1
|
Frezza V, Chellini L, Del Verme A, Paronetto MP. RNA Editing in Cancer Progression. Cancers (Basel) 2023; 15:5277. [PMID: 37958449 PMCID: PMC10648226 DOI: 10.3390/cancers15215277] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/31/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023] Open
Abstract
Coding and noncoding RNA molecules play their roles in ensuring cell function and tissue homeostasis in an ordered and systematic fashion. RNA chemical modifications can occur both at bases and ribose sugar, and, similarly to DNA and histone modifications, can be written, erased, and recognized by the corresponding enzymes, thus modulating RNA activities and fine-tuning gene expression programs. RNA editing is one of the most prevalent and abundant forms of post-transcriptional RNA modification in normal physiological processes. By altering the sequences of mRNAs, it makes them different from the corresponding genomic template. Hence, edited mRNAs can produce protein isoforms that are functionally different from the corresponding genome-encoded variants. Abnormalities in regulatory enzymes and changes in RNA-modification patterns are closely associated with the occurrence and development of various human diseases, including cancer. To date, the roles played by RNA modifications in cancer are gathering increasing interest. In this review, we focus on the role of RNA editing in cancer transformation and provide a new perspective on its impact on tumorigenesis, by regulating cell proliferation, differentiation, invasion, migration, stemness, metabolism, and drug resistance.
Collapse
Affiliation(s)
- Valentina Frezza
- Laboratory of Molecular and Cellular Neurobiology, Fondazione Santa Lucia, CERC, Via del Fosso di Fiorano, 64, 00143 Rome, Italy; (V.F.); (L.C.); (A.D.V.)
| | - Lidia Chellini
- Laboratory of Molecular and Cellular Neurobiology, Fondazione Santa Lucia, CERC, Via del Fosso di Fiorano, 64, 00143 Rome, Italy; (V.F.); (L.C.); (A.D.V.)
| | - Arianna Del Verme
- Laboratory of Molecular and Cellular Neurobiology, Fondazione Santa Lucia, CERC, Via del Fosso di Fiorano, 64, 00143 Rome, Italy; (V.F.); (L.C.); (A.D.V.)
| | - Maria Paola Paronetto
- Laboratory of Molecular and Cellular Neurobiology, Fondazione Santa Lucia, CERC, Via del Fosso di Fiorano, 64, 00143 Rome, Italy; (V.F.); (L.C.); (A.D.V.)
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Piazza Lauro de Bosis, 15, 00135 Rome, Italy
| |
Collapse
|
2
|
Naumann JA, Argyris PP, Carpenter MA, Gupta HB, Chen Y, Temiz NA, Zhou Y, Durfee C, Proehl J, Koniar BL, Conticello SG, Largaespada DA, Brown WL, Aihara H, Vogel RI, Harris RS. DNA Deamination Is Required for Human APOBEC3A-Driven Hepatocellular Carcinoma In Vivo. Int J Mol Sci 2023; 24:9305. [PMID: 37298259 PMCID: PMC10253583 DOI: 10.3390/ijms24119305] [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: 04/28/2023] [Revised: 05/20/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
Although the APOBEC3 family of single-stranded DNA cytosine deaminases is well-known for its antiviral factors, these enzymes are rapidly gaining attention as prominent sources of mutation in cancer. APOBEC3's signature single-base substitutions, C-to-T and C-to-G in TCA and TCT motifs, are evident in over 70% of human malignancies and dominate the mutational landscape of numerous individual tumors. Recent murine studies have established cause-and-effect relationships, with both human APOBEC3A and APOBEC3B proving capable of promoting tumor formation in vivo. Here, we investigate the molecular mechanism of APOBEC3A-driven tumor development using the murine Fah liver complementation and regeneration system. First, we show that APOBEC3A alone is capable of driving tumor development (without Tp53 knockdown as utilized in prior studies). Second, we show that the catalytic glutamic acid residue of APOBEC3A (E72) is required for tumor formation. Third, we show that an APOBEC3A separation-of-function mutant with compromised DNA deamination activity and wildtype RNA-editing activity is defective in promoting tumor formation. Collectively, these results demonstrate that APOBEC3A is a "master driver" that fuels tumor formation through a DNA deamination-dependent mechanism.
Collapse
Affiliation(s)
- Jordan A. Naumann
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (J.A.N.); (P.P.A.); (W.L.B.); (H.A.)
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
| | - Prokopios P. Argyris
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (J.A.N.); (P.P.A.); (W.L.B.); (H.A.)
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
- Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN 55455, USA
- Division of Oral and Maxillofacial Pathology, College of Dentistry, Ohio State University, Columbus, OH 43210, USA
| | - Michael A. Carpenter
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Harshita B. Gupta
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
| | - Yanjun Chen
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
| | - Nuri A. Temiz
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
- Institute for Health Informatics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yufan Zhou
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
| | - Cameron Durfee
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
| | - Joshua Proehl
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
| | - Brenda L. Koniar
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
| | - Silvestro G. Conticello
- Core Research Laboratory, ISPRO, 50139 Florence, Italy;
- Institute of Clinical Physiology, National Research Council, 56124 Pisa, Italy
| | - David A. Largaespada
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
- Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA
| | - William L. Brown
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (J.A.N.); (P.P.A.); (W.L.B.); (H.A.)
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (J.A.N.); (P.P.A.); (W.L.B.); (H.A.)
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
| | - Rachel I. Vogel
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
- Department of Obstetrics, Gynecology, and Women’s Health, University of Minnesota, Minneapolis, MN 55455, USA
| | - Reuben S. Harris
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| |
Collapse
|
3
|
Shilova ON, Tsyba DL, Shilov ES. Mutagenic Activity of AID/APOBEC Deaminases in Antiviral Defense and Carcinogenesis. Mol Biol 2022; 56:46-58. [PMID: 35194245 PMCID: PMC8852905 DOI: 10.1134/s002689332201006x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 04/23/2021] [Accepted: 06/01/2021] [Indexed: 01/02/2023]
Abstract
Proteins of the AID/APOBEC family are capable of cytidine deamination in nucleic acids forming uracil. These enzymes are involved in mRNA editing, protection against viruses, the introduction of point mutations into DNA during somatic hypermutation, and antibody isotype switching. Since these deaminases, especially AID, are potent mutagens, their expression, activity, and specificity are regulated by several intracellular mechanisms. In this review, we discuss the mechanisms of impaired expression and activation of AID/APOBEC proteins in human tumors and their role in carcinogenesis and tumor progression. Also, the diagnostic and potential therapeutic value of increased expression of AID/APOBEC in different types of tumors is analyzed. We assume that in the case of solid tumors, increased expression of endogenous deaminases can serve as a marker of response to immunotherapy since multiple point mutations in host DNA could lead to amino acid substitutions in tumor proteins and thereby increase the frequency of neoepitopes.
Collapse
Affiliation(s)
- O. N. Shilova
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - D. L. Tsyba
- Pavlov First State Medical University, 197022 St. Petersburg, Russia
- Sirius University of Science and Technology, 354340 Sochi, Russia
| | - E. S. Shilov
- Faculty of Biology, Moscow State University, 119234 Moscow, Russia
| |
Collapse
|
4
|
Soleymanjahi S, Blanc V, Davidson N. APOBEC1 mediated C-to-U RNA editing: target sequence and trans-acting factor contribution to 177 RNA editing events in 119 murine transcripts in-vivo. RNA (NEW YORK, N.Y.) 2021; 27:rna.078678.121. [PMID: 34083494 PMCID: PMC8284327 DOI: 10.1261/rna.078678.121] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 05/31/2021] [Indexed: 05/04/2023]
Abstract
Mammalian C-to-U RNA editing was described more than 30 years ago as a single nucleotide modification in small intestinal Apob RNA, later shown to be mediated by the RNA-specific cytidine deaminase APOBEC1. Reports of other examples of C-to-U RNA editing, coupled with the advent of genome-wide transcriptome sequencing, identified an expanded range of APOBEC1 targets. Here we analyze the cis-acting regulatory components of verified murine C-to-U RNA editing targets, including nearest neighbor as well as flanking sequence requirements and folding predictions. RNA secondary structure of the editing cassette was associated with editing frequency and exhibited minimal free energy values comparable to small nuclear RNAs. We summarize findings demonstrating the relative importance of trans-acting factors (A1CF, RBM47) acting in concert with APOBEC1. Co-factor dominance was associated with editing frequency, with RNAs targeted by both RBM47 and A1CF edited at a lower frequency than RBM47 dominant targets. Using this information, we developed a multivariable linear regression model to predict APOBEC1 dependent C-to-U RNA editing efficiency, incorporating factors independently associated with editing frequencies based on 103 Sanger-confirmed editing sites, which accounted for 84% of the observed variance. This model also predicted a composite score for available human C-to-U RNA targets, which again correlated with editing frequency.
Collapse
|
5
|
Destefanis E, Avşar G, Groza P, Romitelli A, Torrini S, Pir P, Conticello SG, Aguilo F, Dassi E. A mark of disease: how mRNA modifications shape genetic and acquired pathologies. RNA (NEW YORK, N.Y.) 2021; 27:367-389. [PMID: 33376192 PMCID: PMC7962492 DOI: 10.1261/rna.077271.120] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
RNA modifications have recently emerged as a widespread and complex facet of gene expression regulation. Counting more than 170 distinct chemical modifications with far-reaching implications for RNA fate, they are collectively referred to as the epitranscriptome. These modifications can occur in all RNA species, including messenger RNAs (mRNAs) and noncoding RNAs (ncRNAs). In mRNAs the deposition, removal, and recognition of chemical marks by writers, erasers and readers influence their structure, localization, stability, and translation. In turn, this modulates key molecular and cellular processes such as RNA metabolism, cell cycle, apoptosis, and others. Unsurprisingly, given their relevance for cellular and organismal functions, alterations of epitranscriptomic marks have been observed in a broad range of human diseases, including cancer, neurological and metabolic disorders. Here, we will review the major types of mRNA modifications and editing processes in conjunction with the enzymes involved in their metabolism and describe their impact on human diseases. We present the current knowledge in an updated catalog. We will also discuss the emerging evidence on the crosstalk of epitranscriptomic marks and what this interplay could imply for the dynamics of mRNA modifications. Understanding how this complex regulatory layer can affect the course of human pathologies will ultimately lead to its exploitation toward novel epitranscriptomic therapeutic strategies.
Collapse
Affiliation(s)
- Eliana Destefanis
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
- The EPITRAN COST Action Consortium, COST Action CA16120
| | - Gülben Avşar
- The EPITRAN COST Action Consortium, COST Action CA16120
- Department of Bioengineering, Gebze Technical University, 41400 Kocaeli, Turkey
| | - Paula Groza
- The EPITRAN COST Action Consortium, COST Action CA16120
- Department of Medical Biosciences, Umeå University, 901 87 Umeå, Sweden
- Wallenberg Center for Molecular Medicine, Umeå University, 901 87 Umeå, Sweden
| | - Antonia Romitelli
- The EPITRAN COST Action Consortium, COST Action CA16120
- Core Research Laboratory, ISPRO-Institute for Cancer Research, Prevention and Clinical Network, 50139 Firenze, Italy
- Department of Medical Biotechnologies, Università di Siena, 53100 Siena, Italy
| | - Serena Torrini
- The EPITRAN COST Action Consortium, COST Action CA16120
- Core Research Laboratory, ISPRO-Institute for Cancer Research, Prevention and Clinical Network, 50139 Firenze, Italy
- Department of Medical Biotechnologies, Università di Siena, 53100 Siena, Italy
| | - Pınar Pir
- The EPITRAN COST Action Consortium, COST Action CA16120
- Department of Bioengineering, Gebze Technical University, 41400 Kocaeli, Turkey
| | - Silvestro G Conticello
- The EPITRAN COST Action Consortium, COST Action CA16120
- Core Research Laboratory, ISPRO-Institute for Cancer Research, Prevention and Clinical Network, 50139 Firenze, Italy
- Institute of Clinical Physiology, National Research Council, 56124 Pisa, Italy
| | - Francesca Aguilo
- The EPITRAN COST Action Consortium, COST Action CA16120
- Department of Medical Biosciences, Umeå University, 901 87 Umeå, Sweden
- Wallenberg Center for Molecular Medicine, Umeå University, 901 87 Umeå, Sweden
| | - Erik Dassi
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
- The EPITRAN COST Action Consortium, COST Action CA16120
| |
Collapse
|
6
|
Kurkowiak M, Arcimowicz Ł, Chruściel E, Urban-Wójciuk Z, Papak I, Keegan L, O'Connell M, Kowalski J, Hupp T, Marek-Trzonkowska N. The effects of RNA editing in cancer tissue at different stages in carcinogenesis. RNA Biol 2021; 18:1524-1539. [PMID: 33593231 PMCID: PMC8582992 DOI: 10.1080/15476286.2021.1877024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
RNA editing is one of the most prevalent and abundant forms of post-transcriptional RNA modification observed in normal physiological processes and often aberrant in diseases including cancer. RNA editing changes the sequences of mRNAs, making them different from the source DNA sequence. Edited mRNAs can produce editing-recoded protein isoforms that are functionally different from the corresponding genome-encoded protein isoforms. The major type of RNA editing in mammals occurs by enzymatic deamination of adenosine to inosine (A-to-I) within double-stranded RNAs (dsRNAs) or hairpins in pre-mRNA transcripts. Enzymes that catalyse these processes belong to the adenosine deaminase acting on RNA (ADAR) family. The vast majority of knowledge on the RNA editing landscape relevant to human disease has been acquired using in vitro cancer cell culture models. The limitation of such in vitro models, however, is that the physiological or disease relevance of results obtained is not necessarily obvious. In this review we focus on discussing in vivo occurring RNA editing events that have been identified in human cancer tissue using samples surgically resected or clinically retrieved from patients. We discuss how RNA editing events occurring in tumours in vivo can identify pathological signalling mechanisms relevant to human cancer physiology which is linked to the different stages of cancer progression including initiation, promotion, survival, proliferation, immune escape and metastasis.
Collapse
Affiliation(s)
- Małgorzata Kurkowiak
- International Centre for Cancer Vaccine Science (ICCVS), University of Gdańsk, Gdańsk, Poland
| | - Łukasz Arcimowicz
- International Centre for Cancer Vaccine Science (ICCVS), University of Gdańsk, Gdańsk, Poland
| | - Elżbieta Chruściel
- International Centre for Cancer Vaccine Science (ICCVS), University of Gdańsk, Gdańsk, Poland
| | - Zuzanna Urban-Wójciuk
- International Centre for Cancer Vaccine Science (ICCVS), University of Gdańsk, Gdańsk, Poland
| | - Ines Papak
- International Centre for Cancer Vaccine Science (ICCVS), University of Gdańsk, Gdańsk, Poland
| | - Liam Keegan
- CEITEC Masaryk University, Brno, CZ, Czech Republic
| | | | - Jacek Kowalski
- International Centre for Cancer Vaccine Science (ICCVS), University of Gdańsk, Gdańsk, Poland.,Department of Pathomorphology, Medical University of Gdańsk, Gdańsk, Poland
| | - Ted Hupp
- International Centre for Cancer Vaccine Science (ICCVS), University of Gdańsk, Gdańsk, Poland.,University of Edinburgh, Edinburgh Cancer Research Centre, Edinburgh, Scotland, UK
| | - Natalia Marek-Trzonkowska
- International Centre for Cancer Vaccine Science (ICCVS), University of Gdańsk, Gdańsk, Poland.,Laboratory of Immunoregulation and Cellular Therapies, Department of Family Medicine, Medical University of Gdańsk, Gdańsk, Poland
| |
Collapse
|
7
|
Potential APOBEC-mediated RNA editing of the genomes of SARS-CoV-2 and other coronaviruses and its impact on their longer term evolution. Virology 2021; 556:62-72. [PMID: 33545556 PMCID: PMC7831814 DOI: 10.1016/j.virol.2020.12.018] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/21/2020] [Accepted: 12/21/2020] [Indexed: 12/19/2022]
Abstract
Members of the APOBEC family of cytidine deaminases show antiviral activities in mammalian cells through lethal editing in the genomes of small DNA viruses, herpesviruses and retroviruses, and potentially those of RNA viruses such as coronaviruses. Consistent with the latter, APOBEC-like directional C→U transitions of genomic plus-strand RNA are greatly overrepresented in SARS-CoV-2 genome sequences of variants emerging during the COVID-19 pandemic. A C→U mutational process may leave evolutionary imprints on coronavirus genomes, including extensive homoplasy from editing and reversion at targeted sites and the occurrence of driven amino acid sequence changes in viral proteins. If sustained over longer periods, this process may account for the previously reported marked global depletion of C and excess of U bases in human seasonal coronavirus genomes. This review synthesizes the current knowledge on APOBEC evolution and function and the evidence of their role in APOBEC-mediated genome editing of SARS-CoV-2 and other coronaviruses. SARS-CoV-2 sequence variants contain an overabundance of C- > U transitions C- > U transitions are the hallmark of the activity of APOBEC cytosine deaminases Further work is needed to determine APOBEC's role in coronavirus evolution
Collapse
|
8
|
Chieca M, Torrini S, Conticello SG. Live-Cell Quantification of APOBEC1-Mediated RNA Editing: A Comparison of RNA Editing Assays. Methods Mol Biol 2021; 2181:69-81. [PMID: 32729075 DOI: 10.1007/978-1-0716-0787-9_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
APOBEC1 is a member of the AID/APOBECs, a group of deaminases responsible for the editing of C>U in both DNA and RNA. APOBEC1 is physiologically involved in C>U RNA editing: while hundreds of targets have been discovered in mice, in humans the only well-characterized target of APOBEC1 is the apolipoprotein B (ApoB) transcript. APOBEC1 edits a CAA codon into a stop codon, which causes the translation of a truncated form of ApoB. A number of assays have been developed to investigate this process. Early assays, poisoned primer extension and Sanger sequencing, have focused on accuracy and sensitivity but rely on extraction of the RNA from tissues and cells. More recently, the need to visualize the RNA editing process directly in live cells have led to the development of fluorescence-based tools. These assays detect RNA editing through reporters whose editing causes a change in cellular localization or a change in fluorescent properties. Here we review the available assays to quantify RNA editing, and we present the protocol for cytofluorimetric analysis using a double-fluorescent reporter.
Collapse
Affiliation(s)
- Martina Chieca
- Core Research Laboratory, ISPRO-Institute for Cancer Research, Prevention and Clinical Network, Firenze, Italy.,Department of Medical Biotechnologies, Università di Siena, Siena, Italy
| | - Serena Torrini
- Core Research Laboratory, ISPRO-Institute for Cancer Research, Prevention and Clinical Network, Firenze, Italy.,Department of Medical Biotechnologies, Università di Siena, Siena, Italy
| | - Silvestro G Conticello
- Core Research Laboratory, ISPRO-Institute for Cancer Research, Prevention and Clinical Network, Firenze, Italy. .,Institute of Clinical Physiology, CNR, Pisa, Italy.
| |
Collapse
|
9
|
Hakata Y, Miyazawa M. Deaminase-Independent Mode of Antiretroviral Action in Human and Mouse APOBEC3 Proteins. Microorganisms 2020; 8:microorganisms8121976. [PMID: 33322756 PMCID: PMC7764128 DOI: 10.3390/microorganisms8121976] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 02/06/2023] Open
Abstract
Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3 (APOBEC3) proteins (APOBEC3s) are deaminases that convert cytosines to uracils predominantly on a single-stranded DNA, and function as intrinsic restriction factors in the innate immune system to suppress replication of viruses (including retroviruses) and movement of retrotransposons. Enzymatic activity is supposed to be essential for the APOBEC3 antiviral function. However, it is not the only way that APOBEC3s exert their biological function. Since the discovery of human APOBEC3G as a restriction factor for HIV-1, the deaminase-independent mode of action has been observed. At present, it is apparent that both the deaminase-dependent and -independent pathways are tightly involved not only in combating viruses but also in human tumorigenesis. Although the deaminase-dependent pathway has been extensively characterized so far, understanding of the deaminase-independent pathway remains immature. Here, we review existing knowledge regarding the deaminase-independent antiretroviral functions of APOBEC3s and their molecular mechanisms. We also discuss the possible unidentified molecular mechanism for the deaminase-independent antiretroviral function mediated by mouse APOBEC3.
Collapse
Affiliation(s)
- Yoshiyuki Hakata
- Department of Immunology, Kindai University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan;
- Correspondence: ; Tel.: +81-72-367-7660
| | - Masaaki Miyazawa
- Department of Immunology, Kindai University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan;
- Kindai University Anti-Aging Center, 3-4-1 Kowakae, Higashiosaka, Osaka 577-8502, Japan
| |
Collapse
|
10
|
Wolfe AD, Li S, Goedderz C, Chen XS. The structure of APOBEC1 and insights into its RNA and DNA substrate selectivity. NAR Cancer 2020; 2:zcaa027. [PMID: 33094286 PMCID: PMC7556403 DOI: 10.1093/narcan/zcaa027] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/05/2020] [Accepted: 09/10/2020] [Indexed: 02/06/2023] Open
Abstract
APOBEC1 (APO1), a member of AID/APOBEC nucleic acid cytosine deaminase family, can edit apolipoprotein B mRNA to regulate cholesterol metabolism. This APO1 RNA editing activity requires a cellular cofactor to achieve tight regulation. However, no cofactors are required for deamination on DNA by APO1 and other AID/APOBEC members, and aberrant deamination on genomic DNA by AID/APOBEC deaminases has been linked to cancer. Here, we present the crystal structure of APO1, which reveals a typical APOBEC deaminase core structure, plus a unique well-folded C-terminal domain that is highly hydrophobic. This APO1 C-terminal hydrophobic domain (A1HD) interacts to form a stable dimer mainly through hydrophobic interactions within the dimer interface to create a four-stranded β-sheet positively charged surface. Structure-guided mutagenesis within this and other regions of APO1 clarified the importance of the A1HD in directing RNA and cofactor interactions, providing insights into the structural basis of selectivity on DNA or RNA substrates.
Collapse
Affiliation(s)
- Aaron D Wolfe
- Genetics, Molecular and Cellular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Shuxing Li
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Cody Goedderz
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Xiaojiang S Chen
- Genetics, Molecular and Cellular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| |
Collapse
|
11
|
Carlaw TM, Zhang LH, Ross CJD. CRISPR/Cas9 Editing: Sparking Discussion on Safety in Light of the Need for New Therapeutics. Hum Gene Ther 2020; 31:794-807. [PMID: 32586150 DOI: 10.1089/hum.2020.111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Recent advances in genome sequencing have greatly improved our ability to understand and identify the causes of genetic diseases. However, there remains an urgent need for innovative, safe, and effective treatments for these diseases. CRISPR-based genome editing systems have become important and powerful tools in the laboratory, and efforts are underway to translate these into patient therapies. Therapeutic base editing is one form of genome engineering that has gained much interest because of its simplicity, specificity, and effectiveness. Base editors are a fusion of a partially deactivated Cas9 enzyme with nickase function, together with a base-modifying enzyme. They are capable of precisely targeting and repairing a pathogenic mutation to restore the normal function of a gene, ideally without disturbing the rest of the genome. In the past year, research has identified new safety concerns of base editors and sparked new innovations to improve their safety. In this review, we provide an overview of the recent advances in the safety and effectiveness of therapeutic base editors and prime editing.
Collapse
Affiliation(s)
| | - Lin-Hua Zhang
- Faculty of Pharmaceutical Sciences; University of British Columbia, Vancouver, Canada
| | - Colin J D Ross
- Faculty of Pharmaceutical Sciences; University of British Columbia, Vancouver, Canada
| |
Collapse
|
12
|
Yang X, Yang J, Liang X, Chen Q, Jiang S, Liu H, Gao Y, Ren Z, Shi YW, Li S, Yu Y, Zhong M, Yang X. Landscape of Dysregulated Placental RNA Editing Associated With Preeclampsia. Hypertension 2020; 75:1532-1541. [DOI: 10.1161/hypertensionaha.120.14756] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Dysregulated RNA editing is well documented in several diseases, such as cancer and neurodegenerative diseases. The extent to which RNA editing might be involved in diseases originated in the placenta remains unknown. Here, we have systematically profiled RNA editome on the placentae, 9 from patients with early-onset severe preeclampsia (EOSPE) and 32 from normal subjects, and a widespread RNA editing dysregulation in EOSPE has been identified. The mis-edited gene set is enriched with known preeclampsia-associated genes and differentially expressed genes in EOSPE. The RNA editing events at 2 microRNA binding sites in 3′-untranslated region of the
LEP
mRNA were generated, which could inhibit the microRNA-induced mRNA downregulation of
LEP
in placenta-derived cell line, consistent with the observation in the placentae of preeclampsia patients. These results demonstrate the association of dysregulated placental RNA editing with preeclampsia, and providing a resource for further study on the role of RNA editing in the pathogenesis of this disease.
Collapse
Affiliation(s)
- Xiaoxue Yang
- From the Center for Genetics and Developmental Systems Biology, Department of Obstetrics and Gynecology, Nanfang Hospital (Xiaoxue Yang, J.Y., X.L., Q.C., S.J., H.L., Y.G., Z.R., Y.Y., M.Z., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
| | - Jing Yang
- From the Center for Genetics and Developmental Systems Biology, Department of Obstetrics and Gynecology, Nanfang Hospital (Xiaoxue Yang, J.Y., X.L., Q.C., S.J., H.L., Y.G., Z.R., Y.Y., M.Z., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
- Key Laboratory of Mental Health of the Ministry of Education (J.Y., Y.G., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
- Department of Bioinformatics, School of Basic Medical Sciences (J.Y., Y.G., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
| | - Xiaozhen Liang
- From the Center for Genetics and Developmental Systems Biology, Department of Obstetrics and Gynecology, Nanfang Hospital (Xiaoxue Yang, J.Y., X.L., Q.C., S.J., H.L., Y.G., Z.R., Y.Y., M.Z., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
| | - Qian Chen
- From the Center for Genetics and Developmental Systems Biology, Department of Obstetrics and Gynecology, Nanfang Hospital (Xiaoxue Yang, J.Y., X.L., Q.C., S.J., H.L., Y.G., Z.R., Y.Y., M.Z., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
| | - Sijia Jiang
- From the Center for Genetics and Developmental Systems Biology, Department of Obstetrics and Gynecology, Nanfang Hospital (Xiaoxue Yang, J.Y., X.L., Q.C., S.J., H.L., Y.G., Z.R., Y.Y., M.Z., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
| | - Haihua Liu
- From the Center for Genetics and Developmental Systems Biology, Department of Obstetrics and Gynecology, Nanfang Hospital (Xiaoxue Yang, J.Y., X.L., Q.C., S.J., H.L., Y.G., Z.R., Y.Y., M.Z., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
| | - Yue Gao
- From the Center for Genetics and Developmental Systems Biology, Department of Obstetrics and Gynecology, Nanfang Hospital (Xiaoxue Yang, J.Y., X.L., Q.C., S.J., H.L., Y.G., Z.R., Y.Y., M.Z., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
- Key Laboratory of Mental Health of the Ministry of Education (J.Y., Y.G., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
- Department of Bioinformatics, School of Basic Medical Sciences (J.Y., Y.G., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
| | - Zhonglu Ren
- From the Center for Genetics and Developmental Systems Biology, Department of Obstetrics and Gynecology, Nanfang Hospital (Xiaoxue Yang, J.Y., X.L., Q.C., S.J., H.L., Y.G., Z.R., Y.Y., M.Z., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
| | - Yi-Wu Shi
- Institute of Neuroscience and Department of Neurology, The Second Affiliated Hospital of Guangzhou Medical University, China (Y.-W.S.)
| | - Sheng Li
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, China (S.L.)
| | - Yanhong Yu
- From the Center for Genetics and Developmental Systems Biology, Department of Obstetrics and Gynecology, Nanfang Hospital (Xiaoxue Yang, J.Y., X.L., Q.C., S.J., H.L., Y.G., Z.R., Y.Y., M.Z., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
| | - Mei Zhong
- From the Center for Genetics and Developmental Systems Biology, Department of Obstetrics and Gynecology, Nanfang Hospital (Xiaoxue Yang, J.Y., X.L., Q.C., S.J., H.L., Y.G., Z.R., Y.Y., M.Z., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
| | - Xinping Yang
- From the Center for Genetics and Developmental Systems Biology, Department of Obstetrics and Gynecology, Nanfang Hospital (Xiaoxue Yang, J.Y., X.L., Q.C., S.J., H.L., Y.G., Z.R., Y.Y., M.Z., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
- Key Laboratory of Mental Health of the Ministry of Education (J.Y., Y.G., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
- Department of Bioinformatics, School of Basic Medical Sciences (J.Y., Y.G., Xinping Yang), Southern Medical University, Guangzhou, Guangdong, China
| |
Collapse
|
13
|
Caval V, Jiao W, Berry N, Khalfi P, Pitré E, Thiers V, Vartanian JP, Wain-Hobson S, Suspène R. Mouse APOBEC1 cytidine deaminase can induce somatic mutations in chromosomal DNA. BMC Genomics 2019; 20:858. [PMID: 31726973 PMCID: PMC6854741 DOI: 10.1186/s12864-019-6216-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 10/22/2019] [Indexed: 02/06/2023] Open
Abstract
Background APOBEC1 (A1) enzymes are cytidine deaminases involved in RNA editing. In addition to this activity, a few A1 enzymes have been shown to be active on single stranded DNA. As two human ssDNA cytidine deaminases APOBEC3A (A3A), APOBEC3B (A3B) and related enzymes across the spectrum of placental mammals have been shown to introduce somatic mutations into nuclear DNA of cancer genomes, we explored the mutagenic threat of A1 cytidine deaminases to chromosomal DNA. Results Molecular cloning and expression of various A1 enzymes reveal that the cow, pig, dog, rabbit and mouse A1 have an intracellular ssDNA substrate specificity. However, among all the enzymes studied, mouse A1 appears to be singular, being able to introduce somatic mutations into nuclear DNA with a clear 5’TpC editing context, and to deaminate 5-methylcytidine substituted DNA which are characteristic features of the cancer related mammalian A3A and A3B enzymes. However, mouse A1 activity fails to elicit formation of double stranded DNA breaks, suggesting that mouse A1 possess an attenuated nuclear DNA mutator phenotype reminiscent of human A3B. Conclusions At an experimental level mouse APOBEC1 is remarkable among 12 mammalian A1 enzymes in that it represents a source of somatic mutations in mouse genome, potentially fueling oncogenesis. While the order Rodentia is bereft of A3A and A3B like enzymes it seems that APOBEC1 may well substitute for it, albeit remaining much less active. This modifies the paradigm that APOBEC3 and AID enzymes are the sole endogenous mutator enzymes giving rise to off-target editing of mammalian genomes.
Collapse
Affiliation(s)
- Vincent Caval
- Molecular Retrovirology Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724, Paris cedex 15, France.
| | - Wenjuan Jiao
- Molecular Retrovirology Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724, Paris cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Noémie Berry
- Molecular Retrovirology Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724, Paris cedex 15, France.,Sorbonne Université, Complexité du Vivant, ED515, 75005, Paris, France
| | - Pierre Khalfi
- Molecular Retrovirology Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724, Paris cedex 15, France.,Sorbonne Université, Complexité du Vivant, ED515, 75005, Paris, France
| | - Emmanuelle Pitré
- Molecular Retrovirology Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724, Paris cedex 15, France.,Sorbonne Université, Complexité du Vivant, ED515, 75005, Paris, France
| | - Valérie Thiers
- Molecular Retrovirology Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724, Paris cedex 15, France
| | - Jean-Pierre Vartanian
- Molecular Retrovirology Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724, Paris cedex 15, France
| | - Simon Wain-Hobson
- Molecular Retrovirology Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724, Paris cedex 15, France
| | - Rodolphe Suspène
- Molecular Retrovirology Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724, Paris cedex 15, France
| |
Collapse
|
14
|
Transcriptome-wide off-target RNA editing induced by CRISPR-guided DNA base editors. Nature 2019; 569:433-437. [PMID: 30995674 DOI: 10.1038/s41586-019-1161-z] [Citation(s) in RCA: 393] [Impact Index Per Article: 78.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 04/09/2019] [Indexed: 12/18/2022]
Abstract
CRISPR-Cas base-editor technology enables targeted nucleotide alterations, and is being increasingly used for research and potential therapeutic applications1,2. The most widely used cytosine base editors (CBEs) induce deamination of DNA cytosines using the rat APOBEC1 enzyme, which is targeted by a linked Cas protein-guide RNA complex3,4. Previous studies of the specificity of CBEs have identified off-target DNA edits in mammalian cells5,6. Here we show that a CBE with rat APOBEC1 can cause extensive transcriptome-wide deamination of RNA cytosines in human cells, inducing tens of thousands of C-to-U edits with frequencies ranging from 0.07% to 100% in 38-58% of expressed genes. CBE-induced RNA edits occur in both protein-coding and non-protein-coding sequences and generate missense, nonsense, splice site, and 5' and 3' untranslated region mutations. We engineered two CBE variants bearing mutations in rat APOBEC1 that substantially decreased the number of RNA edits (by more than 390-fold and more than 3,800-fold) in human cells. These variants also showed more precise on-target DNA editing than the wild-type CBE and, for most guide RNAs tested, no substantial reduction in editing efficiency. Finally, we show that an adenine base editor7 can also induce transcriptome-wide RNA edits. These results have implications for the use of base editors in both research and clinical settings, illustrate the feasibility of engineering improved variants with reduced RNA editing activities, and suggest the need to more fully define and characterize the RNA off-target effects of deaminase enzymes in base editor platforms.
Collapse
|
15
|
Wolfe AD, Arnold DB, Chen XS. Comparison of RNA Editing Activity of APOBEC1-A1CF and APOBEC1-RBM47 Complexes Reconstituted in HEK293T Cells. J Mol Biol 2019; 431:1506-1517. [PMID: 30844405 PMCID: PMC6443457 DOI: 10.1016/j.jmb.2019.02.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/22/2019] [Accepted: 02/23/2019] [Indexed: 12/15/2022]
Abstract
RNA editing is an important form of regulating gene expression and activity. APOBEC1 cytosine deaminase was initially characterized as pairing with a cofactor, A1CF, to form an active RNA editing complex that specifically targets APOB RNA in regulating lipid metabolism. Recent studies revealed that APOBEC1 may be involved in editing other potential RNA targets in a tissue-specific manner, and another protein, RBM47, appears to instead be the main cofactor of APOBEC1 for editing APOB RNA. In this report, by expressing APOBEC1 with either A1CF or RBM47 from human or mouse in an HEK293T cell line with no intrinsic APOBEC1/A1CF/RBM47 expression, we have compared direct RNA editing activity on several known cellular target RNAs. By using a sensitive cell-based fluorescence assay that enables comparative quantification of RNA editing through subcellular localization changes of eGFP, the two APOBEC1 cofactors, A1CF and RBM47, showed clear differences for editing activity on APOB and several other tested RNAs, and clear differences were observed when mouse versus human genes were tested. In addition, we have determined the minimal domain requirement of RBM47 needed for activity. These results provide useful functional characterization of RBM47 and direct biochemical evidence for the differential editing selectivity on a number of RNA targets.
Collapse
Affiliation(s)
- Aaron D Wolfe
- Molecular and Computational Biology, Department 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 90089, USA
| | - Don B Arnold
- Molecular and Computational Biology, Department of Biological Sciences, Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Xiaojiang S Chen
- Molecular and Computational Biology, Department 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 90089, USA; Center of Excellence in NanoBiophysics, University of Southern California, Los Angeles, CA 90089, USA; Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA.
| |
Collapse
|
16
|
Abstract
Expression of genetic information is a multistep process which needs to be tightly regulated. One of the regulatory mechanisms is posttranscriptional modification of RNA, which can alter the stability, expression, or protein composition. Therefore, misregulation of this important cellular process can lead to pathological consequences, such as cancer development. It has been shown that alteration in the expression of certain RNA-modifying genes can promote tumorigenesis. Here, we present a mRNA expression analysis-based approach to comprehensively determine the expression of RNA readers/writers/erasers using DNA damage as an example, and then to validate the effect of altered RNA reader/writer/erasers in regulating the DNA damage response.
Collapse
|
17
|
Lerner T, Papavasiliou FN, Pecori R. RNA Editors, Cofactors, and mRNA Targets: An Overview of the C-to-U RNA Editing Machinery and Its Implication in Human Disease. Genes (Basel) 2018; 10:E13. [PMID: 30591678 PMCID: PMC6356216 DOI: 10.3390/genes10010013] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 12/10/2018] [Accepted: 12/20/2018] [Indexed: 12/22/2022] Open
Abstract
One of the most prevalent epitranscriptomic modifications is RNA editing. In higher eukaryotes, RNA editing is catalyzed by one of two classes of deaminases: ADAR family enzymes that catalyze A-to-I (read as G) editing, and AID/APOBEC family enzymes that catalyze C-to-U. ADAR-catalyzed deamination has been studied extensively. Here we focus on AID/APOBEC-catalyzed editing, and review the emergent knowledge regarding C-to-U editing consequences in the context of human disease.
Collapse
Affiliation(s)
- Taga Lerner
- Division of Immune Diversity, Program in Cancer Immunology, German Cancer Research Centre, 69120 Heidelberg, Germany.
- Division of Biosciences, Uni Heidelberg, 69120 Heidelberg, Germany.
| | - F Nina Papavasiliou
- Division of Immune Diversity, Program in Cancer Immunology, German Cancer Research Centre, 69120 Heidelberg, Germany.
| | - Riccardo Pecori
- Division of Immune Diversity, Program in Cancer Immunology, German Cancer Research Centre, 69120 Heidelberg, Germany.
| |
Collapse
|
18
|
Kung CP, Maggi LB, Weber JD. The Role of RNA Editing in Cancer Development and Metabolic Disorders. Front Endocrinol (Lausanne) 2018; 9:762. [PMID: 30619092 PMCID: PMC6305585 DOI: 10.3389/fendo.2018.00762] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 12/03/2018] [Indexed: 12/26/2022] Open
Abstract
Numerous human diseases arise from alterations of genetic information, most notably DNA mutations. Thought to be merely the intermediate between DNA and protein, changes in RNA sequence were an afterthought until the discovery of RNA editing 30 years ago. RNA editing alters RNA sequence without altering the sequence or integrity of genomic DNA. The most common RNA editing events are A-to-I changes mediated by adenosine deaminase acting on RNA (ADAR), and C-to-U editing mediated by apolipoprotein B mRNA editing enzyme, catalytic polypeptide 1 (APOBEC1). Both A-to-I and C-to-U editing were first identified in the context of embryonic development and physiological homeostasis. The role of RNA editing in human disease has only recently started to be understood. In this review, the impact of RNA editing on the development of cancer and metabolic disorders will be examined. Distinctive functions of each RNA editase that regulate either A-to-I or C-to-U editing will be highlighted in addition to pointing out important regulatory mechanisms governing these processes. The potential of developing novel therapeutic approaches through intervention of RNA editing will be explored. As the role of RNA editing in human disease is elucidated, the clinical utility of RNA editing targeted therapies will be needed. This review aims to serve as a bridge of information between past findings and future directions of RNA editing in the context of cancer and metabolic disease.
Collapse
Affiliation(s)
- Che-Pei Kung
- ICCE Institute, Washington University School of Medicine, Saint Louis, MO, United States
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, Saint Louis, MO, United States
| | - Leonard B. Maggi
- ICCE Institute, Washington University School of Medicine, Saint Louis, MO, United States
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, Saint Louis, MO, United States
| | - Jason D. Weber
- ICCE Institute, Washington University School of Medicine, Saint Louis, MO, United States
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, Saint Louis, MO, United States
- Siteman Cancer Center, Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, United States
| |
Collapse
|
19
|
Salter JD, Smith HC. Modeling the Embrace of a Mutator: APOBEC Selection of Nucleic Acid Ligands. Trends Biochem Sci 2018; 43:606-622. [PMID: 29803538 PMCID: PMC6073885 DOI: 10.1016/j.tibs.2018.04.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/25/2018] [Accepted: 04/30/2018] [Indexed: 12/17/2022]
Abstract
The 11-member APOBEC (apolipoprotein B mRNA editing catalytic polypeptide-like) family of zinc-dependent cytidine deaminases bind to RNA and single-stranded DNA (ssDNA) and, in specific contexts, modify select (deoxy)cytidines to (deoxy)uridines. In this review, we describe advances made through high-resolution co-crystal structures of APOBECs bound to mono- or oligonucleotides that reveal potential substrate-specific binding sites at the active site and non-sequence-specific nucleic acid binding sites distal to the active site. We also discuss the effect of APOBEC oligomerization on functionality. Future structural studies will need to address how ssDNA binding away from the active site may enhance catalysis and the mechanism by which RNA binding may modulate catalytic activity on ssDNA. APOBEC proteins catalyze deamination of cytidine or deoxycytidine in either a sequence-specific or semi-specific manner on either DNA or RNA. APOBECs each possess the cytidine deaminase core fold, but sequence and structural differences among loops surrounding the zinc-dependent active site impart differences in sequence-dependent target preferences, binding affinity, catalytic rate, and regulation of substrate access to the active site among the 11 family members. APOBECs also regulate the deamination reaction through additional nucleic acid substrate binding sites located within surface grooves or patches of positive electrostatic potential that are distal to the active site but may do so nonspecifically. Binding of nonsubstrate RNA and RNA-mediated oligomerization by APOBECs that deaminate ssDNA downregulates catalytic activity but also controls APOBEC subcellular or virion localization. The presence of a second, though noncatalytic, cytidine deaminase domain for some APOBECs and the ability of some APOBECs to oligomerize add additional molecular surfaces for positive or negative regulation of catalysis through nucleic acid binding.
Collapse
Affiliation(s)
- Jason D Salter
- OyaGen, Inc., 77 Ridgeland Road, Rochester, NY 14623, USA.
| | - Harold C Smith
- OyaGen, Inc., 77 Ridgeland Road, Rochester, NY 14623, USA; University of Rochester, School of Medicine and Dentistry, Department of Biochemistry and Biophysics, 601 Elmwood Avenue, Rochester, NY 14642, USA.
| |
Collapse
|
20
|
Baysal BE, Sharma S, Hashemikhabir S, Janga SC. RNA Editing in Pathogenesis of Cancer. Cancer Res 2017; 77:3733-3739. [DOI: 10.1158/0008-5472.can-17-0520] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 04/27/2017] [Accepted: 05/22/2017] [Indexed: 11/16/2022]
|
21
|
Way GP, Allaway RJ, Bouley SJ, Fadul CE, Sanchez Y, Greene CS. A machine learning classifier trained on cancer transcriptomes detects NF1 inactivation signal in glioblastoma. BMC Genomics 2017; 18:127. [PMID: 28166733 PMCID: PMC5292791 DOI: 10.1186/s12864-017-3519-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 01/26/2017] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND We have identified molecules that exhibit synthetic lethality in cells with loss of the neurofibromin 1 (NF1) tumor suppressor gene. However, recognizing tumors that have inactivation of the NF1 tumor suppressor function is challenging because the loss may occur via mechanisms that do not involve mutation of the genomic locus. Degradation of the NF1 protein, independent of NF1 mutation status, phenocopies inactivating mutations to drive tumors in human glioma cell lines. NF1 inactivation may alter the transcriptional landscape of a tumor and allow a machine learning classifier to detect which tumors will benefit from synthetic lethal molecules. RESULTS We developed a strategy to predict tumors with low NF1 activity and hence tumors that may respond to treatments that target cells lacking NF1. Using RNAseq data from The Cancer Genome Atlas (TCGA), we trained an ensemble of 500 logistic regression classifiers that integrates mutation status with whole transcriptomes to predict NF1 inactivation in glioblastoma (GBM). On TCGA data, the classifier detected NF1 mutated tumors (test set area under the receiver operating characteristic curve (AUROC) mean = 0.77, 95% quantile = 0.53 - 0.95) over 50 random initializations. On RNA-Seq data transformed into the space of gene expression microarrays, this method produced a classifier with similar performance (test set AUROC mean = 0.77, 95% quantile = 0.53 - 0.96). We applied our ensemble classifier trained on the transformed TCGA data to a microarray validation set of 12 samples with matched RNA and NF1 protein-level measurements. The classifier's NF1 score was associated with NF1 protein concentration in these samples. CONCLUSIONS We demonstrate that TCGA can be used to train accurate predictors of NF1 inactivation in GBM. The ensemble classifier performed well for samples with very high or very low NF1 protein concentrations but had mixed performance in samples with intermediate NF1 concentrations. Nevertheless, high-performing and validated predictors have the potential to be paired with targeted therapies and personalized medicine.
Collapse
Affiliation(s)
- Gregory P. Way
- Genomics and Computational Biology Graduate Program, University of Pennsylvania, Philadelphia, PA USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, 10-131 SCTR 34th and Civic Center Blvd, Philadelphia, PA 19104 USA
| | - Robert J. Allaway
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Dartmouth College, HB 7650, Hanover, NH 03755 USA
| | - Stephanie J. Bouley
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Dartmouth College, HB 7650, Hanover, NH 03755 USA
| | - Camilo E. Fadul
- Department of Neurology, University of Virginia, Charlottesville, VA USA
| | - Yolanda Sanchez
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Dartmouth College, HB 7650, Hanover, NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH USA
| | - Casey S. Greene
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, 10-131 SCTR 34th and Civic Center Blvd, Philadelphia, PA 19104 USA
| |
Collapse
|
22
|
Schaefermeier P, Heinze S. Hippocampal Characteristics and Invariant Sequence Elements Distribution of GLRA2 and GLRA3 C-to-U Editing. Mol Syndromol 2016; 8:85-92. [PMID: 28611548 DOI: 10.1159/000453300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2016] [Indexed: 11/19/2022] Open
Abstract
Glycine receptor α2 and α3 subunit (GLRA2/GLRA3) high-affinity variants, of which the subjacent amino acid substitutions issue from C-to-U RNA editing, are thought to influence tonic inhibition and pathophysiology. In light of the detection of GLRA3 NM_006529:r.1157C>U and GLRA2 NM_002063:r.1416C>U exchanges in hippocampus explants of temporal lobe epilepsy patients, we now examine the healthy situation and relate it to the epileptic situation by ascertaining controls in a legitimate reanalysis. The GLRA2 and GLRA3 editing events that would ultimately result in a glycine receptor with increased affinity occur in the postmortem nonepileptic hippocampus. Most notably, their relative amounts do not significantly differ from those in increased damaged hippocampus explants, whereas curbed relative amounts in epileptic explants without cell loss come out statistically significant. Local sequence alignment reveals invariant sequence stretches consistent in GLRA2/ GLRA3 and other edited transcripts that coincide with known APOB sequence elements. Concerning the essential mooring element, GLRA2/GLRA3 comply strictly only with the motif's 5' part. While this lack of canonical mooring elements and uncertain action of the famous deaminase APOBEC1 suggest a specific regulation of GLRA2/GLRA3 editing, its reduction in the less-damaged epileptic hippocampus could be attributed to anomalous epileptic neurogenesis.
Collapse
Affiliation(s)
- Philipp Schaefermeier
- Charité University Medicine Berlin, Germany,Helmholtz Group RNA Editing and Hyperexcitability Disorders, Max-Delbrück-Centre for Molecular Medicine, Berlin, Germany
| | - Sarah Heinze
- Institute of Forensic Sciences and Legal Medicine, Charité Berlin, Berlin, Germany,Klinikum Oldenburg gGmbH, Oldenburg, Germany,Institute of Forensic Medicine, Johannes Gutenberg University of Mainz, Mainz, Germany
| |
Collapse
|
23
|
Abstract
Apolipoprotein B mRNA Editing Catalytic Polypeptide-like 1 or APOBEC1 was discovered in 1993 as the zinc-dependent cytidine deaminase responsible for the production of an in frame stop codon in apoB mRNA through modification of cytidine at nucleotide position 6666 to uridine. At the time of this discovery there was much speculation concerning the mechanism of base modification RNA editing which has been rekindled by the discovery of multiple C to U RNA editing events in the 3′ UTRs of mRNAs and the finding that other members of the APOBEC family while able to bind RNA, have the biological function of being DNA mutating enzymes. Current research is addressing the mechanism for these nucleotide modification events that appear not to adhere to the mooring sequence-dependent model for APOBEC1 involving the assembly of a multi protein containing editosome. This review will summarize our current understanding of the structure and function of APOBEC proteins and examine how RNA binding to them may be a regulatory mechanism.
Collapse
Affiliation(s)
- Harold C Smith
- a University of Rochester, School of Medicine and Dentistry , Department of Biochemistry and Biophysics , Rochester , NY , USA
| |
Collapse
|
24
|
Abstract
The AID/APOBEC family enzymes convert cytosines in single-stranded DNA to uracils, causing base substitutions and strand breaks. They are induced by cytokines produced during the body's inflammatory response to infections, and they help combat infections through diverse mechanisms. AID is essential for the maturation of antibodies and causes mutations and deletions in antibody genes through somatic hypermutation (SHM) and class-switch recombination (CSR) processes. One member of the APOBEC family, APOBEC1, edits mRNA for a protein involved in lipid transport. Members of the APOBEC3 subfamily in humans (APOBEC3A, APOBEC3B, APOBEC3C, APOBEC3D, APOBEC3F, APOBEC3G, and APOBEC3H) inhibit infections of viruses such as HIV-1, HBV, and HCV, and retrotransposition of endogenous retroelements through mutagenic and nonmutagenic mechanisms. There is emerging consensus that these enzymes can cause mutations in the cellular genome at replication forks or within transcription bubbles depending on the physiological state of the cell and the phase of the cell cycle during which they are expressed. We describe here the state of knowledge about the structures of these enzymes, regulation of their expression, and both the advantageous and deleterious consequences of their expression, including carcinogenesis. We highlight similarities among them and present a holistic view of their regulation and function.
Collapse
Affiliation(s)
- Sachini U Siriwardena
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
| | - Kang Chen
- Department of Obstetrics and Gynecology, Wayne State University , Detroit, Michigan 48201, United States
- Mucosal Immunology Studies Team, National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
- Department of Immunology and Microbiology, Wayne State University School of Medicine , Detroit, Michigan 48201, United States
| | - Ashok S Bhagwat
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
- Department of Immunology and Microbiology, Wayne State University School of Medicine , Detroit, Michigan 48201, United States
| |
Collapse
|
25
|
The APOBEC Protein Family: United by Structure, Divergent in Function. Trends Biochem Sci 2016; 41:578-594. [PMID: 27283515 DOI: 10.1016/j.tibs.2016.05.001] [Citation(s) in RCA: 251] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 04/28/2016] [Accepted: 05/03/2016] [Indexed: 12/13/2022]
Abstract
The APOBEC (apolipoprotein B mRNA editing catalytic polypeptide-like) family of proteins have diverse and important functions in human health and disease. These proteins have an intrinsic ability to bind to both RNA and single-stranded (ss) DNA. Both function and tissue-specific expression varies widely for each APOBEC protein. We are beginning to understand that the activity of APOBEC proteins is regulated through genetic alterations, changes in their transcription and mRNA processing, and through their interactions with other macromolecules in the cell. Loss of cellular control of APOBEC activities leads to DNA hypermutation and promiscuous RNA editing associated with the development of cancer or viral drug resistance, underscoring the importance of understanding how APOBEC proteins are regulated.
Collapse
|
26
|
Polevoda B, McDougall WM, Bennett RP, Salter JD, Smith HC. Structural and functional assessment of APOBEC3G macromolecular complexes. Methods 2016; 107:10-22. [PMID: 26988126 DOI: 10.1016/j.ymeth.2016.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 12/20/2022] Open
Abstract
There are eleven members in the human APOBEC family of proteins that are evolutionarily related through their zinc-dependent cytidine deaminase domains. The human APOBEC gene clusters arose on chromosome 6 and 22 through gene duplication and divergence to where current day APOBEC proteins are functionally diverse and broadly expressed in tissues. APOBEC serve enzymatic and non enzymatic functions in cells. In both cases, formation of higher-order structures driven by APOBEC protein-protein interactions and binding to RNA and/or single stranded DNA are integral to their function. In some circumstances, these interactions are regulatory and modulate APOBEC activities. We are just beginning to understand how macromolecular interactions drive processes such as APOBEC subcellular compartmentalization, formation of holoenzyme complexes, gene targeting, foreign DNA restriction, anti-retroviral activity, formation of ribonucleoprotein particles and APOBEC degradation. Protein-protein and protein-nucleic acid cross-linking methods coupled with mass spectrometry, electrophoretic mobility shift assays, glycerol gradient sedimentation, fluorescence anisotropy and APOBEC deaminase assays are enabling mapping of interacting surfaces that are essential for these functions. The goal of this methods review is through example of our research on APOBEC3G, describe the application of cross-linking methods to characterize and quantify macromolecular interactions and their functional implications. Given the homology in structure and function, it is proposed that these methods will be generally applicable to the discovery process for other APOBEC and RNA and DNA editing and modifying proteins.
Collapse
Affiliation(s)
- Bogdan Polevoda
- Department of Biochemistry and Biophysics, University of Rochester, School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - William M McDougall
- Department of Biochemistry and Biophysics, University of Rochester, School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Ryan P Bennett
- OyaGen, Inc, Rochester BioVenture Center, 77 Ridgeland Road, Rochester, NY 14623, USA
| | - Jason D Salter
- OyaGen, Inc, Rochester BioVenture Center, 77 Ridgeland Road, Rochester, NY 14623, USA
| | - Harold C Smith
- Department of Biochemistry and Biophysics, University of Rochester, School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA; Wilmot Cancer Institute, 601 Elmwood Avenue, Rochester, NY 14642, USA; Center for RNA Biology, 601 Elmwood Avenue, Rochester, NY 14642, USA; OyaGen, Inc, Rochester BioVenture Center, 77 Ridgeland Road, Rochester, NY 14623, USA; Center for AIDS Research, 601 Elmwood Avenue, Rochester, NY 14642, USA.
| |
Collapse
|
27
|
Severi F, Conticello SG. Flow-cytometric visualization of C>U mRNA editing reveals the dynamics of the process in live cells. RNA Biol 2016; 12:389-97. [PMID: 25806564 PMCID: PMC4615904 DOI: 10.1080/15476286.2015.1026033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
APOBEC1 is the catalytic subunit of the complex that edits ApolipoproteinB (ApoB) mRNA, which specifically deaminates cytidine 6666 to uracil in the human transcript. The editing leads to the generation of a stop codon, resulting in the synthesis of a truncated form of ApoB. We have developed a method to quantitatively assay ApoB RNA editing in live cells by using a double fluorescent mCherry-EGFP chimera containing a ∼300bp fragment encompassing the region of ApoB subject to RNA editing. Coexpression of APOBEC1 together with this chimera causes specific RNA editing of the ApoB fragment. The insertion of a stop codon between the mCherry and EGFP thus induces the loss of EGFP fluorescence. Using this method we analyze the dynamics of APOBEC1-dependent RNA editing under various conditions. Namely we show the interplay of APOBEC1 with known interactors (ACF, hnRNP-C1, GRY-RBP) in cells that are RNA editing-proficient (HuH-7) or -deficient (HEK-293T), and the effects of restricted cellular localization of APOBEC1 on the efficiency of the editing. Furthermore, our approach is effective in assaying the induction of RNA editing in Caco-2, a cellular model physiologically capable of ApoB RNA editing.
Collapse
Key Words
- ACF, APOBEC1 Complementation Factor
- ADAR, Adenosine Deaminase, RNA-specific
- ADAT, Adenosine Deaminase, tRNA-specific
- AID/APOBECs
- APOBEC1, Apolipoprotein B mRNA editing enzyme, catalytic polypeptide 1
- ApoB, Apolipoprotein B
- EGFP, Enhanced Green Fluorescent Protein
- FACS, Fluorescence activated cell sorting
- FBS, Fetal bovine serum
- GRY-RBP, Glycine-Arginine-Tyrosine-rich RNA-binding protein
- RBM47, RNA binding motif protein 47
- RNA editing
- cds, coding sequence
- cytosine deaminase
- hnRNP-C1, heterogeneous nuclear ribonucleoprotein C1
- lipid metabolism
- mRNA
- post-transcriptional modification
Collapse
Affiliation(s)
- Francesco Severi
- a Core Research Laboratory; Istituto Toscano Tumori ; Firenze , Italy
| | | |
Collapse
|
28
|
Saraconi G, Severi F, Sala C, Mattiuz G, Conticello SG. The RNA editing enzyme APOBEC1 induces somatic mutations and a compatible mutational signature is present in esophageal adenocarcinomas. Genome Biol 2014; 15:417. [PMID: 25085003 PMCID: PMC4144122 DOI: 10.1186/s13059-014-0417-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 07/17/2014] [Indexed: 12/20/2022] Open
Abstract
Background The AID/APOBECs are deaminases that act on cytosines in a diverse set of pathways and some of them have been linked to the onset of genetic alterations in cancer. Among them, APOBEC1 is the only family member to physiologically target RNA, as the catalytic subunit in the Apolipoprotein B mRNA editing complex. APOBEC1 has been linked to cancer development in mice but its oncogenic mechanisms are not yet well understood. Results We analyze whether expression of APOBEC1 induces a mutator phenotype in vertebrate cells, likely through direct targeting of genomic DNA. We show its ability to increase the inactivation of a stably inserted reporter gene in a chicken cell line that lacks any other AID/APOBEC proteins, and to increase the number of imatinib-resistant clones in a human cellular model for chronic myeloid leukemia through induction of mutations in the BCR-ABL1 fusion gene. Moreover, we find the presence of an AID/APOBEC mutational signature in esophageal adenocarcinomas, a type of tumor where APOBEC1 is expressed, that mimics the one preferred by APOBEC1 in vitro. Conclusions Our findings suggest that the ability of APOBEC1 to trigger genetic alterations represents a major layer in its oncogenic potential. Such APOBEC1-induced mutator phenotypes could play a role in the onset of esophageal adenocarcinomas. APOBEC1 could be involved in cancer promotion at the very early stages of carcinogenesis, as it is highly expressed in Barrett's esophagus, a condition often associated with esophageal adenocarcinoma. Electronic supplementary material The online version of this article (doi:10.1186/s13059-014-0417-z) contains supplementary material, which is available to authorized users.
Collapse
|
29
|
Prohaska KM, Bennett RP, Salter JD, Smith HC. The multifaceted roles of RNA binding in APOBEC cytidine deaminase functions. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:493-508. [PMID: 24664896 DOI: 10.1002/wrna.1226] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 02/13/2014] [Accepted: 02/13/2014] [Indexed: 01/06/2023]
Abstract
Cytidine deaminases have important roles in the regulation of nucleoside/deoxynucleoside pools for DNA and RNA synthesis. The APOBEC family of cytidine deaminases (named after the first member of the family that was described, Apolipoprotein B mRNA Editing Catalytic Subunit 1, also known as APOBEC1 or A1) is a fascinating group of mutagenic proteins that use RNA and single-stranded DNA (ssDNA) as substrates for their cytidine or deoxycytidine deaminase activities. APOBEC proteins and base-modification nucleic acid editing have been the subject of numerous publications, reviews, and speculation. These proteins play diverse roles in host cell defense, protecting cells from invading genetic material, enabling the acquired immune response to antigens and changing protein expression at the level of the genetic code in mRNA or DNA. The amazing power these proteins have for interphase cell functions relies on structural and biochemical properties that are beginning to be understood. At the same time, the substrate selectivity of each member in the family and their regulation remains to be elucidated. This review of the APOBEC family will focus on an open question in regulation, namely what role the interactions of these proteins with RNA have in editing substrate recognition or allosteric regulation of DNA mutagenic and host-defense activities.
Collapse
|
30
|
Baysal BE, De Jong K, Liu B, Wang J, Patnaik SK, Wallace PK, Taggart RT. Hypoxia-inducible C-to-U coding RNA editing downregulates SDHB in monocytes. PeerJ 2013; 1:e152. [PMID: 24058882 PMCID: PMC3775634 DOI: 10.7717/peerj.152] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 08/14/2013] [Indexed: 12/30/2022] Open
Abstract
Background. RNA editing is a post-transcriptional regulatory mechanism that can alter the coding sequences of certain genes in response to physiological demands. We previously identified C-to-U RNA editing (C136U, R46X) which inactivates a small fraction of succinate dehydrogenase (SDH; mitochondrial complex II) subunit B gene (SDHB) mRNAs in normal steady-state peripheral blood mononuclear cells (PBMCs). SDH is a heterotetrameric tumor suppressor complex which when mutated causes paraganglioma tumors that are characterized by constitutive activation of hypoxia inducible pathways. Here, we studied regulation, extent and cell type origin of SDHB RNA editing. Methods. We used short-term cultured PBMCs obtained from random healthy platelet donors, performed monocyte enrichment by cold aggregation, employed a novel allele-specific quantitative PCR method, flow cytometry, immunologic cell separation, gene expression microarray, database analysis and high-throughput RNA sequencing. Results. While the editing rate is low in uncultured monocyte-enriched PBMCs (average rate 2.0%, range 0.4%-6.3%, n = 42), it is markedly upregulated upon exposure to 1% oxygen tension (average rate 18.2%, range 2.8%-49.4%, n = 14) and during normoxic macrophage differentiation in the presence of serum (average rate 10.1%, range 2.7%-18.8%, n = 17). The normoxic induction of SDHB RNA editing was associated with the development of dense adherent aggregates of monocytes in culture. CD14-positive monocyte isolation increased the percentages of C136U transcripts by 1.25-fold in normoxic cultures (n = 5) and 1.68-fold in hypoxic cultures (n = 4). CD14-negative lymphocytes showed no evidence of SDHB editing. The SDHB genomic DNA remained wild-type during increased RNA editing. Microarray analysis showed expression changes in wound healing and immune response pathway genes as the editing rate increased in normoxic cultures. High-throughput sequencing of SDHB and SDHD transcripts confirmed the induction of C136U RNA editing in normoxic cultures but showed no additional verifiable coding edits. Analysis of SDHB RNA sequence data from 16 normal human tissues from the Illumina Body Map and from 45 samples representing 23 different cell types from the ENCODE projects confirmed the occurrence of site-specific C136U editing in whole blood (1.7%) and two primary CD14+ monocyte samples (1.9% and 2.6%). In contrast, the other cell types showed an average of 0.2% and 0.1% C136U editing rates in the two databases, respectively. Conclusions. These findings demonstrate that C-to-U coding RNA editing of certain genes is dynamically induced by physiologically relevant environmental factors and suggest that epigenetic downregulation of SDHB by site-specific RNA editing plays a role in hypoxia adaptation in monocytes.
Collapse
Affiliation(s)
- Bora E Baysal
- Departments of Pathology and Laboratory Medicine, Roswell Park Cancer Institute , Buffalo, NY , USA
| | | | | | | | | | | | | |
Collapse
|
31
|
Abstract
Organisms minimize genetic damage through complex pathways of DNA repair. Yet a gene family--the AID/APOBECs--has evolved in vertebrates with the sole purpose of producing targeted damage in DNA/RNA molecules through cytosine deamination. They likely originated from deaminases involved in A>I editing in tRNAs. AID, the archetypal AID/APOBEC, is the trigger of the somatic diversification processes of the antibody genes. Its homologs may have been associated with the immune system even before the evolution of the antibody genes. The APOBEC3s, arising from duplication of AID, are involved in the restriction of exogenous/endogenous threats such as retroviruses and mobile elements. Another family member, APOBEC1, has (re)acquired the ability to target RNA while maintaining its ability to act on DNA. The AID/APOBECs have shaped the evolution of vertebrate genomes, but their ability to mutate nucleic acids is a double-edged sword: AID is a key player in lymphoproliferative diseases by triggering mutations and chromosomal translocations in B cells, and there is increasing evidence suggesting that other AID/APOBECs could be involved in cancer development as well.
Collapse
|
32
|
Koito A, Ikeda T. Apolipoprotein B mRNA-editing, catalytic polypeptide cytidine deaminases and retroviral restriction. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 3:529-41. [PMID: 22549984 DOI: 10.1002/wrna.1117] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Apolipoprotein B (apo B) messenger RNA (mRNA)-editing, catalytic polypeptide (APOBEC) cytidine deaminases (CDAs), which can insert mutations into DNA and/or RNA as a result of their ability to deaminate cytidine (C) to uridine (U), originated from a branch of the zinc-dependent deaminase superfamily at the beginning of vertebrate radiation. The ability of mammalian CDAs encoded by the APOBEC3 genes to restrict a broad number of endogenous retroelements and exogenous retroviruses, including human immunodeficiency virus-1, is well established. Furthermore, APOBEC1 from a variety of mammalian species, which mediates the C-to-U deamination of apo B mRNA, a protein involved in lipid transport, also has a role in controlling mobile elements. A large portion of the mammalian genome is derived from ancient transposable elements. Retroelements, transported by an intracellular copy-and-paste process involving an RNA intermediate, constitute the majority of these mobile genetic elements. Endogenous retroviruses are long-terminal repeat (LTR)-type retroelements that account for approximately 10% of human and murine genomic DNA. Non-LTR members are present in extremely high copy numbers, with approximately 40% of the human and murine genomes consisting of long-interspersed nuclear element-1 (L1). These L1 elements modify mammalian genomes not only through insertions but also by the indirect replication of non-autonomous retrotransposons. As expected, vertebrate intrinsic immunity has evolved to support a balance between retroelement insertions that cause deleterious gene disruptions and those that confer beneficial genetic diversity. This review discusses the current understanding of the mechanism of action of APOBEC CDAs and their role in controlling retroviruses and retroelements.
Collapse
Affiliation(s)
- Atsushi Koito
- Department of Retrovirology and Self-Defense, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
| | | |
Collapse
|
33
|
Smith HC, Bennett RP, Kizilyer A, McDougall WM, Prohaska KM. Functions and regulation of the APOBEC family of proteins. Semin Cell Dev Biol 2011; 23:258-68. [PMID: 22001110 DOI: 10.1016/j.semcdb.2011.10.004] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 09/30/2011] [Accepted: 10/03/2011] [Indexed: 10/16/2022]
Abstract
APOBEC1 is a cytidine deaminase that edits messenger RNAs and was the first enzyme in the APOBEC family to be functionally characterized. Under appropriate conditions APOBEC1 also deaminates deoxycytidine in single-stranded DNA (ssDNA). The other ten members of the APOBEC family have not been fully characterized however several have deoxycytidine deaminase activity on ssDNAs. Despite the nucleic acid substrate preferences of different APOBEC proteins, a common feature appears to be their intrinsic ability to bind to RNA as well as to ssDNA. RNA binding to APOBEC proteins together with protein-protein interactions, post-translation modifications and subcellular localization serve as biological modulators controlling the DNA mutagenic activity of these potentially genotoxic proteins.
Collapse
Affiliation(s)
- Harold C Smith
- Department of Biochemistry and Biophysics, University of Rochester, School of Medicine and Dentistry, Rochester, NY 14642, USA.
| | | | | | | | | |
Collapse
|
34
|
Wu J, Xie F, Qian K, Gibson AW, Edberg JC, Kimberly RP. FAS mRNA editing in Human Systemic Lupus Erythematosus. Hum Mutat 2011; 32:1268-77. [PMID: 21793106 DOI: 10.1002/humu.21565] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 06/22/2011] [Indexed: 01/29/2023]
Abstract
FAS/FASL system plays a central role in maintaining peripheral immune tolerance. Human Systematic Lupus Erythematosus (SLE) is a prototypic systemic autoimmune disease characterized by expansion of autoreactive lymphocytes. It remains unclear whether a defective FAS/FASL system is involved in the pathogenesis of SLE. In this study, we have discovered a novel nucleotide insertion in FAS mRNA. We demonstrate that this novel FAS mutation occurs at mRNA levels, likely through a site-specific mRNA editing process. The mRNA editing mutation is unique for human FAS because the similar mRNA editing event is absent in other human TNF receptor (TNFR) family genes with death domains (DR5, DR6, and TNFR1) and in murine FAS. The adenine insertion mutation in the coding region message causes the alteration of human FAS mRNA reading frame. Functionally, cells expressing the edited FAS (edFAS) were refractory to FAS-mediated apoptosis. Surprisingly, cells from SLE patients produced significantly more edFAS products compared to cells from normal healthy controls. Additionally, we demonstrated that persistent engagement of T-cell receptor increases human FAS mRNA editing in human T cells. Our data suggest that the site-specific FAS mRNA editing mutation may play a critical role in human immune responses and in the pathogenesis of human chronic inflammatory diseases.
Collapse
Affiliation(s)
- Jianming Wu
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota 55108, USA.
| | | | | | | | | | | |
Collapse
|
35
|
Knoop V. When you can't trust the DNA: RNA editing changes transcript sequences. Cell Mol Life Sci 2011; 68:567-86. [PMID: 20938709 PMCID: PMC11114842 DOI: 10.1007/s00018-010-0538-9] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 09/13/2010] [Accepted: 09/23/2010] [Indexed: 12/25/2022]
Abstract
RNA editing describes targeted sequence alterations in RNAs so that the transcript sequences differ from their DNA template. Since the original discovery of RNA editing in trypanosomes nearly 25 years ago more than a dozen such processes of nucleotide insertions, deletions, and exchanges have been identified in evolutionarily widely separated groups of the living world including plants, animals, fungi, protists, bacteria, and viruses. In many cases gene expression in mitochondria is affected, but RNA editing also takes place in chloroplasts and in nucleocytosolic genetic environments. While some RNA editing systems largely seem to repair defect genes (cryptogenes), others have obvious functions in modulating gene activities. The present review aims for an overview on the current states of research in the different systems of RNA editing by following a historic timeline along the respective original discoveries.
Collapse
Affiliation(s)
- Volker Knoop
- Abteilung Molekulare Evolution, Institut für Zelluläre und Molekulare Botanik (IZMB), Bonn, Germany.
| |
Collapse
|
36
|
Transcriptome-wide sequencing reveals numerous APOBEC1 mRNA-editing targets in transcript 3' UTRs. Nat Struct Mol Biol 2011; 18:230-6. [PMID: 21258325 PMCID: PMC3075553 DOI: 10.1038/nsmb.1975] [Citation(s) in RCA: 181] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 11/10/2010] [Indexed: 12/23/2022]
Abstract
Apolipoprotein B-editing enzyme, catalytic polypeptide-1 (APOBEC1) is a cytidine deaminase, initially identified by its activity in converting a specific cytidine (C) to uridine (U) in apolipoprotein B (apoB) mRNA transcripts in the small intestine. Editing results in translation of a truncated apoB isoform with distinct functions in lipid transport. To address the possibility that APOBEC1 edits additional mRNAs, we developed a transcriptome-wide comparative RNA-Seq screen. We identified and validated 32 previously undescribed mRNA targets of APOBEC1 editing, all of which are located in AU-rich segments of transcript 3′ untranslated regions (3′ UTRs). Further analysis established several characteristic sequence features of editing targets, which were predictive for the identification of additional APOBEC1 substrates. The transcriptomics approach to RNA editing presented here dramatically expands the list of APOBEC1 mRNA editing targets and reveals a novel cellular mechanism for the modification of transcript 3′ UTRs.
Collapse
|
37
|
Blanc V, Davidson NO. APOBEC-1-mediated RNA editing. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 2:594-602. [PMID: 20836050 DOI: 10.1002/wsbm.82] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
RNA editing defines a molecular process by which a nucleotide sequence is modified in the RNA transcript and results in an amino acid change in the recoded message from that specified in the gene. We will restrict our attention to the type of RNA editing peculiar to mammals, i.e., nuclear C to U RNA editing. This category of RNA editing contrasts with RNA modifications described in plants, i.e., organellar RNA editing (reviewed in Ref 1). Mammalian RNA editing is genetically and biochemically classified into two groups, namely insertion-deletional and substitutional. Substitutional RNA editing is exclusive to mammals, again with two types reported, namely adenosine to inosine and cytosine to uracil (C to U). This review will examine mammalian C to U RNA editing of apolipoproteinB (apoB) RNA and the role of the catalytic deaminase Apobec-1. We will speculate on the functions of Apobec-1 beyond C to U RNA editing as implied from its ability to bind AU-rich RNAs and discuss evidence that dysregulation of Apobec-1 expression might be associated with carcinogenesis through aberrant RNA editing or altered RNA stability.
Collapse
Affiliation(s)
- Valerie Blanc
- Division of Gastroenterology, Washington University School of Medicine, St. Louis, MO 63105, USA
| | - Nicholas O Davidson
- Division of Gastroenterology, Washington University School of Medicine, St. Louis, MO 63105, USA
| |
Collapse
|
38
|
Chai G, Liu N, Ma J, Li H, Oblinger JL, Prahalad AK, Gong M, Chang LS, Wallace M, Muir D, Guha A, Phipps RJ, Hock JM, Yu X. MicroRNA-10b regulates tumorigenesis in neurofibromatosis type 1. Cancer Sci 2010; 101:1997-2004. [PMID: 20550523 PMCID: PMC11159772 DOI: 10.1111/j.1349-7006.2010.01616.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
MicroRNAs (miRNAs) are frequently deregulated in human tumors, and play important roles in tumor development and progression. The pathological roles of miRNAs in neurofibromatosis type 1 (NF1) tumorigenesis are largely unknown. We demonstrated that miR-10b was up-regulated in primary Schwann cells isolated from NF1 neurofibromas and in cell lines and tumor tissues from malignant peripheral nerve sheath tumors (MPNSTs). Intriguingly, a significantly high level of miR-10b correlated with low neurofibromin expression was found in a neuroectodermal cell line: Ewing's sarcoma SK-ES-1 cells. Antisense inhibiting miR-10b in NF1 MPNST cells reduced cell proliferation, migration and invasion. Furthermore, we showed that NF1 mRNA was the target for miR-10b. Overexpression of miR-10b in 293T cells suppressed neurofibromin expression and activated RAS signaling. Antisense inhibition of miR-10b restored neurofibromin expression in SK-ES-1 cells, and decreased RAS signaling independent of neurofibromin in NF1 MPNST cells. These results suggest that miR-10b may play an important role in NF1 tumorigenesis through targeting neurofibromin and RAS signaling.
Collapse
Affiliation(s)
- Guolin Chai
- Maine Institute for Human Genetics & Health, Bangor, Maine
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Etard C, Roostalu U, Strähle U. Lack of Apobec2-related proteins causes a dystrophic muscle phenotype in zebrafish embryos. ACTA ACUST UNITED AC 2010; 189:527-39. [PMID: 20440001 PMCID: PMC2867308 DOI: 10.1083/jcb.200912125] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Apo2 proteins interact with chaperone Unc45b (but not Hsp90) and are required for correct zebrafish skeletal musculature and heart function. The chaperones Unc45b and Hsp90a are essential for folding of myosin in organisms ranging from worms to humans. We show here that zebrafish Unc45b, but not Hsp90a, binds to the putative cytidine deaminase Apobec2 (Apo2) in an interaction that requires the Unc45/Cro1p/She4p-related (UCS) and central domains of Unc45b. Morpholino oligonucleotide-mediated knockdown of the two related proteins Apo2a and Apo2b causes a dystrophic phenotype in the zebrafish skeletal musculature and impairs heart function. These phenotypic traits are shared with mutants of unc45b, but not with hsp90a mutants. Apo2a and -2b act nonredundantly and bind to each other in vitro, which suggests a heteromeric functional complex. Our results demonstrate that Unc45b and Apo2 proteins act in a Hsp90a-independent pathway that is required for integrity of the myosepta and myofiber attachment. Because the only known function of Unc45b is that of a chaperone, Apo2 proteins may be clients of Unc45b but other yet unidentified processes cannot be excluded.
Collapse
Affiliation(s)
- Christelle Etard
- Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe in the Helmholtz Association, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | | | | |
Collapse
|
40
|
Nakae A, Tanaka T, Miyake K, Hase M, Mashimo T. Comparing methods of detection and quantitation of RNA editing of rat glycine receptor alpha3. Int J Biol Sci 2008; 4:397-405. [PMID: 18974845 PMCID: PMC2575349 DOI: 10.7150/ijbs.4.397] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Accepted: 10/20/2008] [Indexed: 11/13/2022] Open
Abstract
Background: Recently, it has become evident that RNA editing-related
changes are important in the modulation of neuronal information processing.
Alternatively edited transcripts, when meagerly present, are hard to detect.
Significant functional consequences may result, however, from small differences
in editing efficiency. Moreover, it is difficult to evaluate the ratio of edited
transcripts. The glycine receptor alpha3 subunit (GlyR alpha3) is expressed in
the spinal cord, and transcripts of GlyR alpha3 are susceptible to RNA editing.
The physiological role of this editing is still unclear. To analyze changes in
RNA editing in various animal models, we need reliable and practical ways to
detect and quantitate GlyR alpha3 RNA editing. Results: We identified and assessed different ways of detecting
edited RNA transcripts, including direct sequencing, denaturing high performance
chromatography (DHPLC), allele-specific real-time PCR with TaqMan probes, and
PCR with allele-specific primers. Using PCR with allele-specific primers on
standard PCR products for edited and nonedited GlyR alpha3, we were able to
detect as little as a 0.5% incidence of edited transcripts. We were able to
detect a 5% incidence of RNA editing using direct sequencing and 2% using DHPLC.
We could accurately determine the ratio of edited to non-edited RNA using DHPLC,
direct sequencing, and allele-specific real-time PCR with TaqMan probes. Conclusion: We demonstrated exact and sensitive methods of detecting
RNA editing. In prepared samples, we showed means of quantitating the incidence
of editing of a particular site. The demonstrated methodologies should be very
useful when extended to the evaluation of other types of RNA editing and single
base mutations.
Collapse
Affiliation(s)
- Aya Nakae
- Department of Anesthesiology & Intensive Care, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita City, Osaka, Japan.
| | | | | | | | | |
Collapse
|
41
|
|
42
|
Bennett RP, Presnyak V, Wedekind JE, Smith HC. Nuclear Exclusion of the HIV-1 host defense factor APOBEC3G requires a novel cytoplasmic retention signal and is not dependent on RNA binding. J Biol Chem 2007; 283:7320-7. [PMID: 18165230 DOI: 10.1074/jbc.m708567200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Human APOBEC3G (hA3G) is a host factor that defends against HIV-1 as well as other exogenous retroviruses and endogenous retroelements. To this end, hA3G is restricted to the cytoplasm of T lymphocytes where it interacts with viral RNA and proteins to assemble with viral particles causing a post-entry block during reverse transcription. hA3G also exhibits a mechanism to inhibit the reverse transcription of retroelements by RNA binding and sequestration into mRNA processing centers in the cytoplasm. We have determined that the molecular basis for this specialized property of hA3G is a novel cytoplasmic retention signal (CRS) that is necessary and sufficient to restrict wild-type hA3G and chimeric constructs to the cytoplasm. The CRS resides within amino acids 113-128 and is embedded within a basic flanking sequence and does not require RNA binding to retain hA3G in the cytoplasm. Paralogs of hA3G that have nuclear or cytoplasmic distributions differ from hA3G within the region encompassing the CRS motif with respect to charge and amino acid composition. We propose that the CRS enables hA3G to interact with cytoplasmic factors, and thereby enables hA3G to serve in host cell defense by restricting an antiviral sentinel to the cytoplasm. The CRS lies in a region involved in both Gag and Vif interactions; therefore, identification of this motif has important implications for the design of therapeutics that target HIV-1 while maintaining antiviral and cellular functions.
Collapse
Affiliation(s)
- Ryan P Bennett
- Department of Biochemistry & Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
| | | | | | | |
Collapse
|
43
|
Blanc V, Henderson JO, Newberry RD, Xie Y, Cho SJ, Newberry EP, Kennedy S, Rubin DC, Wang HL, Luo J, Davidson NO. Deletion of the AU-rich RNA binding protein Apobec-1 reduces intestinal tumor burden in Apc(min) mice. Cancer Res 2007; 67:8565-73. [PMID: 17875695 DOI: 10.1158/0008-5472.can-07-1593] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The RNA-specific cytidine deaminase apobec-1 is an AU-rich RNA binding protein that binds the 3' untranslated region (UTR) of cyclooxygenase-2 (Cox-2) mRNA and stabilizes its turnover in vitro. Cox-2 overexpression accompanies intestinal adenoma formation in both humans and mice. Evidence from both genetic deletion studies as well as from pharmacologic inhibition has implicated Cox-2 in the development of intestinal adenomas in experimental animals and in adenomas and colorectal cancer in humans. Here, we show that small intestinal adenoma formation is dramatically reduced in compound Apc(min/+) apobec-1(-/-) mice when compared with the parental Apc(min/+) strain. This reduced tumor burden was found in association with increased small intestinal apoptosis and reduced proliferation in small intestinal crypt-villus units from compound Apc(min/+) apobec-1(-/-) mice. Intestinal adenomas from compound Apc(min/+) apobec-1(-/-) mice showed a <2-fold increase in Cox-2 mRNA abundance and reduced prostaglandin E(2) content compared with adenomas from the parental Apc(min/+) strain. In addition, there was reduced expression in adenomas from compound Apc(min/+) apobec-1(-/-) mice of other mRNAs (including epidermal growth factor receptor, peroxisome proliferator-activated receptor delta, prostaglandin receptor EP4, and c-myc), each containing the apobec-1 consensus binding site within their 3'-UTR. Adenovirus-mediated apobec-1 introduction into HCA-7 (colorectal cancer) cells showed a dose-dependent increase in Cox-2 protein and stabilization of endogenous Cox-2 mRNA. These findings suggest that deletion of apobec-1, by modulating expression of AU-rich RNA targets, provides an important mechanism for attenuating a dominant genetic restriction point in intestinal adenoma formation.
Collapse
Affiliation(s)
- Valerie Blanc
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Mehler MF, Mattick JS. Noncoding RNAs and RNA Editing in Brain Development, Functional Diversification, and Neurological Disease. Physiol Rev 2007; 87:799-823. [PMID: 17615389 DOI: 10.1152/physrev.00036.2006] [Citation(s) in RCA: 224] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The progressive maturation and functional plasticity of the nervous system in health and disease involve a dynamic interplay between the transcriptome and the environment. There is a growing awareness that the previously unexplored molecular and functional interface mediating these complex gene-environmental interactions, particularly in brain, may encompass a sophisticated RNA regulatory network involving the twin processes of RNA editing and multifaceted actions of numerous subclasses of non-protein-coding RNAs. The mature nervous system encompasses a wide range of cell types and interconnections. Long-term changes in the strength of synaptic connections are thought to underlie memory retrieval, formation, stabilization, and effector functions. The evolving nervous system involves numerous developmental transitions, such as neurulation, neural tube patterning, neural stem cell expansion and maintenance, lineage elaboration, differentiation, axonal path finding, and synaptogenesis. Although the molecular bases for these processes are largely unknown, RNA-based epigenetic mechanisms appear to be essential for orchestrating these precise and versatile biological phenomena and in defining the etiology of a spectrum of neurological diseases. The concerted modulation of RNA editing and the selective expression of non-protein-coding RNAs during seminal as well as continuous state transitions may comprise the plastic molecular code needed to couple the intrinsic malleability of neural network connections to evolving environmental influences to establish diverse forms of short- and long-term memory, context-specific behavioral responses, and sophisticated cognitive capacities.
Collapse
Affiliation(s)
- Mark F Mehler
- Institute for Brain Disorders and Neural Regeneration, Department of Neurology, Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
| | | |
Collapse
|
45
|
Smith HC. Measuring editing activity and identifying cytidine-to-uridine mRNA editing factors in cells and biochemical isolates. Methods Enzymol 2007; 424:389-416. [PMID: 17662851 DOI: 10.1016/s0076-6879(07)24018-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cytidine deaminases with the capacity to act on nucleic acids play a critical role in regulating the proteome through diversification of expressed sequence beyond that encoded in the genome. A family of these enzymes, known as the APOBEC family of cytidine deaminases, has been identified in mammalian cells. APOBEC-1 edits messenger RNA, whereas other family members affect mRNA coding capacity by editing single-stranded DNA in expressed regions of the genomes. Biochemical isolation and analysis of APOBEC proteins and their interacting factors have led to an understanding of the diverse cellular processes including lipoprotein metabolism, antibody production, viral infectivity, and cancer. Practical approaches will be described for the measurement of editing activity and the analysis of proteins involved in C-to-U and dC-to-dU editing.
Collapse
Affiliation(s)
- Harold C Smith
- Department of Biochemistry, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| |
Collapse
|
46
|
Levanon K, Eisenberg E, Rechavi G, Levanon EY. Letter from the editor: Adenosine-to-inosine RNA editing in Alu repeats in the human genome. EMBO Rep 2006; 6:831-5. [PMID: 16138094 PMCID: PMC1369171 DOI: 10.1038/sj.embor.7400507] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Accepted: 07/18/2005] [Indexed: 01/01/2023] Open
Abstract
Adenosine-to-inosine (A-to-I) RNA editing increases the complexity of the human transcriptome and is essential for maintenance of normal life in mammals. Most A-to-I substitutions occur within repetitive elements in the genome, mainly in Alu repeats. The phenomenon of A-to-I editing is far less abundant in mice, rats, chickens and flies than in humans, which correlates with the relative under-representation of Alu repeats in these non-primate genomes. Here, we review the recent results of bioinformatic and laboratory approaches that have estimated the extent of the editing phenomenon. We discuss the possible biological relevance of the editing pathway, its possible interaction with other cellular pathways that respond to double-stranded RNA and its possible contribution to the accelerated evolution of primates.
Collapse
Affiliation(s)
- Keren Levanon
- Institute of Oncology, Sheba Medical Center, Tel Hashomer, 52621 Israel
| | - Eli Eisenberg
- School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Gideon Rechavi
- Department of Pediatric Hemato-Oncology, Safra Children's Hospital, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Erez Y. Levanon
- Department of Pediatric Hemato-Oncology, Safra Children's Hospital, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
- Compugen Ltd, 72 Pinchas Rosen Street, Tel Aviv 69512, Israel
- Tel: +972 3765 8503; Fax: +972 3 765 8555;
| |
Collapse
|
47
|
Storlazzi CT, Von Steyern FV, Domanski HA, Mandahl N, Mertens F. Biallelic somatic inactivation of the NF1 gene through chromosomal translocations in a sporadic neurofibroma. Int J Cancer 2005; 117:1055-7. [PMID: 15986446 DOI: 10.1002/ijc.21248] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neurofibroma is a benign tumor originating from Schwann cells in peripheral nerve sheaths and may occur as a sporadic tumor or as part of the dominantly inherited tumor syndrome NF1. NF1 is caused by constitutional mutations in the NF1 gene, located in chromosome band 17q11. Whereas the involvement of the NF1 gene in neurofibroma development in NF1 patients has been fairly well characterized, the significance of inactivation of this gene in sporadic neurofibromas remains less well investigated. Inactivation of both copies of NF1 has been described in a few neurofibromas from NF1 patients, and LOH at the same locus has been reported in additional cases. In the present study, we report the cytogenetic and molecular cytogenetic findings in a sporadic neurofibroma that at G-banding analysis showed a translocation between one chromosome 2 and the long arms of both copies of chromosome 17. FISH analysis using a set of 3 BAC clones covering the entire coding region of NF1 revealed the complete loss of one allele and the deletion of the 5' portion of the second allele as a result of 2 translocation events. To the best of our knowledge, this represents the first demonstration of a somatic biallelic inactivation of the NF1 gene in neurofibroma, providing further evidence for the importance of NF1 inactivation also in sporadic neurofibromas.
Collapse
|
48
|
Meier JC, Henneberger C, Melnick I, Racca C, Harvey RJ, Heinemann U, Schmieden V, Grantyn R. RNA editing produces glycine receptor alpha3(P185L), resulting in high agonist potency. Nat Neurosci 2005; 8:736-44. [PMID: 15895087 DOI: 10.1038/nn1467] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Accepted: 04/20/2005] [Indexed: 11/09/2022]
Abstract
The function of supramedullary glycine receptors (GlyRs) is still unclear. Using Wistar rat collicular slices, we demonstrate GlyR-mediated inhibition of spike discharge elicited by low glycine (10 microM). Searching for the molecular basis of this phenomenon, we identified a new GlyR isoform. GlyR alpha3(P185L), a result of cytidine 554 deamination, confers high glycine sensitivity (EC50 approximately 5 microM) to neurons and thereby promotes the generation of sustained chloride conductances associated with tonic inhibition. The level of GlyR alpha3-C554U RNA editing is sensitive to experimentally induced brain lesion, inhibition of cytidine deamination by zebularine and inhibition of mRNA transcription by actinomycin D, but not to blockade of protein synthesis by cycloheximide. Conditional regulation of GlyR alpha3(P185L) is thus likely to be part of a post-transcriptional adaptive mechanism in neurons with enhanced excitability.
Collapse
Affiliation(s)
- Jochen C Meier
- Department of Developmental Physiology, Johannes-Mueller Center of Physiology, Charité University Medicine, 10117 Berlin, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Kwak S, Kawahara Y. Deficient RNA editing of GluR2 and neuronal death in amyotropic lateral sclerosis. J Mol Med (Berl) 2004; 83:110-20. [PMID: 15624111 DOI: 10.1007/s00109-004-0599-z] [Citation(s) in RCA: 176] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Accepted: 08/18/2004] [Indexed: 12/11/2022]
Abstract
One plausible hypothesis for selective neuronal death in sporadic amyotropic lateral sclerosis (ALS) is excitotoxicity mediated by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors, which are a subtype of ionotropic glutamate receptors. The Ca2+ conductance of AMPA receptors differs markedly depending on whether the GluR2 (or GluR-B) subunit is a component of the receptor. The properties of GluR2 are generated posttranscriptionally by RNA editing at the Q/R site in the putative second membrane domain (M2), during which the glutamine (Q) codon is substituted by an arginine (R) codon. AMPA receptors containing the unedited form of GluR2Q have high Ca2+ permeability in contrast to the low Ca2+ conductance of those containing the edited form of GluR2R. The role of Ca(2+)-permeable AMPA receptors, particularly GluR2 Q/R site RNA editing status, in neuronal death has been clearly demonstrated both in mice deficient in editing at the GluR2 Q/R site and in mice transgenic for an artificial Ca(2+)-permeable GluR2 subunit. We analyzed the expression level of mRNA of each AMPA receptor subunit in individual motor neurons, as well as the editing efficiency of GluR2 mRNA at the Q/R site in the single neuron level in control subjects and ALS cases. There was no significant difference as to the expression profile of AMPA receptor subunits or the proportion of GluR2 mRNA to total GluRs mRNA between normal subjects and ALS cases. By contrast, the editing efficiency varied greatly, from 0% to 100%, among the motor neurons of each individual with ALS, and was not complete in 44 of them (56%), whereas it remained 100% in normal controls. In addition, GluR2 editing efficiency was more than 99% in the cerebellar Purkinje cells of ALS, spinocerebellar degeneration and normal control groups. Thus, GluR2 underediting occurs in a disease specific and region selective manner. GluR2 modification by RNA editing is a biologically crucial event for neuronal survival, and its deficiency is a direct cause of neuronal death. Therefore, marked reduction of RNA editing in ALS motor neurons may be a direct cause of the selective motor neuron death seen in ALS. It is likely that the molecular mechanism underlying the deficiency in RNA editing is a reduction in the activity of ADAR2, a double- strand RNA specific deaminase. The restoration of this enzyme activity in ALS motor neurons may open the novel strategy for specific ALS therapy.
Collapse
Affiliation(s)
- Shin Kwak
- Department of Neurology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-8655 Tokyo, Japan.
| | | |
Collapse
|
50
|
Wang L, Kimble J, Wickens M. Tissue-specific modification of gld-2 mRNA in C. elegans: likely C-to-U editing. RNA (NEW YORK, N.Y.) 2004; 10:1444-8. [PMID: 15317977 PMCID: PMC1370630 DOI: 10.1261/rna.7570804] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Seventeen years after the discovery of tissue-specific apoB mRNA editing, only three nucleus-encoded mRNAs have been shown to undergo C-to-U editing. All three mRNAs occur in mammals. apoB mRNA editing is tissue-specific and occurs normally, whereas NF1 and NAT1 mRNA editing is found largely in tumors. Here we report the first example of C-to-U RNA editing in Caenorhabditis elegans. The gld-2 gene encodes an atypical poly(A) polymerase that governs the mitosis/meiosis decision in the germ line as well as progression through meiosis and early embryogenesis. At least two of its alternatively spliced transcripts are germline-specific. We find that most and perhaps all germline-specific transcripts generated by the gld-2 gene undergo C-to-U editing, but that somatic transcripts show no detectable editing. The gld-2 C-to-U editing event changes the codon from CCG to CUG, which is predicted to cause a proline to leucine substitution in the protein sequence. Our findings suggest the presence of a sequence- and tissue-specific cytidine deaminase acting on RNA, or CDAR. This CDAR modifies a specific base in gld-2 mRNA, and acts only in the germline.
Collapse
Affiliation(s)
- Liaoteng Wang
- Department of Biochemistry, 433 Babcock Drive, University of Wisconsin-Madison, 53706, USA
| | | | | |
Collapse
|