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Xu J, Liu Z, Zhang Z, Wu T. Unlocking the Full Potential of Cas12a: Exploring the Effects of Substrate and Reaction Conditions on Trans-Cleavage Activity. Anal Chem 2023. [PMID: 37392174 DOI: 10.1021/acs.analchem.3c01307] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2023]
Abstract
The trans-cleavage activity of Cas12a has been widely used with various applications. Here, we report that the trans-cleavage activity of Cas12a can be significantly affected by the fluorescent probe length and reaction buffer. The optimal probe length for Cas12a is found to be 15 nucleotides, and the optimal buffer is NEBuffer 4. Compared to the popularly used reaction conditions, the activity of Cas12a is improved by about 50-fold. In addition, the detection limit of Cas12a for DNA targets has been reduced by nearly three orders of magnitude. Our method provides a powerful tool for Cas12a trans-cleavage activity applications.
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Affiliation(s)
- Jie Xu
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhujun Liu
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhen Zhang
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Tongbo Wu
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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2
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Li D, Lv Y, Xia H, Huang J, Liu W, Yu J, Jing G, Liu W, Sun Y, Li W. Target-activated multivalent sensing platform for improving the sensitivity and selectivity of Hg2+ detection. Anal Chim Acta 2023; 1256:341123. [PMID: 37037627 DOI: 10.1016/j.aca.2023.341123] [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: 01/05/2023] [Revised: 03/17/2023] [Accepted: 03/18/2023] [Indexed: 04/03/2023]
Abstract
Sensitivity and selectivity are critical parameters to evaluate the performance of sensors. For trace detection, it remains a challenge to design a new sensor that achieves high sensitivity and selectivity simultaneously. Here, we present a target-activated dual Mg2+-dependent DNAzyme (MNAzyme) that served as a simple sensing model to explore the multivalency in improving the analytical sensitivity and selectivity for target detection. Mercury ion (Hg2+), a notorious toxic metal ion, was selected as a model target. In the presence of Hg2+, the thymine-rich regions of the hairpin probe and primer could hybridize to form a stable duplex via the thymine-Hg2+-thymine structure. Then, an intact enzyme sequence was exposed and two separate enzyme fragments were close to each other, generating a dual MNAzyme. Benefiting from the localized high-concentration of the enzyme strand, the dual MNAzyme showed a remarkable improvement in binding stability. The catalytic rate constant of the dual MNAzyme was theoretically 1.60 times higher than that of the monomeric counterpart, and the sensitivity and selectivity had 4.50 and 1.44-fold enhancement, respectively. When the dual MNAzyme was used for sensor applications, the limit of detection was determined to be 0.04 and 0.2 nM via UV-vis spectrophotometer and naked eye, respectively. Meanwhile, the method offered desirable selectivity toward Hg2+ against other metal ions. With the advantages of simple operation, high sensitivity, and desirable selectivity, the developed multivalent sensing platform could be easily expanded in the future for the on-site detection of other low-abundance analytes.
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Affiliation(s)
- Dongyan Li
- College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, China
| | - Yuxiong Lv
- College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, China
| | - Huaiyue Xia
- College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, China
| | - Jing Huang
- State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha, 410004, China
| | - Wenjie Liu
- College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, China
| | - Jianna Yu
- College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, China
| | - Guoxing Jing
- College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, China
| | - Wen Liu
- College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, China
| | - Yingying Sun
- College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, China
| | - Wenshan Li
- College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, China.
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Ye W, Zhang Z, Wang C, Feng Z, Hu Z, Liu Q, Wu T. Detection of small molecules by extending the terminal protection to the polymerase. Microchem J 2023. [DOI: 10.1016/j.microc.2023.108701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
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Nuclear factor Nrf2 promotes glycosidase OGG1 expression by activating the AKT pathway to enhance leukemia cell resistance to cytarabine. J Biol Chem 2022; 299:102798. [PMID: 36528059 PMCID: PMC9823221 DOI: 10.1016/j.jbc.2022.102798] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 12/01/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022] Open
Abstract
Chemotherapy resistance is the dominant challenge in the treatment of acute myeloid leukemia (AML). Nuclear factor E2-related factor 2 (Nrf2) exerts a vital function in drug resistance of many tumors. Nevertheless, the potential molecular mechanism of Nrf2 regulating the base excision repair pathway that mediates AML chemotherapy resistance remains unclear. Here, in clinical samples, we found that the high expression of Nrf2 and base excision repair pathway gene encoding 8-hydroxyguanine DNA glycosidase (OGG1) was associated with AML disease progression. In vitro, Nrf2 and OGG1 were highly expressed in drug-resistant leukemia cells. Upregulation of Nrf2 in leukemia cells by lentivirus transfection could decrease the sensitivity of leukemia cells to cytarabine, whereas downregulation of Nrf2 in drug-resistant cells could enhance leukemia cell chemosensitivity. Meanwhile, we found that Nrf2 could positively regulate OGG1 expression in leukemia cells. Our chromatin immunoprecipitation assay revealed that Nrf2 could bind to the promoter of OGG1. Furthermore, the use of OGG1 inhibitor TH5487 could partially reverse the inhibitory effect of upregulated Nrf2 on leukemia cell apoptosis. In vivo, downregulation of Nrf2 could increase the sensitivity of leukemia cell to cytarabine and decrease OGG1 expression. Mechanistically, Nrf2-OGG1 axis-mediated AML resistance might be achieved by activating the AKT signaling pathway to regulate downstream apoptotic proteins. Thus, this study reveals a novel mechanism of Nrf2-promoting drug resistance in leukemia, which may provide a potential therapeutic target for the treatment of drug-resistant/refractory leukemia.
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Sun J, Li C, Hu Y, Ding Y, Wu T. A structure change-induced fluorescent biosensor for uracil-DNA glycosylase activity detection based on the substrate preference of Lambda exonuclease. Talanta 2022; 243:123350. [DOI: 10.1016/j.talanta.2022.123350] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/24/2022] [Accepted: 02/28/2022] [Indexed: 01/03/2023]
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Sun J, Antczak NM, Gahlon HL, Sturla SJ. Molecular beacons with oxidized bases report on substrate specificity of DNA oxoguanine glycosylases. Chem Sci 2022; 13:4295-4302. [PMID: 35509469 PMCID: PMC9007065 DOI: 10.1039/d1sc05648d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 02/15/2022] [Indexed: 11/21/2022] Open
Abstract
DNA glycosylase enzymes recognize and remove structurally distinct modified forms of DNA bases, thereby repairing genomic DNA from chemically induced damage or erasing epigenetic marks. However, these enzymes are often promiscuous, and advanced tools are needed to evaluate and engineer their substrate specificity. Thus, in the present study, we developed a new strategy to rapidly profile the substrate specificity of 8-oxoguanine glycosylases, which cleave biologically relevant oxidized forms of guanine. We monitored the enzymatic excision of fluorophore-labeled oligonucleotides containing synthetic modifications 8-oxoG and FapyG, or G. Using this molecular beacon approach, we identified several hOGG1 mutants with higher specificity for FapyG than 8-oxoG. This approach and the newly synthesized probes will be useful for the characterization of glycosylase substrate specificity and damage excision mechanisms, as well as for evaluating engineered enzymes with altered reactivities.
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Affiliation(s)
- Jingjing Sun
- Department of Health Sciences and Technology, ETH Zürich Zürich 8092 Switzerland
- Department of Biological Engineering, Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139 USA
| | - Nicole M Antczak
- Department of Health Sciences and Technology, ETH Zürich Zürich 8092 Switzerland
- Department of Chemistry, Skidmore College 815 North Broadway Saratoga Springs NY 12866 USA
| | - Hailey L Gahlon
- Department of Health Sciences and Technology, ETH Zürich Zürich 8092 Switzerland
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zürich Zürich 8092 Switzerland
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Ouyang Y, Liu Y, Deng Y, He H, Huang J, Ma C, Wang K. Recent advances in biosensor for DNA glycosylase activity detection. Talanta 2021; 239:123144. [PMID: 34923254 DOI: 10.1016/j.talanta.2021.123144] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/09/2021] [Accepted: 12/11/2021] [Indexed: 10/19/2022]
Abstract
Base excision repair (BER) is vital for maintaining the integrity of the genome under oxidative damage. DNA glycosylase initiates the BER pathway recognizes and excises the mismatched substrate base leading to the apurinic/apyrimidinic site generation, and simultaneously breaks the single-strand DNA. As the aberrant activity of DNA glycosylase is associated with numerous diseases, including cancer, immunodeficiency, and atherosclerosis, the detection of DNA glycosylase is significant from bench to bedside. In this review, we summarized novel DNA strategies in the past five years for DNA glycosylase activity detection, which are classified into fluorescence, colorimetric, electrochemical strategies, etc. We also highlight the current limitations and look into the future of DNA glycosylase activity monitoring.
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Affiliation(s)
- Yuzhen Ouyang
- School of Life Sciences, Central South University, Changsha, 410013, China; Clinical Medicine Eight-year Program, Xiangya School of Medicine, Central South University, Changsha, 410078, China
| | - Yifan Liu
- School of Life Sciences, Central South University, Changsha, 410013, China; Clinical Medicine Eight-year Program, Xiangya School of Medicine, Central South University, Changsha, 410078, China
| | - Yuan Deng
- School of Life Sciences, Central South University, Changsha, 410013, China
| | - Hailun He
- School of Life Sciences, Central South University, Changsha, 410013, China
| | - Jin Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, 410082, China.
| | - Changbei Ma
- School of Life Sciences, Central South University, Changsha, 410013, China.
| | - Kemin Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, 410082, China
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