1
|
Tang X, Deng Y, Liang Y, Liao D, Wen F, Zhang Y. An RNA Helicase DHX33 Inhibitor Shows Broad Anticancer Activity via Inducing Ferroptosis in Cancer Cells. ACS OMEGA 2024; 9:28372-28384. [PMID: 38973855 PMCID: PMC11223218 DOI: 10.1021/acsomega.4c02265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 07/09/2024]
Abstract
RNA helicase DHX33 has been identified as a critical factor promoting cancer development. In the present study, a previously developed small molecule inhibitor for DHX33, KY386, was found to robustly kill cancer cells via a new path, the ferroptosis pathway. Mechanistically, DHX33 promotes the expression of critical players in lipid metabolism including FADS1, FADS2, and SCD1 genes, thereby sensitizing cancer cells to ferroptosis mediated cell death. Our study reveals a novel mechanism of DHX33 in promoting tumorigenesis and highlights that pharmacological targeting DHX33 can be a feasible option in human cancers. Normally differentiated cells are insensitive to DHX33 inhibition, and DHX33 inhibitors have little cellular toxicity in vitro and in vivo. Our studies demonstrated that DHX33 inhibitors can be promising anticancer agents with great potential for cancer treatment.
Collapse
Affiliation(s)
| | | | | | - Deqing Liao
- Shenzhen KeYe Life Technologies
Co., Ltd, Shenzhen, Guangdong 518155, China
| | - Fuyu Wen
- Shenzhen KeYe Life Technologies
Co., Ltd, Shenzhen, Guangdong 518155, China
| | - Yandong Zhang
- Shenzhen KeYe Life Technologies
Co., Ltd, Shenzhen, Guangdong 518155, China
| |
Collapse
|
2
|
Nie G, Chen S, Song Q, Zou D, Li M, Tang X, Deng Y, Huang B, Yang M, Lv G, Zhang Y. DHX33 mediates p53 to regulate mevalonate pathway gene transcription in human cancers. Biochim Biophys Acta Gen Subj 2024; 1868:130547. [PMID: 38143011 DOI: 10.1016/j.bbagen.2023.130547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 12/15/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023]
Abstract
Tumor suppressor p53 is frequently null or mutated in human cancers. Here in this study, DHX33 protein was found to be induced in p53 null cells in vitro, and in p53 mutant lung tumorigenesis in vivo. Cholesterol metabolism through mevalonate pathway is pivotal for cell proliferation and is frequently altered in human cancers. Mice carrying mutant p53 and KrasG12D alleles showed upregulation of mevalonate pathway gene expression. However upon DHX33 loss, their upregulation was significantly debilitated. Additionally, in many human cancer cells, DHX33 knockdown caused inhibition of mavelonate pathway gene transcription. We propose DHX33 locates downstream of mutant p53 and Ras to regulate mevalonate pathway gene transcription and thereby supports cancer development in vivo.
Collapse
Affiliation(s)
- Guangli Nie
- Shenzhen KeYe Life Technologies Co., Ltd, Shenzhen, Guangdong 518000, China
| | - Shiyun Chen
- Shenzhen KeYe Life Technologies Co., Ltd, Shenzhen, Guangdong 518000, China; Southern University of Science and Technology, Shenzhen, China
| | - Qingzhi Song
- Department of Gastrointestinal Surgery, Peking University Shenzhen Hospital, China
| | - Dongxu Zou
- Shenzhen KeYe Life Technologies Co., Ltd, Shenzhen, Guangdong 518000, China
| | - Maggie Li
- Shenzhen College of International Education, Shenzhen, China
| | - Xiyu Tang
- Shenzhen KeYe Life Technologies Co., Ltd, Shenzhen, Guangdong 518000, China
| | - Yuanlian Deng
- Shenzhen KeYe Life Technologies Co., Ltd, Shenzhen, Guangdong 518000, China
| | - Bizhou Huang
- Shenzhen KeYe Life Technologies Co., Ltd, Shenzhen, Guangdong 518000, China
| | - Mengxia Yang
- Shenzhen KeYe Life Technologies Co., Ltd, Shenzhen, Guangdong 518000, China
| | - Guoqing Lv
- Shenzhen College of International Education, Shenzhen, China.
| | - Yandong Zhang
- Shenzhen KeYe Life Technologies Co., Ltd, Shenzhen, Guangdong 518000, China; Southern University of Science and Technology, Shenzhen, China.
| |
Collapse
|
3
|
Kundu S, Jaiswal M, Babu Mullapudi V, Guo J, Kamat M, Basso KB, Guo Z. Investigation of Glycosylphosphatidylinositol (GPI)-Plasma Membrane Interaction in Live Cells and the Influence of GPI Glycan Structure on the Interaction. Chemistry 2024; 30:e202303047. [PMID: 37966101 PMCID: PMC10922586 DOI: 10.1002/chem.202303047] [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: 09/19/2023] [Revised: 11/05/2023] [Accepted: 11/15/2023] [Indexed: 11/16/2023]
Abstract
Glycosylphosphatidylinositols (GPIs) need to interact with other components in the cell membrane to transduce transmembrane signals. A bifunctional GPI probe was employed for photoaffinity-based proximity labelling and identification of GPI-interacting proteins in the cell membrane. This probe contained the entire core structure of GPIs and was functionalized with photoreactive diazirine and clickable alkyne to facilitate its crosslinking with proteins and attachment of an affinity tag. It was disclosed that this probe was more selective than our previously reported probe containing only a part structure of the GPI core for cell membrane incorporation and an improved probe for studying GPI-cell membrane interaction. Eighty-eight unique membrane proteins, many of which are related to GPIs/GPI-anchored proteins, were identified utilizing this probe. The proteomics dataset is a valuable resource for further analyses and data mining to find new GPI-related proteins and signalling pathways. A comparison of these results with those of our previous probe provided direct evidence for the profound impact of GPI glycan structure on its interaction with the cell membrane.
Collapse
Affiliation(s)
- Sayan Kundu
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Mohit Jaiswal
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | | | - Jiatong Guo
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Manasi Kamat
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Kari B Basso
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
- UF Health Cancer Centre, University of Florida, Gainesville, FL 32611, USA
| |
Collapse
|
4
|
Wang Y, Nie G, Wang X, Ge W, Zhang Y. Development of small molecule inhibitors targeting RNA helicase DHX33 as anti-cancer agents. Bioorg Med Chem Lett 2023; 96:129505. [PMID: 37838340 DOI: 10.1016/j.bmcl.2023.129505] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 09/19/2023] [Accepted: 10/07/2023] [Indexed: 10/16/2023]
Abstract
RNA helicase DHX33 has been identified to be a critical factor in promoting cancer development. Genetic deletion of DHX33 significantly blocks tumorigenesis. Importantly, its helicase activity was found to be pivotal for exerting cellular functions. Herein we used a helicase-based high throughput screening (HTS) to discover DHX33 inhibitors from Chembridge chemical library containing 15,000 small molecules. We identified a hit compound containing benzimidazole ring that demonstrated activity against DHX33 with certain selectivity. Further structural optimization led to the design and synthesis of a series of analog inhibitors. Considering the potential role of DHX33 in cancer development, the compounds were evaluated based on the cytotoxicity activity in U251-MG cancer cells in vitro. Among them, compound IVa (KY386) was identified to be a selective inhibitor for DHX33 helicase with potent anti-cancer activity and moderate metabolic stability. These results support the promising role of DHX33 inhibitors for development of novel anti-cancer drugs.
Collapse
Affiliation(s)
- Yingcai Wang
- Shenzhen KeYe Life Technologies Co., Ltd, Shenzhen, Guangdong 518000, China; Acme Bioscience, Inc, Palo Alto, CA 94303, USA
| | - Guangli Nie
- Shenzhen KeYe Life Technologies Co., Ltd, Shenzhen, Guangdong 518000, China
| | - Xingshun Wang
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China; Southern University of Science and Technology, Shenzhen 518055, China
| | - Wei Ge
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Yandong Zhang
- Shenzhen KeYe Life Technologies Co., Ltd, Shenzhen, Guangdong 518000, China.
| |
Collapse
|
5
|
Bohnsack KE, Yi S, Venus S, Jankowsky E, Bohnsack MT. Cellular functions of eukaryotic RNA helicases and their links to human diseases. Nat Rev Mol Cell Biol 2023; 24:749-769. [PMID: 37474727 DOI: 10.1038/s41580-023-00628-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2023] [Indexed: 07/22/2023]
Abstract
RNA helicases are highly conserved proteins that use nucleoside triphosphates to bind or remodel RNA, RNA-protein complexes or both. RNA helicases are classified into the DEAD-box, DEAH/RHA, Ski2-like, Upf1-like and RIG-I families, and are the largest class of enzymes active in eukaryotic RNA metabolism - virtually all aspects of gene expression and its regulation involve RNA helicases. Mutation and dysregulation of these enzymes have been linked to a multitude of diseases, including cancer and neurological disorders. In this Review, we discuss the regulation and functional mechanisms of RNA helicases and their roles in eukaryotic RNA metabolism, including in transcription regulation, pre-mRNA splicing, ribosome assembly, translation and RNA decay. We highlight intriguing models that link helicase structure, mechanisms of function (such as local strand unwinding, translocation, winching, RNA clamping and displacing RNA-binding proteins) and biological roles, including emerging connections between RNA helicases and cellular condensates formed through liquid-liquid phase separation. We also discuss associations of RNA helicases with human diseases and recent efforts towards the design of small-molecule inhibitors of these pivotal regulators of eukaryotic gene expression.
Collapse
Affiliation(s)
- Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.
| | - Soon Yi
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Sarah Venus
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Eckhard Jankowsky
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Moderna, Cambridge, MA, USA.
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.
- Göttingen Centre for Molecular Biosciences, University of Göttingen, Göttingen, Germany.
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
| |
Collapse
|
6
|
Wang X, Chen S, Wen F, Zeng Y, Zhang Y. RNA helicase DHX33 regulates HMGB family genes in human cancer cells. Cell Signal 2023; 110:110832. [PMID: 37543097 DOI: 10.1016/j.cellsig.2023.110832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/26/2023] [Accepted: 07/28/2023] [Indexed: 08/07/2023]
Abstract
RNA helicase DHX33 has been shown to be aberrantly expressed in various human cancers, however, its role in tumorigenesis remains incompletely understood. In this report, we uncovered that a family of DNA architecture proteins, HMGBs, can be regulated by DHX33 in cancer cells but not in normal cells. Specifically, DHX33 knockdown caused the downregulation of HMGBs at the levels of both gene transcription and protein expression. Notably, in RAS driven lung tumorigenesis, nuclear HMGBs proteins can be induced via DHX33. When DHX33 was knocked out, HMGBs overexpression was debilitated. Mechanistically, DHX33 was found to bind to the promoters of HMGB family genes and regulated their transcription through demethylation on gene promoters. Our study reveals a novel mechanism for DHX33 to promote tumorigenesis and highlights its therapeutic value in human cancers.
Collapse
Affiliation(s)
- Xingshun Wang
- The Sixth Affiliated Hospital of Kunming Medical University, Yuxi, Yunnan 653199, China
| | - Shiyun Chen
- Shenzhen KeYe Life Technologies, Co., Ltd, Shenzhen, Guangdong 518122, China; Southern University of Science and Technology, Shenzhen, China
| | - Fuyu Wen
- Shenzhen KeYe Life Technologies, Co., Ltd, Shenzhen, Guangdong 518122, China
| | - Yong Zeng
- The Sixth Affiliated Hospital of Kunming Medical University, Yuxi, Yunnan 653199, China.
| | - Yandong Zhang
- Shenzhen KeYe Life Technologies, Co., Ltd, Shenzhen, Guangdong 518122, China.
| |
Collapse
|
7
|
Patent Highlights June–July 2022. Pharm Pat Anal 2022; 12:5-11. [PMID: 36511078 DOI: 10.4155/ppa-2022-0043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A snapshot of noteworthy recent developments in the patent literature of relevance to pharmaceutical and medical research and development.
Collapse
|
8
|
Ying S, Zhang Z, Zhang Y, Hao Z, Chai R, Qiu H, Wang Y, Zhu X, Wang J, Sun G, Lin F. MoDHX35, a DEAH-Box Protein, Is Required for Appressoria Formation and Full Virulence of the Rice Blast Fungus, Magnaporthe oryzae. Int J Mol Sci 2022; 23:ijms23169015. [PMID: 36012276 PMCID: PMC9409162 DOI: 10.3390/ijms23169015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/02/2022] [Accepted: 08/09/2022] [Indexed: 11/25/2022] Open
Abstract
The DExD/H-box protein family encompasses a large number of RNA helicases that are involved in RNA metabolism and a variety of physiological functions in different species. However, there is limited knowledge of whether DExD/H-box proteins play a role in the pathogenicity of plant fungal pathogens. In the present work, the DExD/H-box protein MoDHX35, which belongs to the DEAH subfamily, was shown to be crucial in appressoria formation and full virulence of the rice blast fungus, Magnaporthe oryzae. The predicted protein sequence of MoDHX35 had typical DEAH-box domains, showed 47% identity to DHX35 in Homo species, but had no orthologs in Saccharomyces cerevisiae. Deletion of the MoDHX35 gene resulted in reduced tolerance of the mutants to doxorubicin, a nucleic acid synthesis disturbing agent, suggesting the involvement of MoDHX35 in RNA metabolism. MoDHX35-deleted mutants exhibited normal vegetative growth, conidia generation and conidial germination, but showed a reduced appressorium formation rate and attenuated virulence. Our work demonstrates the involvement of DEAH-box protein functions in the pathogenicity of plant fungal pathogens.
Collapse
Affiliation(s)
- Shumin Ying
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 310029, China
| | - Zhen Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Yanan Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 310029, China
| | - Zhongna Hao
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Rongyao Chai
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Haiping Qiu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Yanli Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Xueming Zhu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Jiaoyu Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
- Correspondence: (J.W.); (G.S.); Tel.: +86-571-85074309 (J.W.); +86-571-86409108 (G.S.)
| | - Guochang Sun
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
- Correspondence: (J.W.); (G.S.); Tel.: +86-571-85074309 (J.W.); +86-571-86409108 (G.S.)
| | - Fucheng Lin
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| |
Collapse
|
9
|
Garousi S, Jahanbakhsh Godehkahriz S, Esfahani K, Lohrasebi T, Mousavi A, Hatef Salmanian A, Rezvani M, Moein M. Meta-Analysis of EGF-Stimulated Normal and Cancer Cell Lines to Discover EGF-Associated Oncogenic Signaling Pathways and Prognostic Biomarkers. IRANIAN JOURNAL OF BIOTECHNOLOGY 2022; 20:e3245. [PMID: 36381277 PMCID: PMC9618017 DOI: 10.30498/ijb.2022.323464.3245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Although epidermal growth factor (EGF) controls many crucial processes in the human body, it can increase the risk of developing cancer when overexpresses. OBJECTIVES This study focused on detecting cancer-associated genes that are dysregulated by EGF overexpression. MATERIALS AND METHODS To identify differentially expressed genes (DEGs), two independent meta-analyses with normal and cancer RNA-Seq samples treated by EGF were conducted. The new DEGs detected only via two meta-analyses were used in all downstream analyses. To reach count data, the tools of FastQC, Trimmomatic, HISAT2, SAMtools, and HTSeq-count were employed. DEGs in each individual RNA-Seq study and the meta-analysis of RNA-Seq studies were identified using DESeq2 and metaSeq R package, respectively. MCODE detected densely interconnected top clusters in the protein-protein interaction (PPI) network of DEGs obtained from normal and cancer datasets. The DEGs were then introduced to Enrichr and ClueGO/CluePedia, and terms, pathways, and hub genes enriched in Gene Ontology (GO) and KEGG and Reactome were detected. RESULTS The meta-analysis of normal and cancer datasets revealed 990 and 541 new DEGs, all upregulated. A number of DEGs were enriched in protein K48-linked deubiquitination, ncRNA processing, ribosomal large subunit binding, and protein processing in endoplasmic reticulum. Hub genes overexpression (DHX33, INTS8, NMD3, OTUD4, P4HB, RPS3A, SEC13, SKP1, USP34, USP9X, and YOD1) in tumor samples were validated by TCGA and GTEx databases. Overall survival and disease-free survival analysis also confirmed worse survival in patients with hub genes overexpression. CONCLUSIONS The detected hub genes could be used as cancer biomarkers when EGF overexpresses.
Collapse
Affiliation(s)
- Shahrokh Garousi
- Department of plant genetics and production engineering, Faculty of agriculture and natural resources, University of Mohaghegh Ardabili, Ardabil, Iran
| | - Sodabeh Jahanbakhsh Godehkahriz
- Department of plant genetics and production engineering, Faculty of agriculture and natural resources, University of Mohaghegh Ardabili, Ardabil, Iran
| | - Kasra Esfahani
- Plant Bioproducts Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Tahmineh Lohrasebi
- Plant Bioproducts Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Amir Mousavi
- Plant Molecular Biotechnology Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Ali Hatef Salmanian
- Plant Bioproducts Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Mahsa Rezvani
- Institute of Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Maryam Moein
- Institute of Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| |
Collapse
|
10
|
Castelli LM, Benson BC, Huang WP, Lin YH, Hautbergue GM. RNA Helicases in Microsatellite Repeat Expansion Disorders and Neurodegeneration. Front Genet 2022; 13:886563. [PMID: 35646086 PMCID: PMC9133428 DOI: 10.3389/fgene.2022.886563] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/25/2022] [Indexed: 11/17/2022] Open
Abstract
Short repeated sequences of 3-6 nucleotides are causing a growing number of over 50 microsatellite expansion disorders, which mainly present with neurodegenerative features. Although considered rare diseases in relation to the relatively low number of cases, these primarily adult-onset conditions, often debilitating and fatal in absence of a cure, collectively pose a large burden on healthcare systems in an ageing world population. The pathological mechanisms driving disease onset are complex implicating several non-exclusive mechanisms of neuronal injury linked to RNA and protein toxic gain- and loss- of functions. Adding to the complexity of pathogenesis, microsatellite repeat expansions are polymorphic and found in coding as well as in non-coding regions of genes. They form secondary and tertiary structures involving G-quadruplexes and atypical helices in repeated GC-rich sequences. Unwinding of these structures by RNA helicases plays multiple roles in the expression of genes including repeat-associated non-AUG (RAN) translation of polymeric-repeat proteins with aggregating and cytotoxic properties. Here, we will briefly review the pathogenic mechanisms mediated by microsatellite repeat expansions prior to focus on the RNA helicases eIF4A, DDX3X and DHX36 which act as modifiers of RAN translation in C9ORF72-linked amyotrophic lateral sclerosis/frontotemporal dementia (C9ORF72-ALS/FTD) and Fragile X-associated tremor/ataxia syndrome (FXTAS). We will further review the RNA helicases DDX5/17, DHX9, Dicer and UPF1 which play additional roles in the dysregulation of RNA metabolism in repeat expansion disorders. In addition, we will contrast these with the roles of other RNA helicases such as DDX19/20, senataxin and others which have been associated with neurodegeneration independently of microsatellite repeat expansions. Finally, we will discuss the challenges and potential opportunities that are associated with the targeting of RNA helicases for the development of future therapeutic approaches.
Collapse
Affiliation(s)
- Lydia M Castelli
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Bridget C Benson
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Wan-Ping Huang
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Ya-Hui Lin
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Guillaume M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom.,Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom.,Healthy Lifespan Institute (HELSI), University of Sheffield, Sheffield, United Kingdom
| |
Collapse
|
11
|
DEAD/H-box helicases:Anti-viral and pro-viral roles during infections. Virus Res 2021; 309:198658. [PMID: 34929216 DOI: 10.1016/j.virusres.2021.198658] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 11/26/2021] [Accepted: 12/14/2021] [Indexed: 02/08/2023]
Abstract
DEAD/H-box RNA helicases make the prominent family of helicases super family-2 which take part in almost all RNA-related processes, from initiation of transcription to RNA decay pathways. In addition to these RNA-related activities, in recent years a certain number of these helicases are reported to play important roles in anti-viral immunity through various ways. Along with RLHs, endosomal TLRs, and cytosolic DNA receptors, many RNA helicases including DDX3, DHX9, DDX6, DDX41, DHX33, DDX60, DHX36 and DDX1-DDX21-DHX36 complex act as viral nucleic acid sensors or co-sensors. These helicases mostly follow RLHs-MAVS and STING mediated signaling cascades to trigger induction of type-I interferons and pro-inflammatory cytokines. Many of them also function as downstream adaptor molecules (DDX3), segments of stress and processing bodies (DDX3 and DDX6) or negative regulators (DDX19, DDX24, DDX25, DDX39A and DDX46). On the contrary, many studies indicated that several DEAD/H-box helicases such as DDX1, DDX3, DDX6, DDX24, and DHX9 could be exploited by viruses to evade innate immune responses, suggesting that these helicases seem to have a dual function as anti-viral innate immune mediators and viral replication cofactors. In this review, we summarized the current knowledge on several representative DEAD/H-box helicases, with an emphasis on their functions in innate immunity responses, involved in their anti-viral and pro-viral roles.
Collapse
|
12
|
Wang Y, Wang F. Post-Translational Modifications of Deubiquitinating Enzymes: Expanding the Ubiquitin Code. Front Pharmacol 2021; 12:685011. [PMID: 34177595 PMCID: PMC8224227 DOI: 10.3389/fphar.2021.685011] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/25/2021] [Indexed: 12/14/2022] Open
Abstract
Post-translational modifications such as ubiquitination play important regulatory roles in several biological processes in eukaryotes. This process could be reversed by deubiquitinating enzymes (DUBs), which remove conjugated ubiquitin molecules from target substrates. Owing to their role as essential enzymes in regulating all ubiquitin-related processes, the abundance, localization, and catalytic activity of DUBs are tightly regulated. Dysregulation of DUBs can cause dramatic physiological consequences and a variety of disorders such as cancer, and neurodegenerative and inflammatory diseases. Multiple factors, such as transcription and translation of associated genes, and the presence of accessory domains, binding proteins, and inhibitors have been implicated in several aspects of DUB regulation. Beyond this level of regulation, emerging studies show that the function of DUBs can be regulated by a variety of post-translational modifications, which significantly affect the abundance, localization, and catalytic activity of DUBs. The most extensively studied post-translational modification of DUBs is phosphorylation. Besides phosphorylation, ubiquitination, SUMOylation, acetylation, oxidation, and hydroxylation are also reported in DUBs. In this review, we summarize the current knowledge on the regulatory effects of post-translational modifications of DUBs.
Collapse
Affiliation(s)
- Yanfeng Wang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Feng Wang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, China
| |
Collapse
|
13
|
Sergeeva O, Zatsepin T. RNA Helicases as Shadow Modulators of Cell Cycle Progression. Int J Mol Sci 2021; 22:2984. [PMID: 33804185 PMCID: PMC8001981 DOI: 10.3390/ijms22062984] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/06/2021] [Accepted: 03/10/2021] [Indexed: 02/07/2023] Open
Abstract
The progress of the cell cycle is directly regulated by modulation of cyclins and cyclin-dependent kinases. However, many proteins that control DNA replication, RNA transcription and the synthesis and degradation of proteins can manage the activity or levels of master cell cycle regulators. Among them, RNA helicases are key participants in RNA metabolism involved in the global or specific tuning of cell cycle regulators at the level of transcription and translation. Several RNA helicases have been recently evaluated as promising therapeutic targets, including eIF4A, DDX3 and DDX5. However, targeting RNA helicases can result in side effects due to the influence on the cell cycle. In this review, we discuss direct and indirect participation of RNA helicases in the regulation of the cell cycle in order to draw attention to downstream events that may occur after suppression or inhibition of RNA helicases.
Collapse
Affiliation(s)
- Olga Sergeeva
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30b1, 121205 Moscow, Russia;
| | - Timofei Zatsepin
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30b1, 121205 Moscow, Russia;
- Department of Chemistry, Lomonosov Moscow State University, 119992 Moscow, Russia
| |
Collapse
|
14
|
Wang X, Feng W, Peng C, Chen S, Ji H, Zhong H, Ge W, Zhang Y. Targeting RNA helicase DHX33 blocks Ras-driven lung tumorigenesis in vivo. Cancer Sci 2020; 111:3564-3575. [PMID: 32767810 PMCID: PMC7540983 DOI: 10.1111/cas.14601] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/01/2020] [Accepted: 07/13/2020] [Indexed: 02/06/2023] Open
Abstract
Ras has been found to be mutated in 30% of non‐small cell lung cancers, and its mutation has been regarded as a causal factor underlying tumorigenesis. However, no successful medicine has been developed so far to inhibit Ras for lung cancer treatment. We have previously identified DHX33 as a Ras downstream effector, promoting cell cycle progression and cell growth. In this study, with the K‐Ras (G12D);DHX33 (lox/lox) mouse model, we discovered that genetic ablation of DHX33 inhibited tumor development. We further found that ablation of DHX33 altered the expression of nearly 2000 genes which are critical in cancer development such as cell cycle, apoptosis, glycolysis, Wnt signaling, and cell migration. Our study for the first time demonstrates the pivotal role of the DHX33 in Ras‐driven lung cancer development in vivo and highlights that pharmacological targeting DHX33 can be a feasible option in treating Ras‐mutant lung cancers.
Collapse
Affiliation(s)
- Xingshun Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China.,Faculty of Health Sciences, University of Macau, Macau, China
| | - Weimin Feng
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Cheng Peng
- Department of Biology, Southern University of Science and Technology, Shenzhen, China.,Faculty of Health Sciences, University of Macau, Macau, China
| | - Shiyun Chen
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Hongbin Ji
- State Key Laboratory of Cell Biology, Shanghai, China.,CAS Center for Excellence in Molecular Cell Science, Shanghai, China.,Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, Shanghai Tech University, Shanghai, China
| | - Hanbing Zhong
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Wei Ge
- Faculty of Health Sciences, University of Macau, Macau, China
| | - Yandong Zhang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China.,KeYe Life Technologies Co., Ltd, Shenzhen, China
| |
Collapse
|
15
|
Peng C, Hou ST, Deng CX, Zhang Y. Function of DHX33 in promoting Warburg effect via regulation of glycolytic genes. J Cell Physiol 2020; 236:981-996. [PMID: 32617965 DOI: 10.1002/jcp.29909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 06/15/2020] [Accepted: 06/15/2020] [Indexed: 01/21/2023]
Abstract
Cancer cells metabolize glucose through glycolysis to promote cell proliferation even with abundant oxygen. Multiple glycolysis genes are deregulated during cancer development. Despite intensive effort, the cause of their deregulation remains incompletely understood. Here in this study, we discovered that DHX33 plays a critical role in Warburg effect of cancer cells. DHX33 deficient cells have markedly reduced glycolysis activity. Through RNA-seq analysis, we found multiple critical genes involved in Warburg effect were downregulated after DHX33 deficiency. These genes include lactate dehydrogenase A (LDHA), pyruvate dehydrogenase kinase 1 (PDK1), pyruvate kinase muscle isoform 2 (PKM2), enolase 1 (ENO1), ENO2, hexokinase 1/2, among others. With LDHA, PDK1, and PKM2 as examples, we further revealed that DHX33 altered the epigenetic marks around the promoter of glycolytic genes. This is through DHX33 in complex with Gadd45a-a growth arrest and DNA damage protein. DHX33 is required for the loading of Gadd45a and DNA dioxygenase Tet1 at the promoter sites, which resulted in active DNA demethylation and enhanced histone H4 acetylation. We conclude that DHX33 changes local epigenetic marks in favor of the transcription of glycolysis genes to promote cancer cell proliferation. Our study highlights the significance of RNA helicase DHX33 in Warburg effect and cancer therapeutics.
Collapse
Affiliation(s)
- Cheng Peng
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Sheng-Tao Hou
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Chu-Xia Deng
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Yandong Zhang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Shenzhen KeYe Life Technologies, Co., Ltd., Shenzhen, Guangdong, China
| |
Collapse
|
16
|
General and Target-Specific DExD/H RNA Helicases in Eukaryotic Translation Initiation. Int J Mol Sci 2020; 21:ijms21124402. [PMID: 32575790 PMCID: PMC7352612 DOI: 10.3390/ijms21124402] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/19/2022] Open
Abstract
DExD (DDX)- and DExH (DHX)-box RNA helicases, named after their Asp-Glu-x-Asp/His motifs, are integral to almost all RNA metabolic processes in eukaryotic cells. They play myriad roles in processes ranging from transcription and mRNA-protein complex remodeling, to RNA decay and translation. This last facet, translation, is an intricate process that involves DDX/DHX helicases and presents a regulatory node that is highly targetable. Studies aimed at better understanding this family of conserved proteins have revealed insights into their structures, catalytic mechanisms, and biological roles. They have also led to the development of chemical modulators that seek to exploit their essential roles in diseases. Herein, we review the most recent insights on several general and target-specific DDX/DHX helicases in eukaryotic translation initiation.
Collapse
|
17
|
Feng W, Chen S, Wang J, Wang X, Chen H, Ning W, Zhang Y. DHX33 Recruits Gadd45a To Cause DNA Demethylation and Regulates a Subset of Gene Transcription. Mol Cell Biol 2020; 40:MCB.00460-19. [PMID: 32312884 PMCID: PMC7296211 DOI: 10.1128/mcb.00460-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 04/12/2020] [Indexed: 02/07/2023] Open
Abstract
RNA helicase DHX33 was found to regulate the transcription of multiple genes involved in cancer development. But the underlying molecular mechanism remains unclear. Here, we found DHX33 associated extensively with gene promoters at CG-rich region. Its deficiency reduced the loading of active RNA polymerase II at gene promoters. Furthermore, we observed a functional interaction between DHX33, AP-2β, and DNA demethylation protein Gadd45a (growth arrest and DNA damage inductile protein 45a) at specific gene promoters. DHX33 is required to recruit GADD45a, thereby causing local DNA demethylation through further recruiting ten-eleven-translocation (Tet) methylcytosine dioxygenase enzyme, as manifested by reduced 5-hydroxymethyl cytosine levels for a subset of genes after DHX33 deficiency. This process might involve R-loop formation in GC skew as a guidance signal at promoter sites. Our report provides for the first time, to our knowledge, original evidence that DHX33 alters epigenetic marks and regulates specific gene transcription through interaction with Gadd45a.
Collapse
Affiliation(s)
- Weimin Feng
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Shiyun Chen
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Jiuling Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Xingshun Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Huaiyong Chen
- Department of Basic Medicine, Haihe Clinic College of Tianjin Medical University, Tianjin, China
- Key Research Laboratory for Infectious Disease Prevention for State Administration of Traditional Chinese Medicine, Tianjin Institute of Respiratory Diseases, Tianjin Haihe Hospital, Tianjin, China
| | - Wen Ning
- School of Life Sciences, Nankai University, Tianjin, China
| | - Yandong Zhang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Shenzhen KeYe Life Technologies, Co., Ltd., Shenzhen, China
| |
Collapse
|
18
|
Xing Y, Yang W, Liu G, Cui X, Meng H, Zhao H, Zhao X, Li J, Liu Z, Zhang MQ, Cai L. Dynamic Alternative Splicing During Mouse Preimplantation Embryo Development. Front Bioeng Biotechnol 2020; 8:35. [PMID: 32117919 PMCID: PMC7019016 DOI: 10.3389/fbioe.2020.00035] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 01/15/2020] [Indexed: 11/13/2022] Open
Abstract
The mechanism of alternative pre-mRNA splicing (AS) during preimplantation development is largely unknown. In order to capture the dynamic changes of AS occurring during embryogenesis, we carried out bioinformatics analysis based on scRNA-seq data over the time-course preimplantation development in mouse. We detected numerous previously-unreported differentially expressed genes at specific developmental stages and investigated the nature of AS at both minor and major zygotic genome activation (ZGA). The AS and differential AS atlas over preimplantation development were established. The differentially alternatively spliced genes (DASGs) are likely to be key splicing factors (SFs) during preimplantation development. We also demonstrated that there is a regulatory cascade of AS events in which some key SFs are regulated by differentially AS of their own gene transcripts. Moreover, 212 isoform switches (ISs) during preimplantation development were detected, which may be critical for decoding the mechanism of early embryogenesis. Importantly, we uncovered that zygotic AS activation (ZASA) is in conformity with ZGA and revealed that AS is coupled with transcription during preimplantation development. Our results may provide a deeper insight into the regulation of early embryogenesis.
Collapse
Affiliation(s)
- Yongqiang Xing
- School of Life Science and Technology, Inner Mongolia University of Science and Technology, Baotou, China.,The Inner Mongolia Key Laboratory of Functional Genome Bioinformatics, Inner Mongolia University of Science and Technology, Baotou, China
| | - Wuritu Yang
- The Key Laboratory of Mammalian Reproductive Biology and Biotechnology of the Ministry of Education, Inner Mongolia University, Hohhot, China
| | - Guoqing Liu
- School of Life Science and Technology, Inner Mongolia University of Science and Technology, Baotou, China.,The Inner Mongolia Key Laboratory of Functional Genome Bioinformatics, Inner Mongolia University of Science and Technology, Baotou, China
| | - Xiangjun Cui
- School of Life Science and Technology, Inner Mongolia University of Science and Technology, Baotou, China.,The Inner Mongolia Key Laboratory of Functional Genome Bioinformatics, Inner Mongolia University of Science and Technology, Baotou, China
| | - Hu Meng
- School of Life Science and Technology, Inner Mongolia University of Science and Technology, Baotou, China.,The Inner Mongolia Key Laboratory of Functional Genome Bioinformatics, Inner Mongolia University of Science and Technology, Baotou, China
| | - Hongyu Zhao
- School of Life Science and Technology, Inner Mongolia University of Science and Technology, Baotou, China.,The Inner Mongolia Key Laboratory of Functional Genome Bioinformatics, Inner Mongolia University of Science and Technology, Baotou, China
| | - Xiujuan Zhao
- School of Life Science and Technology, Inner Mongolia University of Science and Technology, Baotou, China.,The Inner Mongolia Key Laboratory of Functional Genome Bioinformatics, Inner Mongolia University of Science and Technology, Baotou, China
| | - Jun Li
- School of Life Science and Technology, Inner Mongolia University of Science and Technology, Baotou, China.,The Inner Mongolia Key Laboratory of Functional Genome Bioinformatics, Inner Mongolia University of Science and Technology, Baotou, China
| | - Zhe Liu
- School of Life Science and Technology, Inner Mongolia University of Science and Technology, Baotou, China
| | - Michael Q Zhang
- Department of Biological Sciences, Center for Systems Biology, The University of Texas at Dallas, Richardson, TX, United States
| | - Lu Cai
- School of Life Science and Technology, Inner Mongolia University of Science and Technology, Baotou, China.,The Inner Mongolia Key Laboratory of Functional Genome Bioinformatics, Inner Mongolia University of Science and Technology, Baotou, China
| |
Collapse
|
19
|
Zhu Y, Du Y, Zhang Y. DHX33 promotes colon cancer development downstream of Wnt signaling. Gene 2020; 735:144402. [PMID: 32004669 DOI: 10.1016/j.gene.2020.144402] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 02/05/2023]
Abstract
Colon cancer is one of the most common malignancies in the world; there is no effective therapeutic treatment after surgery. Our previous studies indicate that RNA helicase DHX33 plays a critical role in cell proliferation and cell growth. Here in this study, DHX33 is found to be highly expressed in colon cancer tissues and colon cancer cell lines. Knockdown of DHX33 significantly decreased cell proliferation and triggered apoptosis. Mechanistically, DHX33 was found to transcriptionally control multiple critical genes involved in cell cycle, apoptosis and migration. DHX33 deficiency caused decreased tumor growth for colon cancer cells in a xenograft model in vivo. With Wnt/β-cateninactivator and inhibitors, we further discovered that Wnt/β-catenin pathway regulates DHX33 transcriptionally. This study for the first time demonstratesthe important role of DHX33 in colon cancer development and reveals the underlying molecular mechanism. We also provide the initial evidence for the relationship between DHX33 and Wnt/β-catenin signaling pathway in colon cancer development.
Collapse
Affiliation(s)
- Yaju Zhu
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Yichen Du
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Yandong Zhang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| |
Collapse
|
20
|
Migration of Small Ribosomal Subunits on the 5' Untranslated Regions of Capped Messenger RNA. Int J Mol Sci 2019; 20:ijms20184464. [PMID: 31510048 PMCID: PMC6769788 DOI: 10.3390/ijms20184464] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/01/2019] [Accepted: 09/05/2019] [Indexed: 12/12/2022] Open
Abstract
Several control mechanisms of eukaryotic gene expression target the initiation step of mRNA translation. The canonical translation initiation pathway begins with cap-dependent attachment of the small ribosomal subunit (SSU) to the messenger ribonucleic acid (mRNA) followed by an energy-dependent, sequential ‘scanning’ of the 5′ untranslated regions (UTRs). Scanning through the 5′UTR requires the adenosine triphosphate (ATP)-dependent RNA helicase eukaryotic initiation factor (eIF) 4A and its efficiency contributes to the specific rate of protein synthesis. Thus, understanding the molecular details of the scanning mechanism remains a priority task for the field. Here, we studied the effects of inhibiting ATP-dependent translation and eIF4A in cell-free translation and reconstituted initiation reactions programmed with capped mRNAs featuring different 5′UTRs. An aptamer that blocks eIF4A in an inactive state away from mRNA inhibited translation of capped mRNA with the moderately structured β-globin sequences in the 5′UTR but not that of an mRNA with a poly(A) sequence as the 5′UTR. By contrast, the nonhydrolysable ATP analogue β,γ-imidoadenosine 5′-triphosphate (AMP-PNP) inhibited translation irrespective of the 5′UTR sequence, suggesting that complexes that contain ATP-binding proteins in their ATP-bound form can obstruct and/or actively block progression of ribosome recruitment and/or scanning on mRNA. Further, using primer extension inhibition to locate SSUs on mRNA (‘toeprinting’), we identify an SSU complex which inhibits primer extension approximately eight nucleotides upstream from the usual toeprinting stop generated by SSUs positioned over the start codon. This ‘−8 nt toeprint’ was seen with mRNA 5′UTRs of different length, sequence and structure potential. Importantly, the ‘−8 nt toeprint’ was strongly stimulated by the presence of the cap on the mRNA, as well as the presence of eIFs 4F, 4A/4B and ATP, implying active scanning. We assembled cell-free translation reactions with capped mRNA featuring an extended 5′UTR and used cycloheximide to arrest elongating ribosomes at the start codon. Impeding scanning through the 5′UTR in this system with elevated magnesium and AMP-PNP (similar to the toeprinting conditions), we visualised assemblies consisting of several SSUs together with one full ribosome by electron microscopy, suggesting direct detection of scanning intermediates. Collectively, our data provide additional biochemical, molecular and physical evidence to underpin the scanning model of translation initiation in eukaryotes.
Collapse
|
21
|
Su D, Yuan B, Su C, Zhang Y. A 54-kDa short variant of DHX33 functions in regulating mRNA translation. J Cell Physiol 2019; 234:15308-15319. [PMID: 30684270 DOI: 10.1002/jcp.28178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/10/2019] [Indexed: 01/24/2023]
Abstract
DEAH box protein DHX33 has been found to be necessary for cell proliferation and early development of multicellular organisms. It plays diverse roles in regulating gene transcription, ribosome RNA synthesis, and protein translation. Dysregulation of DHX33 has been observed in various human cancers. In this study, we identified a short DHX33 variant in cells. The short DHX33 (hereafter referred to as DHX33-2) has only 534 amino acids, which completely matches the C-terminal helicase domain of full-length DHX33 (DHX33-1). Different from DHX33-1, which mainly localizes to the nucleus, DHX33-2 preferentially localizes to the cytoplasm. Through protein immunoprecipitation and RNA- immunoprecipitation analysis, we found that DHX33-2 interacts with DDX3, eIF3, hnRNPs, poly (A) binding protein, and a subset of mRNAs. Further RNA sequencing analysis showed that DHX33 binds to a subset of mRNAs important in cell proliferation. DHX33-2 stimulates the translation for specific mRNAs. Our study for the first time demonstrates the function of a short DHX33 variant in protein translation.
Collapse
Affiliation(s)
- Dan Su
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Baolei Yuan
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Chenjing Su
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Yandong Zhang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| |
Collapse
|
22
|
DHX33 Interacts with AP-2β To Regulate Bcl-2 Gene Expression and Promote Cancer Cell Survival. Mol Cell Biol 2019; 39:MCB.00017-19. [PMID: 31182639 DOI: 10.1128/mcb.00017-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 05/29/2019] [Indexed: 12/31/2022] Open
Abstract
The RNA helicase DHX33 has been found to be overexpressed in human cancers, where it promotes cancer development. Previous reports have shown that DHX33 deficiency caused cancer cell apoptosis, but the underlying mechanism remains unknown. In this study, we discovered that DHX33 regulates Bcl-2 family protein expression. In multiple human cancer cell lines, DHX33 was found to stimulate the transcription of Bcl-2 Mechanistically, we found that DHX33 interacts with the AP-2β transcription factor and acts as a coactivator to stimulate Bcl-2 gene transcription. DHX33 deficiency abolished the loading of AP-2β onto the promoter of Bcl-2 and thereby reduced the recruitment of active RNA polymerase II during transcription initiation. Acute knockdown of DHX33 in multiple human cancer cells caused decreased Bcl-2 protein level, which ultimately triggered mitochondrion-mediated cellular apoptosis. In addition, we found that normal human lung and mammary epithelial cells were less sensitive to acute DHX33 knockdown, implying that cancer cells are uniquely responsive to DHX33 reduction. These data support the notion that disruption of DHX33 function could be an important application for cancer therapy.
Collapse
|
23
|
Perčulija V, Ouyang S. Diverse Roles of DEAD/DEAH-Box Helicases in Innate Immunity and Diseases. HELICASES FROM ALL DOMAINS OF LIFE 2019. [PMCID: PMC7158350 DOI: 10.1016/b978-0-12-814685-9.00009-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
DEAD/DEAH-box helicases are enzymes that belong to the DEAD/H-box family of SF2 helicase superfamily. These enzymes are essential in RNA metabolism, where they are involved in a number of processes that require manipulation of RNA structure. Recent studies have found that some DEAD/DEAH-box helicases play important roles in innate immunity, where they act as sensors of cytosolic DNA/RNA, as adaptor proteins, or as regulators of signaling and gene expression. In spite of their function in immunity, DEAD/DEAH-box helicases can also be hijacked and exploited by viruses to circumvent detection and aid in viral replication. These findings not only imply that DEAD/DEAH-box helicases have a broader function than previously thought, but also give us a much better understanding of immune mechanisms and diseases that arise due to the dysregulation or evasion thereof. In this chapter, we demonstrate the known scope of activities of human DEAD/DEAH-box helicases in innate immunity and interaction with viruses or other pathogens. Additionally, we give an outline of diseases in which they are, or may be, involved in the context of immunity.
Collapse
|
24
|
Wang J, Yuan Z, Zhang Y. Alternative translation initiation from two in-frame start codons in DHX33 gene. Biochem Biophys Res Commun 2018; 502:501-507. [PMID: 29864424 DOI: 10.1016/j.bbrc.2018.05.201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 05/29/2018] [Indexed: 11/20/2022]
Abstract
DHX33 has been shown to play key roles in promoting cell proliferation. We have previously found that DHX33 protein is a doublet. In this report, we discovered that DHX33 doublet is due to alternative translation initiation by two in-frame initiation codons. This is supported by studies from both cell lines and mouse models. DHX33 translation initiation from either AUG codon happens at equal efficiency. Short DHX33 protein has similar cellular location and functions with full-length DHX33. Our results suggest that leaky scanning normally occur in DHX33 mRNA translation, which may serve as a safeguard mechanism to ensure optimal DHX33 translation efficiency. This is the first report of DEAD/DEAH box proteins that can be regulated by alternative translation initiation.
Collapse
Affiliation(s)
- Jiuling Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China; Bioimaging Core, Faculty of Health Sciences, University of Macau, Macau, China
| | - Zhen Yuan
- Bioimaging Core, Faculty of Health Sciences, University of Macau, Macau, China
| | - Yandong Zhang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| |
Collapse
|
25
|
Wang X, Ge W, Zhang Y. Recombinant DHX33 Protein Possesses Dual DNA/RNA Helicase Activity. Biochemistry 2018; 58:250-258. [PMID: 29870660 DOI: 10.1021/acs.biochem.8b00166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RNA helicase DHX33 has been shown to participate in a variety of cellular activities, including ribosome biogenesis, protein translation, and gene transcription. We and others further discovered that DHX33 is strongly expressed in several types of human cancers and plays important roles in promoting cancer cell proliferation. To better understand the molecular mechanism for DHX33 in exerting its biological functions, we purified recombinant DHX33 and performed biochemical studies in vitro. DHX33 protein was found to have ATPase activity that is dependent on DNA or RNA duplexes. The ATPase activity of DHX33 is coupled with its RNA/DNA unwinding activity. If a key residue in the ATP binding site were mutated, the mutant DHX33 could not unwind DNA/RNA duplexes. Furthermore, a deletion mutant of a RKK motif previously identified to be involved in ribosome DNA binding could still unwind DNA duplexes, albeit with reduced efficiency. In summary, our study reveals that purified DHX33 protein possesses unwinding activity toward DNA and RNA duplexes.
Collapse
Affiliation(s)
- Xingshun Wang
- Department of Biology , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , P. R. China.,Faculty of Health Sciences , University of Macau , Macau , China
| | - Wei Ge
- Faculty of Health Sciences , University of Macau , Macau , China
| | - Yandong Zhang
- Department of Biology , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , P. R. China
| |
Collapse
|
26
|
Shirokikh NE, Preiss T. Translation initiation by cap-dependent ribosome recruitment: Recent insights and open questions. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1473. [PMID: 29624880 DOI: 10.1002/wrna.1473] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 02/02/2018] [Accepted: 02/14/2018] [Indexed: 12/14/2022]
Abstract
Gene expression universally relies on protein synthesis, where ribosomes recognize and decode the messenger RNA template by cycling through translation initiation, elongation, and termination phases. All aspects of translation have been studied for decades using the tools of biochemistry and molecular biology available at the time. Here, we focus on the mechanism of translation initiation in eukaryotes, which is remarkably more complex than prokaryotic initiation and is the target of multiple types of regulatory intervention. The "consensus" model, featuring cap-dependent ribosome entry and scanning of mRNA leader sequences, represents the predominantly utilized initiation pathway across eukaryotes, although several variations of the model and alternative initiation mechanisms are also known. Recent advances in structural biology techniques have enabled remarkable molecular-level insights into the functional states of eukaryotic ribosomes, including a range of ribosomal complexes with different combinations of translation initiation factors that are thought to represent bona fide intermediates of the initiation process. Similarly, high-throughput sequencing-based ribosome profiling or "footprinting" approaches have allowed much progress in understanding the elongation phase of translation, and variants of them are beginning to reveal the remaining mysteries of initiation, as well as aspects of translation termination and ribosomal recycling. A current view on the eukaryotic initiation mechanism is presented here with an emphasis on how recent structural and footprinting results underpin axioms of the consensus model. Along the way, we further outline some contested mechanistic issues and major open questions still to be addressed. This article is categorized under: Translation > Translation Mechanisms Translation > Translation Regulation RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
Collapse
Affiliation(s)
- Nikolay E Shirokikh
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
- Victor Chang Cardiac Research Institute, Darlinghurst, Australia
| | - Thomas Preiss
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
- Victor Chang Cardiac Research Institute, Darlinghurst, Australia
| |
Collapse
|
27
|
Fraile JM, Campos-Iglesias D, Rodríguez F, Astudillo A, Vilarrasa-Blasi R, Verdaguer-Dot N, Prado MA, Paulo JA, Gygi SP, Martín-Subero JI, Freije JMP, López-Otín C. Loss of the deubiquitinase USP36 destabilizes the RNA helicase DHX33 and causes preimplantation lethality in mice. J Biol Chem 2017; 293:2183-2194. [PMID: 29273634 DOI: 10.1074/jbc.m117.788430] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 12/19/2017] [Indexed: 12/22/2022] Open
Abstract
Deubiquitinases are proteases with a wide functional diversity that profoundly impact multiple biological processes. Among them, the ubiquitin-specific protease 36 (USP36) has been implicated in the regulation of nucleolar activity. However, its functional relevance in vivo has not yet been fully described. Here, we report the generation of an Usp36-deficient mouse model to examine the function of this enzyme. We show that Usp36 depletion is lethal in preimplantation mouse embryos, where it blocks the transition from morula to blastocyst during embryonic development. USP36 reduces the ubiquitination levels and increases the stability of the DEAH-box RNA helicase DHX33, which is critically involved in ribosomal RNA synthesis and mRNA translation. In agreement with this finding, O-propargyl-puromycin incorporation experiments, Northern blot, and electron microscopy analyses demonstrated the role of USP36 in ribosomal RNA and protein synthesis. Finally, we show that USP36 down-regulation alters cell proliferation in human cancer cells by inducing both apoptosis and cell cycle arrest, and that reducing DHX33 levels through short hairpin RNA interference has the same effect. Collectively, these results support that Usp36 is essential for cell and organism viability because of its role in ribosomal RNA processing and protein synthesis, which is mediated, at least in part, by regulating DHX33 stability.
Collapse
Affiliation(s)
- Julia M Fraile
- From the Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, 33006-Oviedo, Spain
| | - Diana Campos-Iglesias
- From the Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, 33006-Oviedo, Spain
| | - Francisco Rodríguez
- From the Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, 33006-Oviedo, Spain
| | - Aurora Astudillo
- the Servicio de Anatomía Patológica, Hospital Universitario Central de Asturias, 33006-Oviedo, Spain
| | - Roser Vilarrasa-Blasi
- the Departamento de Anatomía Patológica, Farmacología y Microbiología, Universitat de Barcelona, IDIBAPS, 08036-Barcelona, Spain
| | - Nuria Verdaguer-Dot
- the Departamento de Anatomía Patológica, Farmacología y Microbiología, Universitat de Barcelona, IDIBAPS, 08036-Barcelona, Spain
| | - Miguel A Prado
- the Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, and
| | - Joao A Paulo
- the Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, and
| | - Steven P Gygi
- the Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, and
| | - José I Martín-Subero
- the Departamento de Anatomía Patológica, Farmacología y Microbiología, Universitat de Barcelona, IDIBAPS, 08036-Barcelona, Spain
| | - José M P Freije
- From the Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, 33006-Oviedo, Spain, .,the Centro de Investigación Biomédica en Red de Cáncer, Spain
| | - Carlos López-Otín
- From the Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, 33006-Oviedo, Spain, .,the Centro de Investigación Biomédica en Red de Cáncer, Spain
| |
Collapse
|
28
|
Fu J, Liu Y, Wang X, Yuan B, Zhang Y. Role of DHX33 in c-Myc-induced cancers. Carcinogenesis 2017; 38:649-660. [PMID: 28498893 DOI: 10.1093/carcin/bgx041] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 04/12/2017] [Indexed: 12/25/2022] Open
Abstract
Oncogene c-Myc is frequently amplified and activated in human cancers. Deregulation of c-Myc protein has been shown to occur in 30% of all human cancers, especially in hematopoietic malignancies. As a transcription factor, c-Myc has been shown to regulate up to 15% of all human genome genes, controlling diverse cellular activities including cell cycle, ribosome biogenesis, protein synthesis, metabolism, apoptosis and angiogenesis. In this report, we provide evidence that the RNA helicase DHX33 is a critical downstream target of c-Myc. Myc binds to DHX33 upstream promoter region and stimulates its transcription. Elevated DHX33 protein is pivotal for c-Myc to drive tumor formation. Knockdown of DHX33 to basal levels in c-Myc overexpressing cells significantly reduced cell proliferation, cell migration and anchorage-independent cell growth in vitro and in vivo. Additionally, we found that DHX33 promotes MMP9, MMP14 and urokinase-type plasminogen activator (PLAU) transcription by directly binding to their promoters, thus promoting cancer cell migration. DHX33 protein was overexpressed in a certain subset of human non-Hodgkin's lymphoma tissues. Finally, knockdown of DHX33 significantly inhibits the development of Myc-induced acute myeloid leukemia. Overall, our results implicate the important role for DHX33 in Myc-induced cancer and point toward its potential therapeutic value in Myc driven cancers.
Collapse
Affiliation(s)
- Jijun Fu
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Yuchu Liu
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Xingshun Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Baolei Yuan
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Yandong Zhang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| |
Collapse
|
29
|
DHX33 Transcriptionally Controls Genes Involved in the Cell Cycle. Mol Cell Biol 2016; 36:2903-2917. [PMID: 27601587 DOI: 10.1128/mcb.00314-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/30/2016] [Indexed: 02/08/2023] Open
Abstract
The RNA helicase DHX33 has been shown to be a critical regulator of cell proliferation and growth. However, the underlying mechanisms behind DHX33 function remain incompletely understood. We present original evidence in multiple cell lines that DHX33 transcriptionally controls the expression of genes involved in the cell cycle, notably cyclin, E2F1, cell division cycle (CDC), and minichromosome maintenance (MCM) genes. DHX33 physically associates with the promoters of these genes and controls the loading of active RNA polymerase II onto these promoters. DHX33 deficiency abrogates cell cycle progression and DNA replication and leads to cell apoptosis. In zebrafish, CRISPR-mediated knockout of DHX33 results in downregulation of cyclin A2, cyclin B2, cyclin D1, cyclin E2, cdc6, cdc20, E2F1, and MCM complexes in DHX33 knockout embryos. Additionally, we found the overexpression of DHX33 in a subset of non-small-cell lung cancers and in Ras-mutated human lung cancer cell lines. Forced reduction of DHX33 in these cancer cells abolished tumor formation in vivo Our study demonstrates for the first time that DHX33 acts as a direct transcriptional regulator to promote cell cycle progression and plays an important role in driving cell proliferation during both embryo development and tumorigenesis.
Collapse
|
30
|
The multiple functions of RNA helicases as drivers and regulators of gene expression. Nat Rev Mol Cell Biol 2016; 17:426-38. [PMID: 27251421 DOI: 10.1038/nrm.2016.50] [Citation(s) in RCA: 178] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
RNA helicases comprise the largest family of enzymes involved in the metabolism of mRNAs, the processing and fate of which rely on their packaging into messenger ribonucleoprotein particles (mRNPs). In this Review, we describe how the capacity of some RNA helicases to either remodel or lock the composition of mRNP complexes underlies their pleiotropic functions at different steps of the gene expression process. We illustrate the roles of RNA helicases in coordinating gene expression steps and programmes, and propose that RNA helicases function as molecular drivers and guides of the progression of their mRNA substrates from one RNA-processing factory to another, to a productive mRNA pool that leads to protein synthesis or to unproductive mRNA pools that are stored or degraded.
Collapse
|
31
|
Tian QH, Zhang MF, Luo RG, Fu J, He C, Hu G, Zeng JS. DHX33 expression is increased in hepatocellular carcinoma and indicates poor prognosis. Biochem Biophys Res Commun 2016; 473:1163-1169. [DOI: 10.1016/j.bbrc.2016.04.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 04/08/2016] [Indexed: 01/22/2023]
|
32
|
Green KM, Linsalata AE, Todd PK. RAN translation-What makes it run? Brain Res 2016; 1647:30-42. [PMID: 27060770 DOI: 10.1016/j.brainres.2016.04.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/24/2016] [Accepted: 04/01/2016] [Indexed: 12/14/2022]
Abstract
Nucleotide-repeat expansions underlie a heterogeneous group of neurodegenerative and neuromuscular disorders for which there are currently no effective therapies. Recently, it was discovered that such repetitive RNA motifs can support translation initiation in the absence of an AUG start codon across a wide variety of sequence contexts, and that the products of these atypical translation initiation events contribute to neuronal toxicity. This review examines what we currently know and do not know about repeat associated non-AUG (RAN) translation in the context of established canonical and non-canonical mechanisms of translation initiation. We highlight recent findings related to RAN translation in three repeat expansion disorders: CGG repeats in fragile X-associated tremor ataxia syndrome (FXTAS), GGGGCC repeats in C9orf72 associated amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) and CAG repeats in Huntington disease. These studies suggest that mechanistic differences may exist for RAN translation dependent on repeat type, repeat reading frame, and the surrounding sequence context, but that for at least some repeats, RAN translation retains a dependence on some of the canonical translational initiation machinery. This article is part of a Special Issue entitled SI:RNA Metabolism in Disease.
Collapse
Affiliation(s)
- Katelyn M Green
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, United States; Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Alexander E Linsalata
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, United States; Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Peter K Todd
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, United States; Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, MI, United States; Veterans Affairs Medical Center, Ann Arbor, MI, United States.
| |
Collapse
|