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Stitz R, Stoiber F, Silye R, Vlachos G, Andaloro S, Rebhan E, Dunzinger M, Pühringer F, Gallo C, El-Heliebi A, Heitzer E, Hauser-Kronberger C. Clinical Implementation of a Noninvasive, Multi-Analyte Droplet Digital PCR Test to Screen for Androgen Receptor Alterations. J Mol Diagn 2024; 26:467-478. [PMID: 38522838 DOI: 10.1016/j.jmoldx.2024.02.009] [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: 09/03/2023] [Revised: 01/14/2024] [Accepted: 02/13/2024] [Indexed: 03/26/2024] Open
Abstract
Alterations of the androgen receptor (AR) are associated with resistance to AR-directed therapy in prostate cancer. Thus, it is crucial to develop robust detection methods for AR alterations as predictive biomarkers to enable applicability in clinical practice. We designed and validated five multiplex droplet digital PCR assays for reliable detection of 12 AR targets including AR amplification, AR splice variant 7, and 10 AR hotspot mutations, as well as AR and KLK3 gene expression from plasma-derived cell-free DNA and cell-free RNA. The assays demonstrated excellent analytical sensitivity and specificity ranging from 95% to 100% (95% CI, 75% to 100%). Intrarun and interrun variation analyses revealed a high level of repeatability and reproducibility. The developed assays were applied further in peripheral blood samples from 77 patients with advanced prostate cancer to assess their feasibility in a real-world scenario. Optimizing the reverse transcription of RNA increased the yield of plasma-derived cell-free RNA by 30-fold. Among 23 patients with castration-resistant prostate cancer, 6 patients (26.1%) had one or a combination of several AR alterations, whereas only 2 of 54 patients (3.7%) in the hormone-sensitive stage showed AR alterations. These findings were consistent with other studies and suggest that implementation of comprehensive AR status detection in clinical practice is feasible and can support the treatment decision-making process.
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Affiliation(s)
- Regina Stitz
- Department of Pathology, Salzkammergutklinikum Vöcklabruck, Vöcklabruck, Austria; Doctoral Program Medical Science, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Franz Stoiber
- Department of Urology Medicine, Salzkammergutklinikum Vöcklabruck, Vöcklabruck, Austria
| | - Renè Silye
- Department of Pathology, Salzkammergutklinikum Vöcklabruck, Vöcklabruck, Austria
| | - Georgios Vlachos
- Institute of Human Genetics, Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, Graz, Austria; Christian Doppler Laboratory for Liquid Biopsies for Early Detection of Cancer, Medical University of Graz, Graz, Austria
| | - Silvia Andaloro
- Institute of Human Genetics, Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, Graz, Austria
| | - Elisabeth Rebhan
- Department of Pathology, Salzkammergutklinikum Vöcklabruck, Vöcklabruck, Austria
| | - Michael Dunzinger
- Department of Urology Medicine, Salzkammergutklinikum Vöcklabruck, Vöcklabruck, Austria
| | - Franz Pühringer
- Department of Pathology, Salzkammergutklinikum Vöcklabruck, Vöcklabruck, Austria
| | - Caroline Gallo
- Department of Pathology, Salzkammergutklinikum Vöcklabruck, Vöcklabruck, Austria
| | - Amin El-Heliebi
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Centre, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Ellen Heitzer
- Institute of Human Genetics, Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, Graz, Austria; Christian Doppler Laboratory for Liquid Biopsies for Early Detection of Cancer, Medical University of Graz, Graz, Austria.
| | - Cornelia Hauser-Kronberger
- Department of Pathology, Salzkammergutklinikum Vöcklabruck, Vöcklabruck, Austria; Department of Anatomy and Cell Biology, Paracelsus Medical University Salzburg, Salzburg, Austria.
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2
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Wang M, Liu H, Ren J, Huang Y, Deng Y, Liu Y, Chen Z, Chow FWN, Leung PHM, Li S. Enzyme-Assisted Nucleic Acid Amplification in Molecular Diagnosis: A Review. BIOSENSORS 2023; 13:bios13020160. [PMID: 36831926 PMCID: PMC9953907 DOI: 10.3390/bios13020160] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/03/2023] [Accepted: 01/05/2023] [Indexed: 06/12/2023]
Abstract
Infectious diseases and tumors have become the biggest medical challenges in the 21st century. They are driven by multiple factors such as population growth, aging, climate change, genetic predispositions and more. Nucleic acid amplification technologies (NAATs) are used for rapid and accurate diagnostic testing, providing critical information in order to facilitate better follow-up treatment and prognosis. NAATs are widely used due their high sensitivity, specificity, rapid amplification and detection. It should be noted that different NAATs can be selected according to different environments and research fields; for example, isothermal amplification with a simple operation can be preferred in developing countries or resource-poor areas. In the field of translational medicine, CRISPR has shown great prospects. The core component of NAAT lies in the activity of different enzymes. As the most critical material of nucleic acid amplification, the key role of the enzyme is self-evident, playing the upmost important role in molecular diagnosis. In this review, several common enzymes used in NAATs are compared and described in detail. Furthermore, we summarize both the advances and common issues of NAATs in clinical application.
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Affiliation(s)
- Meiling Wang
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices, Hunan University of Technology, Zhuzhou 412007, China
| | - Hongna Liu
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices, Hunan University of Technology, Zhuzhou 412007, China
| | - Jie Ren
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices, Hunan University of Technology, Zhuzhou 412007, China
| | - Yunqi Huang
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices, Hunan University of Technology, Zhuzhou 412007, China
| | - Yan Deng
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices, Hunan University of Technology, Zhuzhou 412007, China
| | - Yuan Liu
- Hengyang Medical School, University of South China, Hengyang 421001, China
| | - Zhu Chen
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices, Hunan University of Technology, Zhuzhou 412007, China
| | - Franklin Wang-Ngai Chow
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong 999077, China
| | - Polly Hang-Mei Leung
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong 999077, China
| | - Song Li
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices, Hunan University of Technology, Zhuzhou 412007, China
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3
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Qin X, Wang X, Xu K, Zhang Y, Tian H, Li Y, Qi B, Yang X. Quantitative analysis of miRNAs using SplintR ligase-mediated ligation of complementary-pairing probes enhanced by RNase H (SPLICER)-qPCR. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 31:241-255. [PMID: 36700047 PMCID: PMC9842969 DOI: 10.1016/j.omtn.2022.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022]
Abstract
Here, a method using SplintR ligase-mediated ligation of complementary-pairing probes enhanced by RNase H (SPLICER) for miRNAs quantification was established. The strategy has two steps: (1) ligation of two DNA probes specifically hybridize to target miRNA and (2) qPCR amplifying the ligated probe. The miRNA-binding regions of the probes are stem-looped, a motif significantly reduces nonspecific ligation at high ligation temperature (65°C). The ends of the probes are designed complementary to form a paired probe, facilitating the recognition of target miRNAs with low concentrations. RNase H proved to be able to stabilize the heteroduplex formed by the probe and target miRNA, contributing to enhanced sensitivity (limit of detection = 60 copies). High specificity (discriminating homology miRNAs differing only one nucleotide), wide dynamic range (seven orders of magnitude) and ability to accurately detect plant miRNAs (immune to hindrance of 2'-O-methyl moiety) enable SPLICER comparable with the commercially available TaqMan and miRCURY assays. SYBR green I, rather than expensive hydrolysis or locked nucleic acid probes indispensable to TaqMan and miRCURY assays, is adequate for SPLICER. The method was efficient (<1 h), economical ($7 per sample), and robust (able to detect xeno-miRNAs in mammalian bodies), making it a powerful tool for molecular diagnosis and corresponding therapy.
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Affiliation(s)
- Xinshu Qin
- College of Food Engineering and Nutritional Science, Shaanxi Normal University, No. 620 West Chang’an Avenue, Xi’an 710062, Shaanxi, China
| | - Xingyu Wang
- College of Food Engineering and Nutritional Science, Shaanxi Normal University, No. 620 West Chang’an Avenue, Xi’an 710062, Shaanxi, China,Corresponding author: Xingyu Wang, College of Food Engineering and Nutritional Science, Shaanxi Normal University, No. 620 West Chang’an Avenue, Xi’an 710054, Shaanxi, China.
| | - Ke Xu
- Department of Joint Surgery, Hong Hui Hospital, Xi’an Jiaotong University, Xi’an 710054, Shaanxi, China
| | - Yi Zhang
- Department of Food Science, The Pennsylvania State University, University Park, PA 16802, USA
| | - Hongye Tian
- College of Food Engineering and Nutritional Science, Shaanxi Normal University, No. 620 West Chang’an Avenue, Xi’an 710062, Shaanxi, China
| | - Yinglei Li
- College of Food Engineering and Nutritional Science, Shaanxi Normal University, No. 620 West Chang’an Avenue, Xi’an 710062, Shaanxi, China
| | - Bangran Qi
- College of Food Engineering and Nutritional Science, Shaanxi Normal University, No. 620 West Chang’an Avenue, Xi’an 710062, Shaanxi, China
| | - Xingbin Yang
- College of Food Engineering and Nutritional Science, Shaanxi Normal University, No. 620 West Chang’an Avenue, Xi’an 710062, Shaanxi, China,Corresponding author: Xingbin Yang, College of Food Engineering and Nutritional Science, Shaanxi Normal University, No. 620 West Chang’an Avenue, Xi’an 710054, Shaanxi, China.
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4
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Kandabashi M, Yano H, Hara H, Ogawa S, Kamoda K, Ishibashi S, Himeda K, Baba M, Takita T, Yasukawa K. Analysis of ribonucleotide content in the genomic DNA of ribonuclease H2 A subunit (RH2A)-knockout NIH3T3 cells after transient expression of wild-type RH2A or RH2A variants with an Aicardi-Goutières syndrome-causing mutation. J Biochem 2022; 172:225-231. [DOI: 10.1093/jb/mvac056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 07/03/2022] [Indexed: 11/13/2022] Open
Abstract
Summary
Ribonuclease (RNase) H2 is involved in the removal of ribonucleotides embedded in genomic DNA. Eukaryotic RNase H2 is a heterotrimer consisting of the catalytic A subunit (RH2A) and the accessory B and C subunits. This study aimed to compare the cellular activities of wild-type ribonuclease (RNase) H2 and its variants with a mutation causing neuroinflammatory autoimmune disease, Aicardi-Goutières syndrome (AGS). We first analyzed cellular RNase H2 activity and ribonucleotide content in the genomic DNA of RH2A-knockout (KO) mouse fibroblast NIH3T3 cells after transfection with a transient expression plasmid encoding mouse wild-type RH2A. From four hours after transfection, the RNase H2 activity increased, and the amount of ribonucleotides decreased, as compared with the corresponding non-transfected RH2A-KO cells. This demonstrated the rapidness of ribonucleotide turnover in mammalian genomic DNA and the importance of continuous expression of RNase H2 to maintain the ribonucleotide amount low. Next, we expressed mouse RH2A variants with a mutation corresponding to a human AGS-causing mutation in RH2A-KO NIH3T3 cells. Neither increase in RNase H2 activity nor decrease in ribonucleotide amount were observed for G37S; however, both conditions were observed for N213I and R293H. This corresponded with our previous results on the activity of recombinant human RNase H2 variants.
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Affiliation(s)
- Mako Kandabashi
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Haruna Yano
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Haruka Hara
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Saori Ogawa
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kana Kamoda
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Shu Ishibashi
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kohei Himeda
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Misato Baba
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Teisuke Takita
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kiyoshi Yasukawa
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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5
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Martin JA, Palmer AG. Comparisons of Ribonuclease HI Homologs and Mutants Uncover a Multistate Model for Substrate Recognition. J Am Chem Soc 2022; 144:5342-5349. [PMID: 35312304 PMCID: PMC9149773 DOI: 10.1021/jacs.1c11897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ribonuclease HI (RNHI) nonspecifically cleaves the RNA strand of RNA:DNA hybrid duplexes in a myriad of biological processes. Several RNHI homologs contain an extended domain, termed the handle region, which is critical to substrate binding. Nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) simulations have suggested a kinetic model in which the handle region can exist in open (substrate-binding competent) or closed (substrate-binding incompetent) states in homologs containing arginine or lysine at position 88 (using sequence numbering of E. coli RNHI), while the handle region populates states intermediate between the open and closed conformers in homologs with asparagine at residue 88 [Stafford, K. A., et al., PLoS Comput. Biol. 2013, 9, 1-10]. NMR parameters characterizing handle region dynamics are highly correlated with enzymatic activity for RNHI homologs with two-state (open/closed) handle regions [Martin, J. A., et al., Biochemistry 2020, 59, 3201-3205]. The work presented herein shows that homologs containing asparagine 88 display distinct structural features compared with their counterparts containing arginine or lysine 88. Comparisons of RNHI homologs and site-directed mutants with asparagine 88 support a kinetic model for handle region dynamics that includes 12 unique transitions between eight conformations. Overall, these findings present an example of the structure-function relationships of enzymes and spotlight the use of NMR spectroscopy and MD simulations in uncovering fine details of conformational preferences.
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Affiliation(s)
- James A Martin
- Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Arthur G Palmer
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, United States
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6
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Oscorbin IP, Filipenko ML. M-MuLV reverse transcriptase: Selected properties and improved mutants. Comput Struct Biotechnol J 2021; 19:6315-6327. [PMID: 34900141 PMCID: PMC8640165 DOI: 10.1016/j.csbj.2021.11.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 11/12/2021] [Accepted: 11/18/2021] [Indexed: 11/06/2022] Open
Abstract
Reverse transcriptases (RTs) are enzymes synthesizing DNA using RNA as the template and serving as the standard tools in modern biotechnology and molecular diagnostics. To date, the most commonly used reverse transcriptase is the enzyme from Moloney murine leukemia virus, M-MuLV RT. Since its discovery, M-MuLV RT has become indispensable for modern RNA studies; the range of M-MuLV RT applications is vast, from scientific tasks to clinical testing of human pathogens. This review will give a brief description of the structure, thermal stability, processivity, and fidelity, focusing on improving M-MuLV RT for practical usage.
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Affiliation(s)
- Igor P Oscorbin
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 8 Lavrentiev Avenue, Novosibirsk 630090, Russia
| | - Maxim L Filipenko
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 8 Lavrentiev Avenue, Novosibirsk 630090, Russia
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7
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Ilina TV, Brosenitsch T, Sluis-Cremer N, Ishima R. Retroviral RNase H: Structure, mechanism, and inhibition. Enzymes 2021; 50:227-247. [PMID: 34861939 DOI: 10.1016/bs.enz.2021.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
All retroviruses encode the enzyme, reverse transcriptase (RT), which is involved in the conversion of the single-stranded viral RNA genome into double-stranded DNA. RT is a multifunctional enzyme and exhibits DNA polymerase and ribonuclease H (RNH) activities, both of which are essential to the reverse-transcription process. Despite the successful development of polymerase-targeting antiviral drugs over the last three decades, no bona fide inhibitor against the RNH activity of HIV-1 RT has progressed to clinical evaluation. In this review article, we describe the retroviral RNH function and inhibition, with primary consideration of the structural aspects of inhibition.
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Affiliation(s)
- Tatiana V Ilina
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Teresa Brosenitsch
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Nicolas Sluis-Cremer
- Department of Medicine, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Rieko Ishima
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
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8
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Harrison JJEK, Tuske S, Das K, Ruiz FX, Bauman JD, Boyer PL, DeStefano JJ, Hughes SH, Arnold E. Crystal Structure of a Retroviral Polyprotein: Prototype Foamy Virus Protease-Reverse Transcriptase (PR-RT). Viruses 2021; 13:v13081495. [PMID: 34452360 PMCID: PMC8402755 DOI: 10.3390/v13081495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/21/2021] [Accepted: 07/26/2021] [Indexed: 12/23/2022] Open
Abstract
In most cases, proteolytic processing of the retroviral Pol portion of the Gag-Pol polyprotein precursor produces protease (PR), reverse transcriptase (RT), and integrase (IN). However, foamy viruses (FVs) express Pol separately from Gag and, when Pol is processed, only the IN domain is released. Here, we report a 2.9 Å resolution crystal structure of the mature PR-RT from prototype FV (PFV) that can carry out both proteolytic processing and reverse transcription but is in a configuration not competent for proteolytic or polymerase activity. PFV PR-RT is monomeric and the architecture of PFV PR is similar to one of the subunits of HIV-1 PR, which is a dimer. There is a C-terminal extension of PFV PR (101-145) that consists of two helices which are adjacent to the base of the RT palm subdomain, and anchors PR to RT. The polymerase domain of PFV RT consists of fingers, palm, thumb, and connection subdomains whose spatial arrangements are similar to the p51 subunit of HIV-1 RT. The RNase H and polymerase domains of PFV RT are connected by flexible linkers. Significant spatial and conformational (sub)domain rearrangements are therefore required for nucleic acid binding. The structure of PFV PR-RT provides insights into the conformational maturation of retroviral Pol polyproteins.
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Affiliation(s)
- Jerry Joe E. K. Harrison
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
- Department of Medicinal Chemistry, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA
- Department of Chemistry, University of Ghana, Legon P.O. Box LG 56, Ghana
| | - Steve Tuske
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
| | - Kalyan Das
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, 3000 Leuven, Belgium
| | - Francesc X. Ruiz
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
| | - Joseph D. Bauman
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
| | - Paul L. Boyer
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702, USA; (P.L.B.); (S.H.H.)
| | - Jeffrey J. DeStefano
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, MD 20742, USA;
| | - Stephen H. Hughes
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702, USA; (P.L.B.); (S.H.H.)
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
- Department of Medicinal Chemistry, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
- Correspondence:
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9
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Manigrasso J, De Vivo M, Palermo G. Controlled Trafficking of Multiple and Diverse Cations Prompts Nucleic Acid Hydrolysis. ACS Catal 2021; 11:8786-8797. [PMID: 35145762 DOI: 10.1021/acscatal.1c01825] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Recent in crystallo reaction intermediates have detailed how nucleic acid hydrolysis occurs in the RNA ribonuclease H1 (RNase H1), a fundamental metalloenzyme involved in maintaining the human genome. At odds with the previous characterization, these in crystallo structures unexpectedly captured multiple metal ions (K+ and Mg2+) transiently bound in the vicinity of the two-metal-ion active site. Using multi-microsecond all-atom molecular dynamics and free-energy simulations, we investigated the functional implications of the dynamic exchange of multiple K+ and Mg2+ ions at the RNase H1 reaction center. We found that such ions are timely positioned at non-overlapping locations near the active site, at different stages of catalysis, being crucial for both reactants' alignment and leaving group departure. We also found that this cation trafficking is tightly regulated by variations of the solution's ionic strength and is aided by two conserved second-shell residues, E188 and K196, suggesting a mechanism for the cations' recruitment during catalysis. These results indicate that controlled trafficking of multi-cation dynamics, opportunely prompted by second-shell residues, is functionally essential to the complex enzymatic machinery of the RNase H1. These findings revise the current knowledge on the RNase H1 catalysis and open new catalytic possibilities for other similar metalloenzymes including, but not limited to, CRISPR-Cas9, group II intron ribozyme and the human spliceosome.
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Affiliation(s)
- Jacopo Manigrasso
- Laboratory of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Genoa, 16163, Italy.,Department of Bioengineering, University of California Riverside, Riverside, CA 52512, United States
| | - Marco De Vivo
- Laboratory of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Genoa, 16163, Italy
| | - Giulia Palermo
- Department of Bioengineering, University of California Riverside, Riverside, CA 52512, United States.,Department of Chemistry, University of California Riverside, Riverside, CA 52512, United States
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10
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Zhao F, Liu A, Gong X, Chen H, Wei J, Chen B, Chen S, Yang R, Fan Y, Mao R. Hypoxia-induced RNASEH2A limits activation of cGAS-STING signaling in HCC and predicts poor prognosis. TUMORI JOURNAL 2021; 108:63-76. [PMID: 34165025 DOI: 10.1177/03008916211026019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Hypoxia is a hallmark of solid cancers, including hepatocellular carcinoma (HCC). There is scarce information about how hypoxia avoids immunologic stress and maintains a cancer-promoting microenvironment. METHODS The Cancer Genome Atlas, RNA-seq data, and Oncomine database were used to discover the correlation of RNASEH2A with tumor progression; then expression of RNASEH2A mRNA and protein were detected in HCC tissues and cells subjected to hypoxia or with the treatment of CoCl2 via real-time quantitative polymerase chain reaction and immunochemistry assays. Finally, the effect of RNASEH2A on cell proliferation and the involved signaling pathway was explored further. RESULTS RNASEH2A was positively correlated with tumor grade, size, vascular invasion, and poor prognosis. The expression of RNASEH2A mRNA and protein were increased and dependent on hypoxia-inducible factor 2α in HCC tissues and cell lines. Knockout of RNASEH2A in HCC cells greatly reduced cell proliferation and induced the transcription of multiple cGAS-STING (cyclic GMP-AMP synthase-stimulator of interferon genes) targeted type 1 interferon-related genes, including IFIT1, USP18, and CXCL10, which suggests knockout of RNASEH2A may produce immunologic stress and tumor suppressive effects. CONCLUSIONS RNASEH2A plays a critical role and potentially predicts patient outcomes in HCC, which uncovers a new mechanism that RNASEH2A contributes to limit immunologic stress of cancer cells in the context of hypoxia.
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Affiliation(s)
- Fengbo Zhao
- Laboratory of Medical Science, School of Medicine, Nantong University, Jiangsu, China
| | - Aifen Liu
- Laboratory of Medical Science, School of Medicine, Nantong University, Jiangsu, China
| | - Xiu Gong
- Laboratory of Medical Science, School of Medicine, Nantong University, Jiangsu, China
| | - Hao Chen
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Jiangsu, China
| | - Jinhuan Wei
- Laboratory of Medical Science, School of Medicine, Nantong University, Jiangsu, China
| | - Bin Chen
- Laboratory of Medical Science, School of Medicine, Nantong University, Jiangsu, China
| | - Shiyin Chen
- Laboratory of Medical Science, School of Medicine, Nantong University, Jiangsu, China
| | - Riyun Yang
- Laboratory of Medical Science, School of Medicine, Nantong University, Jiangsu, China
| | - Yihui Fan
- Laboratory of Medical Science, School of Medicine, Nantong University, Jiangsu, China.,Department of Pathogen Biology, School of Medicine, Nantong University, Jiangsu, China
| | - Renfang Mao
- Laboratory of Medical Science, School of Medicine, Nantong University, Jiangsu, China.,Department of Pathophysiology, School of Medicine, Nantong University, Jiangsu, China
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11
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Martin JA, Robustelli P, Palmer AG. Quantifying the Relationship between Conformational Dynamics and Enzymatic Activity in Ribonuclease HI Homologues. Biochemistry 2020; 59:3201-3205. [PMID: 32813972 DOI: 10.1021/acs.biochem.0c00500] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ribonuclease HI (RNHI), a ubiquitous, non-sequence-specific endonuclease, cleaves the RNA strand in RNA/DNA hybrids. RNHI functions in replication and genome maintenance, and retroviral reverse transcriptases contain an essential ribonuclease H domain. Nuclear magnetic resonance (NMR) spectroscopy combined with molecular dynamics (MD) simulations suggests a model in which the extended handle region domain of Escherichia coli RNHI populates (substrate-binding-competent) "open" and (substrate-binding-incompetent) "closed" states, while the thermophilic Thermus thermophilus RNHI mainly populates the closed state at 300 K [Stafford, K. A., Robustelli, P., and Palmer, A. G., III (2013) PLoS Comput. Biol. 9, 1-10]. In addition, an in silico-designed mutant E. coli Val98Ala RNHI was predicted to populate primarily the closed state. The work presented here validates this model and confirms the predicted properties of the designed mutant. MD simulations suggest that the conformational preferences of the handle region correlate with the conformations of Trp85, Thr92, and Val101. NMR residual dipolar coupling constants, three-bond scalar coupling constants, and chemical shifts experimentally define the conformational states of these residues and hence of the handle domain. These NMR parameters correlate with the Michaelis constants for RNHI homologues, confirming the important role of the handle region in the modulation of substrate recognition and illustrating the power of NMR spectroscopy in dissecting the conformational preferences underlying enzyme function.
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Affiliation(s)
- James A Martin
- Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Paul Robustelli
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Arthur G Palmer
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, United States
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12
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Stadelmayer B, Diederichs A, Chapus F, Rivoire M, Neveu G, Alam A, Fraisse L, Carter K, Testoni B, Zoulim F. Full-length 5'RACE identifies all major HBV transcripts in HBV-infected hepatocytes and patient serum. J Hepatol 2020; 73:40-51. [PMID: 32087349 DOI: 10.1016/j.jhep.2020.01.028] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 01/10/2020] [Accepted: 01/15/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND & AIMS Covalently closed circular DNA (cccDNA) is the episomal form of the HBV genome that stably resides in the nucleus of infected hepatocytes. cccDNA is the template for the transcription of 6 major viral RNAs, i.e. preC, pg, preS1/2, S and HBx RNA. All viral transcripts share the same 3' end and are all to various degrees subsets of each other. Especially under infection conditions, it has been difficult to study in depth the transcription of the different viral transcripts. We thus wanted to develop a method with which we could easily detect the full spectrum of viral RNAs in any lab. METHODS We set up an HBV full-length 5'RACE (rapid amplification of cDNA ends) method with which we measured and characterized the full spectrum of viral RNAs in cell culture and in chronically infected patients. RESULTS In addition to canonical HBx transcripts coding for full-length X, we identified shorter HBx transcripts potentially coding for short X proteins. We showed that interferon-β treatment leads to a strong reduction of preC and pgRNAs but has only a moderate effect on the other viral transcripts. We found pgRNA, 1 spliced pgRNA variant and a variety of HBx transcripts associated with viral particles generated by HepAD38 cells. The different HBx RNAs are both capped and uncapped. Lastly, we identified 3 major categories of circulating RNA species in patients with chronic HBV infection: pgRNA, spliced pgRNA variants and HBx. CONCLUSIONS This HBV full-length 5'RACE method should significantly contribute to the understanding of HBV transcription during the course of infection and therapy and may guide the development of novel therapies aimed at targeting cccDNA. LAY SUMMARY Especially under infection conditions, it has been difficult to study the different hepatitis B virus transcripts in depth. This study introduces a new method that can be used in any standard lab to discriminate all hepatitis B viral transcripts in cell culture and in the serum of patients.
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Affiliation(s)
- Bernd Stadelmayer
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France.
| | - Audrey Diederichs
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France
| | - Fleur Chapus
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France
| | - Michel Rivoire
- INSERM U1032, Centre Léon Bérard (CLB), 69008 Lyon, France
| | - Gregory Neveu
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Antoine Alam
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Laurent Fraisse
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Kara Carter
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Barbara Testoni
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France
| | - Fabien Zoulim
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France; Hospices Civils de Lyon (HCL), 69002 Lyon, France.
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13
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Baba M, Kojima K, Nishimura T, Sugiura T, Takita T, Uehara R, Crouch RJ, Yasukawa K. Val143 of human ribonuclease H2 is not critical for, but plays a role in determining catalytic activity and substrate specificity. PLoS One 2020; 15:e0228774. [PMID: 32069311 PMCID: PMC7028304 DOI: 10.1371/journal.pone.0228774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 01/22/2020] [Indexed: 11/18/2022] Open
Abstract
Ribonuclease H2 (RNase H2) exhibits both single ribonucleotide excision activity (activity A) and RNA strand degrading activity (activity B). Val143 of human RNase H2 is located at the active site and is conserved in eukaryotic RNase H2. In this study, we explored the role of Val143 in catalytic activity and substrate specificity. Nineteen single variants at amino acid position 143 were expressed in E. coli, and all variants except for V143C and V143M were purified from the cells. When the activity of the wild-type human RNase H2 (WT) was set as 100%, the relative activities A and B of the 17 variants were in the range of 0.05–130 and 0.02–42%, respectively. When the ratio of the relative activity A to the relative activity B of WT was set as 1, the ratios of the 17 variants were in the range of 0.2–5.7. This indicates that valine is optimal for balancing the two activities. The ratios for V143Y and V143W were relatively high (5.6 and 5.5, respectively), suggesting that the bulky residues like tyrosine and tryptophan at position 143 caused steric hindrance with the 2’-OH of the sugar moiety of the ribonucleotide at the 5’ side of the scissile phosphodiester bond. The ratio for V143Q was relatively low (0.2). These results suggested that Val143 is not critical for, but plays a role in determining catalytic activity and substrate specificity.
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Affiliation(s)
- Misato Baba
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kenji Kojima
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takuto Nishimura
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takuya Sugiura
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Teisuke Takita
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Ryo Uehara
- Section on Formation of RNA, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Noji-higashi, Shiga, Japan
| | - Robert J. Crouch
- Section on Formation of RNA, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
| | - Kiyoshi Yasukawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
- * E-mail:
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14
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Nishimura T, Baba M, Ogawa S, Kojima K, Takita T, Crouch RJ, Yasukawa K. Characterization of six recombinant human RNase H2 bearing Aicardi-Goutiéres syndrome causing mutations. J Biochem 2019; 166:537-545. [PMID: 31529068 DOI: 10.1093/jb/mvz073] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 09/02/2019] [Indexed: 01/18/2023] Open
Abstract
Mammalian RNase H2 is a heterotrimeric enzyme consisting of one catalytic subunit (A) and two accessory subunits (B and C). RNase H2 is involved in the removal of a single ribonucleotide embedded in genomic DNA and removal of RNA of RNA/DNA hybrids. In humans, mutation of the RNase H2 gene causes a severe neuroinflammatory disorder Aicardi-Goutières syndrome (AGS). Here, we examined the activity and stability of six recombinant human RNase H2 variants bearing one AGS-causing mutation, A-G37S (Gly37 in the A subunit is replaced with Ser), A-N212I, A-R291H, B-A177T, B-V185G, or C-R69W. The activity of A-G37S was 0.3-1% of that of the wild-type RNase H2 (WT), while those of other five variants were 51-120%. In circular dichroism measurement, the melting temperatures of variants were 50-53°C, lower than that of WT (56°C). These results suggested that A-G37S had decreased activity and stability than WT, while other five variants had decreased stability but retained activity. In gel filtration chromatography of the purified enzyme preparation, WT migrated as a heterotrimer, while A-R291H eluted in two separate peaks containing either the heterotrimer or only the A subunit, suggesting that some AGS-causing mutations affect the heterotrimer-forming stability of RNase H2.
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Affiliation(s)
- Takuto Nishimura
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
| | - Misato Baba
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
| | - Saori Ogawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
| | - Kenji Kojima
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
| | - Teisuke Takita
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
| | - Robert J Crouch
- Section on Formation of RNA, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kiyoshi Yasukawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
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15
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Minarovits J, Niller HH. Truncated oncoproteins of retroviruses and hepatitis B virus: A lesson in contrasts. INFECTION GENETICS AND EVOLUTION 2019; 73:342-357. [DOI: 10.1016/j.meegid.2019.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/14/2019] [Accepted: 05/27/2019] [Indexed: 02/07/2023]
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16
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An R, Kawai H, Asanuma H, Komiyama M, Liang X. Isothermal double-cycle catalytic system using DNAzyme and RNase H for the highly selective one-pot detection of oligonucleotides. Analyst 2019; 144:2773-2779. [PMID: 30869659 DOI: 10.1039/c8an02520g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
With the use of a double-cycle system involving two catalytic reactions by RNase H and DNAzyme, the signal of oligoDNAs has been specifically amplified in an isothermal mode. The precursor of DNAzyme was introduced to the system as a ring-structured and inactivated form, which involves the 6-nt RNA portion being complementary to target oligoDNA. In the presence of target oligoDNA, the RNA portion forms a DNA/RNA hetero-duplex and is cut by RNase H. This scission converts the precursor to catalytically active DNAzyme, which in turn disconnects the molecular beacon to produce the amplified signal. Because the covalent bonds were disconnected to provide discrete structural changes in both cycles, high sensitivity and specificity are obtained, indicating the strong potential of this double catalytic cycle method for versatile applications.
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Affiliation(s)
- Ran An
- College of Food Science and Engineering, Ocean University of China, Qingdao, 266003, P. R. China.
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17
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Tsukiashi M, Baba M, Kojima K, Himeda K, Takita T, Yasukawa K. Construction and characterization of ribonuclease H2 knockout NIH3T3 cells. J Biochem 2019; 165:249-256. [PMID: 30481312 DOI: 10.1093/jb/mvy101] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 11/13/2018] [Indexed: 11/13/2022] Open
Abstract
Ribonuclease H (RNase H) specifically hydrolyzes the 5'-phosphodiester bonds of the RNA of RNA/DNA hybrid. Both types 1 and 2 RNases H act on the RNA strand of the hybrid, while only type 2 acts on the single ribonucleotide embedded in DNA duplex. In this study, to explore the role of mammalian type 2 RNase H (RNase H2) in cells, we constructed the RNase H2 knockout NIH3T3 cells (KO cells) by CRISPR/Cas9 system. KO cells hydrolyzed RNA strands in RNA/DNA hybrid, but not single ribonucleotides in DNA duplex, while wild-type NIH3T3 cells (WT cells) hydrolyzed both. Genomic DNA in the KO cells was more heavily hydrolyzed than in the WT cells by the alkaline or RNase H2 treatment, suggesting that the KO cells contained more ribonucleotides in genomic DNA than the WT cells. The growth rate of the KO cells was 60% of that of the WT cells. Expression of interferon-stimulated genes (ISGs) in the KO cells was not markedly elevated compared with the WT cells. These results suggest that in NIH3T3 cells, RNase H2 is crucial for suppressing the accumulation of ribonucleotides in genomic DNA but not for the expression of ISGs.
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Affiliation(s)
- Motoki Tsukiashi
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Misato Baba
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Kenji Kojima
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Kohei Himeda
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Teisuke Takita
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Kiyoshi Yasukawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
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18
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Chen AY, Adamek RN, Dick BL, Credille CV, Morrison CN, Cohen SM. Targeting Metalloenzymes for Therapeutic Intervention. Chem Rev 2019; 119:1323-1455. [PMID: 30192523 PMCID: PMC6405328 DOI: 10.1021/acs.chemrev.8b00201] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Metalloenzymes are central to a wide range of essential biological activities, including nucleic acid modification, protein degradation, and many others. The role of metalloenzymes in these processes also makes them central for the progression of many diseases and, as such, makes metalloenzymes attractive targets for therapeutic intervention. Increasing awareness of the role metalloenzymes play in disease and their importance as a class of targets has amplified interest in the development of new strategies to develop inhibitors and ultimately useful drugs. In this Review, we provide a broad overview of several drug discovery efforts focused on metalloenzymes and attempt to map out the current landscape of high-value metalloenzyme targets.
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Affiliation(s)
- Allie Y Chen
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Rebecca N Adamek
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Benjamin L Dick
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Cy V Credille
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Christine N Morrison
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Seth M Cohen
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
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19
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Bai L, Zhang X, Kozlowski M, Li W, Wu M, Liu J, Chen L, Zhang J, Huang Y, Yuan Z. Extracellular Hepatitis B Virus RNAs Are Heterogeneous in Length and Circulate as Capsid-Antibody Complexes in Addition to Virions in Chronic Hepatitis B Patients. J Virol 2018; 92:e00798-18. [PMID: 30282709 PMCID: PMC6258948 DOI: 10.1128/jvi.00798-18] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/04/2018] [Indexed: 12/13/2022] Open
Abstract
Extracellular HBV RNA has been detected in both HBV-replicating cell culture media and sera from chronic hepatitis B (CHB) patients, but its exact origin and composition remain controversial. Here, we demonstrated that extracellular HBV RNA species were of heterogeneous lengths, ranging from the length of pregenomic RNA to a few hundred nucleotides. In cell models, these RNAs were predominantly associated with naked capsids, although virions also harbored a minority of them. Moreover, HBV RNAs in hepatitis B patients' blood circulation were localized in unenveloped capsids in the form of capsid-antibody complexes (CACs) and in virions. Furthermore, we showed that extracellular HBV RNAs could serve as the template for viral DNA synthesis. In conclusion, extracellular HBV RNAs mainly consist of pgRNA or the pgRNA species degraded by the RNase H domain of the polymerase in the process of viral DNA synthesis and circulate as CACs and virions. Their presence in blood circulation of CHB patients may be exploited to develop novel biomarkers for HBV persistence.IMPORTANCE Although increasing evidence suggests the presence of extracellular HBV RNA species, their origin and molecular forms are still under debate. In addition to the infectious virions, HBV is known to secrete several species of incomplete viral particles, including hepatitis B surface antigen (HBsAg) particles, naked capsids, and empty virions, during its replication cycle. Here, we demonstrated that extracellular HBV RNAs were associated with naked capsids and virions in HepAD38 cells. Interestingly, we found that unenveloped capsids circulate in the blood of hepatitis B patients in the form of CACs and, together with virions, serve as vehicles carrying these RNA molecules. Moreover, extracellular HBV RNAs are heterogeneous in length and represent either pregenomic RNA (pgRNA) or products of incomplete reverse transcription during viral replication. These findings provide a conceptual basis for further application of extracellular RNA species as novel biomarkers for HBV persistence.
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Affiliation(s)
- Lu Bai
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Xiaonan Zhang
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Maya Kozlowski
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Weixia Li
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Min Wu
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Jiangxia Liu
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Liang Chen
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Jiming Zhang
- Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Yuxian Huang
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
- Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Zhenghong Yuan
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
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20
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Developing and Evaluating Inhibitors against the RNase H Active Site of HIV-1 Reverse Transcriptase. J Virol 2018; 92:JVI.02203-17. [PMID: 29643235 DOI: 10.1128/jvi.02203-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/31/2018] [Indexed: 12/25/2022] Open
Abstract
We tested three compounds for their ability to inhibit the RNase H (RH) and polymerase activities of HIV-1 reverse transcriptase (RT). A high-resolution crystal structure (2.2 Å) of one of the compounds showed that it chelates the two magnesium ions at the RH active site; this prevents the RH active site from interacting with, and cleaving, the RNA strand of an RNA-DNA heteroduplex. The compounds were tested using a variety of substrates: all three compounds inhibited the polymerase-independent RH activity of HIV-1 RT. Time-of-addition experiments showed that the compounds were more potent if they were bound to RT before the nucleic acid substrate was added. The compounds significantly inhibited the site-specific cleavage required to generate the polypurine tract (PPT) RNA primer that initiates the second strand of viral DNA synthesis. The compounds also reduced the polymerase activity of RT; this ability was a result of the compounds binding to the RH active site. These compounds appear to be relatively specific; they do not inhibit either Escherichia coli RNase HI or human RNase H2. The compounds inhibit the replication of an HIV-1-based vector in a one-round assay, and their potencies were only modestly decreased by mutations that confer resistance to integrase strand transfer inhibitors (INSTIs), nucleoside analogs, or nonnucleoside RT inhibitors (NNRTIs), suggesting that their ability to block HIV replication is related to their ability to block RH cleavage. These compounds appear to be useful leads that can be used to develop more potent and specific compounds.IMPORTANCE Despite advances in HIV-1 treatment, drug resistance is still a problem. Of the four enzymatic activities found in HIV-1 proteins (protease, RT polymerase, RT RNase H, and integrase), only RNase H has no approved therapeutics directed against it. This new target could be used to design and develop new classes of inhibitors that would suppress the replication of the drug-resistant variants that have been selected by the current therapeutics.
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Arnold AE, Malek-Adamian E, Le PU, Meng A, Martínez-Montero S, Petrecca K, Damha MJ, Shoichet MS. Antibody-Antisense Oligonucleotide Conjugate Downregulates a Key Gene in Glioblastoma Stem Cells. MOLECULAR THERAPY. NUCLEIC ACIDS 2018; 11:518-527. [PMID: 29858087 PMCID: PMC5992475 DOI: 10.1016/j.omtn.2018.04.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 03/29/2018] [Accepted: 04/13/2018] [Indexed: 12/17/2022]
Abstract
Glioblastoma stem cells (GSCs) are invasive, treatment-resistant brain cancer cells that express downregulated in renal cell carcinoma (DRR), also called FAM107A, a genetic driver of GSC invasion. We developed antibody-antisense oligonucleotide (AON) conjugates to target and reduce DRR/FAM107A expression. Specifically, we used antibodies against antigens expressed on the GSCs, such as CD44 and EphA2, conjugated to chemically modified AONs against DRR/FAM107A, which were designed as chimeras of DNA and 2'-deoxy-2'-fluoro-beta-D-arabinonucleic acid (FANA) for increased nuclease stability and mRNA affinity. We demonstrate that these therapeutic conjugates successfully internalize, accumulate, and reduce DRR/FAM107A expression in patient-derived GSCs. This is the first example of an antibody-antisense strategy against cancer stem cells.
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Affiliation(s)
- Amy E Arnold
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada
| | - Elise Malek-Adamian
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada
| | - Phuong U Le
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada
| | - Anika Meng
- Division of Engineering Science, University of Toronto, 35 St. George Street, Toronto, ON M5S 1A4, Canada
| | - Saúl Martínez-Montero
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada
| | - Kevin Petrecca
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada
| | - Masad J Damha
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada.
| | - Molly S Shoichet
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada; Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9, Canada.
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22
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Blanco-Melo D, Gifford RJ, Bieniasz PD. Reconstruction of a replication-competent ancestral murine endogenous retrovirus-L. Retrovirology 2018; 15:34. [PMID: 29716624 PMCID: PMC5930517 DOI: 10.1186/s12977-018-0416-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 04/10/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND About 10% of the mouse genome is composed of endogenous retroviruses (ERVs) that represent a molecular fossil record of past retroviral infections. One such retrovirus, murine ERV-L (MuERV-L) is an env-deficient ERV that has undergone episodic proliferation, with the most recent amplification occurring ~ 2 million years ago. MuERV-L related sequences have been co-opted by mice for antiretroviral defense, and possibly as promoters for some genes that regulate totipotency in early mouse embryos. However, MuERV-L sequences present in modern mouse genomes have not been observed to replicate. RESULTS Here, we describe the reconstruction of an ancestral MuERV-L (ancML) sequence through paleovirological analyses of MuERV-L elements in the modern mouse genome. The resulting MuERV-L (ancML) sequence was synthesized and a reporter gene embedded. The reconstructed MuERV-L (ancML) could replicate in a manner that is dependent on reverse transcription and generated de novo integrants. Notably, MuERV-L (ancML) exhibited a narrow host range. Interferon-α could reduce MuERV-L (ancML) replication, suggesting the existence of interferon-inducible genes that could inhibit MuERV-L replication. While mouse APOBEC3 was able to restrict the replication of MuERV-L (ancML), inspection of endogenous MuERV-L sequences suggested that the impact of APOBEC3 mediated hypermutation on MuERV-L has been minimal. CONCLUSION The reconstruction of an ancestral MuERV-L sequence highlights the potential for the retroviral fossil record to illuminate ancient events and enable studies of the impact of retroviral elements on animal evolution.
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Affiliation(s)
- Daniel Blanco-Melo
- Laboratory of Retrovirology and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Robert J Gifford
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Paul D Bieniasz
- Laboratory of Retrovirology and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA.
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An Evolutionary/Biochemical Connection between Promoter- and Primer-Dependent Polymerases Revealed by Systematic Evolution of Ligands by Exponential Enrichment. J Bacteriol 2018; 200:JB.00579-17. [PMID: 29339418 DOI: 10.1128/jb.00579-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/11/2018] [Indexed: 01/06/2023] Open
Abstract
DNA polymerases (DNAPs) recognize 3' recessed termini on duplex DNA and carry out nucleotide catalysis. Unlike promoter-specific RNA polymerases (RNAPs), no sequence specificity is required for binding or initiation of catalysis. Despite this, previous results indicate that viral reverse transcriptases bind much more tightly to DNA primers that mimic the polypurine tract. In the current report, primer sequences that bind with high affinity to Taq and Klenow polymerases were identified using a modified systematic evolution of ligands by exponential enrichment (SELEX) approach. Two Taq-specific primers that bound ∼10 (Taq1) and over 100 (Taq2) times more stably than controls to Taq were identified. TaqI contained 8 nucleotides (5'-CACTAAAG-3') that matched the phage T3 RNAP "core" promoter. Both primers dramatically outcompeted primers with similar binding thermodynamics in PCRs. Similarly, exonuclease- Klenow polymerase also selected a high-affinity primer that contained a related core promoter sequence from phage T7 RNAP (5'-ACTATAG-3'). For both Taq and Klenow, even small modifications to the sequence resulted in large losses in binding affinity, suggesting that binding was highly sequence specific. The results are discussed in the context of possible effects on multiprimer (multiplex) PCR assays, molecular information theory, and the evolution of RNAPs and DNAPs.IMPORTANCE This work further demonstrates that primer-dependent DNA polymerases can have strong sequence biases leading to dramatically tighter binding to specific sequences. These may be related to biological function or be a consequence of the structural architecture of the enzyme. New sequence specificity for Taq and Klenow polymerases were uncovered, and among them were sequences that contained the core promoter elements from T3 and T7 phage RNA polymerase promoters. This suggests the intriguing possibility that phage RNA polymerases exploited intrinsic binding affinities of ancestral DNA polymerases to develop their promoters. Conversely, DNA polymerases could have evolved from related RNA polymerases and retained the intrinsic binding preference despite there being no clear function for such a preference in DNA biology.
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Kielpinski LJ, Hagedorn PH, Lindow M, Vinther J. RNase H sequence preferences influence antisense oligonucleotide efficiency. Nucleic Acids Res 2018; 45:12932-12944. [PMID: 29126318 PMCID: PMC5728404 DOI: 10.1093/nar/gkx1073] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/19/2017] [Indexed: 12/24/2022] Open
Abstract
RNase H cleaves RNA in RNA-DNA duplexes. It is present in all domains of life as well as in multiple viruses and is essential for mammalian development and for human immunodeficiency virus replication. Here, we developed a sequencing-based method to measure the cleavage of thousands of different RNA-DNA duplexes and thereby comprehensively characterized the sequence preferences of HIV-1, human and Escherichia coli RNase H enzymes. We find that the catalytic domains of E. coli and human RNase H have nearly identical sequence preferences, which correlate with the efficiency of RNase H-recruiting antisense oligonucleotides. The sequences preferred by HIV-1 RNase H are distributed in the HIV genome in a way suggesting selection for efficient RNA cleavage during replication. Our findings can be used to improve the design of RNase H-recruiting antisense oligonucleotides and show that sequence preferences of HIV-1 RNase H may have shaped evolution of the viral genome and contributed to the use of tRNA-Lys3 as primer during viral replication.
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Affiliation(s)
- Lukasz J Kielpinski
- Roche Pharmaceutical Discovery and Early Development, Therapeutic Modalities, Roche Innovation Center Copenhagen, Fremtidsvej 3, DK-2970 Hørsholm, Denmark
| | - Peter H Hagedorn
- Roche Pharmaceutical Discovery and Early Development, Therapeutic Modalities, Roche Innovation Center Copenhagen, Fremtidsvej 3, DK-2970 Hørsholm, Denmark
| | - Morten Lindow
- Roche Pharmaceutical Discovery and Early Development, Therapeutic Modalities, Roche Innovation Center Copenhagen, Fremtidsvej 3, DK-2970 Hørsholm, Denmark
| | - Jeppe Vinther
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
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25
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Structure of HIV-1 reverse transcriptase cleaving RNA in an RNA/DNA hybrid. Proc Natl Acad Sci U S A 2018; 115:507-512. [PMID: 29295939 DOI: 10.1073/pnas.1719746115] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
HIV-1 reverse transcriptase (RT) contains both DNA polymerase and RNase H activities to convert the viral genomic RNA to dsDNA in infected host cells. Here we report the 2.65-Å resolution structure of HIV-1 RT engaging in cleaving RNA in an RNA/DNA hybrid. A preferred substrate sequence is absolutely required to enable the RNA/DNA hybrid to adopt the distorted conformation needed to interact properly with the RNase H active site in RT. Substituting two nucleotides 4 bp upstream from the cleavage site results in scissile-phosphate displacement by 4 Å. We also have determined the structure of HIV-1 RT complexed with an RNase H-resistant polypurine tract sequence, which adopts a rigid structure and is accommodated outside of the nuclease active site. Based on this newly gained structural information and a virtual drug screen, we have identified an inhibitor specific for the viral RNase H but not for its cellular homologs.
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26
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Baba M, Kojima K, Nakase R, Imai S, Yamasaki T, Takita T, Crouch RJ, Yasukawa K. Effects of neutral salts and pH on the activity and stability of human RNase H2. J Biochem 2017; 162:211-219. [PMID: 28402412 DOI: 10.1093/jb/mvx021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 02/13/2017] [Indexed: 11/14/2022] Open
Abstract
Ribonuclease H (RNase H) specifically degrades the RNA of RNA/DNA hybrid. Recent study has shown that a single ribonucleotide is embedded in DNA double strand at every few thousand base pairs in human genome, and human RNase H2 is involved in its removal. Here, we examined the effects of neutral salts and pH on the activity and stability of human RNase H2. NaCl, KCl, RbCl and NaBr increased the activity to 170-390% at 10-60 mM, while LiCl, LiBr and CsCl inhibited it, suggesting that species of cation, but not anion, is responsible for the effect on activity. NaCl and KCl increased the stability by decreasing the first-order rate constant of the inactivation to 50-60% at 60-80 mM. The activity at 25-35 °C exhibited a narrow bell-shaped pH-dependence with the acidic and alkaline pKe (pKe1 and pKe2) values of 7.3 - 7.6 and 8.1 - 8.8, respectively. Enthalpy changes (ΔH°) of deprotonation were 5 ± 21 kJ mol-1 for pKe1 and 68 ± 25 kJ mol-1 for pKe2. These results suggest that the ionizable groups responsible for pKe1 may be two out of Asp34, Glu35 and Asp141 of DEDD motif, and that for pKe2 may be Lys69 of DSK motif.
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Affiliation(s)
- Misato Baba
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kenji Kojima
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Rihoko Nakase
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Shota Imai
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Tomomi Yamasaki
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Teisuke Takita
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Robert J Crouch
- Section on Formation of RNA, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kiyoshi Yasukawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
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Döring J, Hurek T. Arm-specific cleavage and mutation during reverse transcription of 2΄,5΄-branched RNA by Moloney murine leukemia virus reverse transcriptase. Nucleic Acids Res 2017; 45:3967-3984. [PMID: 28160599 PMCID: PMC5399748 DOI: 10.1093/nar/gkx073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 01/30/2017] [Indexed: 11/14/2022] Open
Abstract
Branchpoint nucleotides of intron lariats induce pausing of DNA synthesis by reverse transcriptases (RTs), but it is not known yet how they direct RT RNase H activity on branched RNA (bRNA). Here, we report the effects of the two arms of bRNA on branchpoint-directed RNA cleavage and mutation produced by Moloney murine leukemia virus (M-MLV) RT during DNA polymerization. We constructed a long-chained bRNA template by splinted-ligation. The bRNA oligonucleotide is chimeric and contains DNA to identify RNA cleavage products by probe hybridization. Unique sequences surrounding the branchpoint facilitate monitoring of bRNA purification by terminal-restriction fragment length polymorphism analysis. We evaluate the M-MLV RT-generated cleavage and mutational patterns. We find that cleavage of bRNA and misprocessing of the branched nucleotide proceed arm-specifically. Bypass of the branchpoint from the 2΄-arm causes single-mismatch errors, whereas bypass from the 3΄-arm leads to deletion mutations. The non-template arm is cleaved when reverse transcription is primed from the 3΄-arm but not from the 2΄-arm. This suggests that RTs flip ∼180° at branchpoints and RNases H cleave the non-template arm depending on its accessibility. Our observed interplay between M-MLV RT and bRNA would be compatible with a bRNA-mediated control of retroviral and related retrotransposon replication.
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Affiliation(s)
- Jessica Döring
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), University of Bremen, PO Box 330440, D-28334 Bremen, Germany
| | - Thomas Hurek
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), University of Bremen, PO Box 330440, D-28334 Bremen, Germany
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Samara NL, Gao Y, Wu J, Yang W. Detection of Reaction Intermediates in Mg 2+-Dependent DNA Synthesis and RNA Degradation by Time-Resolved X-Ray Crystallography. Methods Enzymol 2017; 592:283-327. [PMID: 28668125 DOI: 10.1016/bs.mie.2017.03.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Structures of enzyme-substrate/product complexes have been studied for over four decades but have been limited to either before or after a chemical reaction. Recently using in crystallo catalysis combined with X-ray diffraction, we have discovered that many enzymatic reactions in nucleic acid metabolism require additional metal ion cofactors that are not present in the substrate or product state. By controlling metal ions essential for catalysis, the in crystallo approach has revealed unprecedented details of reaction intermediates. Here we present protocols used for successful studies of Mg2+-dependent DNA polymerases and ribonucleases that are applicable to analyses of a variety of metal ion-dependent reactions.
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Affiliation(s)
- Nadine L Samara
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD, United States; Section on Biological Chemistry, NIDCR, National Institutes of Health, Bethesda, MD, United States
| | - Yang Gao
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD, United States
| | - Jinjun Wu
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD, United States
| | - Wei Yang
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD, United States.
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Menéndez-Arias L, Sebastián-Martín A, Álvarez M. Viral reverse transcriptases. Virus Res 2016; 234:153-176. [PMID: 28043823 DOI: 10.1016/j.virusres.2016.12.019] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 12/19/2016] [Accepted: 12/24/2016] [Indexed: 12/11/2022]
Abstract
Reverse transcriptases (RTs) play a major role in the replication of Retroviridae, Metaviridae, Pseudoviridae, Hepadnaviridae and Caulimoviridae. RTs are enzymes that are able to synthesize DNA using RNA or DNA as templates (DNA polymerase activity), and degrade RNA when forming RNA/DNA hybrids (ribonuclease H activity). In retroviruses and LTR retrotransposons (Metaviridae and Pseudoviridae), the coordinated action of both enzymatic activities converts single-stranded RNA into a double-stranded DNA that is flanked by identical sequences known as long terminal repeats (LTRs). RTs of retroviruses and LTR retrotransposons are active as monomers (e.g. murine leukemia virus RT), homodimers (e.g. Ty3 RT) or heterodimers (e.g. human immunodeficiency virus type 1 (HIV-1) RT). RTs lack proofreading activity and display high intrinsic error rates. Besides, high recombination rates observed in retroviruses are promoted by poor processivity that causes template switching, a hallmark of reverse transcription. HIV-1 RT inhibitors acting on its polymerase activity constitute the backbone of current antiretroviral therapies, although novel drugs, including ribonuclease H inhibitors, are still necessary to fight HIV infections. In Hepadnaviridae and Caulimoviridae, reverse transcription leads to the formation of nicked circular DNAs that will be converted into episomal DNA in the host cell nucleus. Structural and biochemical information on their polymerases is limited, although several drugs inhibiting HIV-1 RT are known to be effective against the human hepatitis B virus polymerase. In this review, we summarize current knowledge on reverse transcription in the five virus families and discuss available biochemical and structural information on RTs, including their biosynthesis, enzymatic activities, and potential inhibition.
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Affiliation(s)
- Luis Menéndez-Arias
- Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid, Spain.
| | - Alba Sebastián-Martín
- Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Mar Álvarez
- Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid, Spain
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Li A, Li J, Johnson KA. HIV-1 Reverse Transcriptase Polymerase and RNase H (Ribonuclease H) Active Sites Work Simultaneously and Independently. J Biol Chem 2016; 291:26566-26585. [PMID: 27777303 DOI: 10.1074/jbc.m116.753160] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/20/2016] [Indexed: 01/15/2023] Open
Abstract
HIV reverse transcriptase plays a central role in viral replication and requires coordination of both polymerase and RNase H activities. Although this coordination is crucial in viral replication, whether a DNA/RNA hybrid can simultaneously engage both active sites has yet to be determined as structural and kinetic analyses have provided contradictory results. Single nucleotide incorporation and RNase H cleavage were examined using presteady-state kinetics with global data analysis. The results revealed three interconverting reverse transcriptase-DNA/RNA species; 43% were active for both sites simultaneously, 27% showed only polymerase activity, and the remaining 30% were nonproductive. Our data clearly demonstrated that the DNA/RNA hybrid could contact both active sites simultaneously, although the single nucleotide incorporation (105 s-1) was ∼5-fold faster than the cleavage (23 s-1). By using a series of primers with different lengths, we found that a string of at least 4-6 nucleotides downstream of the cleaving site was required for efficient RNA cleavage. This was corroborated by our observations that during processive nucleotide incorporation, sequential rounds of RNA cleavage occurred each time after ∼6 nucleotides were incorporated. More importantly, during processive primer extension, pyrophosphate (PPi) release was rate-limiting so that the average rate of nucleotide incorporation (∼28 s-1) was comparable with that of net RNA cleavage (∼27 nucleotides(s)). Although polymerization is efficient and processive, RNase H is inefficient and periodic. This combination allows the two catalytic centers of HIVRT to work simultaneously at similar speeds without being tightly coupled.
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Affiliation(s)
- An Li
- From the The University of Texas at Austin, Institute for Cell and Molecular Biology, Department of Molecular Biosciences, Austin, Texas 78712
| | - Jiawen Li
- From the The University of Texas at Austin, Institute for Cell and Molecular Biology, Department of Molecular Biosciences, Austin, Texas 78712
| | - Kenneth A Johnson
- From the The University of Texas at Austin, Institute for Cell and Molecular Biology, Department of Molecular Biosciences, Austin, Texas 78712
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Wu S, Zhang X, Han J. A Computational Model for Predicting RNase H Domain of Retrovirus. PLoS One 2016; 11:e0161913. [PMID: 27574780 PMCID: PMC5019361 DOI: 10.1371/journal.pone.0161913] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 08/15/2016] [Indexed: 11/21/2022] Open
Abstract
RNase H (RNH) is a pivotal domain in retrovirus to cleave the DNA-RNA hybrid for continuing retroviral replication. The crucial role indicates that RNH is a promising drug target for therapeutic intervention. However, annotated RNHs in UniProtKB database have still been insufficient for a good understanding of their statistical characteristics so far. In this work, a computational RNH model was proposed to annotate new putative RNHs (np-RNHs) in the retroviruses. It basically predicts RNH domains through recognizing their start and end sites separately with SVM method. The classification accuracy rates are 100%, 99.01% and 97.52% respectively corresponding to jack-knife, 10-fold cross-validation and 5-fold cross-validation test. Subsequently, this model discovered 14,033 np-RNHs after scanning sequences without RNH annotations. All these predicted np-RNHs and annotated RNHs were employed to analyze the length, hydrophobicity and evolutionary relationship of RNH domains. They are all related to retroviral genera, which validates the classification of retroviruses to a certain degree. In the end, a software tool was designed for the application of our prediction model. The software together with datasets involved in this paper can be available for free download at https://sourceforge.net/projects/rhtool/files/?source=navbar.
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Affiliation(s)
- Sijia Wu
- School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, China
| | - Xinman Zhang
- School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, China
| | - Jiuqiang Han
- School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, China
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Feng S, Cao Z. Is the role of human RNase H2 restricted to its enzyme activity? PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 121:66-73. [PMID: 26603688 DOI: 10.1016/j.pbiomolbio.2015.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Revised: 11/12/2015] [Accepted: 11/17/2015] [Indexed: 11/16/2022]
Abstract
In human cells, ribonuclease (RNase) H2 complex is the predominant source of RNase H activities with possible roles in nucleic acid metabolism to preserve genome stability and to prevent immune activation. Dysfunction mutations in any of the three subunits of human RNase H2 complex can result in embryonic/perinatal lethality or cause Aicardi-Goutières syndrome (AGS). Most recently, increasing findings have shown that human RNase H2 proteins play roles beyond the RNase H2 enzymatic activities in health and disease. Firstly, the biochemical and structural properties of human RNase H2 proteins allow their interactions with various partner proteins that may support functions other than RNase H2 enzymatic activities. Secondly, the disparities of clinical presentations of AGS with different AGS-mutations and the biochemical and structural analysis of AGS-mutations, especially the results from both AGS-knockin and RNase H2-null mouse models, suggest that human RNase H2 complex has certain cellular functions beyond the RNase H2 enzymatic activities to prevent the innate-immune-mediated inflammation. Thirdly, the subunit proteins RNASEH2A and RNASEH2B respectively, not related to the RNase H2 enzymatic activities, have been shown to play a certain role in the pathophysiological processes of different cancer types. In this minireview, we aims to provide a brief overview of the most recent investigations into the biological functions of human RNase H2 proteins and the underlying mechanisms of their actions, emphasizing on the new insights into the roles of human RNase H2 proteins playing beyond the RNase H2 enzymatic activities in health and disease.
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Affiliation(s)
- Shaolong Feng
- The School of Public Health, University of South China, Hengyang 421001, China.
| | - Zhaohui Cao
- The School of Pharmacy and Life Sciences, University of South China, Hengyang 421001, China
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Measuring specificity in multi-substrate/product systems as a tool to investigate selectivity in vivo. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1864:70-6. [PMID: 26321598 DOI: 10.1016/j.bbapap.2015.08.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 08/07/2015] [Accepted: 08/25/2015] [Indexed: 01/24/2023]
Abstract
Multiple substrate enzymes present a particular challenge when it comes to understanding their activity in a complex system. Although a single target may be easy to model, it does not always present an accurate representation of what that enzyme will do in the presence of multiple substrates simultaneously. Therefore, there is a need to find better ways to both study these enzymes in complicated systems, as well as accurately describe the interactions through kinetic parameters. This review looks at different methods for studying multiple substrate enzymes, as well as explores options on how to most accurately describe an enzyme's activity within these multi-substrate systems. Identifying and defining this enzymatic activity should help clear the way to using in vitro systems to accurately predicting the behavior of multi-substrate enzymes in vivo. This article is part of a Special Issue entitled: Physiological Enzymology and Protein Functions.
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Rausch JW, Tian M, Li Y, Angelova L, Bagaya BS, Krebs KC, Qian F, Zhu C, Arts EJ, Le Grice SFJ, Gao Y. SiRNA-induced mutation in HIV-1 polypurine tract region and its influence on viral fitness. PLoS One 2015; 10:e0122953. [PMID: 25860884 PMCID: PMC4393142 DOI: 10.1371/journal.pone.0122953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 02/16/2015] [Indexed: 02/06/2023] Open
Abstract
Converting single-stranded viral RNA into double stranded DNA for integration is an essential step in HIV-1 replication. Initial polymerization of minus-strand DNA is primed from a host derived tRNA, whereas subsequent plus-strand synthesis requires viral primers derived from the 3' and central polypurine tracts (3' and cPPTs). The 5' and 3' termini of these conserved RNA sequence elements are precisely cleaved by RT-associated RNase H to generate specific primers that are used to initiate plus-strand DNA synthesis. In this study, siRNA wad used to produce a replicative HIV-1 variant contained G(-1)A and T(-16)A substitutions within/adjacent to the 3'PPT sequence. Introducing either or both mutations into the 3'PPT region or only the G(-1)A substitution in the cPPT region of NL4-3 produced infectious virus with decreased fitness relative to the wild-type virus. In contrast, introducing the T(-16)A or both mutations into the cPPT rendered the virus(es) incapable of replication, most likely due to the F185L integrase mutation produced by this nucleotide substitution. Finally, the effects of G(-1)A and T(-16)A mutations on cleavage of the 3'PPT were examined using an in vitro RNase H cleavage assay. Substrate containing both mutations was mis-cleaved to a greater extent than either wild-type substrate or substrate containing the T(-16)A mutation alone, which is consistent with the observed effects of the equivalent nucleotide substitutions on the replication fitness of NL4-3 virus. In conclusion, siRNA targeting of the HIV-1 3'PPT region can substantially suppress virus replication, and this selective pressure can be used to generate infectious virus containing mutations within or near the HIV-1 PPT. Moreover, in-depth analysis of the resistance mutations demonstrates that although virus containing a G(-1)A mutation within the 3'PPT is capable of replication, this nucleotide substitution shifts the 3'-terminal cleavage site in the 3'PPT by one nucleotide (nt) and significantly reduces viral fitness.
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Affiliation(s)
- Jason W. Rausch
- HIV Drug Resistance Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Meijuan Tian
- Division of Infectious Diseases, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Yuejin Li
- Division of Infectious Diseases, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Lora Angelova
- Division of Infectious Diseases, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Bernard S. Bagaya
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Kendall C. Krebs
- Division of Infectious Diseases, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Feng Qian
- Suzhou Fifth People’s Hospital, Suzhou, Jiangsu, China
| | - Chuanwu Zhu
- Suzhou Fifth People’s Hospital, Suzhou, Jiangsu, China
| | - Eric J. Arts
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada
| | - Stuart F. J. Le Grice
- HIV Drug Resistance Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Yong Gao
- Division of Infectious Diseases, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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Palermo G, Cavalli A, Klein ML, Alfonso-Prieto M, Dal Peraro M, De Vivo M. Catalytic metal ions and enzymatic processing of DNA and RNA. Acc Chem Res 2015; 48:220-8. [PMID: 25590654 DOI: 10.1021/ar500314j] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CONSPECTUS: Two-metal-ion-dependent nucleases cleave the phosphodiester bonds of nucleic acids via the two-metal-ion (2M) mechanism. Several high-resolution X-ray structures portraying the two-metal-aided catalytic site, together with mutagenesis and kinetics studies, have demonstrated a functional role of the ions for catalysis in numerous metallonucleases. Overall, the experimental data confirm the general mechanistic hypothesis for 2M-aided phosphoryl transfer originally reported by Steitz and Steitz ( Proc. Natl. Acad. Sci. U.S.A. 1993 , 90 ( 14 ), 6498 - 6502 ). This seminal paper proposed that one metal ion favors the formation of the nucleophile, while the nearby second metal ion facilitates leaving group departure during RNA hydrolysis. Both metals were suggested to stabilize the enzymatic transition state. Nevertheless, static X-ray structures alone cannot exhaustively unravel how the two ions execute their functional role along the enzymatic reaction during processing of DNA or RNA strands when moving from reactants to products, passing through metastable intermediates and high-energy transition states. In this Account, we discuss the role of multiscale molecular simulations in further disclosing mechanistic insights of 2M-aided catalysis for two prototypical enzymatic targets for drug discovery, namely, ribonuclease H (RNase H) and type II topoisomerase (topoII). In both examples, first-principles molecular simulations, integrated with structural data, emphasize a cooperative motion of the bimetal motif during catalysis. The coordinated motion of both ions is crucial for maintaining a flexible metal-centered structural architecture exquisitely tailored to accommodate the DNA or RNA sugar-phosphate backbone during phosphodiester bond cleavage. Furthermore, our analysis of RNase H and the N-terminal domain (PAN) of influenza polymerase shows that classical molecular dynamics simulations coupled with enhanced sampling techniques have contributed to describe the modulatory effect of metal ion concentration and metal uptake on the 2M mechanism and efficiency. These aspects all point to the emerging and intriguing role of additional adjacent ions potentially involved in the modulation of phosphoryl transfer reactions and enzymatic turnover in 2M-catalysis, as recently observed experimentally in polymerase η and homing endonuclease I-DmoI. These computational results, integrated with experimental findings, describe and reinforce the nascent concept of a functional and cooperative dynamics of the catalytic metal ions during the 2M-dependent enzymatic processing of DNA and RNA. Encouraged by the insights provided by computational approaches, we foresee further experiments that will feature the functional and joint dynamics of the catalytic metal ions for nucleic acid processing. This could impact the de novo design of artificial metallonucleases and the rational design of potent metal-chelating inhibitors of pharmaceutically relevant enzymes.
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Affiliation(s)
- Giulia Palermo
- Department
of Drug Discovery and Development, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
| | - Andrea Cavalli
- Department
of Drug Discovery and Development, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
- Department
of Pharmacy and Biotechnology, University of Bologna, Via Belmeloro
6, I-40126 Bologna, Italy
| | - Michael L. Klein
- Institute
for Computational Molecular Science, Temple University, SERC Building, 1925 North 12th Street, Philadelphia Pennsylvania 19122, United States
| | - Mercedes Alfonso-Prieto
- Institute
for Computational Molecular Science, Temple University, SERC Building, 1925 North 12th Street, Philadelphia Pennsylvania 19122, United States
| | - Matteo Dal Peraro
- Institute
of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne - EPFL, 1015 Lausanne, Switzerland
- Swiss Institute of Bioinformatics - SIB, 1015 Lausanne, Switzerland
| | - Marco De Vivo
- Department
of Drug Discovery and Development, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
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Enzymatic Activities of RNase H Domains of HIV-1 Reverse Transcriptase with Substrate Binding Domains of Bacterial RNases H1 and H2. Mol Biotechnol 2015; 57:526-38. [DOI: 10.1007/s12033-015-9846-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Ultradeep pyrosequencing and molecular modeling identify key structural features of hepatitis B virus RNase H, a putative target for antiviral intervention. J Virol 2013; 88:574-82. [PMID: 24173223 DOI: 10.1128/jvi.03000-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Last-generation nucleoside/nucleotide analogues are potent against hepatitis B virus (HBV) and have a high barrier to resistance. However, delayed responses have been observed in patients previously exposed to other drugs of the same class, long-term resistance is possible, and cure of infection cannot be achieved with these therapies, emphasizing the need for alternative therapeutic approaches. The HBV RNase H represents an interesting target because its enzyme activity is essential to the HBV life cycle. The goal of our study was to characterize the structure of the HBV RNase H by computing a 3-dimensional molecular model derived from E. coli RNase H and analyzing 2,326 sequences of all HBV genotypes available in public databases and 958,000 sequences generated by means of ultradeep pyrosequencing of sequences from a homogenous population of 73 treatment-naive patients infected with HBV genotype D. Our data revealed that (i) the putative 4th catalytic residue displays unexpected variability that could be explained by the overlap of the HBx gene and has no apparent impact on HBV replicative capacity and that (ii) the C-helix-containing basic protrusion, which is required to guide the RNA/DNA heteroduplex into the catalytic site, is highly conserved and bears unique structural properties that can be used to target HBV-specific RNase H inhibitors without cross-species activity. The model shows substantial differences from other known RNases H and paves the way for functional and structural studies as a prerequisite to the development of new inhibitors of the HBV cell cycle specifically targeting RNase H activity.
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Chang W, Jääskeläinen M, Li SP, Schulman AH. BARE retrotransposons are translated and replicated via distinct RNA pools. PLoS One 2013; 8:e72270. [PMID: 23940808 PMCID: PMC3735527 DOI: 10.1371/journal.pone.0072270] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 07/14/2013] [Indexed: 01/02/2023] Open
Abstract
The replication of Long Terminal Repeat (LTR) retrotransposons, which can constitute over 80% of higher plant genomes, resembles that of retroviruses. A major question for retrotransposons and retroviruses is how the two conflicting roles of their transcripts, in translation and reverse transcription, are balanced. Here, we show that the BARE retrotransposon, despite its organization into just one open reading frame, produces three distinct classes of transcripts. One is capped, polyadenylated, and translated, but cannot be copied into cDNA. The second is not capped or polyadenylated, but is destined for packaging and ultimate reverse transcription. The third class is capped, polyadenylated, and spliced to favor production of a subgenomic RNA encoding only Gag, the protein forming virus-like particles. Moreover, the BARE2 subfamily, which cannot synthesize Gag and is parasitic on BARE1, does not produce the spliced sub-genomic RNA for translation but does make the replication competent transcripts, which are packaged into BARE1 particles. To our knowledge, this is first demonstration of distinct RNA pools for translation and transcription for any retrotransposon.
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Affiliation(s)
- Wei Chang
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, Helsinki, Finland
| | - Marko Jääskeläinen
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, Helsinki, Finland
| | - Song-ping Li
- Genome-Scale Biology Program, University of Helsinki, Biomedicum, Helsinki, Finland
| | - Alan H. Schulman
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, Helsinki, Finland
- Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen, Finland
- * E-mail:
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Choudhury R, Tsai YS, Dominguez D, Wang Y, Wang Z. Engineering RNA endonucleases with customized sequence specificities. Nat Commun 2013; 3:1147. [PMID: 23093184 PMCID: PMC3612931 DOI: 10.1038/ncomms2154] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 09/21/2012] [Indexed: 01/16/2023] Open
Abstract
Specific cleavage of RNAs is critical for in vitro manipulation of RNA and for in vivo gene silencing. Here we engineer artificial site-specific RNA endonucleases (ASREs) to function analogously to DNA restriction enzymes. We combine a general RNA cleavage domain with a series of Pumilio/FBF (PUF) domains that specifically recognize different 8-nt RNA sequences. The resulting ASREs specifically recognize RNA substrates and efficiently cleave near their binding sites. ASREs can be devised to recognize and cleave various RNA target sequences, providing a useful tool to manipulate RNAs in vitro. In addition, we generate designer ASREs to specifically silence an endogenous gene in E. coli, as well as a mitochondrial-encoded gene in human cells, suggesting that ASREs can serve as a gene silencing tool with designed specificity.
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Affiliation(s)
- Rajarshi Choudhury
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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Chon H, Sparks JL, Rychlik M, Nowotny M, Burgers PM, Crouch RJ, Cerritelli SM. RNase H2 roles in genome integrity revealed by unlinking its activities. Nucleic Acids Res 2013; 41:3130-43. [PMID: 23355612 PMCID: PMC3597693 DOI: 10.1093/nar/gkt027] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ribonuclease H2 (RNase H2) protects genome integrity by its dual roles of resolving transcription-related R-loops and ribonucleotides incorporated in DNA during replication. To unlink these two functions, we generated a Saccharomyces cerevisiae RNase H2 mutant that can resolve R-loops but cannot cleave single ribonucleotides in DNA. This mutant definitively correlates the 2-5 bp deletions observed in rnh201Δ strains with single rNMPs in DNA. It also establishes a connection between R-loops and Sgs1-mediated replication reinitiation at stalled forks and identifies R-loops uniquely processed by RNase H2. In mouse, deletion of any of the genes coding for RNase H2 results in embryonic lethality, and in humans, RNase H2 hypomorphic mutations cause Aicardi-Goutières syndrome (AGS), a neuroinflammatory disorder. To determine the contribution of R-loops and rNMP in DNA to the defects observed in AGS, we characterized in yeast an AGS-related mutation, which is impaired in processing both substrates, but has sufficient R-loop degradation activity to complement the defects of rnh201Δ sgs1Δ strains. However, this AGS-related mutation accumulates 2-5 bp deletions at a very similar rate as the deletion strain.
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Affiliation(s)
- Hyongi Chon
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
| | - Justin L. Sparks
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
| | - Monika Rychlik
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
| | - Marcin Nowotny
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
| | - Peter M. Burgers
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
| | - Robert J. Crouch
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland,*To whom correspondence should be addressed. Tel: +1 301 496 4082; Fax: +1 301 496 0243;
| | - Susana M. Cerritelli
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
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Lyonnais S, Gorelick RJ, Heniche-Boukhalfa F, Bouaziz S, Parissi V, Mouscadet JF, Restle T, Gatell JM, Le Cam E, Mirambeau G. A protein ballet around the viral genome orchestrated by HIV-1 reverse transcriptase leads to an architectural switch: from nucleocapsid-condensed RNA to Vpr-bridged DNA. Virus Res 2013; 171:287-303. [PMID: 23017337 PMCID: PMC3552025 DOI: 10.1016/j.virusres.2012.09.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 09/13/2012] [Accepted: 09/14/2012] [Indexed: 12/15/2022]
Abstract
HIV-1 reverse transcription is achieved in the newly infected cell before viral DNA (vDNA) nuclear import. Reverse transcriptase (RT) has previously been shown to function as a molecular motor, dismantling the nucleocapsid complex that binds the viral genome as soon as plus-strand DNA synthesis initiates. We first propose a detailed model of this dismantling in close relationship with the sequential conversion from RNA to double-stranded (ds) DNA, focusing on the nucleocapsid protein (NCp7). The HIV-1 DNA-containing pre-integration complex (PIC) resulting from completion of reverse transcription is translocated through the nuclear pore. The PIC nucleoprotein architecture is poorly understood but contains at least two HIV-1 proteins initially from the virion core, namely integrase (IN) and the viral protein r (Vpr). We next present a set of electron micrographs supporting that Vpr behaves as a DNA architectural protein, initiating multiple DNA bridges over more than 500 base pairs (bp). These complexes are shown to interact with NCp7 bound to single-stranded nucleic acid regions that are thought to maintain IN binding during dsDNA synthesis, concurrently with nucleocapsid complex dismantling. This unexpected binding of Vpr conveniently leads to a compacted but filamentous folding of the vDNA that should favor its nuclear import. Finally, nucleocapsid-like aggregates engaged in dsDNA synthesis appear to efficiently bind to F-actin filaments, a property that may be involved in targeting complexes to the nuclear envelope. More generally, this article highlights unique possibilities offered by in vitro reconstitution approaches combined with macromolecular imaging to gain insights into the mechanisms that alter the nucleoprotein architecture of the HIV-1 genome, ultimately enabling its insertion into the nuclear chromatin.
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MESH Headings
- DNA Packaging
- DNA, Viral/chemistry
- DNA, Viral/genetics
- DNA, Viral/metabolism
- Genome, Viral
- HIV Integrase/genetics
- HIV Integrase/metabolism
- HIV Reverse Transcriptase/genetics
- HIV Reverse Transcriptase/metabolism
- HIV-1/chemistry
- HIV-1/enzymology
- HIV-1/genetics
- HIV-1/metabolism
- Humans
- RNA, Viral/chemistry
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Reverse Transcription
- gag Gene Products, Human Immunodeficiency Virus/genetics
- gag Gene Products, Human Immunodeficiency Virus/metabolism
- vpr Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
| | - Robert J. Gorelick
- AIDS and Cancer Virus Program; SAIC-Frederick, Inc.; Frederick National Laboratory for Cancer Research; Frederick, MD USA
| | - Fatima Heniche-Boukhalfa
- Maintenance des génomes, Microscopies Moléculaire et Bionanosciences; UMR 8126 CNRS-Université Paris Sud, Villejuif, F-94805, France
| | - Serge Bouaziz
- Laboratoire de Cristallographie et RMN biologiques; UMR 8015 CNRS-Université Paris Descartes; Paris, F-75006, France
| | - Vincent Parissi
- Laboratoire de Microbiologie Fondamentale et Pathogénicité, UMR5234 CNRS-Université Bordeaux Segalen, France
| | | | - Tobias Restle
- Institute of Molecular Medicine, University of Lübeck, Center for Structural and Cell Biology in Medicine (CSCM), D-23538 Lübeck, Germany
| | | | - Eric Le Cam
- Maintenance des génomes, Microscopies Moléculaire et Bionanosciences; UMR 8126 CNRS-Université Paris Sud, Villejuif, F-94805, France
| | - Gilles Mirambeau
- AIDS Research Group; IDIBAPS; E-08036 Barcelona, Spain
- Faculté de Biologie; UPMC Sorbonne Universités; Paris, F-75005, France
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Broecker F, Andrae K, Moelling K. Premature activation of the HIV RNase H drives the virus into suicide: a novel microbicide? AIDS Res Hum Retroviruses 2012; 28:1397-403. [PMID: 22931114 DOI: 10.1089/aid.2012.0067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Sexual transmission of HIV is the major cause of spread of HIV in Africa and the Third World and is an unmet medical need. Recently, microbicides have attracted attention because they allow females to protect themselves and their offspring. We are exploiting one of the four retroviral enzymes, the ribonuclease H, RNase H, as a novel approach for a microbicide. It is the only enzyme of HIV not yet targeted by antiretroviral therapy. The enzyme is linked to the reverse transcriptase (RT) and hydrolyzes the RNA moiety of RNA-DNA hybrids. The RNase H is located inside virus particles and normally functions during viral replication inside cells. Here we show that activating the RNase H prematurely inside the virus particles destroys the viral genome and abrogates viral infectivity. The antiviral compound consists of a synthetic oligodeoxynucleotide (ODN), which creates an artificial RNA-DNA hybrid substrate for the RNase H inside the particle. The compound was analyzed in mouse models including humanized SCID mice and the vagina of mice. Infection was reduced up to 1000-fold or could be completely prevented. The compound is suitable as microbicide or to prevent mother-to-child transmission.
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Affiliation(s)
- Felix Broecker
- University of Zurich, Zurich, Switzerland
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | | | - Karin Moelling
- University of Zurich, Zurich, Switzerland
- Max Planck Institute for Molecular Genetics, Berlin, Germany
- Heinrich Pette Institute, Hamburg, Germany
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43
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Abstract
Ribonucleases H or RNases H are conserved and exist in almost every organism. They generate and remove RNA primers, which are required for DNA replication. RNases H hydrolyze RNA in RNA-DNA hybrids. RNases H and related enzymes contribute to reduction of gene expression in antisense and small-interfering RNA mechanisms for gene silencing. Retroviruses code for RNases H, which are required for DNA provirus synthesis. Their RNase H is fused to the reverse transcriptase and essential for virus replication inside the cell. Retroviruses code for four enzymes, three of which have been targeted by antiretroviral therapies. A drug against the fourth one, the retroviral RNase H, does not yet exist. The viral but not cellular RNases H should be targeted by drug design. Some details will be discussed here. Furthermore, a compound is described, which enables the RNase H to kill cell-free HIV particles by driving the virus into suicide - with potential use as a microbicide.
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44
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Lindén J, Ranta J, Pohjanvirta R. Bayesian modeling of reproducibility and robustness of RNA reverse transcription and quantitative real-time polymerase chain reaction. Anal Biochem 2012; 428:81-91. [DOI: 10.1016/j.ab.2012.06.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 06/08/2012] [Indexed: 10/28/2022]
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HIV-1 Reverse Transcriptase Still Remains a New Drug Target: Structure, Function, Classical Inhibitors, and New Inhibitors with Innovative Mechanisms of Actions. Mol Biol Int 2012; 2012:586401. [PMID: 22778958 PMCID: PMC3388302 DOI: 10.1155/2012/586401] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 04/03/2012] [Indexed: 12/21/2022] Open
Abstract
During the retrotranscription process, characteristic of all retroviruses, the viral ssRNA genome is converted into integration-competent dsDNA. This process is accomplished by the virus-coded reverse transcriptase (RT) protein, which is a primary target in the current treatments for HIV-1 infection. In particular, in the approved therapeutic regimens two classes of drugs target RT, namely, nucleoside RT inhibitors (NRTIs) and nonnucleoside RT inhibitors (NNRTIs). Both classes inhibit the RT-associated polymerase activity: the NRTIs compete with the natural dNTP substrate and act as chain terminators, while the NNRTIs bind to an allosteric pocket and inhibit polymerization noncompetitively. In addition to these two classes, other RT inhibitors (RTIs) that target RT by distinct mechanisms have been identified and are currently under development. These include translocation-defective RTIs, delayed chain terminators RTIs, lethal mutagenesis RTIs, dinucleotide tetraphosphates, nucleotide-competing RTIs, pyrophosphate analogs, RT-associated RNase H function inhibitors, and dual activities inhibitors. This paper describes the HIV-1 RT function and molecular structure, illustrates the currently approved RTIs, and focuses on the mechanisms of action of the newer classes of RTIs.
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The removal of RNA primers from DNA synthesized by the reverse transcriptase of the retrotransposon Tf1 is stimulated by Tf1 integrase. J Virol 2012; 86:6222-30. [PMID: 22491446 DOI: 10.1128/jvi.00009-12] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The Tf1 retrotransposon represents a group of long terminal repeat retroelements that use an RNA self-primer for initiating reverse transcription while synthesizing the minus-sense DNA strand. Tf1 reverse transcriptase (RT) was found earlier to generate the self-primer in vitro. Here, we show that this RT can remove from the synthesized cDNA the entire self-primer as well as the complete polypurine tract (PPT) sequence (serving as a second primer for cDNA synthesis). However, these primer removals, mediated by the RNase H activity of Tf1 RT, are quite inefficient. Interestingly, the integrase of Tf1 stimulated the specific Tf1 RT-directed cleavage of both the self-primer and PPT, although there was no general enhancement of the RT's RNase H activity (and the integrase by itself is devoid of any primer cleavage). The RTs of two prototype retroviruses, murine leukemia virus and human immunodeficiency virus, showed only a partial and nonspecific cleavage of both Tf1-associated primers with no stimulation by Tf1 integrase. Mutagenesis of Tf1 integrase revealed that the complete Tf1 integrase protein (excluding its chromodomain) is required for stimulating the Tf1 RT primer removal activity. Nonetheless, a double mutant integrase that has lost its integration functions can still stimulate the RT's activity, though heat-inactivated integrase cannot enhance primer removals. These findings suggest that the enzymatic activity of Tf1 integrase is not essential for stimulating the RT-mediated primer removal, while the proper folding of this protein is obligatory for this function. These results highlight possible new functions of Tf1 integrase in the retrotransposon's reverse transcription process.
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47
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Kanaya E, Sakabe T, Nguyen NT, Koikeda S, Koga Y, Takano K, Kanaya S. Cloning of the RNase H genes from a metagenomic DNA library: identification of a new type 1 RNase H without a typical active-site motif. J Appl Microbiol 2011; 109:974-83. [PMID: 20408915 DOI: 10.1111/j.1365-2672.2010.04724.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS The study aimed to combine a metagenomics approach with complementary genetics to identify novel bacterial genes with orthologous functions, with the identification of novel RNase H genes as a test case. METHODS AND RESULTS A metagenomic DNA library was prepared from leaf-and-branch compost and used to screen for the RNase H genes by their abilities to complement the temperature-sensitive growth phenotype of the rnhA mutant Escherichia coli strain MIC3001. Determination of the nucleotide sequences of the cloned DNA fragments allowed us to identify 12 different genes encoding type 1 RNases H. Eleven of them encode novel RNases H, which show 40-72% amino acid sequence identities to those available from database. One of them lacks a typical DEDD/E active-site motif, which is almost fully conserved in various RNases H. CONCLUSIONS Functional screening of environmental DNA without cultivation of microbes is a useful procedure to isolate novel RNase H genes. SIGNIFICANCE AND IMPACT OF THE STUDY One of the identified RNase H genes had no sequence similarity to a previously assumed conserved motif, suggesting multiple catalytic mechanisms exist. This test case illustrates that metagenomics combined with complementary genetics can identify novel genes that are orthologous without sequence similarity to those from cultivated bacteria.
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Affiliation(s)
- E Kanaya
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, Osaka, Japan.
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48
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Tramontano A, Donath A, Bernhart SH, Reiche K, Böhmdorfer G, Stadler PF, Bachmair A. Deletion analysis of the 3' long terminal repeat sequence of plant retrotransposon Tto1 identifies 125 base pairs redundancy as sufficient for first strand transfer. Virology 2011; 412:75-82. [PMID: 21262516 PMCID: PMC3061985 DOI: 10.1016/j.virol.2010.12.059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 10/29/2010] [Accepted: 12/31/2010] [Indexed: 11/30/2022]
Abstract
Retroviruses and many retrotransposons are flanked by sequence repeats called long terminal repeats (LTRs). These sequences contain a promoter region, which is active in the 5′ LTR, and transcription termination signals, which are active in the LTR copy present at the 3′ end. A section in the middle of the LTR, called Redundancy region, occurs at both ends of the mRNA. Here we show that in the copia type retrotransposon Tto1, the promoter and terminator functions of the LTR can be supplied by heterologous sequences, thereby converting the LTR into a significantly shorter sub-terminal repeat. An engineered Tto1 element with 125 instead of the usual 574 base pairs repeated in the 5′ and 3′ region can still promote strand transfer during cDNA synthesis, defining a minimal Redundancy region for this element. Based on this finding, we propose a model for first strand transfer of Tto1.
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Affiliation(s)
- Andrea Tramontano
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany
| | - Alexander Donath
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center of Bioinformatics, University of Leipzig, Härtelstrasse 16–18, D-04107 Leipzig, Germany
| | - Stephan H. Bernhart
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center of Bioinformatics, University of Leipzig, Härtelstrasse 16–18, D-04107 Leipzig, Germany
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Vienna, Austria
| | - Kristin Reiche
- RNomics Group, Fraunhofer Institute for Cell Therapy and Immunology IZI, Perlickstr. 1, D-04103 Leipzig, Germany
| | - Gudrun Böhmdorfer
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria
| | - Peter F. Stadler
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center of Bioinformatics, University of Leipzig, Härtelstrasse 16–18, D-04107 Leipzig, Germany
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Vienna, Austria
- RNomics Group, Fraunhofer Institute for Cell Therapy and Immunology IZI, Perlickstr. 1, D-04103 Leipzig, Germany
- Max Planck Institute for Mathematics in the Sciences, Inselstrasse 22, D-04103 Leipzig, Germany
- Santa Fe Institute, 1399 Hyde Park Rd., Santa Fe, NM 87501, USA
| | - Andreas Bachmair
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany
- Corresponding author. Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria.
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Boesler C, Kruse J, Söderbom F, Hammann C. Sequence and generation of mature ribosomal RNA transcripts in Dictyostelium discoideum. J Biol Chem 2011; 286:17693-703. [PMID: 21454536 DOI: 10.1074/jbc.m110.208306] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The amoeba Dictyostelium discoideum is a well established model organism for studying numerous aspects of cellular and developmental functions. Its ribosomal RNA (rRNA) is encoded in an extrachromosomal palindrome that exists in ∼100 copies in the cell. In this study, we have set out to investigate the sequence of the expressed rRNA. For this, we have ligated the rRNA ends and performed RT-PCR on these circular RNAs. Sequencing revealed that the mature 26 S, 17 S, 5.8 S, and 5 S rRNAs have sizes of 3741, 1871, 162, and 112 nucleotides, respectively. Unlike the published data, all mature rRNAs of the same type uniformly display the same start and end nucleotides in the analyzed AX2 strain. We show the existence of a short lived primary transcript covering the rRNA transcription unit of 17 S, 5.8 S, and 26 S rRNA. Northern blots and RT-PCR reveal that from this primary transcript two precursor molecules of the 17 S and two precursors of the 26 S rRNA are generated. We have also determined the sequences of these precursor molecules, and based on these data, we propose a model for the maturation of the rRNAs in Dictyostelium discoideum that we compare with the processing of the rRNA transcription unit of Saccharomyces cerevisiae.
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Affiliation(s)
- Carsten Boesler
- Heisenberg Research Group Ribogenetics, Technical University of Darmstadt, 64287 Darmstadt, Germany
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Ho MH, De Vivo M, Dal Peraro M, Klein ML. Understanding the effect of magnesium ion concentration on the catalytic activity of ribonuclease H through computation: does a third metal binding site modulate endonuclease catalysis? J Am Chem Soc 2011; 132:13702-12. [PMID: 20731347 DOI: 10.1021/ja102933y] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Ribonuclease H (RNase H) belongs to the nucleotidyl-transferase superfamily and hydrolyzes the phosphodiester linkage on the RNA strand of a DNA/RNA hybrid duplex. Due to its activity in HIV reverse transcription, it represents a promising target for anti-HIV drug design. While crystallographic data have located two ions in the catalytic site, there is ongoing debate concerning just how many metal ions bound at the active site are optimal for catalysis. Indeed, experiments have shown a dependency of the catalytic activity on the Mg(2+) concentration. Moreover, in RNase H, the glutamate residue E188 has been shown to be essential for full enzymatic activation, regardless of the Mg(2+) concentration. The catalytic center is known to contain two Mg(2+) ions, and E188 is not one of the primary metal ligands. Herein, classical molecular dynamics (MD) simulations are employed to study the metal-ligand coordination in RNase H at different concentration of Mg(2+). Importantly, the presence of a third Mg(2+) ion, bound to the second-shell ligand E188, is a persistent feature of the MD simulations. Free energy calculations have identified two distinct conformations, depending on the concentration of Mg(2+). At standard concentration, a third Mg(2+) is found in the catalytic pocket, but it does not perturb the optimal RNase H active conformation. However, at higher concentration, the third Mg(2+) ion heavily perturbs the nucleophilic water and thereby influences the catalytic efficiency of RNase H. In addition, the E188A mutant shows no ability to engage additional Mg(2+) ions near the catalytic pocket. This finding likely explains the decrease in catalytic activity of E188A and also supports the key role of E188 in localizing the third Mg(2+) ion at the active site. Glutamate residues are commonly found surrounding the metal center in the endonuclease family, which suggests that this structural motif may be an important feature to enhance catalytic activity. The present MD calculations support the hypothesis that RNase H can accommodate three divalent metal ions in its catalytic pocket and provide an in-depth understanding of their dynamic role for catalysis.
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Affiliation(s)
- Ming-Hsun Ho
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania, 19104, USA
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