepted: 04/21/2021] [Indexed: 01/14/2023] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with a 5-year survival rate of <8%. Therefore, finding new treatment strategies against PDAC cells is an imperative issue. Betulinic acid (BA), a plant-derived natural compound, has shown great potential to combat cancer owing to its versatile physiological functions. In this study, we observed the impacts of BA on the cell viability and migratory ability of PDAC cell lines, and screened differentially expressed proteins (DEPs) by an LC-MS/MS-based proteomics analysis. Our results showed that BA significantly inhibited the viability and migratory ability of PDAC cells under a relatively low dosage without affecting normal pancreatic cells. Moreover, a functional analysis revealed that BA-induced downregulation of protein clusters that participate in mitochondrial complex 1 activity and oxidative phosphorylation, which was related to decreased expressions of RNA polymerase mitochondrial (POLRMT) and translational activator of cytochrome c oxidase (TACO1), suggesting that the influence on mitochondrial function explains the effect of BA on PDAC cell growth and migration. In addition, BA also dramatically increased Apolipoprotein A1 (APOA1) expression and decreased NLR family CARD domain-containing protein 4 (NLRC4) expression, which may be involved in the dampening of PDAC migration. Notably, altered expression patterns of APOA1 and NLRC4 indicated a favorable clinical prognosis of PDAC. Based on these findings, we identified potential proteins and pathways regulated by BA from a proteomics perspective, which provides a therapeutic window for PDAC.
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Affiliation(s)
- Ching-Feng Chiu
- Graduate Institute of Metabolism and Obesity Sciences, Taipei Medical University, Taipei 11031, Taiwan; (C.-F.C.); (H.-Y.C.); (C.-Z.M.)
- Nutrition Research Center, Taipei Medical University Hospital, Taipei 11031, Taiwan
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Hsin-Yi Chang
- Graduate Institute of Metabolism and Obesity Sciences, Taipei Medical University, Taipei 11031, Taiwan; (C.-F.C.); (H.-Y.C.); (C.-Z.M.)
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei 11031, Taiwan
- Master Program in Clinical Pharmacogenomics and Pharmacoproteomics, College of Pharmacy, Taipei Medical University, Taipei 11031, Taiwan
| | - Chun-Yine Huang
- School of Nutrition and Health Sciences, Taipei Medical University, Taipei 11031, Taiwan;
| | - Chen-Zou Mau
- Graduate Institute of Metabolism and Obesity Sciences, Taipei Medical University, Taipei 11031, Taiwan; (C.-F.C.); (H.-Y.C.); (C.-Z.M.)
| | - Tzu-Ting Kuo
- Ph.D. Program for Cancer Molecular Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University and Academia Sinica, Taipei 11031, Taiwan;
| | - Hsiu-Chuan Lee
- School of Nutrition and Health Sciences, Taipei Medical University, Taipei 11031, Taiwan;
- Correspondence: (H.-C.L.); (S.-Y.H.)
| | - Shih-Yi Huang
- Graduate Institute of Metabolism and Obesity Sciences, Taipei Medical University, Taipei 11031, Taiwan; (C.-F.C.); (H.-Y.C.); (C.-Z.M.)
- Nutrition Research Center, Taipei Medical University Hospital, Taipei 11031, Taiwan
- School of Nutrition and Health Sciences, Taipei Medical University, Taipei 11031, Taiwan;
- Correspondence: (H.-C.L.); (S.-Y.H.)
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13
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Tiwari V, Baptiste BA, Okur MN, Bohr VA. Current and emerging roles of Cockayne syndrome group B (CSB) protein. Nucleic Acids Res 2021; 49:2418-2434. [PMID: 33590097 DOI: 10.1093/nar/gkab085] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 12/11/2022] Open
Abstract
Cockayne syndrome (CS) is a segmental premature aging syndrome caused primarily by defects in the CSA or CSB genes. In addition to premature aging, CS patients typically exhibit microcephaly, progressive mental and sensorial retardation and cutaneous photosensitivity. Defects in the CSB gene were initially thought to primarily impair transcription-coupled nucleotide excision repair (TC-NER), predicting a relatively consistent phenotype among CS patients. In contrast, the phenotypes of CS patients are pleiotropic and variable. The latter is consistent with recent work that implicates CSB in multiple cellular systems and pathways, including DNA base excision repair, interstrand cross-link repair, transcription, chromatin remodeling, RNAPII processing, nucleolin regulation, rDNA transcription, redox homeostasis, and mitochondrial function. The discovery of additional functions for CSB could potentially explain the many clinical phenotypes of CSB patients. This review focuses on the diverse roles played by CSB in cellular pathways that enhance genome stability, providing insight into the molecular features of this complex premature aging disease.
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Affiliation(s)
- Vinod Tiwari
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Beverly A Baptiste
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Mustafa N Okur
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Vilhelm A Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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14
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Marygold SJ, Alic N, Gilmour DS, Grewal SS. In silico identification of Drosophila melanogaster genes encoding RNA polymerase subunits. MICROPUBLICATION BIOLOGY 2020; 2020. [PMID: 33274328 PMCID: PMC7704258 DOI: 10.17912/micropub.biology.000320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Steven J Marygold
- FlyBase, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, U.K
| | - Nazif Alic
- Institute of Healthy Ageing and the Research Department of Genetics, Evolution, and Environment, University College London, London, U.K
| | - David S Gilmour
- Pennsylvania State University, Center for Eukaryotic Gene Regulation, University Park, PA, U.S.A
| | - Savraj S Grewal
- Clark H Smith Brain Tumour Centre, Arnie Charbonneau Cancer Institute, & Department of Biochemistry and Molecular Biology, University of Calgary, Alberta, Canada
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15
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Analysis of the Potential for N 4-Hydroxycytidine To Inhibit Mitochondrial Replication and Function. Antimicrob Agents Chemother 2020; 64:AAC.01719-19. [PMID: 31767721 PMCID: PMC6985706 DOI: 10.1128/aac.01719-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 11/18/2019] [Indexed: 02/06/2023] Open
Abstract
N4-Hydroxycytidine (NHC) is an antiviral ribonucleoside analog that acts as a competitive alternative substrate for virally encoded RNA-dependent RNA polymerases. It exhibits measurable levels of cytotoxicity, with 50% cytotoxic concentration values ranging from 7.5 μM in CEM cells and up to >100 μM in other cell lines. N4-Hydroxycytidine (NHC) is an antiviral ribonucleoside analog that acts as a competitive alternative substrate for virally encoded RNA-dependent RNA polymerases. It exhibits measurable levels of cytotoxicity, with 50% cytotoxic concentration values ranging from 7.5 μM in CEM cells and up to >100 μM in other cell lines. The mitochondrial DNA-dependent RNA polymerase (POLRMT) has been shown to incorporate some nucleotide analogs into mitochondrial RNAs, resulting in substantial mitochondrial toxicity. NHC was tested in multiple assays intended to determine its potential to cause mitochondrial toxicity. NHC showed similar cytotoxicity in HepG2 cells incubated in a glucose-free and glucose-containing media, suggesting that NHC does not impair mitochondrial function in this cell line based on the Crabtree effect. We demonstrate that the 5′-triphosphate of NHC can be used by POLRMT for incorporation into nascent RNA chain but does not cause immediate chain termination. In PC-3 cells treated with NHC, the 50% inhibitory concentrations of mitochondrial protein expression inhibition were 2.7-fold lower than those for nuclear-encoded protein expression, but this effect did not result in selective mitochondrial toxicity. A 14-day incubation of HepG2 cells with NHC had no effect on mitochondrial DNA copy number or extracellular lactate levels. In CEM cells treated with NHC at 10 μM, a slight decrease (by ∼20%) in mitochondrial DNA copy number and a corresponding slight increase in extracellular lactate levels were detected, but these effects were not enhanced by an increase in NHC treatment concentration. In summary, the results indicate that mitochondrial impairment by NHC is not the main contributor to the compound’s observed cytotoxicity in these cell lines.
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16
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Dumbrepatil AB, Zegalia KA, Sajja K, Kennedy RT, Marsh ENG. Targeting viperin to the mitochondrion inhibits the thiolase activity of the trifunctional enzyme complex. J Biol Chem 2020; 295:2839-2849. [PMID: 31980458 DOI: 10.1074/jbc.ra119.011526] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/09/2020] [Indexed: 12/20/2022] Open
Abstract
Understanding the mechanisms by which viruses evade host cell immune defenses is important for developing improved antiviral therapies. In an unusual twist, human cytomegalovirus co-opts the antiviral radical SAM enzyme viperin (virus-inhibitory protein, endoplasmic reticulum-associated, interferon-inducible) to enhance viral infectivity. This process involves translocation of viperin to the mitochondrion, where it binds the β-subunit (HADHB) of the mitochondrial trifunctional enzyme complex that catalyzes thiolysis of β-ketoacyl-CoA esters as part of fatty acid β-oxidation. Here we investigated how the interaction between these two enzymes alters their activities and affects cellular ATP levels. Experiments with purified enzymes indicated that viperin inhibits the thiolase activity of HADHB, but, unexpectedly, HADHB activates viperin, leading to synthesis of the antiviral nucleotide 3'-deoxy-3',4'-didehydro-CTP. Measurements of enzyme activities in lysates prepared from transfected HEK293T cells expressing these enzymes mirrored the findings obtained with purified enzymes. Thus, localizing viperin to mitochondria decreased thiolase activity, and coexpression of HADHB significantly increased viperin activity. Furthermore, targeting viperin to mitochondria also increased the rate at which HADHB is retrotranslocated out of mitochondria and degraded, providing an additional mechanism by which viperin reduces HADHB activity. Targeting viperin to mitochondria decreased cellular ATP levels by more than 50%, consistent with the enzyme disrupting fatty acid catabolism. These results provide biochemical insight into the mechanism by which human cytomegalovirus subverts viperin; they also provide a biochemical rationale for viperin's recently discovered role in regulating thermogenesis in adipose tissues.
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Affiliation(s)
- Arti B Dumbrepatil
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Kelcie A Zegalia
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Keerthi Sajja
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Robert T Kennedy
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - E Neil G Marsh
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055; Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055.
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17
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Abstract
DNA replication in human mitochondria has been studied for several decades; however, its mechanism still remains unclear. During the last 15 years, many new experimental data on the mitochondrial replication have appeared, although extremely contradictory. Two asynchronous (strand displacement and RITOLS) and one synchronous (strand-coupled) replication models have been proposed. In the asynchronous models, replication from the origin in the H-chain starts earlier, so that the replication of the two chains ends at different times. The synchronous model is more traditional and implies two replication forks with leading and lagging strands initiated at the same origin. For each of the three models, both confirming and contradicting experimental data exist. Most likely, there is no single model of mitochondrial replication. It is possible that the unique mitochondrial replication machinery that has originated as a results of endosymbiosis has an unexpected variety of replication strategies to maintain the mitochondrial genome. An unusual combination of enzymes of different origin (phage, bacterial, eukaryotic) and unique features of the mitochondrial genome (existance of heavy and light chains, insertions of ribonucleotides, a variety of origins) can allow replication through different mechanisms. In human mitochondria, asynchronous replication seems to dominate; however, synchronous replication is also possible under certain conditions. In the human heart mitochondria, circular mitochondrial DNA (mtDNA) molecules can rearrange in a network of rapidly replicating linear genomes, thereby suggesting possible existence of a wide range of replication mechanisms in the mitochondria. The review describes the main stages of mtDNA replication and enzymes involved in this process, as well as discusses the prospects of mitochondrial replication studies.
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Affiliation(s)
- L A Zinovkina
- Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics, Moscow, 119234, Russia.
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18
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Plant Organelle Genome Replication. PLANTS 2019; 8:plants8100358. [PMID: 31546578 PMCID: PMC6843274 DOI: 10.3390/plants8100358] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/14/2019] [Accepted: 09/18/2019] [Indexed: 12/21/2022]
Abstract
Mitochondria and chloroplasts perform essential functions in respiration, ATP production, and photosynthesis, and both organelles contain genomes that encode only some of the proteins that are required for these functions. The proteins and mechanisms for organelle DNA replication are very similar to bacterial or phage systems. The minimal replisome may consist of DNA polymerase, a primase/helicase, and a single-stranded DNA binding protein (SSB), similar to that found in bacteriophage T7. In Arabidopsis, there are two genes for organellar DNA polymerases and multiple potential genes for SSB, but there is only one known primase/helicase protein to date. Genome copy number varies widely between type and age of plant tissues. Replication mechanisms are only poorly understood at present, and may involve multiple processes, including recombination-dependent replication (RDR) in plant mitochondria and perhaps also in chloroplasts. There are still important questions remaining as to how the genomes are maintained in new organelles, and how genome copy number is determined. This review summarizes our current understanding of these processes.
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19
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Sun S, Wu C, Yang C, Chen J, Wang X, Nan Y, Huang Z, Ma L. Prognostic roles of mitochondrial transcription termination factors in non-small cell lung cancer. Oncol Lett 2019; 18:3453-3462. [PMID: 31516563 PMCID: PMC6732965 DOI: 10.3892/ol.2019.10680] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 05/02/2019] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial transcription termination factors (MTERFs) regulate mitochondrial gene transcription and metabolism in numerous types of cells. Previous studies have indicated that MTERFs serve pivotal roles in the pathogenesis of various cancer types. However, the expression and prognostic roles of MTERFs in patients with non-small cell lung cancer (NSCLC) remain elusive. The present study investigated the gene alteration frequency and expression level using Gene Expression Omnibus datasets and reverse transcription-quantitative polymerase chain reaction, and evaluated the prognostic roles of MTERFs in patients with NSCLC using the Kaplan-Meier plotter database. In human lung cancer tissues, it was observed that the mRNA levels of MTERF1, 2, 3 and 4 were positively associated with the copy number of these genes. The mRNA expression levels of MTERF1 and 3 were significantly increased in NSCLC tissues compared with adjacent non-tumor tissues; however, the mRNA expression of MTERF2 was significantly decreased in NSCLC tissues. High mRNA expression levels of MTERF1, 2, 3 and 4 were strongly associated with an improved overall survival rate (OS) in patients with lung adenocarcinoma. Additionally, high mRNA expression levels of MTERF1, 2, 3 and 4 were also strongly associated with an improved OS of patients with NSCLC in the earlier stages of disease (stage I) or patients with negative surgical margins. These results indicate the critical prognostic values of MTERF expression levels in NSCLC. The findings of the present study may be beneficial for understanding the molecular biology mechanism of NSCLC and for generating effective therapeutic approaches for patients with NSCLC.
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Affiliation(s)
- Shuangyan Sun
- Department of Radiology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Chunjiao Wu
- Department of Thoracic Oncology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Changliang Yang
- Department of Thoracic Oncology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Jian Chen
- Department of Interventional Radiology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Xiu Wang
- Department of Interventional Radiology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Yingji Nan
- Department of Radiology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Zhicheng Huang
- Department of Radiology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Lixia Ma
- Department of Thoracic Oncology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
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20
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Development of a fluorescence-based method for the rapid determination of Zika virus polymerase activity and the screening of antiviral drugs. Sci Rep 2019; 9:5397. [PMID: 30932009 PMCID: PMC6444013 DOI: 10.1038/s41598-019-41998-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 03/20/2019] [Indexed: 12/14/2022] Open
Abstract
Zika virus (ZIKV) is an emerging pathogen that has been associated with large numbers of cases of severe neurologic disease, including Guillain-Barré syndrome and microcephaly. Despite its recent establishment as a serious global public health concern there are no licensed therapeutics to control this virus. Accordingly, there is an urgent need to develop methods for the high-throughput screening of antiviral agents. We describe here a fluorescence-based method to monitor the real-time polymerization activity of Zika virus RNA-dependent RNA polymerase (RdRp). By using homopolymeric RNA template molecules, de novo RNA synthesis can be detected with a fluorescent dye, which permits the specific quantification and kinetics of double-strand RNA formation. ZIKV RdRp activity detected using this fluorescence-based assay positively correlated with traditional assays measuring the incorporation of radiolabeled nucleotides. We also validated this method as a suitable assay for the identification of ZIKV inhibitors targeting the viral polymerase using known broad-spectrum inhibitors. The assay was also successfully adapted to detect RNA polymerization activity by different RdRps, illustrated here using purified RdRps from hepatitis C virus and foot-and-mouth disease virus. The potential of fluorescence-based approaches for the enzymatic characterization of viral polymerases, as well as for high-throughput screening of antiviral drugs, are discussed.
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21
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Abeti R, Zeitlberger A, Peelo C, Fassihi H, Sarkany RPE, Lehmann AR, Giunti P. Xeroderma pigmentosum: overview of pharmacology and novel therapeutic strategies for neurological symptoms. Br J Pharmacol 2019; 176:4293-4301. [PMID: 30499105 DOI: 10.1111/bph.14557] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 08/06/2018] [Accepted: 09/19/2018] [Indexed: 12/11/2022] Open
Abstract
Xeroderma pigmentosum (XP) encompasses a group of rare diseases characterized in most cases by malfunction of nucleotide excision repair (NER), which results in an increased sensitivity to UV radiation in affected individuals. Approximately 25-30% of XP patients present with neurological symptoms, such as sensorineural deafness, mental deterioration and ataxia. Although it is known that dysfunctional DNA repair is the primary pathogenesis in XP, growing evidence suggests that mitochondrial pathophysiology may also occur. This appears to be secondary to dysfunctional NER but may contribute to the neurodegenerative process in these patients. The available pharmacological treatments in XP mostly target the dermal manifestations of the disease. In the present review, we outline how current understanding of the pathophysiology of XP could be used to develop novel therapies to counteract the neurological symptoms. Moreover, the coexistence of cancer and neurodegeneration present in XP led us to focus on possible new avenues targeting mitochondrial pathophysiology. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.
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Affiliation(s)
- Rosella Abeti
- Ataxia Centre, Department of Clinical and Movement Neurosciences, University College London, Institute of Neurology London, London, UK
| | - Anna Zeitlberger
- Ataxia Centre, Department of Clinical and Movement Neurosciences, University College London, Institute of Neurology London, London, UK
| | - Colm Peelo
- Ataxia Centre, Department of Clinical and Movement Neurosciences, University College London, Institute of Neurology London, London, UK
| | - Hiva Fassihi
- National Xeroderma Pigmentosum Service, St John's Institute of Dermatology Guy's and St Thomas' Foundation Trust, London, UK
| | - Robert P E Sarkany
- National Xeroderma Pigmentosum Service, St John's Institute of Dermatology Guy's and St Thomas' Foundation Trust, London, UK
| | - Alan R Lehmann
- Genome Damage and Stability Centre, University of Sussex, Brighton, UK
| | - Paola Giunti
- Ataxia Centre, Department of Clinical and Movement Neurosciences, University College London, Institute of Neurology London, London, UK.,National Xeroderma Pigmentosum Service, St John's Institute of Dermatology Guy's and St Thomas' Foundation Trust, London, UK
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22
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Dengue drug discovery: Progress, challenges and outlook. Antiviral Res 2018; 163:156-178. [PMID: 30597183 DOI: 10.1016/j.antiviral.2018.12.016] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/22/2018] [Accepted: 12/25/2018] [Indexed: 12/14/2022]
Abstract
In the context of the only available vaccine (DENGVAXIA) that was marketed in several countries, but poses higher risks to unexposed individuals, the development of antivirals for dengue virus (DENV), whilst challenging, would bring significant benefits to public health. Here recent progress in the field of DENV drug discovery made in academic laboratories and industry is reviewed. Characteristics of an ideal DENV antiviral molecule, given the specific immunopathology provoked by this acute viral infection, are described. New chemical classes identified from biochemical, biophysical and phenotypic screens that target viral (especially NS4B) and host proteins, offer promising opportunities for further development. In particular, new methodologies ("omics") can accelerate the discovery of much awaited flavivirus specific inhibitors. Challenges and opportunities in lead identification activities as well as the path to clinical development of dengue drugs are discussed. To galvanize DENV drug discovery, collaborative public-public partnerships and open-access resources will greatly benefit both the DENV research community and DENV patients.
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23
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Freedman H, Winter P, Tuszynski J, Tyrrell DL, Houghton M. A computational approach for predicting off-target toxicity of antiviral ribonucleoside analogues to mitochondrial RNA polymerase. J Biol Chem 2018; 293:9696-9705. [PMID: 29739852 DOI: 10.1074/jbc.ra118.002588] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 05/04/2018] [Indexed: 12/18/2022] Open
Abstract
In the development of antiviral drugs that target viral RNA-dependent RNA polymerases, off-target toxicity caused by the inhibition of the human mitochondrial RNA polymerase (POLRMT) is a major liability. Therefore, it is essential that all new ribonucleoside analogue drugs be accurately screened for POLRMT inhibition. A computational tool that can accurately predict NTP binding to POLRMT could assist in evaluating any potential toxicity and in designing possible salvaging strategies. Using the available crystal structure of POLRMT bound to an RNA transcript, here we created a model of POLRMT with an NTP molecule bound in the active site. Furthermore, we implemented a computational screening procedure that determines the relative binding free energy of an NTP analogue to POLRMT by free energy perturbation (FEP), i.e. a simulation in which the natural NTP molecule is slowly transformed into the analogue and back. In each direction, the transformation was performed over 40 ns of simulation on our IBM Blue Gene Q supercomputer. This procedure was validated across a panel of drugs for which experimental dissociation constants were available, showing that NTP relative binding free energies could be predicted to within 0.97 kcal/mol of the experimental values on average. These results demonstrate for the first time that free-energy simulation can be a useful tool for predicting binding affinities of NTP analogues to a polymerase. We expect that our model, together with similar models of viral polymerases, will be very useful in the screening and future design of NTP inhibitors of viral polymerases that have no mitochondrial toxicity.
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Affiliation(s)
- Holly Freedman
- From the Li Ka Shing Applied Virology Institute, Department of Medical Microbiology and Immunology and
| | - Philip Winter
- the Department of Oncology, University of Alberta, Edmonton, Alberta T6G 2R7, Canada
| | - Jack Tuszynski
- the Department of Oncology, University of Alberta, Edmonton, Alberta T6G 2R7, Canada.,the Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada and
| | - D Lorne Tyrrell
- From the Li Ka Shing Applied Virology Institute, Department of Medical Microbiology and Immunology and
| | - Michael Houghton
- From the Li Ka Shing Applied Virology Institute, Department of Medical Microbiology and Immunology and
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24
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Simple In Vitro Assay To Evaluate the Incorporation Efficiency of Ribonucleotide Analog 5'-Triphosphates into RNA by Human Mitochondrial DNA-Dependent RNA Polymerase. Antimicrob Agents Chemother 2018; 62:AAC.01830-17. [PMID: 29180528 PMCID: PMC5786792 DOI: 10.1128/aac.01830-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/21/2017] [Indexed: 01/27/2023] Open
Abstract
There is a growing body of evidence suggesting that some ribonucleoside/ribonucleotide analogs may be incorporated into mitochondrial RNA by human mitochondrial DNA-dependent RNA polymerase (POLRMT) and disrupt mitochondrial RNA synthesis. An assessment of the incorporation efficiency of a ribonucleotide analog 5′-triphosphate by POLRMT may be used to evaluate the potential mitochondrial toxicity of the analog early in the development process. In this report, we provide a simple method to prepare active recombinant POLRMT. A robust in vitro nonradioactive primer extension assay was developed to assay the incorporation efficiency of ribonucleotide analog 5′-triphosphates. Our results show that many ribonucleotide analogs, including some antiviral compounds currently in various preclinical or clinical development stages, can be incorporated into newly synthesized RNA by POLRMT and that the incorporation of some of them can lead to chain termination. The discrimination (D) values of ribonucleotide analog 5′-triphosphates over those of natural ribonucleotide triphosphates (rNTPs) were measured to evaluate the incorporation efficiency of the ribonucleotide analog 5′-triphosphates by POLRMT. The discrimination values of natural rNTPs under the condition of misincorporation by POLRMT were used as a reference to evaluate the potential mitochondrial toxicity of ribonucleotide analogs. We propose the following criteria for the potential mitochondrial toxicity of ribonucleotide analogs based on D values: a safe compound has a D value of >105; a potentially toxic compound has a D value of >104 but <105; and a toxic compound has a D value of <104. This report provides a simple screening method that should assist investigators in designing ribonucleoside-based drugs having lower mitochondrial toxicity.
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Young MJ. Off-Target Effects of Drugs that Disrupt Human Mitochondrial DNA Maintenance. Front Mol Biosci 2017; 4:74. [PMID: 29214156 PMCID: PMC5702650 DOI: 10.3389/fmolb.2017.00074] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 10/31/2017] [Indexed: 12/17/2022] Open
Abstract
Nucleoside reverse transcriptase inhibitors (NRTIs) were the first drugs used to treat human immunodeficiency virus (HIV) the cause of acquired immunodeficiency syndrome. Development of severe mitochondrial toxicity has been well documented in patients infected with HIV and administered NRTIs. In vitro biochemical experiments have demonstrated that the replicative mitochondrial DNA (mtDNA) polymerase gamma, Polg, is a sensitive target for inhibition by metabolically active forms of NRTIs, nucleotide reverse transcriptase inhibitors (NtRTIs). Once incorporated into newly synthesized daughter strands NtRTIs block further DNA polymerization reactions. Human cell culture and animal studies have demonstrated that cell lines and mice exposed to NRTIs display mtDNA depletion. Further complicating NRTI off-target effects on mtDNA maintenance, two additional DNA polymerases, Pol beta and PrimPol, were recently reported to localize to mitochondria as well as the nucleus. Similar to Polg, in vitro work has demonstrated both Pol beta and PrimPol incorporate NtRTIs into nascent DNA. Cell culture and biochemical experiments have also demonstrated that antiviral ribonucleoside drugs developed to treat hepatitis C infection act as off-target substrates for POLRMT, the mitochondrial RNA polymerase and primase. Accompanying the above-mentioned topics, this review examines: (1) mtDNA maintenance in human health and disease, (2) reports of DNA polymerases theta and zeta (Rev3) localizing to mitochondria, and (3) additional drugs with off-target effects on mitochondrial function. Lastly, mtDNA damage may induce cell death; therefore, the possibility of utilizing compounds that disrupt mtDNA maintenance to kill cancer cells is discussed.
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Affiliation(s)
- Matthew J Young
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL, United States
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Wang D, Li GD, Fan Y, Zhang DF, Bi R, Yu XF, Long H, Li YY, Yao YG. The mtDNA replication-related genes TFAM and POLG are associated with leprosy in Han Chinese from Southwest China. J Dermatol Sci 2017; 88:349-356. [PMID: 28958595 DOI: 10.1016/j.jdermsci.2017.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/07/2017] [Accepted: 09/13/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND The pathogen Mycobacterium leprae of leprosy is heavily dependent on the host energy metabolites and nutritional products for survival. Previously we and others have identified associations of several mitochondrion-related genes and mitochondrial DNA (mtDNA) copy number alterations with leprosy and/or its subtype. We hypothesized that genetic variants of mtDNA replication-related genes would affect leprosy. OBJECTIVE We aimed to identify genetic associations between the mtDNA replication-related genes TFAM, POLG and leprosy. METHODS Genetic association study was performed in 2898 individuals from two independent sample sets in Yunnan Province, China. We first screened 7 tag SNPs of TFAM and POLG in 527 leprosy cases and 583 controls (Sample I). Expression quantitative trait loci (eQTL) analysis and differential mRNA expression were analyzed to discern potential effect of risk variants. The entire exon region of TFAM and POLG were further analyzed in 798 leprosy cases and 990 controls (Sample II; 4327 East Asians from the ExAC dataset was included as a reference control) by using targeted gene sequencing for fine mapping potentially causal variants. RESULTS Two tag SNPs of TFAM (rs1049432, P=0.007) and POLG (rs3176238, P=0.006) were associated with multibacillary leprosy (MB) in Sample I and the significance survived correction for multiple comparisons. SNPs rs1937 of TFAM (which was linked with rs1049432) and rs61756401 of POLG were associated with leprosy, whereas no potentially causative coding variants were identified in Sample II. The eQTL analysis showed that rs1049432 was a significant cis eQTL for TFAM in nerve tissue (P=1.20×10-12), and rs3176238 was a significant cis eQTL for POLG in nerve (P=3.90×10-13) and skin tissues (P=2.50×10-11). Consistently, mRNA level of POLG was differentially expressed in leprotic skin lesions. CONCLUSIONS Genetic variants of TFAM and POLG were associated with leprosy in Han Chinese, presumably by affecting gene expression.
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Affiliation(s)
- Dong Wang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China
| | - Guo-Dong Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China; Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Yu Fan
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China
| | - Deng-Feng Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China
| | - Rui Bi
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China
| | - Xiu-Feng Yu
- Wenshan Institute of Dermatology, Wenshan, Yunnan, 663000, China
| | - Heng Long
- Wenshan Institute of Dermatology, Wenshan, Yunnan, 663000, China
| | - Yu-Ye Li
- Department of Dermatology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Yong-Gang Yao
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China; Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
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Sultana S, Solotchi M, Ramachandran A, Patel SS. Transcriptional fidelities of human mitochondrial POLRMT, yeast mitochondrial Rpo41, and phage T7 single-subunit RNA polymerases. J Biol Chem 2017; 292:18145-18160. [PMID: 28882896 DOI: 10.1074/jbc.m117.797480] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 08/23/2017] [Indexed: 12/31/2022] Open
Abstract
Single-subunit RNA polymerases (RNAPs) are present in phage T7 and in mitochondria of all eukaryotes. This RNAP class plays important roles in biotechnology and cellular energy production, but we know little about its fidelity and error rates. Herein, we report the error rates of three single-subunit RNAPs measured from the catalytic efficiencies of correct and all possible incorrect nucleotides. The average error rates of T7 RNAP (2 × 10-6), yeast mitochondrial Rpo41 (6 × 10-6), and human mitochondrial POLRMT (RNA polymerase mitochondrial) (2 × 10-5) indicate high accuracy/fidelity of RNA synthesis resembling those of replicative DNA polymerases. All three RNAPs exhibit a distinctly high propensity for GTP misincorporation opposite dT, predicting frequent A→G errors in RNA with rates of ∼10-4 The A→C, G→A, A→U, C→U, G→U, U→C, and U→G errors mostly due to pyrimidine-purine mismatches were relatively frequent (10-5-10-6), whereas C→G, U→A, G→C, and C→A errors from purine-purine and pyrimidine-pyrimidine mismatches were rare (10-7-10-10). POLRMT also shows a high C→A error rate on 8-oxo-dG templates (∼10-4). Strikingly, POLRMT shows a high mutagenic bypass rate, which is exacerbated by TEFM (transcription elongation factor mitochondrial). The lifetime of POLRMT on terminally mismatched elongation substrate is increased in the presence of TEFM, which allows POLRMT to efficiently bypass the error and continue with transcription. This investigation of nucleotide selectivity on normal and oxidatively damaged DNA by three single-subunit RNAPs provides the basic information to understand the error rates in mitochondria and, in the case of T7 RNAP, to assess the quality of in vitro transcribed RNAs.
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Affiliation(s)
- Shemaila Sultana
- From the Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School and
| | - Mihai Solotchi
- School of Arts and Sciences, Rutgers University, Piscataway, New Jersey 08854
| | - Aparna Ramachandran
- From the Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School and
| | - Smita S Patel
- From the Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School and
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Byrnes J, Hauser K, Norona L, Mejia E, Simmerling C, Garcia-Diaz M. Base Flipping by MTERF1 Can Accommodate Multiple Conformations and Occurs in a Stepwise Fashion. J Mol Biol 2016; 428:2542-2556. [PMID: 26523681 PMCID: PMC4851923 DOI: 10.1016/j.jmb.2015.10.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 10/14/2015] [Accepted: 10/20/2015] [Indexed: 11/28/2022]
Abstract
Human mitochondrial transcription termination occurs within the leu-tRNA gene and is mediated by the DNA binding protein MTERF1. The crystal structure of MTERF1 bound to the canonical termination sequence reveals a rare base flipping event that involves the eversion of three nucleotides. These nucleotides are stabilized by stacking interactions with three MTERF1 residues, which are essential not only for base flipping but also for termination activity. To further understand the mechanism of base flipping, we examined each of the individual stacking interactions in structural, energetic and functional detail. Individual substitutions of Arg162, Tyr288 and Phe243 have revealed unequal contributions to overall termination activity. Furthermore, our work identifies an important role for Phe322 in the base flipping mechanism and we demonstrate how Phe322 and Phe243 are important for coupling base flipping between the heavy and light strand DNA chains. We propose a stepwise model for the base flipping process that recapitulates our observations. Finally, we show that MTERF1 has the ability to accommodate alternate active conformations. The adaptability of base flipping has implications for MTERF1 function and for the putative function of MTERF1 at alternative binding sites in human mitochondria.
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Affiliation(s)
- James Byrnes
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Kevin Hauser
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA
| | - Leah Norona
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Edison Mejia
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Carlos Simmerling
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA; Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Miguel Garcia-Diaz
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA.
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29
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Bar-Yaacov D, Hadjivasiliou Z, Levin L, Barshad G, Zarivach R, Bouskila A, Mishmar D. Mitochondrial Involvement in Vertebrate Speciation? The Case of Mito-nuclear Genetic Divergence in Chameleons. Genome Biol Evol 2015; 7:3322-36. [PMID: 26590214 PMCID: PMC4700957 DOI: 10.1093/gbe/evv226] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Compatibility between the nuclear (nDNA) and mitochondrial (mtDNA) genomes is important for organismal health. However, its significance for major evolutionary processes such as speciation is unclear, especially in vertebrates. We previously identified a sharp mtDNA-specific sequence divergence between morphologically indistinguishable chameleon populations (Chamaeleo chamaeleon recticrista) across an ancient Israeli marine barrier (Jezreel Valley). Because mtDNA introgression and gender-based dispersal were ruled out, we hypothesized that mtDNA spatial division was maintained by mito-nuclear functional compensation. Here, we studied RNA-seq generated from each of ten chameleons representing the north and south populations and identified candidate nonsynonymous substitutions (NSSs) matching the mtDNA spatial distribution. The most prominent NSS occurred in 14 nDNA-encoded mitochondrial proteins. Increased chameleon sample size (N = 70) confirmed the geographic differentiation in POLRMT, NDUFA5, ACO1, LYRM4, MARS2, and ACAD9. Structural and functionality evaluation of these NSSs revealed high functionality. Mathematical modeling suggested that this mito-nuclear spatial divergence is consistent with hybrid breakdown. We conclude that our presented evidence and mathematical model underline mito-nuclear interactions as a likely role player in incipient speciation in vertebrates.
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Affiliation(s)
- Dan Bar-Yaacov
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Zena Hadjivasiliou
- Centre for Mathematics, Physics and Engineering in the Life Sciences and Experimental Biology, UCL, London, United Kingdom Department of Genetics, Evolution and Environment, UCL, London, United Kingdom
| | - Liron Levin
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Gilad Barshad
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Raz Zarivach
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Amos Bouskila
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Dan Mishmar
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
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30
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The complex crosstalk between mitochondria and the nucleus: What goes in between? Int J Biochem Cell Biol 2015; 63:10-5. [DOI: 10.1016/j.biocel.2015.01.026] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 01/21/2015] [Accepted: 01/29/2015] [Indexed: 12/22/2022]
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31
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Moriyama T, Tajima N, Sekine K, Sato N. Localization and phylogenetic analysis of enzymes related to organellar genome replication in the unicellular rhodophyte Cyanidioschyzon merolae. Genome Biol Evol 2014; 6:228-37. [PMID: 24407855 PMCID: PMC3914683 DOI: 10.1093/gbe/evu009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Plants and algae possess plastids and mitochondria harboring their own genomes, which are replicated by the apparatus consisting of DNA polymerase, DNA primase, DNA helicase, DNA topoisomerase, single-stranded DNA maintenance protein, DNA ligase, and primer removal enzyme. In the higher plant Arabidopsis thaliana, organellar replication-related enzymes (OREs) are similar in plastids and mitochondria because many of them are dually targeted to plastids and mitochondria. In the red algae, there is a report about a DNA replicase, plant/protist organellar DNA polymerase, which is localized to both plastids and mitochondria. However, other OREs remain unclear in algae. Here, we identified OREs possibly localized to organelles in the unicellular rhodophyte Cyanidioschyzon merolae. We then examined intracellular localization of green fluorescent protein-fusion proteins of these enzymes in C. merolae, whose cell has a single plastid and a single mitochondrion and is suitable for localization analysis, demonstrating that the plastid and the mitochondrion contain markedly different components of replication machinery. Phylogenetic analyses revealed that the organelle replication apparatus was composed of enzymes of various different origins, such as proteobacterial, cyanobacterial, and eukaryotic, in both red algae and green plants. Especially in the red alga, many enzymes of cyanobacterial origin remained. Finally, on the basis of the results of localization and phylogenetic analyses, we propose a model on the succession of OREs in eukaryotes.
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Affiliation(s)
- Takashi Moriyama
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan
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32
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Moriyama T, Sato N. Enzymes involved in organellar DNA replication in photosynthetic eukaryotes. FRONTIERS IN PLANT SCIENCE 2014; 5:480. [PMID: 25278952 PMCID: PMC4166229 DOI: 10.3389/fpls.2014.00480] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 08/30/2014] [Indexed: 05/18/2023]
Abstract
Plastids and mitochondria possess their own genomes. Although the replication mechanisms of these organellar genomes remain unclear in photosynthetic eukaryotes, several organelle-localized enzymes related to genome replication, including DNA polymerase, DNA primase, DNA helicase, DNA topoisomerase, single-stranded DNA maintenance protein, DNA ligase, primer removal enzyme, and several DNA recombination-related enzymes, have been identified. In the reference Eudicot plant Arabidopsis thaliana, the replication-related enzymes of plastids and mitochondria are similar because many of them are dual targeted to both organelles, whereas in the red alga Cyanidioschyzon merolae, plastids and mitochondria contain different replication machinery components. The enzymes involved in organellar genome replication in green plants and red algae were derived from different origins, including proteobacterial, cyanobacterial, and eukaryotic lineages. In the present review, we summarize the available data for enzymes related to organellar genome replication in green plants and red algae. In addition, based on the type and distribution of replication enzymes in photosynthetic eukaryotes, we discuss the transitional history of replication enzymes in the organelles of plants.
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Affiliation(s)
- Takashi Moriyama
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
- Japan Science and Technology Agency – Core Research for Evolutional Science and TechnologyTokyo, Japan
| | - Naoki Sato
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
- Japan Science and Technology Agency – Core Research for Evolutional Science and TechnologyTokyo, Japan
- *Correspondence: Naoki Sato, Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan e-mail:
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Fluorescent methods to study transcription initiation and transition into elongation. EXPERIENTIA SUPPLEMENTUM (2012) 2014; 105:105-30. [PMID: 25095993 PMCID: PMC4430081 DOI: 10.1007/978-3-0348-0856-9_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The DNA-dependent RNA polymerases induce specific conformational changes in the promoter DNA during transcription initiation. Fluorescence spectroscopy sensitively monitors these DNA conformational changes in real time and at equilibrium providing powerful ways to estimate interactions in transcriptional complexes and to assess how transcription is regulated by the promoter DNA sequence, transcription factors, and small ligands. Ensemble fluorescence methods described here probe the individual steps of promoter binding, bending, opening, and transition into the elongation using T7 phage and mitochondrial transcriptional systems as examples.
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Kotiadis VN, Duchen MR, Osellame LD. Mitochondrial quality control and communications with the nucleus are important in maintaining mitochondrial function and cell health. Biochim Biophys Acta Gen Subj 2013; 1840:1254-65. [PMID: 24211250 PMCID: PMC3970188 DOI: 10.1016/j.bbagen.2013.10.041] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 10/14/2013] [Accepted: 10/29/2013] [Indexed: 12/14/2022]
Abstract
BACKGROUND The maintenance of cell metabolism and homeostasis is a fundamental characteristic of living organisms. In eukaryotes, mitochondria are the cornerstone of these life supporting processes, playing leading roles in a host of core cellular functions, including energy transduction, metabolic and calcium signalling, and supporting roles in a number of biosynthetic pathways. The possession of a discrete mitochondrial genome dictates that the maintenance of mitochondrial 'fitness' requires quality control mechanisms which involve close communication with the nucleus. SCOPE OF REVIEW This review explores the synergistic mechanisms that control mitochondrial quality and function and ensure cellular bioenergetic homeostasis. These include antioxidant defence mechanisms that protect against oxidative damage caused by reactive oxygen species, while regulating signals transduced through such free radicals. Protein homeostasis controls import, folding, and degradation of proteins underpinned by mechanisms that regulate bioenergetic capacity through the mitochondrial unfolded protein response. Autophagic machinery is recruited for mitochondrial turnover through the process of mitophagy. Mitochondria also communicate with the nucleus to exact specific transcriptional responses through retrograde signalling pathways. MAJOR CONCLUSIONS The outcome of mitochondrial quality control is not only reliant on the efficient operation of the core homeostatic mechanisms but also in the effective interaction of mitochondria with other cellular components, namely the nucleus. GENERAL SIGNIFICANCE Understanding mitochondrial quality control and the interactions between the organelle and the nucleus will be crucial in developing therapies for the plethora of diseases in which the pathophysiology is determined by mitochondrial dysfunction. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
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Affiliation(s)
- Vassilios N Kotiadis
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, UK; UCL Consortium for Mitochondrial Research, University College London, WC1E 6BT, UK
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, UK; UCL Consortium for Mitochondrial Research, University College London, WC1E 6BT, UK
| | - Laura D Osellame
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, UK; UCL Consortium for Mitochondrial Research, University College London, WC1E 6BT, UK.
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Adeva M, González-Lucán M, Seco M, Donapetry C. Enzymes involved in l-lactate metabolism in humans. Mitochondrion 2013; 13:615-29. [DOI: 10.1016/j.mito.2013.08.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/29/2013] [Accepted: 08/30/2013] [Indexed: 12/20/2022]
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36
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Structure of human mitochondrial RNA polymerase elongation complex. Nat Struct Mol Biol 2013; 20:1298-303. [PMID: 24096365 PMCID: PMC4321815 DOI: 10.1038/nsmb.2683] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 09/04/2013] [Indexed: 12/22/2022]
Abstract
The crystal structure of the human mitochondrial RNA polymerase (mtRNAP) transcription elongation complex was determined at 2.65 Å resolution. The structure reveals a 9–base pair hybrid formed between the DNA template and the RNA transcript and one turn of DNA both upstream and downstream of the hybrid. Comparisons with the distantly related RNAP from bacteriophage T7 indicates conserved mechanisms for substrate binding and nucleotide incorporation, but also strong mechanistic differences. Whereas T7 RNAP refolds during the transition from initiation to elongation, mtRNAP adopts an intermediary conformation that is capable of elongation without refolding. The intercalating hairpin that melts DNA during T7 RNAP initiation separates RNA from DNA during mtRNAP elongation. Newly synthesized RNA exits towards the PPR domain, a unique feature of mtRNAP with conserved RNA recognition motifs.
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37
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Kasashima K, Nagao Y, Endo H. Dynamic regulation of mitochondrial genome maintenance in germ cells. Reprod Med Biol 2013; 13:11-20. [PMID: 24482608 PMCID: PMC3890057 DOI: 10.1007/s12522-013-0162-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 07/04/2013] [Indexed: 12/11/2022] Open
Abstract
Mitochondria play a crucial role in the development and function of germ cells. Mitochondria contain a maternally inherited genome that should be transmitted to offspring without reactive oxygen species‐induced damage during germ line development. Germ cells are also involved in the mitochondrial DNA (mtDNA) bottleneck; thus, the appropriate regulation of mtDNA in these cells is very important for this characteristic transmission. In this review, we focused on unique regulation of the mitochondrial genome in animal germ cells; paternal elimination and the mtDNA bottleneck in females. We also summarized the mitochondrial nucleoid factors involved in various mtDNA regulation pathways. Among them, mitochondrial transcription factor A (TFAM), which has pleiotropic and essential roles in mtDNA maintenance, appears to have putative roles in germ cell regulation.
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Affiliation(s)
- Katsumi Kasashima
- Department of Biochemistry, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 Japan
| | - Yasumitsu Nagao
- Center for Experimental Medicine, Jichi Medical University, Shimotsuke, Tochigi 329-0498 Japan
| | - Hitoshi Endo
- Department of Biochemistry, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 Japan
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38
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Teng CY, Dang Y, Danne JC, Waller RF, Green BR. Mitochondrial Genes of Dinoflagellates Are Transcribed by a Nuclear-Encoded Single-Subunit RNA Polymerase. PLoS One 2013; 8:e65387. [PMID: 23840326 PMCID: PMC3686807 DOI: 10.1371/journal.pone.0065387] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 04/27/2013] [Indexed: 11/18/2022] Open
Abstract
Dinoflagellates are a large group of algae that contribute significantly to marine productivity and are essential photosynthetic symbionts of corals. Although these algae have fully-functioning mitochondria and chloroplasts, both their organelle genomes have been highly reduced and the genes fragmented and rearranged, with many aberrant transcripts. However, nothing is known about their RNA polymerases. We cloned and sequenced the gene for the nuclear-encoded mitochondrial polymerase (RpoTm) of the dinoflagellate Heterocapsa triquetra and showed that the protein presequence targeted a GFP construct into yeast mitochondria. The gene belongs to a small gene family, which includes a variety of 3′-truncated copies that may have originated by retroposition. The catalytic C-terminal domain of the protein shares nine conserved sequence blocks with other single-subunit polymerases and is predicted to have the same fold as the human enzyme. However, the N-terminal (promoter binding/transcription initiation) domain is not well-conserved. In conjunction with the degenerate nature of the mitochondrial genome, this suggests a requirement for novel accessory factors to ensure the accurate production of functional mRNAs.
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Affiliation(s)
- Chang Ying Teng
- Botany Department, University of British Columbia, Vancouver, B.C., Canada
- Life Sciences Department, Ludong University, Yantai, Shandong, China
| | - Yunkun Dang
- Botany Department, University of British Columbia, Vancouver, B.C., Canada
| | - Jillian C. Danne
- School of Botany, University of Melbourne, Melbourne, Victoria, Australia
| | - Ross F. Waller
- School of Botany, University of Melbourne, Melbourne, Victoria, Australia
| | - Beverley R. Green
- Botany Department, University of British Columbia, Vancouver, B.C., Canada
- * E-mail:
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39
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Scheibye-Knudsen M, Croteau DL, Bohr VA. Mitochondrial deficiency in Cockayne syndrome. Mech Ageing Dev 2013; 134:275-83. [PMID: 23435289 PMCID: PMC3663877 DOI: 10.1016/j.mad.2013.02.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 01/24/2013] [Accepted: 02/08/2013] [Indexed: 01/05/2023]
Abstract
Cockayne syndrome is a rare inherited disorder characterized by accelerated aging, cachectic dwarfism and many other features. Recent work has implicated mitochondrial dysfunction in the pathogenesis of this disease. This is particularly interesting since mitochondrial deficiencies are believed to be important in the aging process. In this review, we discuss recent findings of mitochondrial pathology in Cockayne syndrome and suggest possible mechanisms for the mitochondrial dysfunction.
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Affiliation(s)
| | - Deborah L. Croteau
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, USA
| | - Vilhelm A. Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, USA
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40
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Lightowlers RN, Chrzanowska-Lightowlers ZMA. Human pentatricopeptide proteins: only a few and what do they do? RNA Biol 2013; 10:1433-8. [PMID: 23635806 PMCID: PMC3858426 DOI: 10.4161/rna.24770] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Pentatricopeptide repeat (PPR) proteins constitute a large family of RNA-binding proteins that contain a canonical 35 residue repeat motif. Originally identified in Arabidopsis thaliana, family members are found in protists, fungi, and metazoan but are by far most abundant in plant organelles. Seven examples have been identified in human mitochondria and roles have been tentatively ascribed to each. In this review, we briefly outline each of these PPR proteins and discuss the role each is believed to play in facilitating mitochondrial gene expression.
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Affiliation(s)
- Robert N Lightowlers
- The Wellcome Trust Centre for Mitochondrial Research; Institute for Cell and Molecular Biosciences; Newcastle University; The Medical School; Framlington Place; Newcastle upon Tyne, UK
| | - Zofia M A Chrzanowska-Lightowlers
- The Wellcome Trust Centre for Mitochondrial Research; Institute for Ageing and Health; Newcastle University; The Medical School; Framlington Place; Newcastle upon Tyne, UK
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41
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Salem AF, Whitaker-Menezes D, Howell A, Sotgia F, Lisanti MP. Mitochondrial biogenesis in epithelial cancer cells promotes breast cancer tumor growth and confers autophagy resistance. Cell Cycle 2012; 11:4174-80. [PMID: 23070475 DOI: 10.4161/cc.22376] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Here, we set out to test the novel hypothesis that increased mitochondrial biogenesis in epithelial cancer cells would "fuel" enhanced tumor growth. For this purpose, we generated MDA-MB-231 cells (a triple-negative human breast cancer cell line) overexpressing PGC-1α and MitoNEET, which are established molecules that drive mitochondrial biogenesis and increased mitochondrial oxidative phosphorylation (OXPHOS). Interestingly, both PGC-1α and MitoNEET increased the abundance of OXPHOS protein complexes, conferred autophagy resistance under conditions of starvation and increased tumor growth by up to ~3-fold. However, this increase in tumor growth was independent of neo-angiogenesis, as assessed by immunostaining and quantitation of vessel density using CD31 antibodies. Quantitatively similar increases in tumor growth were also observed by overexpression of PGC-1β and POLRMT in MDA-MB-231 cells, which are also responsible for mediating increased mitochondrial biogenesis. Thus, we propose that increased mitochondrial "power" in epithelial cancer cells oncogenically promotes tumor growth by conferring autophagy resistance. As such, PGC-1α, PGC-1β, mitoNEET and POLRMT should all be considered as tumor promoters or "metabolic oncogenes." Our results are consistent with numerous previous clinical studies showing that metformin (a weak mitochondrial "poison") prevents the onset of nearly all types of human cancers in diabetic patients. Therefore, metformin (a complex I inhibitor) and other mitochondrial inhibitors should be developed as novel anticancer therapies, targeting mitochondrial metabolism in cancer cells.
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Affiliation(s)
- Ahmed F Salem
- The Jefferson Stem Cell Biology and Regenerative Medicine Center, Thomas Jefferson University, Philadelphia, PA, USA
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42
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Mitochondrial DNA damage and its consequences for mitochondrial gene expression. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1819:979-91. [PMID: 22728831 DOI: 10.1016/j.bbagrm.2012.06.002] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 06/06/2012] [Accepted: 06/14/2012] [Indexed: 12/11/2022]
Abstract
How mitochondria process DNA damage and whether a change in the steady-state level of mitochondrial DNA damage (mtDNA) contributes to mitochondrial dysfunction are questions that fuel burgeoning areas of research into aging and disease pathogenesis. Over the past decade, researchers have identified and measured various forms of endogenous and environmental mtDNA damage and have elucidated mtDNA repair pathways. Interestingly, mitochondria do not appear to contain the full range of DNA repair mechanisms that operate in the nucleus, although mtDNA contains types of damage that are targets of each nuclear DNA repair pathway. The reduced repair capacity may, in part, explain the high mutation frequency of the mitochondrial chromosome. Since mtDNA replication is dependent on transcription, mtDNA damage may alter mitochondrial gene expression at three levels: by causing DNA polymerase γ nucleotide incorporation errors leading to mutations, by interfering with the priming of mtDNA replication by the mitochondrial RNA polymerase, or by inducing transcriptional mutagenesis or premature transcript termination. This review summarizes our current knowledge of mtDNA damage, its repair, and its effects on mtDNA integrity and gene expression. This article is part of a special issue entitled: Mitochondrial Gene Expression.
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