1
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Bartle L, Wellinger RJ. Methods that shaped telomerase research. Biogerontology 2024; 25:249-263. [PMID: 37903970 PMCID: PMC10998806 DOI: 10.1007/s10522-023-10073-8] [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: 08/08/2023] [Accepted: 09/30/2023] [Indexed: 11/01/2023]
Abstract
Telomerase, the ribonucleoprotein (RNP) responsible for telomere maintenance, has a complex life. Complex in that it is made of multiple proteins and an RNA, and complex because it undergoes many changes, and passes through different cell compartments. As such, many methods have been developed to discover telomerase components, delve deep into understanding its structure and function and to figure out how telomerase biology ultimately relates to human health and disease. While some old gold-standard methods are still key for determining telomere length and measuring telomerase activity, new technologies are providing promising new ways to gain detailed information that we have never had access to before. Therefore, we thought it timely to briefly review the methods that have revealed information about the telomerase RNP and outline some of the remaining questions that could be answered using new methodology.
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Affiliation(s)
- Louise Bartle
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Applied Cancer Research Pavilion, 3201 rue Jean-Mignault, Sherbrooke, QC, J1E 4K8, Canada
| | - Raymund J Wellinger
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Applied Cancer Research Pavilion, 3201 rue Jean-Mignault, Sherbrooke, QC, J1E 4K8, Canada.
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2
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Schaich MA, Weaver TM, Roginskaya V, Freudenthal BD, Van Houten B. Single-molecule analysis of purified proteins and nuclear extracts: Insights from 8-oxoguanine glycosylase 1. DNA Repair (Amst) 2024; 134:103625. [PMID: 38237481 DOI: 10.1016/j.dnarep.2024.103625] [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: 10/13/2023] [Revised: 12/15/2023] [Accepted: 01/02/2024] [Indexed: 01/30/2024]
Abstract
By observing one molecule at a time, single-molecule studies can offer detailed insights about biomolecular processes including on rates, off rates, and diffusivity of molecules on strands of DNA. A recent technological advance (Single-molecule Analysis of DNA-binding proteins from Nuclear Extracts, SMADNE) has lowered the barrier to entry for single-molecule studies, and single-molecule dynamics can now be determined directly out of nuclear extracts, providing information in an intermediate environment between purified proteins in isolation and the heterogeneity of a nucleus. To compare and contrast the single-molecule DNA binding dynamics in nuclear extracts versus purified proteins, combined optical tweezers and fluorescence microscopy experiments were performed with purified GFP-tagged 8-oxoguanine glycosylase 1 (OGG1), purified GFP-OGG1 spiked into nuclear extracts, and nuclear extracts from human cells overexpressing GFP-OGG1. We observed differences in undamaged DNA binding during DNA damage search in each of the three conditions. Purified GFP-OGG1 engaged undamaged DNA for a weighted average lifetime of 5.7 s and 21% of these events underwent DNA diffusion after binding. However, unlike other glycosylases studied by SMADNE, OGG1 does not bind non-damaged DNA efficiently in nuclear extracts. In contrast, GFP-OGG1 binding dynamics on DNA substrates containing oxidative damage were relatively similar in all three conditions, with the weighted average binding lifetimes varying from 2.2 s in nuclear extracts to 7.8 s with purified GFP-OGG1 in isolation. Finally, we compared the purified protein and nuclear extract approaches for a catalytically dead OGG1 variant (GFP-OGG1-K249Q). This variant greatly increased the binding lifetime for oxidative DNA damage, with the weighted average lifetime for GFP-OGG1-249Q in nuclear extracts at 15.4 s vs 10.7 s for the purified protein. SMADNE will provide a new window of observation into the behavior of nucleic acid binding proteins only accessible by biophysicists trained in protein purification and protein labeling.
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Affiliation(s)
- Matthew A Schaich
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; UPMC-Hillman Cancer Center, USA
| | - Tyler M Weaver
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | | | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; University of Kansas Cancer Center, Kansas City, KS 66160, USA
| | - Bennett Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; UPMC-Hillman Cancer Center, USA.
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3
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Talbert PB, Henikoff S, Armache KJ. Giant variations in giant virus genome packaging. Trends Biochem Sci 2023; 48:1071-1082. [PMID: 37777391 DOI: 10.1016/j.tibs.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 10/02/2023]
Abstract
Giant viruses (Nucleocytoviricota) have a largely conserved lifecycle, yet how they cram their large genomes into viral capsids is mostly unknown. The major capsid protein and the packaging ATPase (pATPase) comprise a highly conserved morphogenesis module in giant viruses, yet some giant viruses dispense with an icosahedral capsid, and others encode multiple versions of pATPases, including conjoined ATPase doublets, or encode none. Some giant viruses have acquired DNA-condensing proteins to compact their genomes, including sheath-like structures encasing folded DNA or densely packed viral nucleosomes that show a resemblance to eukaryotic nucleosomes at the telomeres. Here, we review what is known and unknown about these ATPases and condensing proteins, and place these variations in the context of viral lifecycles.
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Affiliation(s)
- Paul B Talbert
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Karim-Jean Armache
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
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4
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Li P, Hou S, Wu Q, Chen Y, Wang B, Ren H, Wang J, Zhai Z, Yu Z, Lambert CJ, Jia C, Guo X. The role of halogens in Au-S bond cleavage for energy-differentiated catalysis at the single-bond limit. Nat Commun 2023; 14:7695. [PMID: 38001141 PMCID: PMC10673828 DOI: 10.1038/s41467-023-43639-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
The transformation from one compound to another involves the breaking and formation of chemical bonds at the single-bond level, especially during catalytic reactions that are of great significance in broad fields such as energy conversion, environmental science, life science and chemical synthesis. The study of the reaction process at the single-bond limit is the key to understanding the catalytic reaction mechanism and further rationally designing catalysts. Here, we develop a method to monitor the catalytic process from the perspective of the single-bond energy using high-resolution scanning tunneling microscopy single-molecule junctions. Experimental and theoretical studies consistently reveal that the attack of a halogen atom on an Au atom can reduce the breaking energy of Au-S bonds, thereby accelerating the bond cleavage reaction and shortening the plateau length during the single-molecule junction breaking. Furthermore, the distinction in catalytic activity between different halogen atoms can be compared as well. This study establishes the intrinsic relationship among the reaction activation energy, the chemical bond breaking energy and the single-molecule junction breaking process, strengthening our mastery of catalytic reactions towards precise chemistry.
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Affiliation(s)
- Peihui Li
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, 300350, Tianjin, People's Republic of China
| | - Songjun Hou
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK
| | - Qingqing Wu
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK
| | - Yijian Chen
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, 300350, Tianjin, People's Republic of China
| | - Boyu Wang
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, 300350, Tianjin, People's Republic of China
| | - Haiyang Ren
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, 300350, Tianjin, People's Republic of China
| | - Jinying Wang
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, 300350, Tianjin, People's Republic of China
| | - Zhaoyi Zhai
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, 300350, Tianjin, People's Republic of China
| | - Zhongbo Yu
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, 300350, Tianjin, People's Republic of China.
| | - Colin J Lambert
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK.
| | - Chuancheng Jia
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, 300350, Tianjin, People's Republic of China.
| | - Xuefeng Guo
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, 300350, Tianjin, People's Republic of China.
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Center, College of Chemistry and Molecular Engineering, Peking University, 292 Chengfu Road, Haidian District, 100871, Beijing, People's Republic of China.
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5
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Schaich MA, Weaver TM, Roginskaya V, Freudenthal BD, Van Houten B. Single-molecule analysis of purified proteins and nuclear extracts: insights from 8-oxoguanine glycosylase 1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.01.565178. [PMID: 37961208 PMCID: PMC10635064 DOI: 10.1101/2023.11.01.565178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
By observing one molecule at a time, single-molecule studies can offer detailed insights about biomolecular processes including on rates, off rates, and diffusivity of molecules on strands of DNA. A recent technological advance (Single-molecule Analysis of DNA-binding proteins from Nuclear Extracts, SMADNE) has lowered the barrier to entry for single-molecule studies, and single-molecule dynamics can now be determined directly out of nuclear extracts, providing information in an intermediate environment between purified proteins in isolation and the heterogeneity of a nucleus. To compare and contrast the single-molecule DNA binding dynamics in nuclear extracts versus purified proteins, combined optical tweezers and fluorescence microscopy experiments were performed with purified GFP-tagged 8-oxoguanine glycosylase 1 (OGG1), purified GFP-OGG1 spiked into nuclear extracts, and nuclear extracts from human cells overexpressing GFP-OGG1. We observed differences in undamaged DNA binding during DNA damage search in each of the three conditions. Purified GFP-OGG1 engaged undamaged DNA for a weighted average lifetime of 5.7 s and 21% of these events underwent DNA diffusion after binding. However, unlike other glycosylases studied by SMADNE, OGG1 does not bind non-damaged DNA efficiently in nuclear extracts. In contrast, GFP-OGG1 binding dynamics on DNA substrates containing oxidative damage were relatively similar in all three conditions, with the weighted average binding lifetimes varying from 2.2 s in nuclear extracts to 7.8 s with purified GFP-OGG1 in isolation. Finally, we compared the purified protein and nuclear extract approaches for a catalytically dead OGG1 variant (GFP-OGG1-K249Q). This variant greatly increased the binding lifetime for oxidative DNA damage, with the weighted average lifetime for GFP-OGG1-249Q in nuclear extracts at 15.4 s vs 10.7 s for the purified protein. SMADNE will provide a new window of observation into the behavior of nucleic acid binding proteins only accessible by biophysicists trained in protein purification and protein labeling.
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6
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Wang H, Wang S, Wang H, Tang F, Chen D, Liang Y, Li Z. Amplification-free detection of telomerase activity at the single-cell level via Cas12a-lighting-up single microbeads (Cas12a-LSMBs). LAB ON A CHIP 2023; 23:4674-4679. [PMID: 37795981 DOI: 10.1039/d3lc00598d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
Telomerase overexpresses in almost all cancer cells and has been deemed a universal biomarker for cancer diagnosis and therapy. However, simple and ultrasensitive detection of telomerase activity in single-cells is still a huge challenge. Herein, we wish to report Cas12a-lighting up single microbeads (Cas12a-LSMBs) for ultrasensitive detection of telomerase activity without nucleic acid amplification. In this platform, single-strand DNA reporter (ssDNA reporter)-functionalized single-microbeads (functionalized-SMBs) are employed as a reactor for the trans-cleavage of telomerase-activated CRISPR/Cas12a as well as a reporting unit for fluorescence signal enrichment and visualization. Due to the space-confined effect and signal enrichment mechanism on the surface of the functionalized SMBs, the Cas12a-LSMBs can accurately detect telomerase activity in crude cell lysates with high specificity. Importantly, we have demonstrated that the Cas12a-LSMBs are a reliable and practical tool to detect telomerase activity in single cells and investigate cellular heterogeneity of telomerase activity from cell-to-cell variations.
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Affiliation(s)
- Honghong Wang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
| | - Shuhui Wang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
| | - Hui Wang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
| | - Fu Tang
- School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China
| | - Desheng Chen
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
| | - Yuanwen Liang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
| | - Zhengping Li
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
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7
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Dai Y, Teng X, Zhang Q, Hou H, Li J. Advances and challenges in identifying and characterizing G-quadruplex-protein interactions. Trends Biochem Sci 2023; 48:894-909. [PMID: 37422364 DOI: 10.1016/j.tibs.2023.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 06/01/2023] [Accepted: 06/16/2023] [Indexed: 07/10/2023]
Abstract
G-quadruplexes (G4s) are peculiar nucleic acid secondary structures formed by DNA or RNA and are considered as fundamental features of the genome. Many proteins can specifically bind to G4 structures. There is increasing evidence that G4-protein interactions involve in the regulation of important cellular processes, such as DNA replication, transcription, RNA splicing, and translation. Additionally, G4-protein interactions have been demonstrated to be potential targets for disease treatment. In order to unravel the detailed regulatory mechanisms of G4-binding proteins (G4BPs), biochemical methods for detecting G4-protein interactions with high specificity and sensitivity are highly demanded. Here, we review recent advances in screening and validation of new G4BPs and highlight both their features and limitations.
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Affiliation(s)
- Yicong Dai
- Department of Chemistry, Center for BioAnalytical Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 100084, China; New Cornerstone Science Laboratory, Shenzhen 518054, China
| | - Xucong Teng
- Department of Chemistry, Center for BioAnalytical Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 100084, China; New Cornerstone Science Laboratory, Shenzhen 518054, China
| | - Qiushuang Zhang
- Department of Chemistry, Center for BioAnalytical Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 100084, China; New Cornerstone Science Laboratory, Shenzhen 518054, China
| | - Hongwei Hou
- Beijing Life Science Academy, Beijing 102209, China.
| | - Jinghong Li
- Department of Chemistry, Center for BioAnalytical Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 100084, China; New Cornerstone Science Laboratory, Shenzhen 518054, China; Beijing Life Science Academy, Beijing 102209, China; Center for BioAnalytical Chemistry, Hefei National Laboratory of Physical Science at Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China.
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8
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Rojewski A, Schweiger M, Sgouralis I, Comstock M, Pressé S. An accurate probabilistic step finder for time-series analysis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.19.558535. [PMID: 37786687 PMCID: PMC10541599 DOI: 10.1101/2023.09.19.558535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Noisy time-series data is commonly collected from sources including Förster Resonance Energy Transfer experiments, patch clamp and force spectroscopy setups, among many others. Two of the most common paradigms for the detection of discrete transitions in such time-series data include: hidden Markov models (HMMs) and step-finding algorithms. HMMs, including their extensions to infinite state-spaces, inherently assume in analysis that holding times in discrete states visited are geometrically-or, loosely speaking in common language, exponentially-distributed. Thus the determination of step locations, especially in sparse and noisy data, is biased by HMMs toward identifying steps resulting in geometric holding times. In contrast, existing step-finding algorithms, while free of this restraint, often rely on ad hoc metrics to penalize steps recovered in time traces (by using various information criteria) and otherwise rely on approximate greedy algorithms to identify putative global optima. Here, instead, we devise a robust and general probabilistic (Bayesian) step-finding tool that neither relies on ad hoc metrics to penalize step numbers nor assumes geometric holding times in each state. As the number of steps themselves in a time-series are, a priori unknown, we treat these within a Bayesian nonparametric (BNP) paradigm. We find that the method developed, Bayesian Nonparametric Step (BNP-Step), accurately determines the number and location of transitions between discrete states without any assumed kinetic model and learns the emission distribution characteristic of each state. In doing so, we verify that BNP-Step can analyze sparser data sets containing higher noise and more closely-spaced states than otherwise resolved by current state-of-the-art methods. What is more, BNP-Step rigorously propagates measurement uncertainty into uncertainty over state transition locations, numbers, and emission levels as characterized by the posterior. We demonstrate the performance of BNP-Step on both synthetic data as well as data drawn from force spectroscopy experiments.
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Affiliation(s)
- Alex Rojewski
- Department of Physics, Arizona State University, Tempe, Arizona
- Center for Biological Physics, Arizona State University, Tempe, Arizona
| | - Maxwell Schweiger
- Department of Physics, Arizona State University, Tempe, Arizona
- Center for Biological Physics, Arizona State University, Tempe, Arizona
| | - Ioannis Sgouralis
- Department of Mathematics, University of Tennessee, Knoxville, Knoxville, Tennessee
| | - Matthew Comstock
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan
| | - Steve Pressé
- Department of Physics, Arizona State University, Tempe, Arizona
- Center for Biological Physics, Arizona State University, Tempe, Arizona
- School of Molecular Sciences, Arizona State University, Tempe, Arizona
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9
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Hentschel J, Badstübner M, Choi J, Bagshaw CR, Lapointe CP, Wang J, Jansson LI, Puglisi JD, Stone MD. Real-time detection of human telomerase DNA synthesis by multiplexed single-molecule FRET. Biophys J 2023; 122:3447-3457. [PMID: 37515327 PMCID: PMC10502476 DOI: 10.1016/j.bpj.2023.07.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 02/28/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023] Open
Abstract
Genomic stability in proliferating cells critically depends on telomere maintenance by telomerase reverse transcriptase. Here we report the development and proof-of-concept results of a single-molecule approach to monitor the catalytic activity of human telomerase in real time and with single-nucleotide resolution. Using zero-mode waveguides and multicolor FRET, we recorded the processive addition of multiple telomeric repeats to individual DNA primers. Unlike existing biophysical and biochemical tools, the novel approach enables the quantification of nucleotide-binding kinetics before nucleotide incorporation. Moreover, it provides a means to dissect the unique translocation dynamics that telomerase must undergo after synthesis of each hexameric DNA repeat. We observed an unexpectedly prolonged binding dwell time of dGTP in the enzyme active site at the start of each repeat synthesis cycle, suggesting that telomerase translocation is composed of multiple rate-contributing sub-steps that evade classical biochemical analysis.
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Affiliation(s)
- Jendrik Hentschel
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California; Department of Structural Biology, Stanford University School of Medicine, Stanford, California
| | - Mareike Badstübner
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - Junhong Choi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California
| | - Clive R Bagshaw
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - Christopher P Lapointe
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California
| | - Jinfan Wang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California
| | - Linnea I Jansson
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California
| | - Michael D Stone
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California.
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10
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Tessmer I. The roles of non-productive complexes of DNA repair proteins with DNA lesions. DNA Repair (Amst) 2023; 129:103542. [PMID: 37453245 DOI: 10.1016/j.dnarep.2023.103542] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 06/30/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023]
Abstract
A multitude of different types of lesions is continuously introduced into the DNA inside our cells, and their rapid and efficient repair is fundamentally important for the maintenance of genomic stability and cellular viability. This is achieved by a number of DNA repair systems that each involve different protein factors and employ versatile strategies to target different types of DNA lesions. Intriguingly, specialized DNA repair proteins have also evolved to form non-functional complexes with their target lesions. These proteins allow the marking of innocuous lesions to render them visible for DNA repair systems and can serve to directly recruit DNA repair cascades. Moreover, they also provide links between different DNA repair mechanisms or even between DNA lesions and transcription regulation. I will focus here in particular on recent findings from single molecule analyses on the alkyltransferase-like protein ATL, which is believed to initiate nucleotide excision repair (NER) of non-native NER target lesions, and the base excision repair (BER) enzyme hOGG1, which recruits the oncogene transcription factor Myc to gene promoters under oxidative stress.
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Affiliation(s)
- Ingrid Tessmer
- Rudolf Virchow Center, University of Würzburg, Josef Schneider Str. 2, 97080 Würzburg, Germany
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11
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Lue NF, Autexier C. Orchestrating nucleic acid-protein interactions at chromosome ends: telomerase mechanisms come into focus. Nat Struct Mol Biol 2023; 30:878-890. [PMID: 37400652 PMCID: PMC10539978 DOI: 10.1038/s41594-023-01022-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 05/16/2023] [Indexed: 07/05/2023]
Abstract
Telomerase is a special reverse transcriptase ribonucleoprotein dedicated to the synthesis of telomere repeats that protect chromosome ends. Among reverse transcriptases, telomerase is unique in using a stably associated RNA with an embedded template to synthesize a specified sequence. Moreover, it is capable of iteratively copying the same template region (repeat addition processivity) through multiple rounds of RNA-DNA unpairing and reannealing, that is, the translocation reaction. Biochemical analyses of telomerase over the past 3 decades in protozoa, fungi and mammals have identified structural elements that underpin telomerase mechanisms and have led to models that account for the special attributes of telomerase. Notably, these findings and models can now be interpreted and adjudicated through recent cryo-EM structures of Tetrahymena and human telomerase holoenzyme complexes in association with substrates and regulatory proteins. Collectively, these structures reveal the intricate protein-nucleic acid interactions that potentiate telomerase's unique translocation reaction and clarify how this enzyme reconfigures the basic reverse transcriptase scaffold to craft a polymerase dedicated to the synthesis of telomere DNA. Among the many new insights is the resolution of the telomerase 'anchor site' proposed more than 3 decades ago. The structures also highlight the nearly universal conservation of a protein-protein interface between an oligonucleotide/oligosaccharide-binding (OB)-fold regulatory protein and the telomerase catalytic subunit, which enables spatial and temporal regulation of telomerase function in vivo. In this Review, we discuss key features of the structures in combination with relevant functional analyses. We also examine conserved and divergent aspects of telomerase mechanisms as gleaned from studies in different model organisms.
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Affiliation(s)
- Neal F Lue
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA.
| | - Chantal Autexier
- Lady Davis Institute for Medical Research, Jewish General Hospital and Department of Anatomy and Cell Biology and Department of Medicine, McGill University, Montreal, Quebec, Canada.
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12
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Padmanaban S, Tesmer VM, Nandakumar J. Interaction hub critical for telomerase recruitment and primer-template handling for catalysis. Life Sci Alliance 2023; 6:e202201727. [PMID: 36963832 PMCID: PMC10055720 DOI: 10.26508/lsa.202201727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/26/2023] Open
Abstract
Telomerase processively adds telomeric DNA repeats to chromosome ends using catalytic protein subunit TERT and a template on its RNA subunit TR. Mammalian telomerase is recruited to telomeres by the TEL patch and NOB regions of shelterin component TPP1. Recent cryo-EM structures of human telomerase reveal that a composite TERT TEN-(IFD-TRAP) domain interacts with TPP1. Here, we generate TERT mutants to demonstrate that a three-way TEN-(IFD-TRAP)-TPP1 interaction is critical for telomerase recruitment to telomeres and processive telomere repeat addition. Single mutations of IFD-TRAP at its interface with TR or the DNA primer impair telomerase catalysis. We further reveal the importance of TERT motif 3N and TEN domain loop 99FGF101 in telomerase action. Finally, we demonstrate that TPP1 TEL patch loop residue F172, which undergoes a structural rearrangement to bind telomerase, contributes to the human-mouse species specificity of the telomerase-TPP1 interaction. Our study provides insights into the multiple functions of TERT IFD-TRAP, reveals novel TERT and TPP1 elements critical for function, and helps explain how TPP1 binding licenses robust telomerase action at natural chromosome ends.
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Affiliation(s)
- Shilpa Padmanaban
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Valerie M Tesmer
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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13
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Riccardi M, Martin OJF. Electromagnetic Forces and Torques: From Dielectrophoresis to Optical Tweezers. Chem Rev 2023; 123:1680-1711. [PMID: 36719985 PMCID: PMC9951227 DOI: 10.1021/acs.chemrev.2c00576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Indexed: 02/02/2023]
Abstract
Electromagnetic forces and torques enable many key technologies, including optical tweezers or dielectrophoresis. Interestingly, both techniques rely on the same physical process: the interaction of an oscillating electric field with a particle of matter. This work provides a unified framework to understand this interaction both when considering fields oscillating at low frequencies─dielectrophoresis─and high frequencies─optical tweezers. We draw useful parallels between these two techniques, discuss the different and often unstated assumptions they are based upon, and illustrate key applications in the fields of physical and analytical chemistry, biosensing, and colloidal science.
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Affiliation(s)
- Marco Riccardi
- Nanophotonics and Metrology Laboratory, Swiss Federal Institute of Technology Lausanne (EPFL), EPFL-STI-NAM, Station 11, CH-1015Lausanne, Switzerland
| | - Olivier J. F. Martin
- Nanophotonics and Metrology Laboratory, Swiss Federal Institute of Technology Lausanne (EPFL), EPFL-STI-NAM, Station 11, CH-1015Lausanne, Switzerland
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14
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Favre-Bulle IA, Scott EK. Optical tweezers across scales in cell biology. Trends Cell Biol 2022; 32:932-946. [PMID: 35672197 PMCID: PMC9588623 DOI: 10.1016/j.tcb.2022.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 01/21/2023]
Abstract
Optical tweezers (OT) provide a noninvasive approach for delivering minute physical forces to targeted objects. Controlling such forces in living cells or in vitro preparations allows for the measurement and manipulation of numerous processes relevant to the form and function of cells. As such, OT have made important contributions to our understanding of the structures of proteins and nucleic acids, the interactions that occur between microscopic structures within cells, the choreography of complex processes such as mitosis, and the ways in which cells interact with each other. In this review, we highlight recent contributions made to the field of cell biology using OT and provide basic descriptions of the physics, the methods, and the equipment that made these studies possible.
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Affiliation(s)
- Itia A Favre-Bulle
- Queensland Brain Institute, The University of Queensland, 4067, Brisbane, Australia; School of Mathematics and Physics, The University of Queensland, 4067, Brisbane, Australia.
| | - Ethan K Scott
- Queensland Brain Institute, The University of Queensland, 4067, Brisbane, Australia; Department of Anatomy and Physiology, School of Biomedical Sciences, The University of Melbourne, Parkville, VIC 3010, Australia.
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15
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He Y, Feigon J. Telomerase structural biology comes of age. Curr Opin Struct Biol 2022; 76:102446. [PMID: 36081246 PMCID: PMC9884118 DOI: 10.1016/j.sbi.2022.102446] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 07/22/2022] [Accepted: 07/26/2022] [Indexed: 01/31/2023]
Abstract
Telomerase is an RNA-protein complex comprising telomerase reverse transcriptase, a non-coding telomerase RNA, and proteins involved in biogenesis, assembly, localization, or recruitment. Telomerase synthesizes the telomeric DNA at the 3'-ends of linear chromosomes. During the past decade, structural studies have defined the architecture of Tetrahymena and human telomerase as well as protein and RNA domain structures, but high-resolution details of interactions remained largely elusive. In the past two years, several sub-4 Å cryo-electron microscopy structures of telomerase were published, including Tetrahymena telomerase at different steps of telomere repeat addition and human telomerase with telomere shelterin proteins that recruit telomerase to telomeres. These and other recent structural studies have expanded our understanding of telomerase assembly, mechanism, recruitment, and mutations leading to disease.
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Affiliation(s)
- Yao He
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095-1569, USA; Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095-1569, USA.
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16
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Schmidt JC. Very fast nucleotides on demand. Nat Chem Biol 2022; 18:1043-1044. [PMID: 36131154 DOI: 10.1038/s41589-022-01144-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jens C Schmidt
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA. .,Department of Obstetrics, Gynecology, and Reproductive Biology, Michigan State University, East Lansing, MI, USA.
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17
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Xie J, Ekpo MD, Xiao J, Zhao H, Bai X, Liang Y, Zhao G, Liu D, Tan S. Principles and Protocols For Post-Cryopreservation Quality Evaluation of Stem Cells in Novel Biomedicine. Front Pharmacol 2022; 13:907943. [PMID: 35592426 PMCID: PMC9113563 DOI: 10.3389/fphar.2022.907943] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/13/2022] [Indexed: 01/05/2023] Open
Abstract
Stem cell therapy is a thriving topic of interest among researchers and clinicians due to evidence of its effectiveness and promising therapeutic advantage in numerous disease conditions as presented by novel biomedical research. However, extensive clinical application of stem cells is limited by its storage and transportation. The emergence of cryopreservation technology has made it possible for living organs, tissues, cells and even living organisms to survive for a long time at deep low temperatures. During the cryopreservation process, stem cell preparations are subject to three major damages: osmotic damage, mechanical damage, and peroxidative damage. Therefore, Assessing the effectiveness and safety of stem cells following cryopreservation is fundamental to the quality control of stem cell preparations. This article presents the important biosafety and quality control parameters to be assessed during the manufacturing of clinical grade stem cell products, highlights the significance of preventing cryodamage. and provides a reference for protocols in the quality control of stem cell preparations.
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Affiliation(s)
- Jingxian Xie
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, China.,Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, China
| | - Marlene Davis Ekpo
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, China
| | - Jian Xiao
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Hongbin Zhao
- Hunan Carnation Biotechnology Co. LTD, Changsha, China.,Hainan Nova Doctor Group Co. Ltd, Haikou, China
| | - Xiaoyong Bai
- Hunan Carnation Biotechnology Co. LTD, Changsha, China.,Hainan Nova Doctor Group Co. Ltd, Haikou, China
| | - Yijie Liang
- Hunan Carnation Biotechnology Co. LTD, Changsha, China.,Hainan Nova Doctor Group Co. Ltd, Haikou, China
| | - Guang Zhao
- Hunan Sheng Bao Biological Technology Co., Ltd (in Yinfeng Biological Group., Ltd), Changsha, China
| | - Dong Liu
- Hunan Sheng Bao Biological Technology Co., Ltd (in Yinfeng Biological Group., Ltd), Changsha, China
| | - Songwen Tan
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, China
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18
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Yadav R, Senanayake KB, Comstock MJ. High-Resolution Optical Tweezers Combined with Multicolor Single-Molecule Microscopy. Methods Mol Biol 2022; 2478:141-240. [PMID: 36063322 DOI: 10.1007/978-1-0716-2229-2_8] [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: 06/15/2023]
Abstract
We present an instrument that combines high-resolution optical tweezers and multicolor confocal fluorescence spectroscopy. Biological macromolecules exhibit complex conformation and stoichiometry changes in coordination with their motion and activity. To further our understanding of the complex machinery of life, we need methods that can simultaneously probe more than one degree of freedom of single molecules and complexes. Fluorescence optical tweezers, or "fleezers," combine the capabilities of optical tweezers and single-molecule fluorescence microscopy into a single instrument. Here we present the latest generation of a high-resolution fleezers instrument integrated with multicolor fluorescence spectroscopy. The tweezers portion of the instrument can manipulate biological macromolecules with pN scale forces while measuring subnanometer distances. Simultaneous with tweezers measurements, the multicolor fluorescence capability allows the direct observation of multiple molecules or multiple degrees of freedom which allows, for example, the observation of multiple proteins simultaneously within a complex. The instrument incorporates three fluorescence excitation lasers, all sourced from a single-mode optical fiber allowing a reliable alignment scheme, that allows, for example, three independent fluorescent probes or fluorescence resonance energy transfer (FRET) measurements and also increases flexibility in the choice of fluorescent probes. To avoid photobleaching and improve tweezers stability, the instrument implements a timesharing (using a single trap laser to produce a pair of traps via rapid switching between two locations) and interlacing (turning the trapping beam off when the fluorescence excitation beams are on and vice versa) scheme using acousto-optic modulators (AOM) to rapidly and precisely modulate lasers. Our latest "random phase" trap AOM control method obliterates previous residual trap positioning and bead position measurement errors. Here we present the general design principles and detailed construction and testing protocols for the instrument.
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Affiliation(s)
- Rajeev Yadav
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA
| | - Kasun B Senanayake
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA
| | - Matthew J Comstock
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA.
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19
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Dey A, Monroy-Eklund A, Klotz K, Saha A, Davis J, Li B, Laederach A, Chakrabarti K. In vivo architecture of the telomerase RNA catalytic core in Trypanosoma brucei. Nucleic Acids Res 2021; 49:12445-12466. [PMID: 34850114 PMCID: PMC8643685 DOI: 10.1093/nar/gkab1042] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/11/2021] [Accepted: 10/15/2021] [Indexed: 01/07/2023] Open
Abstract
Telomerase is a unique ribonucleoprotein (RNP) reverse transcriptase that utilizes its cognate RNA molecule as a template for telomere DNA repeat synthesis. Telomerase contains the reverse transcriptase protein, TERT and the template RNA, TR, as its core components. The 5'-half of TR forms a highly conserved catalytic core comprising of the template region and adjacent domains necessary for telomere synthesis. However, how telomerase RNA folding takes place in vivo has not been fully understood due to low abundance of the native RNP. Here, using unicellular pathogen Trypanosoma brucei as a model, we reveal important regional folding information of the native telomerase RNA core domains, i.e. TR template, template boundary element, template proximal helix and Helix IV (eCR4-CR5) domain. For this purpose, we uniquely combined in-cell probing with targeted high-throughput RNA sequencing and mutational mapping under three conditions: in vivo (in WT and TERT-/- cells), in an immunopurified catalytically active telomerase RNP complex and ex vivo (deproteinized). We discover that TR forms at least two different conformers with distinct folding topologies in the insect and mammalian developmental stages of T. brucei. Also, TERT does not significantly affect the RNA folding in vivo, suggesting that the telomerase RNA in T. brucei exists in a conformationally preorganized stable structure. Our observed differences in RNA (TR) folding at two distinct developmental stages of T. brucei suggest that important conformational changes are a key component of T. brucei development.
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Affiliation(s)
- Abhishek Dey
- Department of Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA
| | - Anais Monroy-Eklund
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kaitlin Klotz
- Department of Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA
| | - Arpita Saha
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, Cleveland, OH 44115, USA
| | - Justin Davis
- Department of Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA
| | - Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, Cleveland, OH 44115, USA
| | - Alain Laederach
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kausik Chakrabarti
- To whom correspondence should be addressed. Tel: +1 704 687 1882; Fax: +1 704 687 1488;
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20
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Characterization of G-Quadruplexes Folding/Unfolding Dynamics and Interactions with Proteins from Single-Molecule Force Spectroscopy. Biomolecules 2021; 11:biom11111579. [PMID: 34827577 PMCID: PMC8615981 DOI: 10.3390/biom11111579] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/16/2021] [Accepted: 10/19/2021] [Indexed: 12/19/2022] Open
Abstract
G-quadruplexes (G4s) are stable secondary nucleic acid structures that play crucial roles in many fundamental biological processes. The folding/unfolding dynamics of G4 structures are associated with the replication and transcription regulation functions of G4s. However, many DNA G4 sequences can adopt a variety of topologies and have complex folding/unfolding dynamics. Determining the dynamics of G4s and their regulation by proteins remains challenging due to the coexistence of multiple structures in a heterogeneous sample. Here, in this mini-review, we introduce the application of single-molecule force-spectroscopy methods, such as magnetic tweezers, optical tweezers, and atomic force microscopy, to characterize the polymorphism and folding/unfolding dynamics of G4s. We also briefly introduce recent studies using single-molecule force spectroscopy to study the molecular mechanisms of G4-interacting proteins.
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21
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How DNA damage and non-canonical nucleotides alter the telomerase catalytic cycle. DNA Repair (Amst) 2021; 107:103198. [PMID: 34371388 DOI: 10.1016/j.dnarep.2021.103198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 01/01/2023]
Abstract
Telomeres at the ends of linear chromosomes are essential for genome maintenance and sustained cellular proliferation, but shorten with each cell division. Telomerase, a specialized reverse transcriptase with its own integral RNA template, compensates for this by lengthening the telomeric 3' single strand overhang. Mammalian telomerase has the unique ability to processively synthesize multiple GGTTAG repeats, by translocating along its product and reiteratively copying the RNA template, termed repeat addition processivity (RAP). This unusual form of processivity is distinct from the nucleotide addition processivity (NAP) shared by all other DNA polymerases. In this review, we focus on the minimally active human telomerase catalytic core consisting of the telomerase reverse transcriptase (TERT) and the integral RNA (TR), which catalyzes DNA synthesis. We review the mechanisms by which oxidatively damaged nucleotides, and anti-viral and anti-cancer nucleotide drugs affect the telomerase catalytic cycle. Finally, we offer perspective on how we can leverage telomerase's unique properties, and advancements in understanding of telomerase catalytic mechanism, to selectively manipulate telomerase activity with therapeutics, particularly in cancer treatment.
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22
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The structurally conserved TELR region on shelterin protein TPP1 is essential for telomerase processivity but not recruitment. Proc Natl Acad Sci U S A 2021; 118:2024889118. [PMID: 34282008 DOI: 10.1073/pnas.2024889118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The shelterin protein TPP1 is involved in both recruiting telomerase and stimulating telomerase processivity in human cells. Assessing the in vivo significance of the latter role of TPP1 has been difficult, because TPP1 mutations that perturb telomerase function tend to abolish both telomerase recruitment and processivity. The Saccharomyces cerevisiae telomerase-associated Est3 protein adopts a protein fold similar to the N-terminal region of TPP1. Interestingly, a previous structure-guided mutagenesis study of Est3 revealed a TELR surface region that regulates telomerase function via an unknown mechanism without affecting the interaction between Est3 and telomerase [T. Rao et al., Proc. Natl. Acad. Sci. U.S.A. 111, 214-218 (2014)]. Here, we show that mutations within the structurally conserved TELR region on human TPP1 impaired telomerase processivity while leaving telomerase recruitment unperturbed, hence uncoupling the two roles of TPP1 in regulating telomerase. Telomeres in cell lines containing homozygous TELR mutations progressively shortened to a critical length that caused cellular senescence, despite the presence of abundant telomerase in these cells. Our findings not only demonstrate that telomerase processivity can be regulated by TPP1 in a process separable from its role in recruiting telomerase, but also establish that the in vivo stimulation of telomerase processivity by TPP1 is critical for telomere length homeostasis and long-term viability of human cells.
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23
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Structures of telomerase at several steps of telomere repeat synthesis. Nature 2021; 593:454-459. [PMID: 33981033 DOI: 10.1038/s41586-021-03529-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 04/09/2021] [Indexed: 12/14/2022]
Abstract
Telomerase is unique among the reverse transcriptases in containing a noncoding RNA (known as telomerase RNA (TER)) that includes a short template that is used for the processive synthesis of G-rich telomeric DNA repeats at the 3' ends of most eukaryotic chromosomes1. Telomerase maintains genomic integrity, and its activity or dysregulation are critical determinants of human longevity, stem cell renewal and cancer progression2,3. Previous cryo-electron microscopy structures have established the general architecture, protein components and stoichiometries of Tetrahymena and human telomerase, but our understandings of the details of DNA-protein and RNA-protein interactions and of the mechanisms and recruitment involved remain limited4-6. Here we report cryo-electron microscopy structures of active Tetrahymena telomerase with telomeric DNA at different steps of nucleotide addition. Interactions between telomerase reverse transcriptase (TERT), TER and DNA reveal the structural basis of the determination of the 5' and 3' template boundaries, handling of the template-DNA duplex and separation of the product strand during nucleotide addition. The structure and binding interface between TERT and telomerase protein p50 (a homologue of human TPP17,8) define conserved interactions that are required for telomerase activation and recruitment to telomeres. Telomerase La-related protein p65 remodels several regions of TER, bridging the 5' and 3' ends and the conserved pseudoknot to facilitate assembly of the TERT-TER catalytic core.
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24
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Ghanim GE, Fountain AJ, van Roon AMM, Rangan R, Das R, Collins K, Nguyen THD. Structure of human telomerase holoenzyme with bound telomeric DNA. Nature 2021; 593:449-453. [PMID: 33883742 DOI: 10.1038/s41586-021-03415-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 03/03/2021] [Indexed: 12/15/2022]
Abstract
Telomerase adds telomeric repeats at chromosome ends to compensate for the telomere loss that is caused by incomplete genome end replication1. In humans, telomerase is upregulated during embryogenesis and in cancers, and mutations that compromise the function of telomerase result in disease2. A previous structure of human telomerase at a resolution of 8 Å revealed a vertebrate-specific composition and architecture3, comprising a catalytic core that is flexibly tethered to an H and ACA (hereafter, H/ACA) box ribonucleoprotein (RNP) lobe by telomerase RNA. High-resolution structural information is necessary to develop treatments that can effectively modulate telomerase activity as a therapeutic approach against cancers and disease. Here we used cryo-electron microscopy to determine the structure of human telomerase holoenzyme bound to telomeric DNA at sub-4 Å resolution, which reveals crucial DNA- and RNA-binding interfaces in the active site of telomerase as well as the locations of mutations that alter telomerase activity. We identified a histone H2A-H2B dimer within the holoenzyme that was bound to an essential telomerase RNA motif, which suggests a role for histones in the folding and function of telomerase RNA. Furthermore, this structure of a eukaryotic H/ACA RNP reveals the molecular recognition of conserved RNA and protein motifs, as well as interactions that are crucial for understanding the molecular pathology of many mutations that cause disease. Our findings provide the structural details of the assembly and active site of human telomerase, which paves the way for the development of therapeutic agents that target this enzyme.
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Affiliation(s)
- George E Ghanim
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Adam J Fountain
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | | | - Ramya Rangan
- Biophysics Program, Stanford University, Stanford, CA, USA
| | - Rhiju Das
- Biophysics Program, Stanford University, Stanford, CA, USA.,Department of Biochemistry, Stanford University, Stanford, CA, USA.,Department of Physics, Stanford University, Stanford, CA, USA
| | - Kathleen Collins
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.,California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, USA
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25
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Zhang R, Zhang R, Jiang W, Xu X. A multicolor DNA tetrahedron nanoprobe for analyzing human telomerase in living cells. Chem Commun (Camb) 2021; 57:2188-2191. [PMID: 33527950 DOI: 10.1039/d0cc07893j] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Herein, we report the in situ analysis of human telomerase by a multicolor DNA tetrahedron nanoprobe. The elongated telomeric repeats can hybridize with settled molecular beacons in order, accompanied by sequentially lighted up fluorescence. Imaging telomerase activity, real-time monitoring telomerase action and determining product length distribution in living cells are realized. It detects multiple information of intracellular telomerase and provides deeper insights into the function of telomerase.
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Affiliation(s)
- Ruiyuan Zhang
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P. R. China.
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26
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Chen X, Deng Y, Cao G, Liu X, Gu T, Feng R, Huo D, Xu F, Hou C. An ultrasensitive and point-of-care sensor for the telomerase activity detection. Anal Chim Acta 2021; 1146:61-69. [PMID: 33461720 DOI: 10.1016/j.aca.2020.11.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/23/2020] [Accepted: 11/25/2020] [Indexed: 02/07/2023]
Abstract
Telomerase owns great application potential in diagnosis, therapy, prognosis, and drug screening of cancers. Thus, the ultrasensitive and point-of-care detection of telomerase activity meets the clinical demands extremely. Here, a sensor based on telomerase extends activators to unlock the ssDNase activity of CRISPR/Cas12a was created for the first time to detect the telomerase activity. Based on the fluorescence or CRISPR/Cas12a-based lateral flow assay, we achieve the ultrasensitive and point-of-care detection of telomerase activity in MCF-7 cells low to 57 cells·mL-1 and 5.7 × 102 cells·mL-1 in about 1 h, respectively. Besides, the detection of telomerase activity in different subtype breast cancer cells indicates that the proposed sensor possesses potential in the classification of breast cancer cell subtypes.
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Affiliation(s)
- Xiaolong Chen
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, 400044, PR China
| | - Yuanyi Deng
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, 400044, PR China
| | - Gaihua Cao
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, 400044, PR China
| | - Xinyi Liu
- Hongshen Honors College, Chongqing University, Chongqing, 400044, PR China
| | - Tao Gu
- Hongshen Honors College, Chongqing University, Chongqing, 400044, PR China
| | - Ruoyang Feng
- Hongshen Honors College, Chongqing University, Chongqing, 400044, PR China
| | - Danqun Huo
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, 400044, PR China; Chongqing Key Laboratory of Bio-perception & Intelligent Information Processing, School of Microelectronics and Communication Engineering, Chongqing University, Chongqing, 400044, PR China.
| | - Faliang Xu
- Treatment Center of Breast Diseases, Chongqing Cancer Institute and Hospital, Chongqing University, Chongqing, 400030, PR China.
| | - Changjun Hou
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, 400044, PR China.
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27
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Abdelsattar AS, Mansour Y, Aboul-Ela F. The Perturbed Free-Energy Landscape: Linking Ligand Binding to Biomolecular Folding. Chembiochem 2021; 22:1499-1516. [PMID: 33351206 DOI: 10.1002/cbic.202000695] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/19/2020] [Indexed: 12/24/2022]
Abstract
The effects of ligand binding on biomolecular conformation are crucial in drug design, enzyme mechanisms, the regulation of gene expression, and other biological processes. Descriptive models such as "lock and key", "induced fit", and "conformation selection" are common ways to interpret such interactions. Another historical model, linked equilibria, proposes that the free-energy landscape (FEL) is perturbed by the addition of ligand binding energy for the bound population of biomolecules. This principle leads to a unified, quantitative theory of ligand-induced conformation change, building upon the FEL concept. We call the map of binding free energy over biomolecular conformational space the "binding affinity landscape" (BAL). The perturbed FEL predicts/explains ligand-induced conformational changes conforming to all common descriptive models. We review recent experimental and computational studies that exemplify the perturbed FEL, with emphasis on RNA. This way of understanding ligand-induced conformation dynamics motivates new experimental and theoretical approaches to ligand design, structural biology and systems biology.
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Affiliation(s)
- Abdallah S Abdelsattar
- Center for X-Ray Determination of the Structure of Matter, Zewail City of Science and Technology, Ahmed Zewail Road, October Gardens, 12578, Giza, Egypt
| | - Youssef Mansour
- Center for X-Ray Determination of the Structure of Matter, Zewail City of Science and Technology, Ahmed Zewail Road, October Gardens, 12578, Giza, Egypt
| | - Fareed Aboul-Ela
- Center for X-Ray Determination of the Structure of Matter, Zewail City of Science and Technology, Ahmed Zewail Road, October Gardens, 12578, Giza, Egypt
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28
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Lim CJ, Cech TR. Shaping human telomeres: from shelterin and CST complexes to telomeric chromatin organization. Nat Rev Mol Cell Biol 2021; 22:283-298. [PMID: 33564154 DOI: 10.1038/s41580-021-00328-y] [Citation(s) in RCA: 115] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2021] [Indexed: 01/14/2023]
Abstract
The regulation of telomere length in mammals is crucial for chromosome end-capping and thus for maintaining genome stability and cellular lifespan. This process requires coordination between telomeric protein complexes and the ribonucleoprotein telomerase, which extends the telomeric DNA. Telomeric proteins modulate telomere architecture, recruit telomerase to accessible telomeres and orchestrate the conversion of the newly synthesized telomeric single-stranded DNA tail into double-stranded DNA. Dysfunctional telomere maintenance leads to telomere shortening, which causes human diseases including bone marrow failure, premature ageing and cancer. Recent studies provide new insights into telomerase-related interactions (the 'telomere replisome') and reveal new challenges for future telomere structural biology endeavours owing to the dynamic nature of telomere architecture and the great number of structures that telomeres form. In this Review, we discuss recently determined structures of the shelterin and CTC1-STN1-TEN1 (CST) complexes, how they may participate in the regulation of telomere replication and chromosome end-capping, and how disease-causing mutations in their encoding genes may affect specific functions. Major outstanding questions in the field include how all of the telomere components assemble relative to each other and how the switching between different telomere structures is achieved.
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Affiliation(s)
- Ci Ji Lim
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA. .,Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA. .,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA.
| | - Thomas R Cech
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA. .,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA. .,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA.
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29
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Zhuang X, Wu Q, Zhang A, Liao L, Fang B. Single-molecule biotechnology for protein researches. Chin J Chem Eng 2021. [DOI: 10.1016/j.cjche.2020.10.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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30
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Schrumpfová PP, Fajkus J. Composition and Function of Telomerase-A Polymerase Associated with the Origin of Eukaryotes. Biomolecules 2020; 10:biom10101425. [PMID: 33050064 PMCID: PMC7658794 DOI: 10.3390/biom10101425] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/29/2020] [Accepted: 10/01/2020] [Indexed: 12/19/2022] Open
Abstract
The canonical DNA polymerases involved in the replication of the genome are unable to fully replicate the physical ends of linear chromosomes, called telomeres. Chromosomal termini thus become shortened in each cell cycle. The maintenance of telomeres requires telomerase—a specific RNA-dependent DNA polymerase enzyme complex that carries its own RNA template and adds telomeric repeats to the ends of chromosomes using a reverse transcription mechanism. Both core subunits of telomerase—its catalytic telomerase reverse transcriptase (TERT) subunit and telomerase RNA (TR) component—were identified in quick succession in Tetrahymena more than 30 years ago. Since then, both telomerase subunits have been described in various organisms including yeasts, mammals, birds, reptiles and fish. Despite the fact that telomerase activity in plants was described 25 years ago and the TERT subunit four years later, a genuine plant TR has only recently been identified by our group. In this review, we focus on the structure, composition and function of telomerases. In addition, we discuss the origin and phylogenetic divergence of this unique RNA-dependent DNA polymerase as a witness of early eukaryotic evolution. Specifically, we discuss the latest information regarding the recently discovered TR component in plants, its conservation and its structural features.
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Affiliation(s)
- Petra Procházková Schrumpfová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic;
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
- Correspondence:
| | - Jiří Fajkus
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic;
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
- The Czech Academy of Sciences, Institute of Biophysics, Královopolská 135, 612 65 Brno, Czech Republic
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31
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Bryan TM. G-Quadruplexes at Telomeres: Friend or Foe? Molecules 2020; 25:molecules25163686. [PMID: 32823549 PMCID: PMC7464828 DOI: 10.3390/molecules25163686] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/09/2020] [Accepted: 08/10/2020] [Indexed: 12/28/2022] Open
Abstract
Telomeres are DNA-protein complexes that cap and protect the ends of linear chromosomes. In almost all species, telomeric DNA has a G/C strand bias, and the short tandem repeats of the G-rich strand have the capacity to form into secondary structures in vitro, such as four-stranded G-quadruplexes. This has long prompted speculation that G-quadruplexes play a positive role in telomere biology, resulting in selection for G-rich tandem telomere repeats during evolution. There is some evidence that G-quadruplexes at telomeres may play a protective capping role, at least in yeast, and that they may positively affect telomere maintenance by either the enzyme telomerase or by recombination-based mechanisms. On the other hand, G-quadruplex formation in telomeric DNA, as elsewhere in the genome, can form an impediment to DNA replication and a source of genome instability. This review summarizes recent evidence for the in vivo existence of G-quadruplexes at telomeres, with a focus on human telomeres, and highlights some of the many unanswered questions regarding the location, form, and functions of these structures.
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Affiliation(s)
- Tracy M Bryan
- Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
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Paudel BP, Moye AL, Abou Assi H, El-Khoury R, Cohen SB, Holien JK, Birrento ML, Samosorn S, Intharapichai K, Tomlinson CG, Teulade-Fichou MP, González C, Beck JL, Damha MJ, van Oijen AM, Bryan TM. A mechanism for the extension and unfolding of parallel telomeric G-quadruplexes by human telomerase at single-molecule resolution. eLife 2020; 9:56428. [PMID: 32723475 PMCID: PMC7426096 DOI: 10.7554/elife.56428] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 07/28/2020] [Indexed: 02/07/2023] Open
Abstract
Telomeric G-quadruplexes (G4) were long believed to form a protective structure at telomeres, preventing their extension by the ribonucleoprotein telomerase. Contrary to this belief, we have previously demonstrated that parallel-stranded conformations of telomeric G4 can be extended by human and ciliate telomerase. However, a mechanistic understanding of the interaction of telomerase with structured DNA remained elusive. Here, we use single-molecule fluorescence resonance energy transfer (smFRET) microscopy and bulk-phase enzymology to propose a mechanism for the resolution and extension of parallel G4 by telomerase. Binding is initiated by the RNA template of telomerase interacting with the G-quadruplex; nucleotide addition then proceeds to the end of the RNA template. It is only through the large conformational change of translocation following synthesis that the G-quadruplex structure is completely unfolded to a linear product. Surprisingly, parallel G4 stabilization with either small molecule ligands or by chemical modification does not always inhibit G4 unfolding and extension by telomerase. These data reveal that telomerase is a parallel G-quadruplex resolvase.
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Affiliation(s)
- Bishnu P Paudel
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawara Health and Medical Research Institute, Wollongong, Australia
| | - Aaron Lavel Moye
- Children's Medical Research Institute, University of Sydney, Westmead, Australia
| | - Hala Abou Assi
- Department of Chemistry, McGill University, Montreal, Canada
| | | | - Scott B Cohen
- Children's Medical Research Institute, University of Sydney, Westmead, Australia
| | - Jessica K Holien
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Australia
| | - Monica L Birrento
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawara Health and Medical Research Institute, Wollongong, Australia
| | - Siritron Samosorn
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Srinakharinwirot University, Bangkok, Thailand
| | - Kamthorn Intharapichai
- Department of Biobased Materials Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Japan
| | | | - Marie-Paule Teulade-Fichou
- Institut Curie, PSL Research University, Orsay, France.,Université Paris Sud, Université Paris-Saclay, Orsay, France
| | - Carlos González
- Instituto de Química Física 'Rocasolano', CSIC, Madrid, Spain
| | - Jennifer L Beck
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawara Health and Medical Research Institute, Wollongong, Australia
| | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, Canada
| | - Antoine M van Oijen
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawara Health and Medical Research Institute, Wollongong, Australia
| | - Tracy M Bryan
- Children's Medical Research Institute, University of Sydney, Westmead, Australia
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