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Yang H, Pacheco J, Kim K, Bokani A, Ito F, Ebrahimi D, Chen XS. Molecular mechanism for regulating APOBEC3G DNA editing function by the non-catalytic domain. Nat Commun 2024; 15:8773. [PMID: 39389938 PMCID: PMC11467180 DOI: 10.1038/s41467-024-52671-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 09/17/2024] [Indexed: 10/12/2024] Open
Abstract
APOBEC3G, part of the AID/APOBEC cytidine deaminase family, is crucial for antiviral immunity. It has two zinc-coordinated cytidine-deaminase domains. The non-catalytic N-terminal domain strongly binds to nucleic acids, whereas the C-terminal domain catalyzes C-to-U editing in single-stranded DNA. The interplay between the two domains is not fully understood. Here, we show that DNA editing function of rhesus macaque APOBEC3G on linear and hairpin loop DNA is enhanced by AA or GA dinucleotide motifs present downstream in the 3'-direction of the target-C editing sites. The effective distance between AA/GA and the target-C sites is contingent on the local DNA secondary structure. We present two co-crystal structures of rhesus macaque APOBEC3G bound to ssDNA containing AA and GA, revealing the contribution of the non-catalytic domain in capturing AA/GA DNA. Our findings elucidate the molecular mechanism of APOBEC3G's cooperative function, which is critical for its antiviral role and its contribution to mutations in cancer genomes.
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Affiliation(s)
- Hanjing Yang
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Josue Pacheco
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Kyumin Kim
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Ayub Bokani
- School of Engineering and Technology, CQUniversity, Sydney, NSW, 2000, Australia
| | - Fumiaki Ito
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA
| | - Diako Ebrahimi
- Texas Biomedical Research Institute, San Antonio, TX, 78227, USA
| | - Xiaojiang S Chen
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA.
- Genetic, Molecular and Cellular Biology Program, Keck School of Medicine, Los Angeles, CA, 90033, USA.
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, 90033, USA.
- Center of Excellence in NanoBiophysics, University of Southern California, Los Angeles, CA, 90089, USA.
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2
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Mu Y, Chen Z, Plummer JB, Zelazowska MA, Dong Q, Krug LT, McBride KM. UNG-RPA interaction governs the choice between high-fidelity and mutagenic uracil repair. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.30.591927. [PMID: 38746347 PMCID: PMC11092621 DOI: 10.1101/2024.04.30.591927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Mammalian Uracil DNA glycosylase (UNG) removes uracils and initiates high-fidelity base excision repair to maintain genomic stability. During B cell development, activation-induced cytidine deaminase (AID) creates uracils that UNG processes in an error-prone fashion to accomplish immunoglobulin (Ig) somatic hypermutation (SHM) or class switch recombination (CSR). The mechanism that governs high-fidelity versus mutagenic uracil repair is not understood. The B cell tropic gammaherpesvirus (GHV) encodes a functional homolog of UNG that can process AID induced genomic uracils. GHVUNG does not support hypermutation, suggesting intrinsic properties of UNG influence repair outcome. Noting the structural divergence between the UNGs, we define the RPA interacting motif as the determinant of mutation outcome. UNG or RPA mutants unable to interact with each other, only support high-fidelity repair. In B cells, transversions at the Ig variable region are abated while CSR is supported. Thus UNG-RPA governs the generation of mutations and has implications for locus specific mutagenesis in B cells and deamination associated mutational signatures in cancer.
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3
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Yang H, Pacheco J, Kim K, Ebrahimi D, Ito F, Chen XS. Molecular mechanism for regulating APOBEC3G DNA editing function by the non-catalytic domain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.11.584510. [PMID: 38559028 PMCID: PMC10980023 DOI: 10.1101/2024.03.11.584510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
APOBEC3G (A3G) belongs to the AID/APOBEC cytidine deaminase family and is essential for antiviral immunity. It contains two zinc-coordinated cytidine-deaminase (CD) domains. The N-terminal CD1 domain is non-catalytic but has a strong affinity for nucleic acids, whereas the C-terminal CD2 domain catalyzes C-to-U editing in single-stranded DNA. The interplay between the two domains in DNA binding and editing is not fully understood. Here, our studies on rhesus macaque A3G (rA3G) show that the DNA editing function in linear and hairpin loop DNA is greatly enhanced by AA or GA dinucleotide motifs present downstream (in the 3'-direction) but not upstream (in the 5'-direction) of the target-C editing sites. The effective distance between AA/GA and the target-C sites depends on the local DNA secondary structure. We present two co-crystal structures of rA3G bound to ssDNA containing AA and GA, revealing the contribution of the non-catalytic CD1 domain in capturing AA/GA DNA and explaining our biochemical observations. Our structural and biochemical findings elucidate the molecular mechanism underlying the cooperative function between the non-catalytic and the catalytic domains of A3G, which is critical for its antiviral role and its contribution to genome mutations in cancer.
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Affiliation(s)
- Hanjing Yang
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Josue Pacheco
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Kyumin Kim
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Diako Ebrahimi
- Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Fumiaki Ito
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA90095, USA
| | - Xiaojiang S. Chen
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
- Genetic, Molecular and Cellular Biology Program, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
- Center of Excellence in NanoBiophysics, University of Southern California, Los Angeles, CA 90089, USA
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4
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Kamba K, Wan L, Unzai S, Morishita R, Takaori-Kondo A, Nagata T, Katahira M. Direct inhibition of human APOBEC3 deaminases by HIV-1 Vif independent of the proteolysis pathway. Biophys J 2024; 123:294-306. [PMID: 38115583 PMCID: PMC10870137 DOI: 10.1016/j.bpj.2023.12.015] [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: 04/14/2023] [Revised: 12/01/2023] [Accepted: 12/14/2023] [Indexed: 12/21/2023] Open
Abstract
HIV-1 Vif is known to counteract the antiviral activity of human apolipoprotein B mRNA-editing catalytic polypeptide-like (A3), a cytidine deaminase, in various ways. However, the precise mechanism behind this interaction has remained elusive. Within infected cells, Vif forms a complex called VβBCC, comprising CBFβ and the components of E3 ubiquitin ligase, Elongin B, Elongin C, and Cullin5. Together with the ubiquitin-conjugating enzyme, VβBCC induces ubiquitination-mediated proteasomal degradation of A3. However, Vif exhibits additional counteractive effects. In this study, we elucidate that VβBCC inhibits deamination by A3G, A3F, and A3B independently of proteasomal degradation. Surprisingly, we discovered that this inhibition for A3G is directly attributed to the interaction between VβBCC and the C-terminal domain of A3G. Previously, it was believed that Vif did not interact with the C-terminal domain. Our findings suggest that inhibiting the interaction between VβBCC and the C-terminal domain, as well as the N-terminal domain known to be targeted for ubiquitination, of A3G may be needed to prevent counteraction by Vif.
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Affiliation(s)
- Keisuke Kamba
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, Japan
| | - Li Wan
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, Japan; Graduate School of Energy Science, Kyoto University, Uji, Kyoto, Japan
| | - Satoru Unzai
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Ryo Morishita
- CellFree Sciences Co., Ltd., Matsuyama, Ehime, Japan
| | - Akifumi Takaori-Kondo
- Department of Hematology and Oncology Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Takashi Nagata
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, Japan; Graduate School of Energy Science, Kyoto University, Uji, Kyoto, Japan.
| | - Masato Katahira
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, Japan; Graduate School of Energy Science, Kyoto University, Uji, Kyoto, Japan.
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5
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Budzko L, Hoffa-Sobiech K, Jackowiak P, Figlerowicz M. Engineered deaminases as a key component of DNA and RNA editing tools. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 34:102062. [PMID: 38028200 PMCID: PMC10661471 DOI: 10.1016/j.omtn.2023.102062] [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] [Indexed: 12/01/2023]
Abstract
Over recent years, zinc-dependent deaminases have attracted increasing interest as key components of nucleic acid editing tools that can generate point mutations at specific sites in either DNA or RNA by combining a targeting module (such as a catalytically impaired CRISPR-Cas component) and an effector module (most often a deaminase). Deaminase-based molecular tools are already being utilized in a wide spectrum of therapeutic and research applications; however, their medical and biotechnological potential seems to be much greater. Recent reports indicate that the further development of nucleic acid editing systems depends largely on our ability to engineer the substrate specificity and catalytic activity of the editors themselves. In this review, we summarize the current trends and achievements in deaminase engineering. The presented data indicate that the potential of these enzymes has not yet been fully revealed or understood. Several examples show that even relatively minor changes in the structure of deaminases can give them completely new and unique properties.
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Affiliation(s)
- Lucyna Budzko
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Karolina Hoffa-Sobiech
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Paulina Jackowiak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Marek Figlerowicz
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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6
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Harjes S, Kurup HM, Rieffer AE, Bayarjargal M, Filitcheva J, Su Y, Hale TK, Filichev VV, Harjes E, Harris RS, Jameson GB. Structure-guided inhibition of the cancer DNA-mutating enzyme APOBEC3A. Nat Commun 2023; 14:6382. [PMID: 37821454 PMCID: PMC10567711 DOI: 10.1038/s41467-023-42174-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 09/28/2023] [Indexed: 10/13/2023] Open
Abstract
The normally antiviral enzyme APOBEC3A is an endogenous mutagen in human cancer. Its single-stranded DNA C-to-U editing activity results in multiple mutagenic outcomes including signature single-base substitution mutations (isolated and clustered), DNA breakage, and larger-scale chromosomal aberrations. APOBEC3A inhibitors may therefore comprise a unique class of anti-cancer agents that work by blocking mutagenesis, slowing tumor evolvability, and preventing detrimental outcomes such as drug resistance and metastasis. Here we reveal the structural basis of competitive inhibition of wildtype APOBEC3A by hairpin DNA bearing 2'-deoxy-5-fluorozebularine in place of the cytidine in the TC substrate motif that is part of a 3-nucleotide loop. In addition, the structural basis of APOBEC3A's preference for YTCD motifs (Y = T, C; D = A, G, T) is explained. The nuclease-resistant phosphorothioated derivatives of these inhibitors have nanomolar potency in vitro and block APOBEC3A activity in human cells. These inhibitors may be useful probes for studying APOBEC3A activity in cellular systems and leading toward, potentially as conjuvants, next-generation, combinatorial anti-mutator and anti-cancer therapies.
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Affiliation(s)
- Stefan Harjes
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | | | - Amanda E Rieffer
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota-Twin Cities, Minneapolis, MN, USA
| | - Maitsetseg Bayarjargal
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Jana Filitcheva
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Yongdong Su
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
- Department of Pediatrics, Emory University School of Medicine, and the Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Tracy K Hale
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Vyacheslav V Filichev
- School of Natural Sciences, Massey University, Palmerston North, New Zealand.
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
| | - Elena Harjes
- School of Natural Sciences, Massey University, Palmerston North, New Zealand.
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
| | - Reuben S Harris
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX, USA.
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, TX, USA.
| | - Geoffrey B Jameson
- School of Natural Sciences, Massey University, Palmerston North, New Zealand.
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
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7
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Kouno T, Shibata S, Shigematsu M, Hyun J, Kim TG, Matsuo H, Wolf M. Structural insights into RNA bridging between HIV-1 Vif and antiviral factor APOBEC3G. Nat Commun 2023; 14:4037. [PMID: 37419875 PMCID: PMC10328928 DOI: 10.1038/s41467-023-39796-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 06/29/2023] [Indexed: 07/09/2023] Open
Abstract
Great effort has been devoted to discovering the basis of A3G-Vif interaction, the key event of HIV's counteraction mechanism to evade antiviral innate immune response. Here we show reconstitution of the A3G-Vif complex and subsequent A3G ubiquitination in vitro and report the cryo-EM structure of the A3G-Vif complex at 2.8 Å resolution using solubility-enhanced variants of A3G and Vif. We present an atomic model of the A3G-Vif interface, which assembles via known amino acid determinants. This assembly is not achieved by protein-protein interaction alone, but also involves RNA. The cryo-EM structure and in vitro ubiquitination assays identify an adenine/guanine base preference for the interaction and a unique Vif-ribose contact. This establishes the biological significance of an RNA ligand. Further assessment of interactions between A3G, Vif, and RNA ligands show that the A3G-Vif assembly and subsequent ubiquitination can be controlled by amino acid mutations at the interface or by polynucleotide modification, suggesting that a specific chemical moiety would be a promising pharmacophore to inhibit the A3G-Vif interaction.
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Affiliation(s)
- Takahide Kouno
- Molecular Cryo-Electron Microscopy Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa, 904-0495, Japan.
| | - Satoshi Shibata
- Molecular Cryo-Electron Microscopy Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa, 904-0495, Japan
- Division of Bacteriology, Department of Microbiology and Immunology, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago-shi, Tottori, 683-8503, Japan
| | - Megumi Shigematsu
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Jaekyung Hyun
- Molecular Cryo-Electron Microscopy Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa, 904-0495, Japan
- School of Pharmacy, Sungkyunkwan University, Suwon-si, Gyeonggi-do, 16419, Republic of Korea
| | - Tae Gyun Kim
- Molecular Cryo-Electron Microscopy Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa, 904-0495, Japan
- Department of Efficacy Evaluation, Innovation Center for Vaccine Industry, Gyeongbuk Institute for Bio Industry, Gyeongsanbuk-do, 36618, Republic of Korea
| | - Hiroshi Matsuo
- Cancer Innovation Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Matthias Wolf
- Molecular Cryo-Electron Microscopy Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa, 904-0495, Japan.
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, 115, Taipei, Taiwan.
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8
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Neugebauer ME, Hsu A, Arbab M, Krasnow NA, McElroy AN, Pandey S, Doman JL, Huang TP, Raguram A, Banskota S, Newby GA, Tolar J, Osborn MJ, Liu DR. Evolution of an adenine base editor into a small, efficient cytosine base editor with low off-target activity. Nat Biotechnol 2023; 41:673-685. [PMID: 36357719 PMCID: PMC10188366 DOI: 10.1038/s41587-022-01533-6] [Citation(s) in RCA: 76] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 09/28/2022] [Indexed: 11/12/2022]
Abstract
Cytosine base editors (CBEs) are larger and can suffer from higher off-target activity or lower on-target editing efficiency than current adenine base editors (ABEs). To develop a CBE that retains the small size, low off-target activity and high on-target activity of current ABEs, we evolved the highly active deoxyadenosine deaminase TadA-8e to perform cytidine deamination using phage-assisted continuous evolution. Evolved TadA cytidine deaminases contain mutations at DNA-binding residues that alter enzyme selectivity to strongly favor deoxycytidine over deoxyadenosine deamination. Compared to commonly used CBEs, TadA-derived cytosine base editors (TadCBEs) offer similar or higher on-target activity, smaller size and substantially lower Cas-independent DNA and RNA off-target editing activity. We also identified a TadA dual base editor (TadDE) that performs equally efficient cytosine and adenine base editing. TadCBEs support single or multiplexed base editing at therapeutically relevant genomic loci in primary human T cells and primary human hematopoietic stem and progenitor cells. TadCBEs expand the utility of CBEs for precision gene editing.
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Affiliation(s)
- Monica E Neugebauer
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Alvin Hsu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Mandana Arbab
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Nicholas A Krasnow
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Amber N McElroy
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Smriti Pandey
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Jordan L Doman
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Tony P Huang
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Aditya Raguram
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Samagya Banskota
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Gregory A Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Jakub Tolar
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Mark J Osborn
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA.
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9
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Sianga-Mete R, Hartnady P, Mandikumba WC, Rutherford K, Currin CB, Phelanyane F, Stefan S, Kosakovsky Pond SL, Martin DP. Viral genome sequence datasets display pervasive evidence of strand-specific substitution biases that are best described using non-reversible nucleotide substitution models. RESEARCH SQUARE 2022:rs.3.rs-2407778. [PMID: 36597548 PMCID: PMC9810213 DOI: 10.21203/rs.3.rs-2407778/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Background The vast majority of phylogenetic trees are inferred from molecular sequence data (nucleotides or amino acids) using time-reversible evolutionary models which assume that, for any pair of nucleotide or amino acid characters, the relative rate of X to Y substitution is the same as the relative rate of Y to X substitution. However, this reversibility assumption is unlikely to accurately reflect the actual underlying biochemical and/or evolutionary processes that lead to the fixation of substitutions. Here, we use empirical viral genome sequence data to reveal that evolutionary non-reversibility is pervasive among most groups of viruses. Specifically, we consider two non-reversible nucleotide substitution models: (1) a 6-rate non-reversible model (NREV6) in which Watson-Crick complementary substitutions occur at identical relative rates and which might therefor be most applicable to analyzing the evolution of genomes where both complementary strands are subject to the same mutational processes (such as might be expected for double-stranded (ds) RNA or dsDNA genomes); and (2) a 12-rate non-reversible model (NREV12) in which all relative substitution types are free to occur at different rates and which might therefore be applicable to analyzing the evolution of genomes where the complementary genome strands are subject to different mutational processes (such as might be expected for viruses with single-stranded (ss) RNA or ssDNA genomes). Results Using likelihood ratio and Akaike Information Criterion-based model tests, we show that, surprisingly, NREV12 provided a significantly better fit to 21/31 dsRNA and 20/30 dsDNA datasets than did the general time reversible (GTR) and NREV6 models with NREV6 providing a better fit than NREV12 and GTR in only 5/30 dsDNA and 2/31 dsRNA datasets. As expected, NREV12 provided a significantly better fit to 24/33 ssDNA and 40/47 ssRNA datasets. Next, we used simulations to show that increasing degrees of strand-specific substitution bias decrease the accuracy of phylogenetic inference irrespective of whether GTR or NREV12 is used to describe mutational processes. However, in cases where strand-specific substitution biases are extreme (such as in SARS-CoV-2 and Torque teno sus virus datasets) NREV12 tends to yield more accurate phylogenetic trees than those obtained using GTR. Conclusion We show that NREV12 should, be seriously considered during the model selection phase of phylogenetic analyses involving viral genomic sequences.
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10
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Barzak FM, Ryan TM, Mohammadzadeh N, Harjes S, Kvach MV, Kurup HM, Krause KL, Chelico L, Filichev VV, Harjes E, Jameson GB. Small-Angle X-ray Scattering (SAXS) Measurements of APOBEC3G Provide Structural Basis for Binding of Single-Stranded DNA and Processivity. Viruses 2022; 14:1974. [PMID: 36146779 PMCID: PMC9505750 DOI: 10.3390/v14091974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/05/2022] [Accepted: 08/31/2022] [Indexed: 11/17/2022] Open
Abstract
APOBEC3 enzymes are polynucleotide deaminases, converting cytosine to uracil on single-stranded DNA (ssDNA) and RNA as part of the innate immune response against viruses and retrotransposons. APOBEC3G is a two-domain protein that restricts HIV. Although X-ray single-crystal structures of individual catalytic domains of APOBEC3G with ssDNA as well as full-length APOBEC3G have been solved recently, there is little structural information available about ssDNA interaction with the full-length APOBEC3G or any other two-domain APOBEC3. Here, we investigated the solution-state structures of full-length APOBEC3G with and without a 40-mer modified ssDNA by small-angle X-ray scattering (SAXS), using size-exclusion chromatography (SEC) immediately prior to irradiation to effect partial separation of multi-component mixtures. To prevent cytosine deamination, the target 2'-deoxycytidine embedded in 40-mer ssDNA was replaced by 2'-deoxyzebularine, which is known to inhibit APOBEC3A, APOBEC3B and APOBEC3G when incorporated into short ssDNA oligomers. Full-length APOBEC3G without ssDNA comprised multiple multimeric species, of which tetramer was the most scattering species. The structure of the tetramer was elucidated. Dimeric interfaces significantly occlude the DNA-binding interface, whereas the tetrameric interface does not. This explains why dimers completely disappeared, and monomeric protein species became dominant, when ssDNA was added. Data analysis of the monomeric species revealed a full-length APOBEC3G-ssDNA complex that gives insight into the observed "jumping" behavior revealed in studies of enzyme processivity. This solution-state SAXS study provides the first structural model of ssDNA binding both domains of APOBEC3G and provides data to guide further structural and enzymatic work on APOBEC3-ssDNA complexes.
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Affiliation(s)
- Fareeda M. Barzak
- School of Natural Sciences, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
| | - Timothy M. Ryan
- SAXS/WAXS, Australian Synchrotron/ANSTO, 800 Blackburn Road, Clayton, VIC 3168, Australia
| | - Nazanin Mohammadzadeh
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Stefan Harjes
- School of Natural Sciences, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
| | - Maksim V. Kvach
- School of Natural Sciences, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
| | - Harikrishnan M. Kurup
- School of Natural Sciences, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
| | - Kurt L. Krause
- Department of Biochemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
- Maurice Wilkins Centre, University of Auckland, Auckland 1142, New Zealand
| | - Linda Chelico
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Vyacheslav V. Filichev
- School of Natural Sciences, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
- Maurice Wilkins Centre, University of Auckland, Auckland 1142, New Zealand
| | - Elena Harjes
- School of Natural Sciences, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
- Maurice Wilkins Centre, University of Auckland, Auckland 1142, New Zealand
| | - Geoffrey B. Jameson
- School of Natural Sciences, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
- Maurice Wilkins Centre, University of Auckland, Auckland 1142, New Zealand
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11
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Meissner ME, Talledge N, Mansky LM. Molecular Biology and Diversification of Human Retroviruses. FRONTIERS IN VIROLOGY (LAUSANNE, SWITZERLAND) 2022; 2:872599. [PMID: 35783361 PMCID: PMC9242851 DOI: 10.3389/fviro.2022.872599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Studies of retroviruses have led to many extraordinary discoveries that have advanced our understanding of not only human diseases, but also molecular biology as a whole. The most recognizable human retrovirus, human immunodeficiency virus type 1 (HIV-1), is the causative agent of the global AIDS epidemic and has been extensively studied. Other human retroviruses, such as human immunodeficiency virus type 2 (HIV-2) and human T-cell leukemia virus type 1 (HTLV-1), have received less attention, and many of the assumptions about the replication and biology of these viruses are based on knowledge of HIV-1. Existing comparative studies on human retroviruses, however, have revealed that key differences between these viruses exist that affect evolution, diversification, and potentially pathogenicity. In this review, we examine current insights on disparities in the replication of pathogenic human retroviruses, with a particular focus on the determinants of structural and genetic diversity amongst HIVs and HTLV.
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Affiliation(s)
- Morgan E. Meissner
- Institute for Molecular Virology, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Molecular, Cellular, Developmental Biology and Genetics Graduate Program, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
| | - Nathaniel Talledge
- Institute for Molecular Virology, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Division of Basic Sciences, School of Dentistry, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Masonic Cancer Center, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
| | - Louis M. Mansky
- Institute for Molecular Virology, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Division of Basic Sciences, School of Dentistry, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Molecular, Cellular, Developmental Biology and Genetics Graduate Program, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Masonic Cancer Center, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
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12
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Kitamura K, Fukano K, Que L, Li Y, Wakae K, Muramatsu M. Activities of endogenous APOBEC3s and uracil-DNA-glycosylase affect the hypermutation frequency of hepatitis B virus cccDNA. J Gen Virol 2022; 103. [PMID: 35438620 DOI: 10.1099/jgv.0.001732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) plays a key role in the persistence of viral infection. We have previously shown that overexpression of an antiviral factor APOBEC3G (A3G) induces hypermutation in duck HBV (DHBV) cccDNA, whereas uracil-DNA-glycosylase (UNG) reduces these mutations. In this study, using cell-culture systems, we examined whether endogenous A3s and UNG affect HBV cccDNA mutation frequency. IFNγ stimulation induced a significant increase in endogenous A3G expression and cccDNA hypermutation. UNG inhibition enhanced the IFNγ-mediated hypermutation frequency. Transfection of reconstructed cccDNA revealed that this enhanced hypermutation caused a reduction in viral replication. These results suggest that the balance of endogenous A3s and UNG activities affects HBV cccDNA mutation and replication competency.
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Affiliation(s)
- Kouichi Kitamura
- Department of Virology II, National Institute of Infectious Diseases, Murayama branch, 4-7-1 Gakuen, Musashi-murayama, Tokyo 208-0011, Japan
| | - Kento Fukano
- Department of Virology II, National Institute of Infectious Diseases, Murayama branch, 4-7-1 Gakuen, Musashi-murayama, Tokyo 208-0011, Japan
| | - Lusheng Que
- Department of Virology II, National Institute of Infectious Diseases, Murayama branch, 4-7-1 Gakuen, Musashi-murayama, Tokyo 208-0011, Japan
| | - Yingfang Li
- Department of Virology II, National Institute of Infectious Diseases, Murayama branch, 4-7-1 Gakuen, Musashi-murayama, Tokyo 208-0011, Japan
| | - Kousho Wakae
- Department of Virology II, National Institute of Infectious Diseases, Murayama branch, 4-7-1 Gakuen, Musashi-murayama, Tokyo 208-0011, Japan
| | - Masamichi Muramatsu
- Department of Virology II, National Institute of Infectious Diseases, Murayama branch, 4-7-1 Gakuen, Musashi-murayama, Tokyo 208-0011, Japan
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13
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The current toolbox for APOBEC drug discovery. Trends Pharmacol Sci 2022; 43:362-377. [PMID: 35272863 PMCID: PMC9018551 DOI: 10.1016/j.tips.2022.02.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 02/03/2022] [Accepted: 02/09/2022] [Indexed: 12/14/2022]
Abstract
Mutational processes driving genome evolution and heterogeneity contribute to immune evasion and therapy resistance in viral infections and cancer. APOBEC3 (A3) enzymes promote such mutations by catalyzing the deamination of cytosines to uracils in single-stranded DNA. Chemical inhibition of A3 enzymes may yield an antimutation therapeutic strategy to improve the durability of current drug therapies that are prone to resistance mutations. A3 small-molecule drug discovery efforts to date have been restricted to a single high-throughput biochemical activity assay; however, the arsenal of discovery assays has significantly expanded in recent years. The assays used to study A3 enzymes are reviewed here with an eye towards their potential for small-molecule discovery efforts.
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14
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Liu Y, Lan W, Wang C, Cao C. Two different kinds of interaction modes of deaminase APOBEC3A with single-stranded DNA in solution detected by nuclear magnetic resonance. Protein Sci 2022; 31:443-453. [PMID: 34792260 PMCID: PMC8819843 DOI: 10.1002/pro.4242] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/09/2021] [Accepted: 11/09/2021] [Indexed: 02/03/2023]
Abstract
APOBEC3A (A3A) deaminates deoxycytidine in target motif TC in a single-stranded DNA (we termed it as TC DNA), which mortally mutates viral pathogens and immunoglobulins, and leads to the diversification and lethality of cancers. The crystal structure of A3A-DNA revealed a unique U-shaped recognition mode of target base dC0 . However, when TC DNA was titrated into 15 N-labeled A3A solution, we observed two sets of 1 H-15 N cross-peaks of A3A in HSQC spectra, and two sets of 1 H-1 H cross-peaks of DNA in two-dimensional 13 C,15 N-filtered TOCSY spectra, indicating two different kinds of conformers of either A3A or TC DNA existing in solution. Here, mainly by NMR, we demonstrated that one DNA conformer interacted with one A3A conformer, forming a specific complex A3AS -DNAS in a way almost similar to that observed in the reported crystal A3A-DNA structure, where dC0 inserted into zinc ion binding center. While the other DNA conformer bound with another A3A conformer, but dC0 did not extend into the zinc-binding pocket, forming a nonspecific A3ANS -DNANS complex. The NMR solution structure implied three sites Asn61 , His182 and Arg189 were necessary to DNA recognition. These observations indicate a distinctive way from that reported in X-ray crystal structure, suggesting an unexpected mode of deaminase APOBEC3A to identify target motif TC in DNA in solution.
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Affiliation(s)
- Yaping Liu
- State Key Laboratory of Bioorganic and Natural Product ChemistryCenter for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina,University of Chinese Academy of ScienceBeijingChina
| | - Wenxian Lan
- State Key Laboratory of Bioorganic and Natural Product ChemistryCenter for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina
| | - Chunxi Wang
- State Key Laboratory of Bioorganic and Natural Product ChemistryCenter for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina
| | - Chunyang Cao
- State Key Laboratory of Bioorganic and Natural Product ChemistryCenter for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina,University of Chinese Academy of ScienceBeijingChina
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15
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Curlin JZ, Schmitt K, Remling-Mulder L, Moriarty R, Baczenas JJ, Goff K, O’Connor S, Stenglein M, Marx PA, Akkina R. In vivo infection dynamics and human adaptive changes of SIVsm-derived viral siblings SIVmac239, SIV B670 and SIVhu in humanized mice as a paralog of HIV-2 genesis. FRONTIERS IN VIROLOGY (LAUSANNE, SWITZERLAND) 2021; 1:813606. [PMID: 37168442 PMCID: PMC10168645 DOI: 10.3389/fviro.2021.813606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Simian immunodeficiency virus native to sooty mangabeys (SIVsm) is believed to have given rise to HIV-2 through cross-species transmission and evolution in the human. SIVmac239 and SIVB670, pathogenic to macaques, and SIVhu, isolated from an accidental human infection, also have origins in SIVsm. With their common ancestral lineage as that of HIV-2 from the progenitor SIVsm, but with different passage history in different hosts, they provide a unique opportunity to evaluate cross-species transmission to a new host and their adaptation/evolution both in terms of potential genetic and phenotypic changes. Using humanized mice with a transplanted human system, we evaluated in vivo replication kinetics, CD4+ T cell dynamics and genetic adaptive changes during serial passage with a goal to understand their evolution under human selective immune pressure. All the three viruses readily infected hu-mice causing chronic viremia. While SIVmac and SIVB670 caused CD4+ T cell depletion during sequential passaging, SIVhu with a deletion in nef gene was found to be less pathogenic. Deep sequencing of the genomes of these viruses isolated at different times revealed numerous adaptive mutations of significance that increased in frequency during sequential passages. The ability of these viruses to infect and replicate in humanized mice provides a new small animal model to study SIVs in vivo in addition to more expensive macaques. Since SIVmac and related viruses have been indispensable in many areas of HIV pathogenesis, therapeutics and cure research, availability of this small animal hu-mouse model that is susceptible to both SIV and HIV viruses is likely to open novel avenues of investigation for comparative studies using the same host.
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Affiliation(s)
- James Z. Curlin
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
- Antiviral Discovery, Evaluation and Application Research (ADEAR) Training Program, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Kimberly Schmitt
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Leila Remling-Mulder
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Ryan Moriarty
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - John J. Baczenas
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Kelly Goff
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Shelby O’Connor
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Mark Stenglein
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Preston A. Marx
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
- Tulane National Primate Research Center, Covington, LA, USA
| | - Ramesh Akkina
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
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16
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Gaba A, Hix MA, Suhail S, Flath B, Boysan B, Williams DR, Pelletier T, Emerman M, Morcos F, Cisneros GA, Chelico L. Divergence in Dimerization and Activity of Primate APOBEC3C. J Mol Biol 2021; 433:167306. [PMID: 34666043 PMCID: PMC9202443 DOI: 10.1016/j.jmb.2021.167306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/08/2021] [Accepted: 10/08/2021] [Indexed: 11/21/2022]
Abstract
The APOBEC3 (A3) family of single-stranded DNA cytidine deaminases are host restriction factors that inhibit lentiviruses, such as HIV-1, in the absence of the Vif protein that causes their degradation. Deamination of cytidine in HIV-1 (−)DNA forms uracil that causes inactivating mutations when uracil is used as a template for (+)DNA synthesis. For APOBEC3C (A3C), the chimpanzee and gorilla orthologues are more active than human A3C, and we determined that Old World Monkey A3C from rhesus macaque (rh) is not active against HIV-1. Biochemical, virological, and coevolutionary analyses combined with molecular dynamics simulations showed that the key amino acids needed to promote rhA3C antiviral activity, 44, 45, and 144, also promoted dimerization and changes to the dynamics of loop 1, near the enzyme active site. Although forced evolution of rhA3C resulted in a similar dimer interface with hominid A3C, the key amino acid contacts were different. Overall, our results determine the basis for why rhA3C is less active than human A3C and establish the amino acid network for dimerization and increased activity. Based on identification of the key amino acids determining Old World Monkey antiviral activity we predict that other Old World Monkey A3Cs did not impart anti-lentiviral activity, despite fixation of a key residue needed for hominid A3C activity. Overall, the coevolutionary analysis of the A3C dimerization interface presented also provides a basis from which to analyze dimerization interfaces of other A3 family members.
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Affiliation(s)
- Amit Gaba
- Department of Biochemistry, Microbiology, and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, Canada. https://twitter.com/optimist1023
| | - Mark A Hix
- Department of Chemistry, University of North Texas, Denton, TX, USA. https://twitter.com/markahix
| | - Sana Suhail
- Department of Biological Sciences, Center for Systems Biology, University of Texas at Dallas, Richardson, TX, USA. https://twitter.com/sakuraa_329
| | - Ben Flath
- Department of Biochemistry, Microbiology, and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Brock Boysan
- Department of Chemistry, University of North Texas, Denton, TX, USA
| | - Danielle R Williams
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA. https://twitter.com/dani_renee_
| | - Tomas Pelletier
- Department of Biochemistry, Microbiology, and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Michael Emerman
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA; Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA. https://twitter.com/memerman
| | - Faruck Morcos
- Department of Biological Sciences, Center for Systems Biology, University of Texas at Dallas, Richardson, TX, USA; Department of Bioengineering, University of Texas at Dallas, Dallas, TX, USA. https://twitter.com/MorcosLab
| | - G Andrés Cisneros
- Department of Chemistry, University of North Texas, Denton, TX, USA. https://twitter.com/CisnerosRes
| | - Linda Chelico
- Department of Biochemistry, Microbiology, and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
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17
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Kaake RM, Echeverria I, Kim SJ, Von Dollen J, Chesarino NM, Feng Y, Yu C, Ta H, Chelico L, Huang L, Gross J, Sali A, Krogan NJ. Characterization of an A3G-Vif HIV-1-CRL5-CBFβ Structure Using a Cross-linking Mass Spectrometry Pipeline for Integrative Modeling of Host-Pathogen Complexes. Mol Cell Proteomics 2021; 20:100132. [PMID: 34389466 PMCID: PMC8459920 DOI: 10.1016/j.mcpro.2021.100132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/15/2021] [Accepted: 08/04/2021] [Indexed: 10/24/2022] Open
Abstract
Structural analysis of host-pathogen protein complexes remains challenging, largely due to their structural heterogeneity. Here, we describe a pipeline for the structural characterization of these complexes using integrative structure modeling based on chemical cross-links and residue-protein contacts inferred from mutagenesis studies. We used this approach on the HIV-1 Vif protein bound to restriction factor APOBEC3G (A3G), the Cullin-5 E3 ring ligase (CRL5), and the cellular transcription factor Core Binding Factor Beta (CBFβ) to determine the structure of the (A3G-Vif-CRL5-CBFβ) complex. Using the MS-cleavable DSSO cross-linker to obtain a set of 132 cross-links within this reconstituted complex along with the atomic structures of the subunits and mutagenesis data, we computed an integrative structure model of the heptameric A3G-Vif-CRL5-CBFβ complex. The structure, which was validated using a series of tests, reveals that A3G is bound to Vif mostly through its N-terminal domain. Moreover, the model ensemble quantifies the dynamic heterogeneity of the A3G C-terminal domain and Cul5 positions. Finally, the model was used to rationalize previous structural, mutagenesis and functional data not used for modeling, including information related to the A3G-bound and unbound structures as well as mapping functional mutations to the A3G-Vif interface. The experimental and computational approach described here is generally applicable to other challenging host-pathogen protein complexes.
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Affiliation(s)
- Robyn M Kaake
- Department of Cellular and Molecular Pharmacology, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California, USA; Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, California, USA
| | - Ignacia Echeverria
- Department of Cellular and Molecular Pharmacology, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California, USA; Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Seung Joong Kim
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA
| | - John Von Dollen
- Department of Cellular and Molecular Pharmacology, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California, USA; Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, California, USA
| | - Nicholas M Chesarino
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Yuqing Feng
- Department of Biochemistry, Microbiology, Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Clinton Yu
- Department of Physiology & Biophysics, University of California, Irvine, California, USA
| | - Hai Ta
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Linda Chelico
- Department of Biochemistry, Microbiology, Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Lan Huang
- Department of Physiology & Biophysics, University of California, Irvine, California, USA
| | - John Gross
- Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, California, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Andrej Sali
- Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, California, USA; Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California, USA; Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, California, USA.
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18
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Chen Z, Eggerman TL, Bocharov AV, Baranova IN, Vishnyakova TG, Patterson AP. APOBEC3-induced mutation of the hepatitis virus B DNA genome occurs during its viral RNA reverse transcription into (-)-DNA. J Biol Chem 2021; 297:100889. [PMID: 34181944 PMCID: PMC8321922 DOI: 10.1016/j.jbc.2021.100889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/09/2021] [Accepted: 06/16/2021] [Indexed: 11/17/2022] Open
Abstract
APOBEC3s are innate single-stranded DNA cytidine-to-uridine deaminases that catalyze mutations in both pathogen and human genomes with significant roles in human disease. However, how APOBEC3s mutate a single-stranded DNA that is available momentarily during DNA transcription or replication in vivo remains relatively unknown. In this study, utilizing hepatitis B virus (HBV) viral mutations, we evaluated the mutational characteristics of individual APOBEC3s with reference to the HBV replication process through HBV whole single-strand (-)-DNA genome mutation analyses. We found that APOBEC3s induced C-to-T mutations from the HBV reverse transcription start site continuing through the whole (-)-DNA transcript to the termination site with variable efficiency, in an order of A3B >> A3G > A3H-II or A3C. A3B had a 3-fold higher mutation efficiency than A3H-II or A3C with up to 65% of all HBV genomic cytidines being converted into uridines in a single mutation event, consistent with the A3B localized hypermutation signature in cancer, namely, kataegis. On the other hand, A3C expression led to a 3-fold higher number of mutation-positive HBV genome clones, although each individual clone had a lower number of C-to-T mutations. Like A3B, A3C preferred both 5'-TC and 5'-CC sequences, but to a lesser degree. The APOBEC3-induced HBV mutations were predominantly detected in the HBV rcDNA but were not detectable in other intermediates including HBV cccDNA and pgRNA by primer extension of their PCR amplification products. These data demonstrate that APOBEC3-induced HBV genome mutations occur predominantly when the HBV RNA genome was reversely transcribed into (-)-DNA in the viral capsid.
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Affiliation(s)
- Zhigang Chen
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Thomas L Eggerman
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA; Division of Diabetes, Endocrinology and Metabolic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Alexander V Bocharov
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Irina N Baranova
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Tatyana G Vishnyakova
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Amy P Patterson
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA; National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.
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19
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Hou S, Lee JM, Myint W, Matsuo H, Kurt Yilmaz N, Schiffer CA. Structural basis of substrate specificity in human cytidine deaminase family APOBEC3s. J Biol Chem 2021; 297:100909. [PMID: 34171358 PMCID: PMC8313598 DOI: 10.1016/j.jbc.2021.100909] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 06/21/2021] [Accepted: 06/21/2021] [Indexed: 01/22/2023] Open
Abstract
The human cytidine deaminase family of APOBEC3s (A3s) plays critical roles in both innate immunity and the development of cancers. A3s comprise seven functionally overlapping but distinct members that can be exploited as nucleotide base editors for treating genetic diseases. Although overall structurally similar, A3s have vastly varying deamination activity and substrate preferences. Recent crystal structures of ssDNA-bound A3s together with experimental studies have provided some insights into distinct substrate specificities among the family members. However, the molecular interactions responsible for their distinct biological functions and how structure regulates substrate specificity are not clear. In this study, we identified the structural basis of substrate specificities in three catalytically active A3 domains whose crystal structures have been previously characterized: A3A, A3B- CTD, and A3G-CTD. Through molecular modeling and dynamic simulations, we found an interdependency between ssDNA substrate binding conformation and nucleotide sequence specificity. In addition to the U-shaped conformation seen in the crystal structure with the CTC0 motif, A3A can accommodate the CCC0 motif when ssDNA is in a more linear (L) conformation. A3B can also bind both U- and L-shaped ssDNA, unlike A3G, which can stably recognize only linear ssDNA. These varied conformations are stabilized by sequence-specific interactions with active site loops 1 and 7, which are highly variable among A3s. Our results explain the molecular basis of previously observed substrate specificities in A3s and have implications for designing A3-specific inhibitors for cancer therapy as well as engineering base-editing systems for gene therapy.
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Affiliation(s)
- Shurong Hou
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Jeong Min Lee
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Wazo Myint
- Basic Research Laboratory, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Hiroshi Matsuo
- Basic Research Laboratory, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Nese Kurt Yilmaz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
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20
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Yu W, Li J, Huang S, Li X, Li P, Li G, Liang A, Chi T, Huang X. Harnessing A3G for efficient and selective C-to-T conversion at C-rich sequences. BMC Biol 2021; 19:34. [PMID: 33602235 PMCID: PMC7893952 DOI: 10.1186/s12915-020-00879-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 09/24/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Site-specific C>T DNA base editing has been achieved by recruiting cytidine deaminases to the target C using catalytically impaired Cas proteins; the target C is typically located within 5-nt editing window specified by the guide RNAs. The prototypical cytidine base editor BE3, comprising rat APOBEC1 (rA1) fused to nCas9, can indiscriminately deaminate multiple C's within the editing window and also create substantial off-target edits on the transcriptome. A powerful countermeasure for the DNA off-target editing is to replace rA1 with APOBEC proteins which selectively edit C's in the context of specific motifs, as illustrated in eA3A-BE3 which targets TC. However, analogous editors selective for other motifs have not been described. In particular, it has been challenging to target a particular C in C-rich sequences. Here, we sought to confront this challenge and also to overcome the RNA off-target effects seen in BE3. RESULTS By replacing rA1 with an optimized human A3G (oA3G), we developed oA3G-BE3, which selectively targets CC and CCC and is also free of global off-target effects on the transcriptome. Furthermore, we created oA3G-BE4max, an upgraded version of oA3G-BE3 with robust on-target editing. Finally, we showed that oA3G-BE4max has negligible Cas9-independent off-target effects at the genome. CONCLUSIONS oA3G-BE4max can edit C(C)C with high efficiency and selectivity, which complements eA3A-editors to broaden the collective editing scope of motif selective editors, thus filling a void in the base editing tool box.
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Affiliation(s)
- Wenxia Yu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jianan Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Shisheng Huang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiangyang Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ping Li
- Department of Hematology, Tongji Hospital of Tongji University, Shanghai, 200092, China
| | - Guanglei Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Aibin Liang
- Department of Hematology, Tongji Hospital of Tongji University, Shanghai, 200092, China
| | - Tian Chi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
- Department Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Xingxu Huang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, 200031, China.
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21
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Barzak FM, Ryan TM, Kvach MV, Kurup HM, Aihara H, Harris RS, Filichev VV, Harjes E, Jameson GB. Small-Angle X-ray Scattering Models of APOBEC3B Catalytic Domain in a Complex with a Single-Stranded DNA Inhibitor. Viruses 2021; 13:290. [PMID: 33673243 PMCID: PMC7918907 DOI: 10.3390/v13020290] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 02/02/2021] [Accepted: 02/05/2021] [Indexed: 12/12/2022] Open
Abstract
In normal cells APOBEC3 (A3A-A3H) enzymes as part of the innate immune system deaminate cytosine to uracil on single-stranded DNA (ssDNA) to scramble DNA in order to give protection against a range of exogenous retroviruses, DNA-based parasites, and endogenous retroelements. However, some viruses and cancer cells use these enzymes, especially A3A and A3B, to escape the adaptive immune response and thereby lead to the evolution of drug resistance. We have synthesized first-in-class inhibitors featuring modified ssDNA. We present models based on small-angle X-ray scattering (SAXS) data that (1) confirm that the mode of binding of inhibitor to an active A3B C-terminal domain construct in the solution state is the same as the mode of binding substrate to inactive mutants of A3A and A3B revealed in X-ray crystal structures and (2) give insight into the disulfide-linked inactive dimer formed under the oxidizing conditions of purification.
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Affiliation(s)
- Fareeda M. Barzak
- School of Fundamental Sciences, Massey University, Private Bag 11 222, New Zealand; (F.M.B.); (M.V.K.); (H.M.K.)
| | - Timothy M. Ryan
- SAXS/WAXS, Australian Synchrotron/ANSTO, 800 Blackburn Road, Clayton, VIC 3168, Australia;
| | - Maksim V. Kvach
- School of Fundamental Sciences, Massey University, Private Bag 11 222, New Zealand; (F.M.B.); (M.V.K.); (H.M.K.)
| | - Harikrishnan M. Kurup
- School of Fundamental Sciences, Massey University, Private Bag 11 222, New Zealand; (F.M.B.); (M.V.K.); (H.M.K.)
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (H.A.); (R.S.H.)
| | - Reuben S. Harris
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (H.A.); (R.S.H.)
- Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - Vyacheslav V. Filichev
- School of Fundamental Sciences, Massey University, Private Bag 11 222, New Zealand; (F.M.B.); (M.V.K.); (H.M.K.)
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland 1142, New Zealand
| | - Elena Harjes
- School of Fundamental Sciences, Massey University, Private Bag 11 222, New Zealand; (F.M.B.); (M.V.K.); (H.M.K.)
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland 1142, New Zealand
| | - Geoffrey B. Jameson
- School of Fundamental Sciences, Massey University, Private Bag 11 222, New Zealand; (F.M.B.); (M.V.K.); (H.M.K.)
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland 1142, New Zealand
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22
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Wong L, Vizeacoumar FS, Vizeacoumar FJ, Chelico L. APOBEC1 cytosine deaminase activity on single-stranded DNA is suppressed by replication protein A. Nucleic Acids Res 2021; 49:322-339. [PMID: 33330905 PMCID: PMC7797036 DOI: 10.1093/nar/gkaa1201] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/23/2020] [Accepted: 11/25/2020] [Indexed: 12/22/2022] Open
Abstract
Many APOBEC cytidine deaminase members are known to induce ‘off-target’ cytidine deaminations in 5′TC motifs in genomic DNA that contribute to cancer evolution. In this report, we characterized APOBEC1, which is a possible cancer related APOBEC since APOBEC1 mRNA is highly expressed in certain types of tumors, such as lung adenocarcinoma. We found a low level of APOBEC1-induced DNA damage, as measured by γH2AX foci, in genomic DNA of a lung cancer cell line that correlated to its inability to compete in vitro with replication protein A (RPA) for ssDNA. This suggests that RPA can act as a defense against off-target deamination for some APOBEC enzymes. Overall, the data support the model that the ability of an APOBEC to compete with RPA can better predict genomic damage than combined analysis of mRNA expression levels in tumors and analysis of mutation signatures.
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Affiliation(s)
- Lai Wong
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Frederick S Vizeacoumar
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon S7N 5E5, Canada
| | - Franco J Vizeacoumar
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon S7N 5E5, Canada.,Cancer Research, Saskatchewan Cancer Agency, Saskatoon, Saskatchewan S7S 0A6, Canada
| | - Linda Chelico
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
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23
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Maiti A, Hou S, Schiffer CA, Matsuo H. Interactions of APOBEC3s with DNA and RNA. Curr Opin Struct Biol 2021; 67:195-204. [PMID: 33486429 DOI: 10.1016/j.sbi.2020.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/25/2020] [Accepted: 12/03/2020] [Indexed: 02/06/2023]
Abstract
APOBEC3 enzymes are key enzymes in our innate immune system regulating antiviral response in HIV and unfortunately adding diversity in cancer as they deaminate cytosine. Seven unique single and double domain APOBEC3s provide them with unique activity and specificity profiles for this deamination. Recent crystal and NMR structures of APOBEC3 complexes are unraveling the variety of epitopes involved in binding nucleic acids, including at the catalytic site, elsewhere on the catalytic domain and in the inactive N-terminal domain. The interplay between these diverse interactions is critical to uncovering the mechanisms by which APOBEC3s recognize and process their substrates.
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Affiliation(s)
- Atanu Maiti
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Shurong Hou
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01655, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01655, USA.
| | - Hiroshi Matsuo
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA.
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24
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Granadillo Rodríguez M, Flath B, Chelico L. The interesting relationship between APOBEC3 deoxycytidine deaminases and cancer: a long road ahead. Open Biol 2020; 10:200188. [PMID: 33292100 PMCID: PMC7776566 DOI: 10.1098/rsob.200188] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/26/2020] [Indexed: 12/24/2022] Open
Abstract
Cancer is considered a group of diseases characterized by uncontrolled growth and spread of abnormal cells and is propelled by somatic mutations. Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3) family of enzymes are endogenous sources of somatic mutations found in multiple human cancers. While these enzymes normally act as an intrinsic immune defence against viruses, they can also catalyse 'off-target' cytidine deamination in genomic single-stranded DNA intermediates. The deamination of cytosine forms uracil, which is promutagenic in DNA. Key factors to trigger the APOBEC 'off-target' activity are overexpression in a non-normal cell type, nuclear localization and replication stress. The resulting uracil-induced mutations contribute to genomic variation, which may result in neutral, beneficial or harmful consequences for the cancer. This review summarizes the functional and biochemical basis of the APOBEC3 enzyme activity and highlights their relationship with the most well-studied cancers in this particular context such as breast, lung, bladder, and human papillomavirus-associated cancers. We focus on APOBEC3A, APOBEC3B and APOBEC3H haplotype I because they are the leading candidates as sources of somatic mutations in these and other cancers. Also, we discuss the prognostic value of the APOBEC3 expression in drug resistance and response to therapies.
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Affiliation(s)
| | | | - Linda Chelico
- Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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25
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Maiti A, Myint W, Delviks-Frankenberry KA, Hou S, Kanai T, Balachandran V, Sierra Rodriguez C, Tripathi R, Kurt Yilmaz N, Pathak VK, Schiffer CA, Matsuo H. Crystal Structure of a Soluble APOBEC3G Variant Suggests ssDNA to Bind in a Channel that Extends between the Two Domains. J Mol Biol 2020; 432:6042-6060. [PMID: 33098858 DOI: 10.1016/j.jmb.2020.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/09/2020] [Accepted: 10/16/2020] [Indexed: 11/16/2022]
Abstract
APOBEC3G (A3G) is a single-stranded DNA (ssDNA) cytosine deaminase that can restrict HIV-1 infection by mutating the viral genome. A3G consists of a non-catalytic N-terminal domain (NTD) and a catalytic C-terminal domain (CTD) connected by a short linker. While the CTD catalyzes cytosine deamination, the NTD is believed to provide additional affinity for ssDNA. Structures of both A3G domains have been solved individually; however, a full-length A3G structure has been challenging. Recently, crystal structures of full-length rhesus macaque A3G variants were solved which suggested dimerization mechanisms and RNA binding surfaces, whereas the dimerization appeared to compromise catalytic activity. We determined the crystal structure of a soluble variant of human A3G (sA3G) at 2.5 Å and from these data generated a model structure of wild-type A3G. This model demonstrated that the NTD was rotated 90° relative to the CTD along the major axis of the molecule, an orientation that forms a positively charged channel connected to the CTD catalytic site, consisting of NTD loop-1 and CTD loop-3. Structure-based mutations, in vitro deamination and DNA binding assays, and HIV-1 restriction assays identify R24, located in the NTD loop-1, as essential to a critical interaction with ssDNA. Furthermore, sA3G was shown to bind a deoxy-cytidine dinucleotide near the catalytic Zn2+, yet not in the catalytic position, where the interactions between deoxy-cytidines and CTD loop-1 and loop-7 residues were different from those formed with substrate. These new interactions suggest a mechanism explaining why A3G exhibits a 3' to 5' directional preference in processive deamination.
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Affiliation(s)
- Atanu Maiti
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Wazo Myint
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Krista A Delviks-Frankenberry
- Viral Mutation Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Shurong Hou
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Tapan Kanai
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA; Department of Chemistry, Banasthali University, Banasthali 304022, Rajasthan, India
| | | | | | - Rashmi Tripathi
- Department of Bioscience and Biotechnology, Banasthali University, Banasthali 304022, Rajasthan, India
| | - Nese Kurt Yilmaz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Vinay K Pathak
- Viral Mutation Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Hiroshi Matsuo
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA.
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26
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Hix MA, Wong L, Flath B, Chelico L, Cisneros GA. Single-nucleotide polymorphism of the DNA cytosine deaminase APOBEC3H haplotype I leads to enzyme destabilization and correlates with lung cancer. NAR Cancer 2020; 2:zcaa023. [PMID: 32984821 PMCID: PMC7503452 DOI: 10.1093/narcan/zcaa023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 08/24/2020] [Accepted: 08/28/2020] [Indexed: 12/12/2022] Open
Abstract
A number of APOBEC family DNA cytosine deaminases can induce mutations in tumor cells. APOBEC3H haplotype I is one of the deaminases that has been proposed to cause mutations in lung cancer. Here, we confirmed that APOBEC3H haplotype I can cause uracil-induced DNA damage in lung cancer cells that results in γH2AX foci. Interestingly, the database of cancer biomarkers in DNA repair genes (DNArCdb) identified a single-nucleotide polymorphism (rs139298) of APOBEC3H haplotype I that is involved in lung cancer. While we thought this may increase the activity of APOBEC3H haplotype I, instead we found through computational modeling and cell-based experiments that this single-nucleotide polymorphism causes the destabilization of APOBEC3H Haplotype I. Computational analysis suggests that the resulting K121E change affects the structure of APOBEC3H leading to active site disruption and destabilization of the RNA-mediated dimer interface. A K117E mutation in a K121E background stabilized the APOBEC3H haplotype I, thus enabling biochemical study. Subsequent analysis showed that K121E affected catalytic activity, single-stranded DNA binding and oligomerization on single-stranded DNA. The destabilization of a DNA mutator associated with lung cancer supports the model that too much APOBEC3-induced mutation could result in immune recognition or death of tumor cells.
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Affiliation(s)
- Mark A Hix
- Department of Chemistry, University of North Texas, Denton, TX 76201, USA
| | - Lai Wong
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Ben Flath
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Linda Chelico
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - G Andrés Cisneros
- Department of Chemistry, University of North Texas, Denton, TX 76201, USA
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27
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Delviks-Frankenberry KA, Desimmie BA, Pathak VK. Structural Insights into APOBEC3-Mediated Lentiviral Restriction. Viruses 2020; 12:E587. [PMID: 32471198 PMCID: PMC7354603 DOI: 10.3390/v12060587] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/22/2020] [Accepted: 05/24/2020] [Indexed: 01/18/2023] Open
Abstract
Mammals have developed clever adaptive and innate immune defense mechanisms to protect against invading bacterial and viral pathogens. Human innate immunity is continuously evolving to expand the repertoire of restriction factors and one such family of intrinsic restriction factors is the APOBEC3 (A3) family of cytidine deaminases. The coordinated expression of seven members of the A3 family of cytidine deaminases provides intrinsic immunity against numerous foreign infectious agents and protects the host from exogenous retroviruses and endogenous retroelements. Four members of the A3 proteins-A3G, A3F, A3H, and A3D-restrict HIV-1 in the absence of virion infectivity factor (Vif); their incorporation into progeny virions is a prerequisite for cytidine deaminase-dependent and -independent activities that inhibit viral replication in the host target cell. HIV-1 encodes Vif, an accessory protein that antagonizes A3 proteins by targeting them for polyubiquitination and subsequent proteasomal degradation in the virus producing cells. In this review, we summarize our current understanding of the role of human A3 proteins as barriers against HIV-1 infection, how Vif overcomes their antiviral activity, and highlight recent structural and functional insights into A3-mediated restriction of lentiviruses.
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Affiliation(s)
| | | | - Vinay K. Pathak
- Viral Mutation Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, MD 21702, USA; (K.A.D.-F.); (B.A.D.)
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28
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Branton SA, Ghorbani A, Bolt BN, Fifield H, Berghuis LM, Larijani M. Activation-induced cytidine deaminase can target multiple topologies of double-stranded DNA in a transcription-independent manner. FASEB J 2020; 34:9245-9268. [PMID: 32437054 DOI: 10.1096/fj.201903036rr] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/20/2020] [Accepted: 04/24/2020] [Indexed: 12/30/2022]
Abstract
Activation-induced cytidine deaminase (AID) mutates immunoglobulin genes and acts genome-wide. AID targets robustly transcribed genes, and purified AID acts on single-stranded (ss) but not double-stranded (ds) DNA oligonucleotides. Thus, it is believed that transcription is the generator of ssDNA for AID. Previous cell-free studies examining the relationship between transcription and AID targeting have employed a bacterial colony count assay wherein AID reverts an antibiotic resistance stop codon in plasmid substrates, leading to colony formation. Here, we established a novel assay where kb-long dsDNA of varying topologies is incubated with AID, with or without transcription, followed by direct sequencing. This assay allows for an unselected and in-depth comparison of mutation frequency and pattern of AID targeting in the absence of transcription or across a range of transcription dynamics. We found that without transcription, AID targets breathing ssDNA in supercoiled and, to a lesser extent, in relaxed dsDNA. The most optimal transcription only modestly enhanced AID action on supercoiled dsDNA in a manner dependent on RNA polymerase speed. These data suggest that the correlation between transcription and AID targeting may reflect transcription leading to AID-accessible breathing ssDNA patches naturally occurring in de-chromatinized dsDNA, as much as being due to transcription directly generating ssDNA.
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Affiliation(s)
- Sarah A Branton
- Program in Immunology and Infectious Diseases, Department of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Atefeh Ghorbani
- Program in Immunology and Infectious Diseases, Department of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Brittany N Bolt
- Program in Immunology and Infectious Diseases, Department of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Heather Fifield
- Program in Immunology and Infectious Diseases, Department of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Lesley M Berghuis
- Program in Immunology and Infectious Diseases, Department of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Mani Larijani
- Program in Immunology and Infectious Diseases, Department of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada.,Department of Molecular Biology and Biochemistry, Faculty of Science, Simon Fraser University, Burnaby, BC, Canada
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29
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Sui Y, Qi L, Zhang K, Saini N, Klimczak LJ, Sakofsky CJ, Gordenin DA, Petes TD, Zheng DQ. Analysis of APOBEC-induced mutations in yeast strains with low levels of replicative DNA polymerases. Proc Natl Acad Sci U S A 2020; 117:9440-9450. [PMID: 32277034 PMCID: PMC7196835 DOI: 10.1073/pnas.1922472117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Yeast strains with low levels of the replicative DNA polymerases (alpha, delta, and epsilon) have high levels of chromosome deletions, duplications, and translocations. By examining the patterns of mutations induced in strains with low levels of DNA polymerase by the human protein APOBEC3B (a protein that deaminates cytosine in single-stranded DNA), we show dramatically elevated amounts of single-stranded DNA relative to a wild-type strain. During DNA replication, one strand (defined as the leading strand) is replicated processively by DNA polymerase epsilon and the other (the lagging strand) is replicated as short fragments initiated by DNA polymerase alpha and extended by DNA polymerase delta. In the low DNA polymerase alpha and delta strains, the APOBEC-induced mutations are concentrated on the lagging-strand template, whereas in the low DNA polymerase epsilon strain, mutations occur on the leading- and lagging-strand templates with similar frequencies. In addition, for most genes, the transcribed strand is mutagenized more frequently than the nontranscribed strand. Lastly, some of the APOBEC-induced clusters in strains with low levels of DNA polymerase alpha or delta are greater than 10 kb in length.
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Affiliation(s)
- Yang Sui
- Ocean College, Zhejiang University, 316021 Zhoushan, China
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710
| | - Lei Qi
- Ocean College, Zhejiang University, 316021 Zhoushan, China
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710
| | - Ke Zhang
- Ocean College, Zhejiang University, 316021 Zhoushan, China
| | - Natalie Saini
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709
| | - Leszek J Klimczak
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709
| | - Cynthia J Sakofsky
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709
| | - Dmitry A Gordenin
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709
| | - Thomas D Petes
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710;
| | - Dao-Qiong Zheng
- Ocean College, Zhejiang University, 316021 Zhoushan, China;
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710
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30
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McDaniel YZ, Wang D, Love RP, Adolph MB, Mohammadzadeh N, Chelico L, Mansky LM. Deamination hotspots among APOBEC3 family members are defined by both target site sequence context and ssDNA secondary structure. Nucleic Acids Res 2020; 48:1353-1371. [PMID: 31943071 PMCID: PMC7026630 DOI: 10.1093/nar/gkz1164] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 11/27/2019] [Accepted: 12/02/2019] [Indexed: 12/26/2022] Open
Abstract
The human apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3 (APOBEC3, A3) family member proteins can deaminate cytosines in single-strand (ss) DNA, which restricts human immunodeficiency virus type 1 (HIV-1), retrotransposons, and other viruses such as hepatitis B virus, but can cause a mutator phenotype in many cancers. While structural information exists for several A3 proteins, the precise details regarding deamination target selection are not fully understood. Here, we report the first parallel, comparative analysis of site selection of A3 deamination using six of the seven purified A3 member enzymes, oligonucleotides having 5'TC3' or 5'CT3' dinucleotide target sites, and different flanking bases within diverse DNA secondary structures. A3A, A3F and A3H were observed to have strong preferences toward the TC target flanked by A or T, while all examined A3 proteins did not show a preference for a TC target flanked by a G. We observed that the TC target was strongly preferred in ssDNA regions rather than dsDNA, loop or bulge regions, with flanking bases influencing the degree of preference. CT was also shown to be a potential deamination target. Taken together, our observations provide new insights into A3 enzyme target site selection and how A3 mutagenesis impacts mutation rates.
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Affiliation(s)
- Yumeng Z McDaniel
- Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, MN 55455 USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455 USA
| | - Dake Wang
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455 USA
- Pharmacology Graduate Program, University of Minnesota, Minneapolis, MN 55455 USA
| | - Robin P Love
- Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Madison B Adolph
- Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Nazanin Mohammadzadeh
- Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Linda Chelico
- Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Louis M Mansky
- Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, MN 55455 USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455 USA
- Pharmacology Graduate Program, University of Minnesota, Minneapolis, MN 55455 USA
- Division of Basic Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455 USA
- Department of Microbiology & Immunology, University of Minnesota, Minneapolis, MN 55455 USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455 USA
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31
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Yang H, Ito F, Wolfe AD, Li S, Mohammadzadeh N, Love RP, Yan M, Zirkle B, Gaba A, Chelico L, Chen XS. Understanding the structural basis of HIV-1 restriction by the full length double-domain APOBEC3G. Nat Commun 2020; 11:632. [PMID: 32005813 PMCID: PMC6994475 DOI: 10.1038/s41467-020-14377-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 12/18/2019] [Indexed: 12/17/2022] Open
Abstract
APOBEC3G, a member of the double-domain cytidine deaminase (CD) APOBEC, binds RNA to package into virions and restrict HIV-1 through deamination-dependent or deamination-independent inhibition. Mainly due to lack of a full-length double-domain APOBEC structure, it is unknown how CD1/CD2 domains connect and how dimerization/multimerization is linked to RNA binding and virion packaging for HIV-1 restriction. We report rhesus macaque A3G structures that show different inter-domain packing through a short linker and refolding of CD2. The A3G dimer structure has a hydrophobic dimer-interface matching with that of the previously reported CD1 structure. A3G dimerization generates a surface with intensified positive electrostatic potentials (PEP) for RNA binding and dimer stabilization. Unexpectedly, mutating the PEP surface and the hydrophobic interface of A3G does not abolish virion packaging and HIV-1 restriction. The data support a model in which only one RNA-binding mode is critical for virion packaging and restriction of HIV-1 by A3G. APOBEC3G (A3G) belongs to the DNA/RNA cytosine deaminase family that plays important roles in innate immunity against HIV and internal retroelements. Here the authors report the structures of two full-length A3G variants that provides insight into domain organization, multimerization, RNA binding, and viral restriction.
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Affiliation(s)
- Hanjing Yang
- Molecular and Computational Biology, Departments of Biological Sciences, Chemistry, University of Southern California, Los Angeles, CA, 90089, USA
| | - Fumiaki Ito
- Molecular and Computational Biology, Departments of Biological Sciences, Chemistry, University of Southern California, Los Angeles, CA, 90089, USA
| | - Aaron D Wolfe
- Molecular and Computational Biology, Departments of Biological Sciences, Chemistry, University of Southern California, Los Angeles, CA, 90089, USA.,Genetic, Molecular and Cellular Biology Program, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.,Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, 90033, USA
| | - Shuxing Li
- Molecular and Computational Biology, Departments of Biological Sciences, Chemistry, University of Southern California, Los Angeles, CA, 90089, USA.,Center of Excellence in NanoBiophysics, University of Southern California, Los Angeles, CA, 90089, USA
| | - Nazanin Mohammadzadeh
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Robin P Love
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Maocai Yan
- Molecular and Computational Biology, Departments of Biological Sciences, Chemistry, University of Southern California, Los Angeles, CA, 90089, USA.,School of Pharmacy, Jining Medical University, 276800, Rizhao, Shandong, China
| | - Brett Zirkle
- Molecular and Computational Biology, Departments of Biological Sciences, Chemistry, University of Southern California, Los Angeles, CA, 90089, USA.,Genetic, Molecular and Cellular Biology Program, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Amit Gaba
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Linda Chelico
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Xiaojiang S Chen
- Molecular and Computational Biology, Departments of Biological Sciences, Chemistry, University of Southern California, Los Angeles, CA, 90089, USA. .,Genetic, Molecular and Cellular Biology Program, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA. .,Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, 90033, USA. .,Center of Excellence in NanoBiophysics, University of Southern California, Los Angeles, CA, 90089, USA.
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32
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Morse M, Naufer MN, Feng Y, Chelico L, Rouzina I, Williams MC. HIV restriction factor APOBEC3G binds in multiple steps and conformations to search and deaminate single-stranded DNA. eLife 2019; 8:e52649. [PMID: 31850845 PMCID: PMC6946564 DOI: 10.7554/elife.52649] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 12/18/2019] [Indexed: 12/15/2022] Open
Abstract
APOBEC3G (A3G), an enzyme expressed in primates with the potential to inhibit human immunodeficiency virus type 1 (HIV-1) infectivity, is a single-stranded DNA (ssDNA) deoxycytidine deaminase with two domains, a catalytically active, weakly ssDNA binding C-terminal domain (CTD) and a catalytically inactive, strongly ssDNA binding N-terminal domain (NTD). Using optical tweezers, we measure A3G binding a single, long ssDNA substrate under various applied forces to characterize the binding interaction. A3G binds ssDNA in multiple steps and in two distinct conformations, distinguished by degree of ssDNA contraction. A3G stabilizes formation of ssDNA loops, an ability inhibited by A3G oligomerization. Our data suggests A3G securely binds ssDNA through the NTD, while the CTD samples and potentially deaminates the substrate. Oligomerization of A3G stabilizes ssDNA binding but inhibits the CTD's search function. These processes explain A3G's ability to efficiently deaminate numerous sites across a 10,000 base viral genome during the reverse transcription process.
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Affiliation(s)
- Michael Morse
- Department of PhysicsNortheastern UniversityBostonUnited States
| | - M Nabuan Naufer
- Department of PhysicsNortheastern UniversityBostonUnited States
| | - Yuqing Feng
- Department of Biochemistry, Microbiology and ImmunologyUniversity of SaskatchewanSaskatoonCanada
| | - Linda Chelico
- Department of Biochemistry, Microbiology and ImmunologyUniversity of SaskatchewanSaskatoonCanada
| | - Ioulia Rouzina
- Department of Chemistry and BiochemistryOhio State UniversityColumbusUnited States
| | - Mark C Williams
- Department of PhysicsNortheastern UniversityBostonUnited States
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33
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Solomon WC, Myint W, Hou S, Kanai T, Tripathi R, Kurt Yilmaz N, Schiffer CA, Matsuo H. Mechanism for APOBEC3G catalytic exclusion of RNA and non-substrate DNA. Nucleic Acids Res 2019; 47:7676-7689. [PMID: 31424549 PMCID: PMC6698744 DOI: 10.1093/nar/gkz550] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/06/2019] [Accepted: 06/11/2019] [Indexed: 12/17/2022] Open
Abstract
The potent antiretroviral protein APOBEC3G (A3G) specifically targets and deaminates deoxycytidine nucleotides, generating deoxyuridine, in single stranded DNA (ssDNA) intermediates produced during HIV replication. A non-catalytic domain in A3G binds strongly to RNA, an interaction crucial for recruitment of A3G to the virion; yet, A3G displays no deamination activity for cytidines in viral RNA. Here, we report NMR and molecular dynamics (MD) simulation analysis for interactions between A3Gctd and multiple substrate or non-substrate DNA and RNA, in combination with deamination assays. NMR ssDNA-binding experiments revealed that the interaction with residues in helix1 and loop1 (T201-L220) distinguishes the binding mode of substrate ssDNA from non-substrate. Using 2′-deoxy-2′-fluorine substituted cytidines, we show that a 2′-endo sugar conformation of the target deoxycytidine is favored for substrate binding and deamination. Trajectories of the MD simulation indicate that a ribose 2′-hydroxyl group destabilizes the π-π stacking of the target cytosine and H257, resulting in dislocation of the target cytosine base from the catalytic position. Interestingly, APOBEC3A, which can deaminate ribocytidines, retains the ribocytidine in the catalytic position throughout the MD simulation. Our results indicate that A3Gctd catalytic selectivity against RNA is dictated by both the sugar conformation and 2′-hydroxyl group.
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Affiliation(s)
- William C Solomon
- Department of Biochemistry, Molecular Biology and Biophysics, Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Wazo Myint
- Basic Research Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Shurong Hou
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Tapan Kanai
- Basic Research Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA.,Department of Chemistry, Banasthali University, Banasthali-304022, Rajasthan, India
| | - Rashmi Tripathi
- Department of Bioscience and Biotechnology, Banasthali University, Banasthali-304022, Rajasthan, India
| | - Nese Kurt Yilmaz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Hiroshi Matsuo
- Basic Research Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
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34
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Cortez LM, Brown AL, Dennis MA, Collins CD, Brown AJ, Mitchell D, Mertz TM, Roberts SA. APOBEC3A is a prominent cytidine deaminase in breast cancer. PLoS Genet 2019; 15:e1008545. [PMID: 31841499 PMCID: PMC6936861 DOI: 10.1371/journal.pgen.1008545] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 12/30/2019] [Accepted: 12/01/2019] [Indexed: 11/19/2022] Open
Abstract
APOBEC cytidine deaminases are the second-most prominent source of mutagenesis in sequenced tumors. Previous studies have proposed that APOBEC3B (A3B) is the major source of mutagenesis in breast cancer (BRCA). We show that APOBEC3A (A3A) is the only APOBEC whose expression correlates with APOBEC-induced mutation load and that A3A expression is responsible for cytidine deamination in multiple BRCA cell lines. Comparative analysis of A3A and A3B expression by qRT-PCR, RSEM-normalized RNA-seq, and unambiguous RNA-seq validated the use of RNA-seq to measure APOBEC expression, which indicates that A3A is the primary correlate with APOBEC-mutation load in primary BRCA tumors. We also demonstrate that A3A has >100-fold more cytidine deamination activity than A3B in the presence of cellular RNA, likely explaining why higher levels of A3B expression contributes less to mutagenesis in BRCA. Our findings identify A3A as a major source of cytidine deaminase activity in breast cancer cells and possibly a prominent contributor to the APOBEC mutation signature.
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Affiliation(s)
- Luis M. Cortez
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, United States of America
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, United States of America
| | - Amber L. Brown
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, United States of America
| | - Madeline A. Dennis
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, United States of America
| | - Christopher D. Collins
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, United States of America
| | - Alexander J. Brown
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, United States of America
- School of Molecular Biosciences, Washington State University-Vancouver, Vancouver, WA, United States of America
| | - Debra Mitchell
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, United States of America
| | - Tony M. Mertz
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, United States of America
| | - Steven A. Roberts
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, United States of America
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35
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Diuron exposure and Akt overexpression promote glioma formation through DNA hypomethylation. Clin Epigenetics 2019; 11:159. [PMID: 31727122 PMCID: PMC6854743 DOI: 10.1186/s13148-019-0759-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/01/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Diuron is an environmental component listed as a likely human carcinogen. Several other studies report that diuron can be oncogenic for bladder, urothelial, skin, and mammary cells. No study mentions the putative effect of diuron on the glioma occurrence. OBJECTIVES We here wanted to investigate the effects of diuron exposure on the glioma occurrence while wishing to incriminate a putative implication of DNA methylation modulation in this process. METHODS In in vivo model of glioma, diuron exposure was firstly compared or combined with oncogenic overexpressions already known to promote gliomagenesis. ELISA quantifying the 5-methylcytosine level on DNA was performed to examine the global DNA methylation level. Quantitative real-time polymerase chain reaction and proximity ligation in situ assay were performed to identify the molecular causes of the diuron-induced changes of DNA methylation. The signatures diuron-induced changes of DNA methylation were analyzed in a cohort of 23 GBM patients. RESULTS Diuron exposure is not sufficient to promote glioma, such as the oncogenic overexpression of Akt or Ras. However, the combination of diuron exposure and Akt overexpression promotes glioma. We observed that the diuron/Akt-induced glioma is characterized by three phenotypic signatures characterizing cancer cells: a global DNA hypomethylation, a loss of sensitivity to cell death induction, and a gain of signals of immune escape. Our data associated these phenotypes with three aberrant DNA methylation signatures: the LLT1, PD-L1, and Bcl-w hypomethylations. Strikingly, we observed that these three concomitant hypomethylations were only observed in GBM patients having a potential exposure to diuron via their professional activity. CONCLUSIONS As single player, diuron is not an oncogenic of glioma, but it can participate to the glioma formation in association with other events (also devoid of oncogenic property as single player) such as Akt overexpression.
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36
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Pan Y, Shlyakhtenko LS, Lyubchenko YL. Insight into dynamics of APOBEC3G protein in complexes with DNA assessed by high speed AFM. NANOSCALE ADVANCES 2019; 1:4016-4024. [PMID: 33313478 PMCID: PMC7731963 DOI: 10.1039/c9na00457b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 09/03/2019] [Indexed: 06/12/2023]
Abstract
APOBEC3G (A3G) is a single-stranded DNA (ssDNA) binding protein that restricts the HIV virus by deamination of dC to dU during reverse transcription of the viral genome. A3G has two zing-binding domains: the N-terminal domain (NTD), which efficiently binds ssDNA, and the C-terminal catalytic domain (CTD), which supports deaminase activity of A3G. Until now, structural information on A3G has lacked, preventing elucidation of the molecular mechanisms underlying its interaction with ssDNA and deaminase activity. We have recently built a computational model for the full-length A3G monomer and validated its structure by data obtained from time-lapse High-Speed Atomic Force Microscopy (HS AFM). Here time-lapse HS AFM was applied to directly visualize the structure and dynamics of A3G in complexes with ssDNA. Our results demonstrate a highly dynamic structure of A3G, where two domains of the protein fluctuate between compact globular and extended dumbbell structures. Quantitative analysis of our data revealed a substantial increase in the number of A3G dumbbell structures in the presence of the DNA substrate, suggesting the interaction of A3G with the ssDNA substrate stabilizes this dumbbell structure. Based on these data, we proposed a model explaining the interaction of globular and dumbbell structures of A3G with ssDNA and suggested a possible role of the dumbbell structure in A3G function.
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Affiliation(s)
- Yangang Pan
- Department of Pharmaceutical Sciences, College of Pharmacy, WSH, University of Nebraska Medical CenterOmahaNebraska 68198-6025USA
| | - Luda S. Shlyakhtenko
- Department of Pharmaceutical Sciences, College of Pharmacy, WSH, University of Nebraska Medical CenterOmahaNebraska 68198-6025USA
| | - Yuri L. Lyubchenko
- Department of Pharmaceutical Sciences, College of Pharmacy, WSH, University of Nebraska Medical CenterOmahaNebraska 68198-6025USA
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37
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Silvas TV, Schiffer CA. APOBEC3s: DNA-editing human cytidine deaminases. Protein Sci 2019; 28:1552-1566. [PMID: 31241202 DOI: 10.1002/pro.3670] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 12/22/2022]
Abstract
Nucleic acid editing enzymes are essential components of the human immune system that lethally mutate viral pathogens and somatically mutate immunoglobulins. Among these enzymes are cytidine deaminases of the apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like (APOBEC) super family, each with unique target sequence specificity and subcellular localization. We focus on the DNA-editing APOBEC3 enzymes that have recently attracted attention because of their involvement in cancer and potential in gene-editing applications. We review and compare the crystal structures of APOBEC3 (A3) domains, binding interactions with DNA, substrate specificity, and activity. Recent crystal structures of A3A and A3G bound to ssDNA have provided insights into substrate binding and specificity determinants of these enzymes. Still many unknowns remain regarding potential cooperativity, nucleic acid interactions, and systematic quantification of substrate preference of many APOBEC3s, which are needed to better characterize the biological functions and consequences of misregulation of these gene editors.
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Affiliation(s)
- Tania V Silvas
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts
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38
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Yan X, Lan W, Wang C, Cao C. Structural Investigations on the Interactions between Cytidine Deaminase Human APOBEC3G and DNA. Chem Asian J 2019; 14:2235-2241. [PMID: 31116511 DOI: 10.1002/asia.201900480] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/20/2019] [Indexed: 02/05/2023]
Abstract
Human APOBEC3G (A3G) inhibits the replication of human immunodeficiency virus-1 by deaminating cytidine at the 3'-end in the target motif 5'-CCC-3' in viral cDNA during reverse transcription. It in vitro deaminates two consecutive cytidines in a 3'->5' order. Although a crystal structure of the A3G catalytic domain (A3G-CD2) with DNA was reported, it is unknown why residues involved in enzymatic reaction are distributed widely. Here, we introduced an iodine atom into the C-5 position of cytidine (dC6 I ) in DNA 5'-ATTC4 C5 C6 I A7 ATT-3' (TCCC6 I ). It switches the deamination sequence preference from CCC to TCC, although small dC6 I deamination was observed. Solution structures of A3G-CD2 in complexes with products DNA TCUC6 I and TCUU6 I indicate that the substrate DNA binds A3G-CD2 in TCC and CCC modes. The dC6 deamination correlates with the 4th base type. The CCC mode favours dC6 deamination, while the TCC mode results in dC5 deamination. These studies present an extensive basis to design inhibitors to impede viral evolvability.
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Affiliation(s)
- Xiaoxuan Yan
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Science, 345 Lingling Road, Shanghai, 200032, China.,University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing, 100049, China
| | - Wenxian Lan
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Science, 345 Lingling Road, Shanghai, 200032, China
| | - Chunxi Wang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Science, 345 Lingling Road, Shanghai, 200032, China
| | - Chunyang Cao
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Science, 345 Lingling Road, Shanghai, 200032, China.,University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing, 100049, China
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39
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Hypoxia-induced human deoxyribonuclease I is a cellular restriction factor of hepatitis B virus. Nat Microbiol 2019; 4:1196-1207. [PMID: 30936483 DOI: 10.1038/s41564-019-0405-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 02/11/2019] [Indexed: 12/17/2022]
Abstract
Numerous human APOBEC3 cytidine deaminases have proven to be, inter alia, host cell restriction factors for retroviruses and hepadnaviruses. Although they can bind to genomic RNA and become encapsidated, they are only catalytically active on single-stranded DNA. As there are many cellular deoxyribonucleases (DNases), we hypothesized that a parallel could be struck between APOBEC3 and DNases. For human hepatitis B virus (HBV), we show that DNase I can considerably reduce the virion genome copy number from a variety of transfected or infected cells. DNASE1 is overexpressed and encapsidated in HBV particles in vitro in hypoxic environments and in vivo in cirrhotic patient livers as well as in the serum of infected patients. The use of CoCl2 and dimethyloxalylglycine, mimetic agents used to induce hypoxia by inhibiting prolyl hydroxylase enzymes that stabilize hypoxia-inducible factor (HIF)-1α, showed that the formation of HIF-1α/HIF-1β heterodimers results in the induction of DNASE1. Indeed, transfection with HIF-1α and HIF-1β expression constructs upregulated DNASE1. These findings suggest that human DNase I can impact HBV replication through the catabolism of the DNA genome within the capsid. The activity of DNases in general may explain in part the high frequency of empty or 'light' hepatitis B virions observed in vivo.
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40
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Adolph MB, Ara A, Chelico L. APOBEC3 Host Restriction Factors of HIV-1 Can Change the Template Switching Frequency of Reverse Transcriptase. J Mol Biol 2019; 431:1339-1352. [PMID: 30797859 DOI: 10.1016/j.jmb.2019.02.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 02/14/2019] [Accepted: 02/15/2019] [Indexed: 12/16/2022]
Abstract
The APOBEC3 family of deoxycytidine deaminases has the ability to restrict HIV-1 through deamination-dependent and deamination-independent mechanisms. Although the generation of mutations through deamination of cytosine to uracil in single-stranded HIV-1 (-) DNA is the dominant mechanism of restriction, the deaminase-independent mechanism additionally contributes. Previous observations indicate that APOBEC3 enzymes competitively bind the RNA template or reverse transcriptase (RT) and act as a roadblock to DNA polymerization. Here we studied how the deamination-independent inhibition of HIV-1 RT by APOBEC3C S188I, APOBEC3F, APOBEC3G, and APOBEC3H affected RT template switching. We found that APOBEC3F could promote template switching of RT, and this was dependent on the high affinity with which it bound nucleic acids, suggesting than an APOBEC3 "road-block" can force template switching. Our data demonstrate that the deamination-independent functions of APOBEC3 enzymes extend beyond only disrupting RT DNA polymerization. Since alterations to the RT template switching frequency can result in insertions or deletions, our data support a model in which APOBEC3 enzymes use multiple mechanisms to increase the probability of generating a mutated and nonfunctional virus in addition to cytosine deamination.
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Affiliation(s)
- Madison B Adolph
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada; Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Anjuman Ara
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada; Saskatchewan Cancer Agency and Division of Oncology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Linda Chelico
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
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41
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Hagen B, Kraase M, Indikova I, Indik S. A high rate of polymerization during synthesis of mouse mammary tumor virus DNA alleviates hypermutation by APOBEC3 proteins. PLoS Pathog 2019; 15:e1007533. [PMID: 30768644 PMCID: PMC6395001 DOI: 10.1371/journal.ppat.1007533] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 02/28/2019] [Accepted: 12/14/2018] [Indexed: 11/19/2022] Open
Abstract
Retroviruses have evolved multiple means to counteract host restriction factors such as single-stranded DNA-specific deoxycytidine deaminases (APOBEC3s, A3s). These include exclusion of A3s from virions by an A3-unreactive nucleocapsid or expression of an A3-neutralizing protein (Vif, Bet). However, a number of retroviruses package A3s and do not encode apparent vif- or bet-like genes, yet they replicate in the presence of A3s. The mode by which they overcome deleterious restriction remains largely unknown. Here we show that the prototypic betaretrovirus, mouse mammary tumor virus (MMTV), packages similar amounts of A3s as HIV-1ΔVif, yet its proviruses carry a significantly lower level of A3-mediated deamination events than the lentivirus. The G-to-A mutation rate increases when the kinetics of reverse transcription is reduced by introducing a mutation (F120L) to the DNA polymerase domain of the MMTV reverse transcriptase (RT). A similar A3-sensitizing effect was observed when the exposure time of single-stranded DNA intermediates to A3s during reverse transcription was lengthened by reducing the dNTP concentration or by adding suboptimal concentrations of an RT inhibitor to infected cells. Thus, the MMTV RT has evolved to impede access of A3s to transiently exposed minus DNA strands during reverse transcription, thereby alleviating inhibition by A3 family members. A similar mechanism may be used by other retroviruses and retrotransposons to reduce deleterious effects of A3 proteins.
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Affiliation(s)
- Benedikt Hagen
- Institute of Virology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Martin Kraase
- Institute of Virology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Ivana Indikova
- Institute of Virology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Stanislav Indik
- Institute of Virology, University of Veterinary Medicine Vienna, Vienna, Austria
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42
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Cannataro VL, Gaffney SG, Sasaki T, Issaeva N, Grewal NKS, Grandis JR, Yarbrough WG, Burtness B, Anderson KS, Townsend JP. APOBEC-induced mutations and their cancer effect size in head and neck squamous cell carcinoma. Oncogene 2019; 38:3475-3487. [PMID: 30647454 PMCID: PMC6499643 DOI: 10.1038/s41388-018-0657-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 10/15/2018] [Accepted: 10/17/2018] [Indexed: 12/12/2022]
Abstract
Recent studies have revealed the mutational signatures underlying the somatic evolution of cancer, and the prevalences of associated somatic genetic variants. Here we estimate the intensity of positive selection that drives mutations to high frequency in tumors, yielding higher prevalences than expected on the basis of mutation and neutral drift alone. We apply this approach to a sample of 525 head and neck squamous cell carcinoma exomes, producing a rank-ordered list of gene variants by selection intensity. Our results illustrate the complementarity of calculating the intensity of selection on mutations along with tallying the prevalence of individual substitutions in cancer: while many of the most prevalently-altered genes were heavily selected, their relative importance to the cancer phenotype differs from their prevalence and from their P value, with some infrequent variants exhibiting evidence of strong positive selection. Furthermore, we extend our analysis of effect size by quantifying the degree to which mutational processes (such as APOBEC mutagenesis) contributes mutations that are highly selected, driving head and neck squamous cell carcinoma. We calculate the substitutions caused by APOBEC mutagenesis that make the greatest contribution to cancer phenotype among patients. Lastly, we demonstrate via in vitro biochemical experiments that the APOBEC3B protein can deaminate the cytosine bases at two sites whose mutant states are subject to high net realized selection intensities-PIK3CA E545K and E542K. By quantifying the effects of mutations, we deepen the molecular understanding of carcinogenesis in head and neck squamous cell carcinoma.
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Affiliation(s)
- Vincent L Cannataro
- Department of Biostatistics, Yale School of Public Health, New Haven, CT, USA
| | - Stephen G Gaffney
- Department of Biostatistics, Yale School of Public Health, New Haven, CT, USA
| | - Tomoaki Sasaki
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Natalia Issaeva
- Yale Cancer Center, Yale University, New Haven, CT, USA.,Division of Otolaryngology, Department of Surgery, Yale School of Medicine, New Haven, CT, USA
| | - Nicholas K S Grewal
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | - Jennifer R Grandis
- Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Wendell G Yarbrough
- Yale Cancer Center, Yale University, New Haven, CT, USA.,Division of Otolaryngology, Department of Surgery, Yale School of Medicine, New Haven, CT, USA.,Department of Pathology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Barbara Burtness
- Yale Cancer Center, Yale University, New Haven, CT, USA.,Department of Medicine, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Karen S Anderson
- Department of Pharmacology, Yale University, New Haven, CT, USA.,Yale Cancer Center, Yale University, New Haven, CT, USA.,Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA
| | - Jeffrey P Townsend
- Department of Biostatistics, Yale School of Public Health, New Haven, CT, USA. .,Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA. .,Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT, USA.
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43
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Jin J, Yan X, Liu Y, Lan W, Wang C, Xu B, Cao C. Recent Advances in the Structural Studies on Cytosine Deaminase APOBEC3 Family Members and Their Nucleic Acid Complexes. ACTA CHIMICA SINICA 2019. [DOI: 10.6023/a19080296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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44
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Martinez T, Shapiro M, Bhaduri-McIntosh S, MacCarthy T. Evolutionary effects of the AID/APOBEC family of mutagenic enzymes on human gamma-herpesviruses. Virus Evol 2019; 5:vey040. [PMID: 30792902 PMCID: PMC6371749 DOI: 10.1093/ve/vey040] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The human gamma-herpesviruses, Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus, establish lifelong latency in B cells and are associated with multiple malignancies. Virus-host coevolution often drive changes in both host immunity and in the viral genome. We consider one host immune mechanism, the activation-induced deaminase (AID)/APOBEC family of cytidine deaminases, that induces mutations in viral DNA. AID, the ancestral gene in the family has a conserved role in somatic hypermutation, a key step in antibody affinity maturation. The APOBEC3 subfamily, of which there are seven genes in human, have evolved antiviral functions and have diversified in terms of their expression pattern, subcellular localization, and DNA mutation motifs (hotspots). In this study, we investigated how the human gamma-herpesviruses have evolved to avoid the action of the AID/APOBEC enzymes and determine if these enzymes are contributing to the ongoing evolution of the viruses. We used computational methods to evaluate observed versus expected frequency of AID/APOBEC hotspots in viral genomes and found that the viruses have evolved to limit the representation of AID and certain APOBEC3 motifs. At the same time, the remaining hotspots were highly likely to cause amino acid changes, suggesting prolonged evolutionary pressure of the enzymes on the viruses. To study current hypermutation, as opposed to historical mutation processes, we also analyzed putative mutations derived from alignments of published viral genomes and found again that AID and APOBEC3 appear to target the genome most frequently. New protein variants resulting from AID/APOBEC activity may have important consequences in health, including vaccine development (epitope evolution) and host immune evasion.
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Affiliation(s)
- Teresa Martinez
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY, USA
| | - Maxwell Shapiro
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY, USA
| | - Sumita Bhaduri-McIntosh
- Division of Infectious Diseases, Department of Pediatrics, University of Florida, Gainesville, FL, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | - Thomas MacCarthy
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY, USA
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY, USA
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45
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Pan Y, Zagorski K, Shlyakhtenko LS, Lyubchenko YL. The Enzymatic Activity of APOBE3G Multimers. Sci Rep 2018; 8:17953. [PMID: 30560880 PMCID: PMC6298963 DOI: 10.1038/s41598-018-36372-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 11/02/2018] [Indexed: 11/19/2022] Open
Abstract
APOBEC3G (A3G) belongs to the family of cytosine deaminases that play an important role in the innate immune response. Similar to other, two-domain members of the APOBEC family, A3G is prone to concentration-dependent oligomerization, which is an integral for its function in the cell. It is shown that oligomerization of A3G is related to the packing mechanism into virus particle and, is critical for the so-called roadblock model during reverse transcription of proviral ssDNA. The role of oligomerization for deaminase activity of A3G is widely discussed in the literature; however, its relevance to deaminase activity for different oligomeric forms of A3G remains unclear. Here, using Atomic Force Microscopy, we directly visualized A3G-ssDNA complexes, determined their yield and stoichiometry and in parallel, using PCR assay, measured the deaminase activity of these complexes. Our data demonstrate a direct correlation between the total yield of A3G-ssDNA complexes and their total deaminase activity. Using these data, we calculated the relative deaminase activity for each individual oligomeric state of A3G in the complex. Our results show not only similar deaminase activity for monomer, dimer and tetramer of A3G in the complex, but indicate that larger oligomers of A3G retain their deaminase activity.
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Affiliation(s)
- Yangang Pan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska, 68198-6025, USA
| | - Karen Zagorski
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska, 68198-6025, USA
| | - Luda S Shlyakhtenko
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska, 68198-6025, USA.
| | - Yuri L Lyubchenko
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska, 68198-6025, USA.
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46
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Hou S, Silvas TV, Leidner F, Nalivaika EA, Matsuo H, Kurt Yilmaz N, Schiffer CA. Structural Analysis of the Active Site and DNA Binding of Human Cytidine Deaminase APOBEC3B. J Chem Theory Comput 2018; 15:637-647. [PMID: 30457868 DOI: 10.1021/acs.jctc.8b00545] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
APOBEC3 (A3) proteins, a family of human cytidine deaminases, protect the host from endogenous retro-elements and exogenous viral infections by introducing hypermutations. However, overexpressed A3s can modify genomic DNA to promote tumorigenesis, especially A3B. Despite their overall similarity, A3 proteins have distinct deamination activity. Recently determined A3 structures have revealed the molecular determinants of nucleotide specificity and DNA binding. However, for A3B, the structural basis for regulation of deamination activity and the role of active site loops in coordinating DNA had remained unknown. Using advanced molecular modeling followed by experimental mutational analysis and dynamics simulations, we investigated the molecular mechanism of DNA binding by A3B-CTD. We modeled fully native A3B-DNA structure, and we identified Arg211 in loop 1 as the gatekeeper coordinating DNA and critical residue for nucleotide specificity. We also identified a unique autoinhibited conformation in A3B-CTD that restricts access and binding of DNA to the active site. Our results reveal the structural basis for DNA binding and relatively lower catalytic activity of A3B and provide opportunities for rational design of specific inhibitors to benefit cancer therapeutics.
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Affiliation(s)
- Shurong Hou
- Department of Biochemistry and Molecular Pharmacology , University of Massachusetts Medical School , Worcester , Massachusetts 01655 , United States
| | - Tania V Silvas
- Department of Biochemistry and Molecular Pharmacology , University of Massachusetts Medical School , Worcester , Massachusetts 01655 , United States
| | - Florian Leidner
- Department of Biochemistry and Molecular Pharmacology , University of Massachusetts Medical School , Worcester , Massachusetts 01655 , United States
| | - Ellen A Nalivaika
- Department of Biochemistry and Molecular Pharmacology , University of Massachusetts Medical School , Worcester , Massachusetts 01655 , United States
| | - Hiroshi Matsuo
- Basic Research Laboratory, Leidos Biomedical Research, Inc. , Frederick National Laboratory for Cancer Research , Frederick , Maryland 21702 , United States
| | - Nese Kurt Yilmaz
- Department of Biochemistry and Molecular Pharmacology , University of Massachusetts Medical School , Worcester , Massachusetts 01655 , United States
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology , University of Massachusetts Medical School , Worcester , Massachusetts 01655 , United States
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Kvach MV, Barzak FM, Harjes S, Schares HAM, Jameson GB, Ayoub AM, Moorthy R, Aihara H, Harris RS, Filichev VV, Harki DA, Harjes E. Inhibiting APOBEC3 Activity with Single-Stranded DNA Containing 2'-Deoxyzebularine Analogues. Biochemistry 2018; 58:391-400. [PMID: 30418757 PMCID: PMC6365909 DOI: 10.1021/acs.biochem.8b00858] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
APOBEC3 enzymes form part of the innate immune system by deaminating cytosine to uracil in single-stranded DNA (ssDNA) and thereby preventing the spread of pathogenic genetic information. However, APOBEC mutagenesis is also exploited by viruses and cancer cells to increase rates of evolution, escape adaptive immune responses, and resist drugs. This raises the possibility of APOBEC3 inhibition as a strategy for augmenting existing antiviral and anticancer therapies. Here we show that, upon incorporation into short ssDNAs, the cytidine nucleoside analogue 2'-deoxyzebularine (dZ) becomes capable of inhibiting the catalytic activity of selected APOBEC variants derived from APOBEC3A, APOBEC3B, and APOBEC3G, supporting a mechanism in which ssDNA delivers dZ to the active site. Multiple experimental approaches, including isothermal titration calorimetry, fluorescence polarization, protein thermal shift, and nuclear magnetic resonance spectroscopy assays, demonstrate nanomolar dissociation constants and low micromolar inhibition constants. These dZ-containing ssDNAs constitute the first substrate-like APOBEC3 inhibitors and, together, comprise a platform for developing nucleic acid-based inhibitors with cellular activity.
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Affiliation(s)
- Maksim V Kvach
- Institute of Fundamental Sciences , Massey University , Private Bag 11 222, Palmerston North 4442 , New Zealand
| | - Fareeda M Barzak
- Institute of Fundamental Sciences , Massey University , Private Bag 11 222, Palmerston North 4442 , New Zealand
| | - Stefan Harjes
- Institute of Fundamental Sciences , Massey University , Private Bag 11 222, Palmerston North 4442 , New Zealand
| | | | - Geoffrey B Jameson
- Institute of Fundamental Sciences , Massey University , Private Bag 11 222, Palmerston North 4442 , New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery , Auckland 1142 , New Zealand
| | | | | | | | - Reuben S Harris
- Howard Hughes Medical Institute , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Vyacheslav V Filichev
- Institute of Fundamental Sciences , Massey University , Private Bag 11 222, Palmerston North 4442 , New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery , Auckland 1142 , New Zealand
| | | | - Elena Harjes
- Institute of Fundamental Sciences , Massey University , Private Bag 11 222, Palmerston North 4442 , New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery , Auckland 1142 , New Zealand
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48
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Crystal Structure of Cytidine Deaminase Human APOBEC3F Chimeric Catalytic Domain in Complex with DNA. CHINESE J CHEM 2018. [DOI: 10.1002/cjoc.201800508] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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49
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RNA-Mediated Dimerization of the Human Deoxycytidine Deaminase APOBEC3H Influences Enzyme Activity and Interaction with Nucleic Acids. J Mol Biol 2018; 430:4891-4907. [PMID: 30414963 DOI: 10.1016/j.jmb.2018.11.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/04/2018] [Accepted: 11/04/2018] [Indexed: 12/11/2022]
Abstract
Human APOBEC3H is a single-stranded (ss)DNA deoxycytidine deaminase that inhibits replication of retroelements and HIV-1 in CD4+ T cells. When aberrantly expressed in lung or breast tissue, APOBEC3H can contribute to cancer mutagenesis. These different activities are carried out by different haplotypes of APOBEC3H. Here we studied APOBEC3H haplotype II, which is able to restrict HIV-1 replication and retroelements. We determined how the dimerization mechanism, which is mediated by a double-stranded RNA molecule, influenced interactions with and activity on ssDNA. The data demonstrate that the cellular RNA bound by APOBEC3H does not completely inhibit enzyme activity, in contrast to other APOBEC family members. Despite degradation of the cellular RNA, an approximately 12-nt RNA remains bound to the enzyme, even in the presence of ssDNA. The RNA-mediated dimer is disrupted by mutating W115 on loop 7 or R175 and R176 on helix 6, but this also disrupts protein stability. In contrast, mutation of Y112 and Y113 on loop 7 also destabilizes RNA-mediated dimerization but results in a stable enzyme. Mutants unable to bind cellular RNA are unable to bind RNA oligonucleotides, oligomerize, and deaminate ssDNA in vitro, but ssDNA binding is retained. Comparison of A3H wild type and Y112A/Y113A by fluorescence polarization, single-molecule optical tweezer, and atomic force microscopy experiments demonstrates that RNA-mediated dimerization alters the interactions of A3H with ssDNA and other RNA molecules. Altogether, the biochemical analysis demonstrates that RNA binding is integral to APOBEC3H function.
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50
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Sasaki T, Kudalkar SN, Bertoletti N, Anderson KS. DRONE: Direct Tracking of DNA Cytidine Deamination and Other DNA Modifying Activities. Anal Chem 2018; 90:11735-11740. [PMID: 30256094 PMCID: PMC6410358 DOI: 10.1021/acs.analchem.8b01405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Enzymes that catalyze DNA modifying activities including cytidine deamination and cytosine methylation play important biological roles and have been implicated pathologically in diseases such as cancer. Here, we report Direct Resolution of ONE dalton difference (DRONE), an ultra high performance liquid chromatography (UHPLC)-based analytical method to track a single dalton change in the cytosine-to-uracil conversion catalyzed by the human apolipoprotein B m-RNA editing catalytic polypeptide-like 3 (APOBEC3) cytidine deaminases, implicated in cancer and antiviral defense. Additionally, we demonstrate broad applicability by tracking other important DNA modifications and assessing epigenetic enzyme inhibition. We have extended our methodology to obtain data on two distinct deamination events in the same oligonucleotide substrate designed from a putative APOBEC substrate, diversifying the utility of the described method. DRONE provides an important foundation for in-depth analysis of DNA-modifying enzymes and versatile detection of novel DNA modifications of interest.
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Affiliation(s)
- Tomoaki Sasaki
- Department of Pharmacology, Yale University, 333 Cedar St. SHM B-350 New Haven, CT 06520
| | - Shalley N. Kudalkar
- Department of Pharmacology, Yale University, 333 Cedar St. SHM B-350 New Haven, CT 06520
| | - Nicole Bertoletti
- Department of Pharmacology, Yale University, 333 Cedar St. SHM B-350 New Haven, CT 06520
| | - Karen S. Anderson
- Department of Pharmacology, Yale University, 333 Cedar St. SHM B-350 New Haven, CT 06520
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