1
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Liu MY, Lin KR, Chien YL, Yang BZ, Tsui LY, Chu HP, Wu CSP. ATR phosphorylates DHX9 at serine 321 to suppress R-loop accumulation upon genotoxic stress. Nucleic Acids Res 2024; 52:204-222. [PMID: 37930853 PMCID: PMC10783509 DOI: 10.1093/nar/gkad973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/19/2023] [Accepted: 10/16/2023] [Indexed: 11/08/2023] Open
Abstract
Aberrant DNA/RNA hybrids (R-loops) formed during transcription and replication disturbances pose threats to genome stability. DHX9 is an RNA helicase involved in R-loop resolution, but how DHX9 is regulated in response to genotoxic stress remains unclear. Here we report that DHX9 is phosphorylated at S321 and S688, with S321 phosphorylation primarily induced by ATR after DNA damage. Phosphorylation of DHX9 at S321 promotes its interaction with γH2AX, BRCA1 and RPA, and is required for its association with R-loops under genotoxic stress. Inhibition of ATR or expression of the non-phosphorylatable DHX9S321A prevents DHX9 from interacting with RPA and R-loops, leading to the accumulation of stress-induced R-loops. Furthermore, depletion of RPA reduces the association between DHX9 and γH2AX, and in vitro binding analysis confirms a direct interaction between DHX9 and RPA. Notably, cells with the non-phosphorylatable DHX9S321A variant exhibit hypersensitivity to genotoxic stress, while those expressing the phosphomimetic DHX9S321D variant prevent R-loop accumulation and display resistance to DNA damage agents. In summary, we uncover a new mechanism by which ATR directly regulates DHX9 through phosphorylation to eliminate stress-induced R-loops.
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Affiliation(s)
- Mei-Yin Liu
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
| | - Keng-Ru Lin
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
| | - Yuh-Ling Chien
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
| | - Bing-Ze Yang
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
| | - Li-Yu Tsui
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
| | | | - Ching-Shyi Peter Wu
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
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2
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Xiao K, Ullah I, Yang F, Wang J, Hou C, Liu Y, Li X. Comprehensive bioinformatics analysis of FXR1 across pan-cancer: Unraveling its diagnostic, prognostic, and immunological significance. Medicine (Baltimore) 2023; 102:e36456. [PMID: 38050239 PMCID: PMC10695598 DOI: 10.1097/md.0000000000036456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 11/13/2023] [Indexed: 12/06/2023] Open
Abstract
Fragile X-related protein 1 (FXR1) is an RNA-binding protein that belongs to the fragile X-related (FXR) family. Studies have shown that FXR1 plays an important role in cancer cell proliferation, invasion and migration and is differentially expressed in cancers. This study aimed to gain a comprehensive and systematic understanding of the analysis of FXR1's role in cancers. This would lead to a better understanding of how it contributes to the development and progression of various malignancies. this study conducted through The Cancer Genome Atlas (TCGA), GTEx, cBioPortal, TISIDB, GEPIA2 and HPA databases to investigated FXR1's role in cancers. For data analysis, various software platforms and web platforms were used, such as R, Cytoscape, hiplot plateform. A significant difference in FXR1 expression was observed across molecular and immune subtypes and across types of cancer. FXR1 expression correlates with disease-specific survival (DSS), and overall survival (OS) in several cancer pathways, further in progression-free interval (PFI) in most cancers. Additionally, FXR1 showed a correlation with genetic markers of immunomodulators in different cancer types. Our study provides insights into the role of FXR1 in promoting, inhibiting, and treating diverse cancers. FXR1 has the potential to serve as a diagnostic and prognostic biomarker for cancer, with therapeutic value in immune-based, targeted, or cytotoxic treatments. Further clinical validation and exploration of FXR1 in cancer treatment is necessary.
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Affiliation(s)
- Keyuan Xiao
- Changzhi People’s Hospital Affiliated to Changzhi Medical College, Changzhi, China
| | - Ihsan Ullah
- National Chinmedomics Research Center, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Fan Yang
- Changzhi People’s Hospital Affiliated to Changzhi Medical College, Changzhi, China
| | - Jiao Wang
- Changzhi People’s Hospital Affiliated to Changzhi Medical College, Changzhi, China
| | - Chunxia Hou
- Changzhi People’s Hospital Affiliated to Changzhi Medical College, Changzhi, China
| | - Yuqiang Liu
- National Chinmedomics Research Center, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Xinghua Li
- Changzhi People’s Hospital Affiliated to Changzhi Medical College, Changzhi, China
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3
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Venkadakrishnan J, Lahane G, Dhar A, Xiao W, Bhat KM, Pandita TK, Bhat A. Implications of Translesion DNA Synthesis Polymerases on Genomic Stability and Human Health. Mol Cell Biol 2023; 43:401-425. [PMID: 37439479 PMCID: PMC10448981 DOI: 10.1080/10985549.2023.2224199] [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: 01/31/2023] [Revised: 05/03/2023] [Accepted: 06/01/2023] [Indexed: 07/14/2023] Open
Abstract
Replication fork arrest-induced DNA double strand breaks (DSBs) caused by lesions are effectively suppressed in cells due to the presence of a specialized mechanism, commonly referred to as DNA damage tolerance (DDT). In eukaryotic cells, DDT is facilitated through translesion DNA synthesis (TLS) carried out by a set of DNA polymerases known as TLS polymerases. Another parallel mechanism, referred to as homology-directed DDT, is error-free and involves either template switching or fork reversal. The significance of the DDT pathway is well established. Several diseases have been attributed to defects in the TLS pathway, caused either by mutations in the TLS polymerase genes or dysregulation. In the event of a replication fork encountering a DNA lesion, cells switch from high-fidelity replicative polymerases to low-fidelity TLS polymerases, which are associated with genomic instability linked with several human diseases including, cancer. The role of TLS polymerases in chemoresistance has been recognized in recent years. In addition to their roles in the DDT pathway, understanding noncanonical functions of TLS polymerases is also a key to unraveling their importance in maintaining genomic stability. Here we summarize the current understanding of TLS pathway in DDT and its implication for human health.
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Affiliation(s)
| | - Ganesh Lahane
- Department of Pharmacy, Birla Institute of Technology and Sciences Pilani, Hyderabad Campus, Hyderabad, India
| | - Arti Dhar
- Department of Pharmacy, Birla Institute of Technology and Sciences Pilani, Hyderabad Campus, Hyderabad, India
| | - Wei Xiao
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Canada
| | - Krishna Moorthi Bhat
- Department of Molecular Medicine, University of South Florida, Tampa, Florida, USA
| | - Tej K. Pandita
- Center for Genomics and Precision Medicine, Texas A&M College of Medicine, Houston, Texas, USA
| | - Audesh Bhat
- Center for Molecular Biology, Central University of Jammu, UT Jammu and Kashmir, India
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4
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Wang Y, Guo Y, Song Y, Zou W, Zhang J, Yi Q, Xiao Y, Peng J, Li Y, Yao L. A pan-cancer analysis of the expression and molecular mechanism of DHX9 in human cancers. Front Pharmacol 2023; 14:1153067. [PMID: 37214432 PMCID: PMC10192771 DOI: 10.3389/fphar.2023.1153067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 04/21/2023] [Indexed: 05/24/2023] Open
Abstract
Finding new targets is necessary for understanding tumorigenesis and developing cancer therapeutics. DExH-box helicase 9 (DHX9) plays a central role in many cellular processes but its expression pattern and prognostic value in most types of cancer remain unclear. In this study, we extracted pan-cancer data from TCGA and GEO databases to explore the prognostic and immunological role of DHX9. The expression levels of DHX9 were then verified in tumor specimens by western blot and immunohistochemistry (IHC). The oncogenic roles of DHX9 in cancers were further verified by in vitro experiments. We first verified that DHX9 is highly expressed in most tumors but significantly decreased in kidney and thyroid cancers, and it is prominently correlated with the prognosis of patients with different tumors. The phosphorylation level of DHX9 was also increased in cancers. Enrichment analysis revealed that DHX9 was involved in Spliceosome, RNA transport and mRNA surveillance pathway. Furthermore, DHX9 expression exhibited strong correlations with immune cell infiltration, immune checkpoint genes, and tumor mutational burden (TMB)/microsatellite instability (MSI). In liver, lung, breast and renal cancer cells, the knockdown or depletion of DHX9 significantly affected the proliferation, metastasis and EMT process of cancer cells. In summary, this pan-cancer investigation provides a comprehensive understanding of the prognostic and immunological role of DHX9 in human cancers, and experiments indicated that DHX9 was a potential target for cancer treatment.
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Affiliation(s)
- Yanfeng Wang
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yongxin Guo
- Anesthesia and Operation Center, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Yanping Song
- Department of Anesthesiology, No. 922 Hospital of PLA, Hengyang, Hunan, China
| | - Wenbo Zou
- Department of General Surgery, No. 924 Hospital of PLA Joint Logistic Support Force, Guilin, Guangxi, China
| | - Junjie Zhang
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Qiong Yi
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yujie Xiao
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jing Peng
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yingqi Li
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lei Yao
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders (Xiangya Hospital), Changsha, China
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5
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Shin S, Hyun K, Lee J, Joo D, Kulikowicz T, Bohr V, Kim J, Hohng S. Werner syndrome protein works as a dimer for unwinding and replication fork regression. Nucleic Acids Res 2022; 51:337-348. [PMID: 36583333 PMCID: PMC9841404 DOI: 10.1093/nar/gkac1200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 11/28/2022] [Accepted: 12/05/2022] [Indexed: 12/31/2022] Open
Abstract
The determination of the oligomeric state of functional enzymes is essential for the mechanistic understanding of their catalytic activities. RecQ helicases have diverse biochemical activities, but it is still unclear how their activities are related to their oligomeric states. We use single-molecule multi-color fluorescence imaging to determine the oligomeric states of Werner syndrome protein (WRN) during its unwinding and replication fork regression activities. We reveal that WRN binds to a forked DNA as a dimer, and unwinds it without any change of its oligomeric state. In contrast, WRN binds to a replication fork as a tetramer, and is dimerized during activation of replication fork regression. By selectively inhibiting the helicase activity of WRN on specific strands, we reveal how the active dimers of WRN distinctly use the energy of ATP hydrolysis for repetitive unwinding and replication fork regression.
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Affiliation(s)
| | | | - Jinwoo Lee
- Department of Physics and Astronomy, Institute of Applied Physics, Seoul National University, Seoul, Republic of Korea
| | - Dongwon Joo
- Department of Physics and Astronomy, Institute of Applied Physics, Seoul National University, Seoul, Republic of Korea
| | - Tomasz Kulikowicz
- Section on DNA repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Vilhelm A Bohr
- Section on DNA repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Jaehoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Sungchul Hohng
- To whom correspondence should be addressed. Tel: +82 2 880 6593;
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6
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Tang F, Wang Y, Gao Z, Guo S, Wang Y. Polymerase η Recruits DHX9 Helicase to Promote Replication across Guanine Quadruplex Structures. J Am Chem Soc 2022; 144:14016-14020. [PMID: 35905379 PMCID: PMC9378570 DOI: 10.1021/jacs.2c05312] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
DNA polymerase η (Pol η) catalyzes accurate bypass of ultraviolet light-induced cyclobutane pyrimidine dimers, and it also functions in several other related processes, including bypassing DNA with unusual structures. Here, we performed unbiased proteome-wide profiling of Pol η-interacting proteins by using two independent approaches, i.e., proximity labeling and affinity pull-down followed by LC-MS/MS analysis. We identified several helicases, including DHX9, as novel Pol η-interacting proteins. Additionally, ChIP-Seq analysis showed that Pol η is enriched at guanine quadruplex (G4) structure sites in chromatin. Moreover, Pol η promotes the recruitment of DHX9 to G4 structure loci in chromatin and facilitates DHX9-mediated unwinding of G4 structures. Deficiency in Pol η or DHX9 leads to attenuated replication across G4 regions in genomic DNA. Together, we unveiled the interaction between Pol η and DHX9 and demonstrated that the interaction promotes the replicative bypass of G4 structures in chromatin.
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Affiliation(s)
- Feng Tang
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Yinan Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Zi Gao
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Shiyuan Guo
- Genetics, Genomics and Bioinformatics Graduate Program, University of California, Riverside, California 92521-0403, United States
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
- Genetics, Genomics and Bioinformatics Graduate Program, University of California, Riverside, California 92521-0403, United States
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7
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Chakraborty P, Hiom K. DHX9-dependent recruitment of BRCA1 to RNA promotes DNA end resection in homologous recombination. Nat Commun 2021; 12:4126. [PMID: 34226554 PMCID: PMC8257769 DOI: 10.1038/s41467-021-24341-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 06/07/2021] [Indexed: 01/08/2023] Open
Abstract
Double stranded DNA Breaks (DSB) that occur in highly transcribed regions of the genome are preferentially repaired by homologous recombination repair (HR). However, the mechanisms that link transcription with HR are unknown. Here we identify a critical role for DHX9, a RNA helicase involved in the processing of pre-mRNA during transcription, in the initiation of HR. Cells that are deficient in DHX9 are impaired in the recruitment of RPA and RAD51 to sites of DNA damage and fail to repair DSB by HR. Consequently, these cells are hypersensitive to treatment with agents such as camptothecin and Olaparib that block transcription and generate DSB that specifically require HR for their repair. We show that DHX9 plays a critical role in HR by promoting the recruitment of BRCA1 to RNA as part of the RNA Polymerase II transcription complex, where it facilitates the resection of DSB. Moreover, defects in DHX9 also lead to impaired ATR-mediated damage signalling and an inability to restart DNA replication at camptothecin-induced DSB. Together, our data reveal a previously unknown role for DHX9 in the DNA Damage Response that provides a critical link between RNA, RNA Pol II and the repair of DNA damage by homologous recombination. DHX9 is an RNA helicase involved in the processing of pre-mRNA during transcription. Here the authors reveal a role for DHX9 in the initiation of homologues recombination during the early steps of end-resection.
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Affiliation(s)
- Prasun Chakraborty
- Division of Cellular Medicine, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Scotland, United Kingdom
| | - Kevin Hiom
- Division of Cellular Medicine, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Scotland, United Kingdom.
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8
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Wu C, Shan Y, Wang S, Liu F. Dynamically probing ATP-dependent RNA helicase A-assisted RNA structure conversion using single molecule fluorescence resonance energy transfer. Protein Sci 2021; 30:1157-1168. [PMID: 33837988 DOI: 10.1002/pro.4081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 04/08/2021] [Indexed: 12/16/2022]
Abstract
RNA helicase A (RHA) as a member of DExH-box subgroup of helicase superfamily II, participates in diverse biological processes involved in RNA metabolism in organisms, and these RNA-mediated biological processes rely on RNA structure conversion. However, how RHA regulate the RNA structure conversion was still unknown. In order to unveil the mechanism of RNA structure conversion mediated by RHA, single molecule fluorescence resonance energy transfer was adopted to in our assay, and substrates RNA were from internal ribosome entry site of foot-and-mouth disease virus genome. We first found that the RNA structure conversion by RHA against thermodynamic equilibrium in vitro, and the process of dsRNA YZ converted to dsRNA XY through a tripartite intermediate state. In addition, the rate of the RNA structure conversion and the distribution of dsRNA YZ and XY were affected by ATP concentrations. Our study provides real-time insight into ATP-dependent RHA-assisted RNA structure conversion at the single molecule level, the mechanism displayed by RHA may help in understand how RHA contributes to many biological functions, and the basic mechanistic features illustrated in our work also underlay more complex protein-assisted RNA structure conversions.
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Affiliation(s)
- Chengcheng Wu
- Joint International Research Laboratory of Animal Health and Food Safety of Ministry of Education & Single Molecule Nanometry Laboratory (Sinmolab), Nanjing Agricultural University, Nanjing, China
| | - Yanke Shan
- Joint International Research Laboratory of Animal Health and Food Safety of Ministry of Education & Single Molecule Nanometry Laboratory (Sinmolab), Nanjing Agricultural University, Nanjing, China
| | - Shouyu Wang
- Joint International Research Laboratory of Animal Health and Food Safety of Ministry of Education & Single Molecule Nanometry Laboratory (Sinmolab), Nanjing Agricultural University, Nanjing, China.,Computational Optics Laboratory, Jiangnan University, Wuxi, China
| | - Fei Liu
- Joint International Research Laboratory of Animal Health and Food Safety of Ministry of Education & Single Molecule Nanometry Laboratory (Sinmolab), Nanjing Agricultural University, Nanjing, China
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9
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Das T, Pal S, Ganguly A. Human RecQ helicases in transcription-associated stress management: bridging the gap between DNA and RNA metabolism. Biol Chem 2021; 402:617-636. [PMID: 33567180 DOI: 10.1515/hsz-2020-0324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 01/24/2021] [Indexed: 12/13/2022]
Abstract
RecQ helicases are a highly conserved class of DNA helicases that play crucial role in almost all DNA metabolic processes including replication, repair and recombination. They are able to unwind a wide variety of complex intermediate DNA structures that may result from cellular DNA transactions and hence assist in maintaining genome integrity. Interestingly, a huge number of recent reports suggest that many of the RecQ family helicases are directly or indirectly involved in regulating transcription and gene expression. On one hand, they can remove complex structures like R-loops, G-quadruplexes or RNA:DNA hybrids formed at the intersection of transcription and replication. On the other hand, emerging evidence suggests that they can also regulate transcription by directly interacting with RNA polymerase or recruiting other protein factors that may regulate transcription. This review summarizes the up to date knowledge on the involvement of three human RecQ family proteins BLM, WRN and RECQL5 in transcription regulation and management of transcription associated stress.
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Affiliation(s)
- Tulika Das
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur721302, India
| | - Surasree Pal
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur721302, India
| | - Agneyo Ganguly
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur721302, India
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10
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Pan YQ, Xing L. The Current View on the Helicase Activity of RNA Helicase A and Its Role in Gene Expression. Curr Protein Pept Sci 2020; 22:29-40. [PMID: 33143622 DOI: 10.2174/1389203721666201103084122] [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] [Received: 05/23/2020] [Revised: 08/18/2020] [Accepted: 09/09/2020] [Indexed: 11/22/2022]
Abstract
RNA helicase A (RHA) is a DExH-box helicase that plays regulatory roles in a variety of cellular processes, including transcription, translation, RNA splicing, editing, transport, and processing, microRNA genesis and maintenance of genomic stability. It is involved in virus replication, oncogenesis, and innate immune response. RHA can unwind nucleic acid duplex by nucleoside triphosphate hydrolysis. The insight into the molecular mechanism of helicase activity is fundamental to understanding the role of RHA in the cell. Herein, we reviewed the current advances on the helicase activity of RHA and its relevance to gene expression, particularly, to the genesis of circular RNA.
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Affiliation(s)
- Yuan-Qing Pan
- Institute of Biomedical Sciences, Shanxi University, 92 Wucheng Road, Taiyuan 030006, Shanxi province, China
| | - Li Xing
- Institute of Biomedical Sciences, Shanxi University, 92 Wucheng Road, Taiyuan 030006, Shanxi province, China
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11
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Gulliver C, Hoffmann R, Baillie GS. The enigmatic helicase DHX9 and its association with the hallmarks of cancer. Future Sci OA 2020; 7:FSO650. [PMID: 33437516 PMCID: PMC7787180 DOI: 10.2144/fsoa-2020-0140] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/20/2020] [Indexed: 12/16/2022] Open
Abstract
Much interest has been expended lately in characterizing the association between DExH-Box helicase 9 (DHX9) dysregulation and malignant development, however, the enigmatic nature of DHX9 has caused conflict as to whether it regularly functions as an oncogene or tumor suppressor. The impact of DHX9 on malignancy appears to be cell-type specific, dependent upon the availability of binding partners and activation of inter-connected signaling pathways. Realization of DHX9's pivotal role in the development of several hallmarks of cancer has boosted the enzyme's potential as a cancer biomarker and therapeutic target, opening up novel avenues for exploring DHX9 in precision medicine applications. Our review discusses the ascribed functions of DHX9 in cancer, explores its enigmatic nature and potential as an antineoplastic target.
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Affiliation(s)
- Chloe Gulliver
- Institute of Cardiovascular & Medical Science, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Ralf Hoffmann
- Institute of Cardiovascular & Medical Science, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
- Philips Research Europe, High Tech Campus, Eindhoven, The Netherlands
| | - George S Baillie
- Institute of Cardiovascular & Medical Science, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
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12
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Dhar S, Datta A, Brosh RM. DNA helicases and their roles in cancer. DNA Repair (Amst) 2020; 96:102994. [PMID: 33137625 DOI: 10.1016/j.dnarep.2020.102994] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 12/15/2022]
Abstract
DNA helicases, known for their fundamentally important roles in genomic stability, are high profile players in cancer. Not only are there monogenic helicase disorders with a strong disposition to cancer, it is well appreciated that helicase variants are associated with specific cancers (e.g., breast cancer). Flipping the coin, DNA helicases are frequently overexpressed in cancerous tissues and reduction in helicase gene expression results in reduced proliferation and growth capacity, as well as DNA damage induction and apoptosis of cancer cells. The seminal roles of helicases in the DNA damage and replication stress responses, as well as DNA repair pathways, validate their vital importance in cancer biology and suggest their potential values as targets in anti-cancer therapy. In recent years, many laboratories have characterized the specialized roles of helicase to resolve transcription-replication conflicts, maintain telomeres, mediate cell cycle checkpoints, remodel stalled replication forks, and regulate transcription. In vivo models, particularly mice, have been used to interrogate helicase function and serve as a bridge for preclinical studies that may lead to novel therapeutic approaches. In this review, we will summarize our current knowledge of DNA helicases and their roles in cancer, emphasizing the latest developments.
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Affiliation(s)
- Srijita Dhar
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Arindam Datta
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Robert M Brosh
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
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13
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Mutations in conserved functional domains of human RecQ helicases are associated with diseases and cancer: A review. Biophys Chem 2020; 265:106433. [DOI: 10.1016/j.bpc.2020.106433] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/06/2020] [Accepted: 07/11/2020] [Indexed: 12/12/2022]
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14
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Li M, Klungland A. Modifications and interactions at the R-loop. DNA Repair (Amst) 2020; 96:102958. [PMID: 32961406 DOI: 10.1016/j.dnarep.2020.102958] [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] [Received: 07/17/2020] [Revised: 08/24/2020] [Accepted: 08/28/2020] [Indexed: 10/23/2022]
Abstract
R-loops are tripartite structures consisting of an RNA:DNA hybrid and a displaced single-stranded DNA [1]. They are widespread and occupy up to 5 % of the mammalian genomes [2]. R-loops have a key role in genome stability, and known functions associated with gene regulation, DNA replication, chromatin patterning, immunoglobuline gene recombination and DNA Double-strand break repair [3-7]. Novel methodology, including the application of the S9.6 antibody, have more recently led to detailed knowledge on the genome-wide distribution of the R-loops as well as the identification of the R-loop interactome [8-10]. The regulation of R-loops was recently shown to also depend on dynamic RNA-methylation, including METTL3/14 dependent 6-methylAdenines (m6As) and METTL8 dependent 3-methylCytosines (m3Cs) [11-13].
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Affiliation(s)
- Miaomiao Li
- Department of Microbiology, Oslo University Hospital, Rikshospitalet, NO-0027, Oslo, Norway; Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, NO-0317, Oslo, Norway
| | - Arne Klungland
- Department of Microbiology, Oslo University Hospital, Rikshospitalet, NO-0027, Oslo, Norway; Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, NO-0317, Oslo, Norway.
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15
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Amparo C, Clark J, Bedell V, Murata-Collins JL, Martella M, Pichiorri F, Warner EF, Abdelhamid MAS, Waller ZAE, Smith SS. Duplex DNA from Sites of Helicase-Polymerase Uncoupling Links Non-B DNA Structure Formation to Replicative Stress. Cancer Genomics Proteomics 2020; 17:101-115. [PMID: 32108033 DOI: 10.21873/cgp.20171] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 01/25/2020] [Accepted: 01/27/2020] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Replication impediments can produce helicase-polymerase uncoupling allowing lagging strand synthesis to continue for as much as 6 kb from the site of the impediment. MATERIALS AND METHODS We developed a cloning procedure designed to recover fragments from lagging strand near the helicase halt site. RESULTS A total of 62% of clones from a p53-deficient tumor cell line (PC3) and 33% of the clones from a primary cell line (HPS-19I) were within 5 kb of a G-quadruplex forming sequence. Analyses of a RACK7 gene sequence, that was cloned multiple times from the PC3 line, revealed multiple deletions in region about 1 kb from the cloned region that was present in a non-B conformation. Sequences from the region formed G-quadruplex and i-motif structures under physiological conditions. CONCLUSION Defects in components of non-B structure suppression systems (e.g. p53 helicase targeting) promote replication-linked damage selectively targeted to sequences prone to G-quadruplex and i-motif formation.
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Affiliation(s)
- Camille Amparo
- Division of Urology, City of Hope National Medical Center, Duarte, CA, U.S.A.,Beckman Research Institute, City of Hope, Duarte, CA, U.S.A
| | - Jarrod Clark
- Division of Urology, City of Hope National Medical Center, Duarte, CA, U.S.A.,Beckman Research Institute, City of Hope, Duarte, CA, U.S.A
| | - Victoria Bedell
- Division of Cytogenetics, City of Hope National Medical Center, Duarte, CA, U.S.A
| | | | - Marianna Martella
- Judy and Bernard Briskin Center for Multiple Myeloma Research, City of Hope National Medical Center, Duarte, CA, U.S.A.,Hematological Malignancies and Translational Science, City of Hope National Medical Center, Duarte, CA, U.S.A
| | - Flavia Pichiorri
- Judy and Bernard Briskin Center for Multiple Myeloma Research, City of Hope National Medical Center, Duarte, CA, U.S.A.,Hematological Malignancies and Translational Science, City of Hope National Medical Center, Duarte, CA, U.S.A
| | - Emily F Warner
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, U.K
| | | | - Zoë A E Waller
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, U.K
| | - Steven S Smith
- Beckman Research Institute, City of Hope, Duarte, CA, U.S.A. .,Hematological Malignancies and Translational Science, City of Hope National Medical Center, Duarte, CA, U.S.A
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16
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Palombo R, Verdile V, Paronetto MP. Poison-Exon Inclusion in DHX9 Reduces Its Expression and Sensitizes Ewing Sarcoma Cells to Chemotherapeutic Treatment. Cells 2020; 9:cells9020328. [PMID: 32023846 PMCID: PMC7072589 DOI: 10.3390/cells9020328] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 01/27/2020] [Accepted: 01/29/2020] [Indexed: 02/07/2023] Open
Abstract
Alternative splicing is a combinatorial mechanism by which exons are joined to produce multiple mRNA variants, thus expanding the coding potential and plasticity of eukaryotic genomes. Defects in alternative splicing regulation are associated with several human diseases, including cancer. Ewing sarcoma is an aggressive tumor of bone and soft tissue, mainly affecting adolescents and young adults. DHX9 is a key player in Ewing sarcoma malignancy, and its expression correlates with worse prognosis in patients. In this study, by screening a library of siRNAs, we have identified splicing factors that regulate the alternative inclusion of a poison exon in DHX9 mRNA, leading to its downregulation. In particular, we found that hnRNPM and SRSF3 bind in vivo to this poison exon and suppress its inclusion. Notably, DHX9 expression correlates with that of SRSF3 and hnRNPM in Ewing sarcoma patients. Furthermore, downregulation of SRSF3 or hnRNPM inhibited DHX9 expression and Ewing sarcoma cell proliferation, while sensitizing cells to chemotherapeutic treatment. Hence, our study suggests that inhibition of hnRNPM and SRSF3 expression or activity could be exploited as a therapeutic tool to enhance the efficacy of chemotherapy in Ewing sarcoma.
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Affiliation(s)
- Ramona Palombo
- Laboratory of Cellular and Molecular Neurobiology, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy; (R.P.); (V.V.)
| | - Veronica Verdile
- Laboratory of Cellular and Molecular Neurobiology, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy; (R.P.); (V.V.)
- Department of Movement, Human and Health Sciences, Università degli Studi di Roma “Foro Italico”, Piazza Lauro de Bosis, 15, 00135 Rome, Italy
| | - Maria Paola Paronetto
- Laboratory of Cellular and Molecular Neurobiology, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy; (R.P.); (V.V.)
- Department of Movement, Human and Health Sciences, Università degli Studi di Roma “Foro Italico”, Piazza Lauro de Bosis, 15, 00135 Rome, Italy
- Correspondence: ; Tel.:+39-0636733576
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17
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Ayoubi LE, Dumay-Odelot H, Chernev A, Boissier F, Minvielle-Sébastia L, Urlaub H, Fribourg S, Teichmann M. The hRPC62 subunit of human RNA polymerase III displays helicase activity. Nucleic Acids Res 2019; 47:10313-10326. [PMID: 31529052 PMCID: PMC6821166 DOI: 10.1093/nar/gkz788] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 08/30/2019] [Accepted: 09/12/2019] [Indexed: 11/20/2022] Open
Abstract
In Eukaryotes, tRNAs, 5S RNA and U6 RNA are transcribed by RNA polymerase (Pol) III. Human Pol III is composed of 17 subunits. Three specific Pol III subunits form a stable ternary subcomplex (RPC62-RPC39-RPC32α/β) being involved in pre-initiation complex formation. No paralogues for subunits of this subcomplex subunits have been found in Pols I or II, but hRPC62 was shown to be structurally related to the general Pol II transcription factor hTFIIEα. Here we show that these structural homologies extend to functional similarities. hRPC62 as well as hTFIIEα possess intrinsic ATP-dependent 3′-5′ DNA unwinding activity. The ATPase activities of both proteins are stimulated by single-stranded DNA. Moreover, the eWH domain of hTFIIEα can replace the first eWH (eWH1) domain of hRPC62 in ATPase and DNA unwinding assays. Our results identify intrinsic enzymatic activities in hRPC62 and hTFIIEα.
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Affiliation(s)
- Leyla El Ayoubi
- ARNA Laboratory, Inserm U1212, CNRS UMR 5320, Université de Bordeaux, 33000 Bordeaux, France
| | - Hélène Dumay-Odelot
- ARNA Laboratory, Inserm U1212, CNRS UMR 5320, Université de Bordeaux, 33000 Bordeaux, France
- Correspondence may also be addressed to Hélène Dumay-Odelot.
| | - Aleksandar Chernev
- Max Planck Institute for Biophysical Chemistry, Research group Mass Spectrometry, Am Faßberg 11, 37077 Göttingen, Germany
| | - Fanny Boissier
- ARNA Laboratory, Inserm U1212, CNRS UMR 5320, Université de Bordeaux, 33000 Bordeaux, France
| | | | - Henning Urlaub
- Max Planck Institute for Biophysical Chemistry, Research group Mass Spectrometry, Am Faßberg 11, 37077 Göttingen, Germany
- Bioanalytics, Institute for Clinical Chemistry, University Medical Center, Robert-Koch-Strasse 420, 37075 Göttingen, Germany
| | - Sébastien Fribourg
- ARNA Laboratory, Inserm U1212, CNRS UMR 5320, Université de Bordeaux, 33000 Bordeaux, France
| | - Martin Teichmann
- ARNA Laboratory, Inserm U1212, CNRS UMR 5320, Université de Bordeaux, 33000 Bordeaux, France
- To whom correspondence should be addressed. Tel: +33 5 5757 4647;
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18
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Chang EYC, Tsai S, Aristizabal MJ, Wells JP, Coulombe Y, Busatto FF, Chan YA, Kumar A, Dan Zhu Y, Wang AYH, Fournier LA, Hieter P, Kobor MS, Masson JY, Stirling PC. MRE11-RAD50-NBS1 promotes Fanconi Anemia R-loop suppression at transcription-replication conflicts. Nat Commun 2019; 10:4265. [PMID: 31537797 PMCID: PMC6753070 DOI: 10.1038/s41467-019-12271-w] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 08/30/2019] [Indexed: 12/25/2022] Open
Abstract
Ectopic R-loop accumulation causes DNA replication stress and genome instability. To avoid these outcomes, cells possess a range of anti-R-loop mechanisms, including RNaseH that degrades the RNA moiety in R-loops. To comprehensively identify anti-R-loop mechanisms, we performed a genome-wide trigenic interaction screen in yeast lacking RNH1 and RNH201. We identified >100 genes critical for fitness in the absence of RNaseH, which were enriched for DNA replication fork maintenance factors including the MRE11-RAD50-NBS1 (MRN) complex. While MRN has been shown to promote R-loops at DNA double-strand breaks, we show that it suppresses R-loops and associated DNA damage at transcription-replication conflicts. This occurs through a non-nucleolytic function of MRE11 that is important for R-loop suppression by the Fanconi Anemia pathway. This work establishes a novel role for MRE11-RAD50-NBS1 in directing tolerance mechanisms at transcription-replication conflicts.
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Affiliation(s)
| | - Shuhe Tsai
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | - Maria J Aristizabal
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Vancouver, V5Z 4H4, Canada
| | - James P Wells
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | - Yan Coulombe
- Centre Hospitalier Universitaire de Québec-Universite Laval, Oncology Axis, Quebec City, G1R 2J6, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec City, G1V 0A6, Canada
| | - Franciele F Busatto
- Centre Hospitalier Universitaire de Québec-Universite Laval, Oncology Axis, Quebec City, G1R 2J6, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec City, G1V 0A6, Canada
| | - Yujia A Chan
- The Broad Institute of MIT and Harvard University, Cambridge, MA, 02142, USA
| | - Arun Kumar
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | - Yi Dan Zhu
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | | | | | - Philip Hieter
- Michael Smith Laboratories, University of British Columbia, Vancouver, V6T 1Z4, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, V5Z 4H4, Canada
| | - Michael S Kobor
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Vancouver, V5Z 4H4, Canada
| | - Jean-Yves Masson
- Centre Hospitalier Universitaire de Québec-Universite Laval, Oncology Axis, Quebec City, G1R 2J6, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec City, G1V 0A6, Canada
| | - Peter C Stirling
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada.
- Department of Medical Genetics, University of British Columbia, Vancouver, V5Z 4H4, Canada.
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19
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Ding X, Jia X, Wang C, Xu J, Gao SJ, Lu C. A DHX9-lncRNA-MDM2 interaction regulates cell invasion and angiogenesis of cervical cancer. Cell Death Differ 2019; 26:1750-1765. [PMID: 30518908 PMCID: PMC6748089 DOI: 10.1038/s41418-018-0242-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 10/07/2018] [Accepted: 11/07/2018] [Indexed: 02/05/2023] Open
Abstract
Cervical cancer (CC) is the third most common carcinoma and the fourth leading cause of cancer-associated mortality in women. Here, we report that MDM2-DHX9 interaction mediates CC motility and angiogenesis in a long noncoding RNA-dependent fashion. A long noncoding RNA, named lnc-CCDST, is significantly downregulated in CC tissues, and binds to pro-oncogenic DHX9. DHX9 is upregulated in CC tissue, and promotes CC cell motility and angiogenesis. The lnc-CCDST and DHX9 interaction promotes DHX9 degradation through the ubiquitin proteasome pathway. Furthermore, DHX9 bound to E3 ubiquitin ligase MDM2, and this interaction is enhanced by lnc-CCDST. Thus, lnc-CCDST promotes DHX9 degradation by serving as a scaffold to facilitate the formation of MDM2 and DHX9 complexes. Moreover, HPV oncogenes E6 and E7 abolish the expression of lnc-CCDST resulting in the increase of DHX9. Our results have revealed a novel mechanism by which high-risk HPVs promote motility and angiogenesis of CC by inhibiting expression of lnc-CCDST to disrupt MDM2 and DHX9 interaction, and DHX9 degradation, and identified a potential therapeutic target for CC.
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Affiliation(s)
- Xiangya Ding
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, People's Republic of China
- Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China
- Department of Microbiology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Xuemei Jia
- Department of Gynecology, Nanjing Maternity and Child Health Hospital, the Affiliated Obstetrics and Gynaecology Hospital of Nanjing Medical University, Nanjing, People's Republic of China
| | - Cong Wang
- Department of Pathology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of China
| | - Jingyun Xu
- Department of Microbiology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Shou-Jiang Gao
- Department of Microbiology, Nanjing Medical University, Nanjing, People's Republic of China
- Laboratory of Human Virology and Oncology, Shantou University Medical College, Shantou, Guangdong, China
- UPMC Hillman Cancer Center, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, 15232, USA
| | - Chun Lu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, People's Republic of China.
- Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China.
- Department of Microbiology, Nanjing Medical University, Nanjing, People's Republic of China.
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20
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Cellular RNA Helicase DHX9 Interacts with the Essential Epstein-Barr Virus (EBV) Protein SM and Restricts EBV Lytic Replication. J Virol 2019; 93:JVI.01244-18. [PMID: 30541834 DOI: 10.1128/jvi.01244-18] [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: 08/13/2018] [Accepted: 11/28/2018] [Indexed: 12/11/2022] Open
Abstract
Epstein-Barr virus (EBV) SM protein is an RNA-binding protein that has multiple posttranscriptional gene regulatory functions essential for EBV lytic replication. In this study, we identified an interaction between SM and DHX9, a DExH-box helicase family member, by mass spectrometry and coimmunoprecipitation. DHX9 participates in many cellular pathways involving RNA, including transcription, processing, transport, and translation. DHX9 enhances virus production or infectivity of a wide variety of DNA and RNA viruses. Surprisingly, an increase in EBV late gene expression and virion production occurred upon knockdown of DHX9. To further characterize the SM-DHX9 interaction, we performed immunofluorescence microscopy of EBV-infected cells and found that DHX9 partially colocalized with SM in nuclear foci during EBV lytic replication. However, the positive effect of DHX9 depletion on EBV lytic gene expression was not confined to SM-dependent genes, indicating that the antiviral effect of DHX9 was not mediated through its effects on SM. DHX9 enhanced activation of innate antiviral pathways comprised of several interferon-stimulated genes that are active against EBV. SM inhibited the transcription-activating function of DHX9, which acts through cAMP response elements (CREs), suggesting that SM may also act to counteract DHX9's antiviral functions during lytic replication.IMPORTANCE This study identifies an interaction between Epstein-Barr virus (EBV) SM protein and cellular helicase DHX9, exploring the roles that this interaction plays in viral infection and host defenses. Whereas most previous studies established DHX9 as a proviral factor, we demonstrate that DHX9 may act as an inhibitor of EBV virion production. DHX9 enhanced innate antiviral pathways active against EBV and was needed for maximal expression of several interferon-induced genes. We show that SM binds to and colocalizes DHX9 and may counteract the antiviral function of DHX9. These data indicate that DHX9 possesses antiviral activity and that SM may suppress the antiviral functions of DHX9 through this association. Our study presents a novel host-pathogen interaction between EBV and the host cell.
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21
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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.
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22
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Xie Q, Liu J, Shan Y, Wang S, Liu F. Substrate Determinants for Unwinding Activity of the DExH/D-Box Protein RNA Helicase A. Biochemistry 2018; 57:6662-6668. [PMID: 30406989 DOI: 10.1021/acs.biochem.8b01025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
RNA helicase A (RHA) as a member of the DExH/D-box subgroup of helicase superfamily II is involved in virtually all aspects of RNA metabolism. It exhibits robust RNA helicase activity in vitro. However, little is known about the molecular and physical determinants for RHA substrate recognition and RHA translocation along the nucleic acids. Here, our nondenaturing polyacrylamide gel electrophoresis (PAGE)-based unwinding assays of chemical and structural modified substrates indicate that RHA translocates efficiently along the 3' overhang of RNA, but not DNA, with a requirement of covalent continuity. Ribose-phosphate backbone lesions on both strands of the nucleic acids, especially on the 3' overhang of the loading strand, affect RHA unwinding significantly. Furthermore, RHA requires RNA on the 3' overhang which directly or indirectly connects with the duplex region to mediate productive unwinding. Collectively, these findings propose a basic mechanism of the substrate determinants for RHA backbone tracking during duplex unwinding.
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Affiliation(s)
- Qingyun Xie
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering Laboratory of Animal Immunology, Single Molecule Nanometry Laboratory (Sinmolab), College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , China
| | - Jing Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering Laboratory of Animal Immunology, Single Molecule Nanometry Laboratory (Sinmolab), College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , China
| | - Yanke Shan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering Laboratory of Animal Immunology, Single Molecule Nanometry Laboratory (Sinmolab), College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , China
| | - Shouyu Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering Laboratory of Animal Immunology, Single Molecule Nanometry Laboratory (Sinmolab), College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , China.,Computational Optics Laboratory, School of Science , Jiangnan University , Wuxi , Jiangsu 214122 , China
| | - Fei Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering Laboratory of Animal Immunology, Single Molecule Nanometry Laboratory (Sinmolab), College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , China
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23
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Chakraborty P, Huang JTJ, Hiom K. DHX9 helicase promotes R-loop formation in cells with impaired RNA splicing. Nat Commun 2018; 9:4346. [PMID: 30341290 PMCID: PMC6195550 DOI: 10.1038/s41467-018-06677-1] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 09/06/2018] [Indexed: 01/05/2023] Open
Abstract
R-loops are stable nucleic acid structures that have important physiological functions, but which also pose a significant threat to genomic stability. Increased R-loops cause replication stress and chromosome fragility and have been associated with diseases such as neurodegeneration and cancer. Although excessive R-loops are a feature of cells that are defective in RNA processing, what causes them to form is unclear. Here, we demonstrate that DHX9 (RNA helicase A) promotes the formation of pathological and non-pathological R-loops. In the absence of splicing factors, formation of R-loops correlates with the prolonged association of DHX9 with RNA Polymerase II (RNA Pol II). This leads to the production of DNA–RNA hybrid, which traps RNA Pol II on chromatin with the potential to block DNA replication. Our data provide a molecular mechanism for the formation of R-loops that is relevant to neurodegenerative diseases and cancers in which deregulated RNA processing is a feature. Unresolved R-loops can represent a threat to genome stability. Here the authors reveal that DHX9 helicase can promote R-loop formation in the absence of splicing factors SFPQ and SF3B3.
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Affiliation(s)
- Prasun Chakraborty
- Division of Cellular Medicine, School of Medicine, University of Dundee, Scotland, UK
| | - Jeffrey T J Huang
- Biomarker and Drug Analysis Core Facility, School of Medicine, University of Dundee, Scotland, UK
| | - Kevin Hiom
- Division of Cellular Medicine, School of Medicine, University of Dundee, Scotland, UK.
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24
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Lee T, Pelletier J. Dependence of p53-deficient cells on the DHX9 DExH-box helicase. Oncotarget 2018; 8:30908-30921. [PMID: 28427210 PMCID: PMC5458177 DOI: 10.18632/oncotarget.15889] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 02/21/2017] [Indexed: 12/13/2022] Open
Abstract
DHX9 is a DExH-box helicase family member with key regulatory roles in a broad range of cellular processes. It participates at multiple levels of gene regulation, including DNA replication, transcription, translation, RNA transport, and microRNA processing. It has been implicated in tumorigenesis and recent evidence suggests that it may be a promising chemotherapeutic target. Previous studies have determined that DHX9 suppression elicits an apoptotic or senescence response by activating p53 signaling. Here, we show that DHX9 inhibition can also have deleterious effects in cells lacking functional p53. Loss of DHX9 led to increased cell death in p53-deficient mouse lymphomas and HCT116 human colon cancer cells, and G0/G1 cell cycle arrest in p53-deficient mouse embryonic fibroblasts. Analysis of mRNA levels for p53 transcriptional targets showed that a subset of p53 targets in the p53-null lymphomas and HCT116 cells were activated despite the absence of functional p53. This implies an alternative pathway of DHX9-mediated activation of cell death and cell cycle arrest in p53-deficient cells and supports the feasibility of targeting DHX9 in p53-deficient tumors.
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Affiliation(s)
- Teresa Lee
- Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1Y6, Canada
| | - Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1Y6, Canada.,Department of Oncology, McGill University, Montreal, Quebec, H3G 1Y6, Canada.,Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec, H3G 1Y6, Canada
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25
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Lee T, Pelletier J. The biology of DHX9 and its potential as a therapeutic target. Oncotarget 2018; 7:42716-42739. [PMID: 27034008 PMCID: PMC5173168 DOI: 10.18632/oncotarget.8446] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 03/16/2016] [Indexed: 12/25/2022] Open
Abstract
DHX9 is member of the DExD/H-box family of helicases with a “DEIH” sequence at its eponymous DExH-box motif. Initially purified from human and bovine cells and identified as a homologue of the Drosophila Maleless (MLE) protein, it is an NTP-dependent helicase consisting of a conserved helicase core domain, two double-stranded RNA-binding domains at the N-terminus, and a nuclear transport domain and a single-stranded DNA-binding RGG-box at the C-terminus. With an ability to unwind DNA and RNA duplexes, as well as more complex nucleic acid structures, DHX9 appears to play a central role in many cellular processes. Its functions include regulation of DNA replication, transcription, translation, microRNA biogenesis, RNA processing and transport, and maintenance of genomic stability. Because of its central role in gene regulation and RNA metabolism, there are growing implications for DHX9 in human diseases and their treatment. This review will provide an overview of the structure, biochemistry, and biology of DHX9, its role in cancer and other human diseases, and the possibility of targeting DHX9 in chemotherapy.
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Affiliation(s)
- Teresa Lee
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada.,Department of Oncology, McGill University, Montreal, Quebec, Canada.,Department of Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec, Canada
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26
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Chang EYC, Novoa CA, Aristizabal MJ, Coulombe Y, Segovia R, Chaturvedi R, Shen Y, Keong C, Tam AS, Jones SJM, Masson JY, Kobor MS, Stirling PC. RECQ-like helicases Sgs1 and BLM regulate R-loop-associated genome instability. J Cell Biol 2017; 216:3991-4005. [PMID: 29042409 PMCID: PMC5716281 DOI: 10.1083/jcb.201703168] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 08/16/2017] [Accepted: 09/18/2017] [Indexed: 01/01/2023] Open
Abstract
Sgs1, the orthologue of human Bloom's syndrome helicase BLM, is a yeast DNA helicase functioning in DNA replication and repair. We show that SGS1 loss increases R-loop accumulation and sensitizes cells to transcription-replication collisions. Yeast lacking SGS1 accumulate R-loops and γ-H2A at sites of Sgs1 binding, replication pausing regions, and long genes. The mutation signature of sgs1Δ reveals copy number changes flanked by repetitive regions with high R-loop-forming potential. Analysis of BLM in Bloom's syndrome fibroblasts or by depletion of BLM from human cancer cells confirms a role for Sgs1/BLM in suppressing R-loop-associated genome instability across species. In support of a potential direct effect, BLM is found physically proximal to DNA:RNA hybrids in human cells, and can efficiently unwind R-loops in vitro. Together, our data describe a conserved role for Sgs1/BLM in R-loop suppression and support an increasingly broad view of DNA repair and replication fork stabilizing proteins as modulators of R-loop-mediated genome instability.
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Affiliation(s)
| | - Carolina A Novoa
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada
| | | | - Yan Coulombe
- Genome Stability Laboratory, Centre Hospitalier Universitaire de Québec Research Center, Québec City, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, Canada
| | - Romulo Segovia
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada
| | - Richa Chaturvedi
- Genome Stability Laboratory, Centre Hospitalier Universitaire de Québec Research Center, Québec City, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, Canada
| | - Yaoqing Shen
- Michael Smith Genome Sciences Centre, Vancouver, Canada
| | - Christelle Keong
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada
| | - Annie S Tam
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Steven J M Jones
- Michael Smith Genome Sciences Centre, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Jean-Yves Masson
- Genome Stability Laboratory, Centre Hospitalier Universitaire de Québec Research Center, Québec City, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, Canada
| | - Michael S Kobor
- Centre for Molecular Medicine and Therapeutics, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Peter C Stirling
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada .,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
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27
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Capitanio JS, Montpetit B, Wozniak RW. Nucleoplasmic Nup98 controls gene expression by regulating a DExH/D-box protein. Nucleus 2017; 9:1-8. [PMID: 28934014 PMCID: PMC5973140 DOI: 10.1080/19491034.2017.1364826] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The nucleoporin Nup98 has been linked to the regulation of transcription and RNA metabolism, 1-3 but the mechanisms by which Nup98 contributes to these processes remains largely undefined. Recently, we uncovered interactions between Nup98 and several DExH/D-box proteins (DBPs), a protein family well-known for modulating gene expression and RNA metabolism. 4-6 Analysis of Nup98 and one of these DBPs, DHX9, showed that they directly interact, their association is facilitated by RNA, and Nup98 binding stimulates DHX9 ATPase activity. 7 Furthermore, these proteins were dependent on one another for their proper association with a subset of gene loci to control transcription and modulate mRNA splicing. 7 On the basis of these observations, we proposed that Nup98 functions to regulate DHX9 activity within the nucleoplasm. 7 Since Nup98 is associated with several DBPs, regulation of DHX9 by Nup98 may represent a paradigm for understanding how Nup98, and possibly other FG-Nup proteins, could direct the diverse cellular activities of multiple DBPs.
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Affiliation(s)
| | - Ben Montpetit
- a Department of Cell Biology , University of Alberta , Edmonton , Canada.,b Department of Viticulture and Enology , University of California at Davis , Davis , CA , USA
| | - Richard W Wozniak
- a Department of Cell Biology , University of Alberta , Edmonton , Canada
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28
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Guo J, Jing R, Lv X, Wang X, Li J, Li L, Li C, Wang D, Bi B, Chen X, Yang JH. H2A/K pseudogene mutation may promote cell proliferation. Mutat Res 2016; 787:32-42. [PMID: 26953487 DOI: 10.1016/j.mrfmmm.2016.02.010] [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] [Received: 08/16/2015] [Revised: 01/01/2016] [Accepted: 02/28/2016] [Indexed: 11/16/2022]
Abstract
Little attention has been paid to the histone H2A/K pseudogene. Results from our laboratory showed that 7 of 10 kidney cancer patients carried a mutant H2A/K pseudogene; therefore, we were interested in determining the relationship between mutant H2A/K and cell proliferation. We used shotgun and label-free proteomics methods to study whether mutant H2A/K lncRNAs affected cell proliferation. Quantitative proteomic analysis indicated that the expression of mutant H2A/K lncRNAs resulted in the upregulation of many oncogenes, which promoted cell proliferation. Further interaction analyses revealed that a proliferating cell nuclear antigen (PCNA)-protein interaction network, with PCNA in the center, contributes to cell proliferation in cells expressing the mutant H2A/K lncRNAs. Western blotting confirmed the critical upregulation of PCNA by mutant H2A/K lncRNA expression. Finally, the promotion of cell proliferation by mutant H2A/K lncRNAs (C290T, C228A and A45G) was confirmed using cell proliferation assays. Although we did not determine the exact mechanism by which the oncogenes were upregulated by the mutant H2A/K lncRNAs, we confirmed that the mutant H2A/K lncRNAs promoted cell proliferation by upregulating PCNA and other oncogenes. The hypothesis that cell proliferation is promoted by the mutant H2A/K lncRNAs was supported by the protein expression and cell proliferation assay results. Therefore, mutant H2A/K lncRNAs may be a new factor in renal carcinogenesis.
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Affiliation(s)
- Jisheng Guo
- Cancer Research Center, Shandong University School of Medicine, Jinan 250012, China
| | - Ruirui Jing
- Cancer Research Center, Shandong University School of Medicine, Jinan 250012, China
| | - Xin Lv
- Cancer Research Center, Shandong University School of Medicine, Jinan 250012, China
| | - Xiaoyue Wang
- Cancer Research Center, Shandong University School of Medicine, Jinan 250012, China
| | - Junqiang Li
- Cancer Research Center, Shandong University School of Medicine, Jinan 250012, China
| | - Lin Li
- Cancer Research Center, Shandong University School of Medicine, Jinan 250012, China
| | - Cuiling Li
- Cancer Research Center, Shandong University School of Medicine, Jinan 250012, China
| | - Daoguang Wang
- Cancer Research Center, Shandong University School of Medicine, Jinan 250012, China
| | - Baibing Bi
- Cancer Research Center, Shandong University School of Medicine, Jinan 250012, China
| | - Xinjun Chen
- Cancer Research Center, Shandong University School of Medicine, Jinan 250012, China
| | - Jing-Hua Yang
- Cancer Research Center, Shandong University School of Medicine, Jinan 250012, China; Department of Surgery, VA Boston Healthcare System, Boston University School of Medicine, Boston 510660, MA, USA.
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29
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Erkizan HV, Schneider JA, Sajwan K, Graham GT, Griffin B, Chasovskikh S, Youbi SE, Kallarakal A, Chruszcz M, Padmanabhan R, Casey JL, Üren A, Toretsky JA. RNA helicase A activity is inhibited by oncogenic transcription factor EWS-FLI1. Nucleic Acids Res 2015; 43:1069-80. [PMID: 25564528 PMCID: PMC4333382 DOI: 10.1093/nar/gku1328] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
RNA helicases impact RNA structure and metabolism from transcription through translation, in part through protein interactions with transcription factors. However, there is limited knowledge on the role of transcription factor influence upon helicase activity. RNA helicase A (RHA) is a DExH-box RNA helicase that plays multiple roles in cellular biology, some functions requiring its activity as a helicase while others as a protein scaffold. The oncogenic transcription factor EWS-FLI1 requires RHA to enable Ewing sarcoma (ES) oncogenesis and growth; a small molecule, YK-4-279 disrupts this complex in cells. Our current study investigates the effect of EWS-FLI1 upon RHA helicase activity. We found that EWS-FLI1 reduces RHA helicase activity in a dose-dependent manner without affecting intrinsic ATPase activity; however, the RHA kinetics indicated a complex model. Using separated enantiomers, only (S)-YK-4-279 reverses the EWS-FLI1 inhibition of RHA helicase activity. We report a novel RNA binding property of EWS-FLI1 leading us to discover that YK-4-279 inhibition of RHA binding to EWS-FLI1 altered the RNA binding profile of both proteins. We conclude that EWS-FLI1 modulates RHA helicase activity causing changes in overall transcriptome processing. These findings could lead to both enhanced understanding of oncogenesis and provide targets for therapy.
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Affiliation(s)
- Hayriye Verda Erkizan
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road NW, New Research Building E316, Washington, DC 20007, USA
| | - Jeffrey A Schneider
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road NW, New Research Building E316, Washington, DC 20007, USA
| | - Kamal Sajwan
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road NW, New Research Building E316, Washington, DC 20007, USA
| | - Garrett T Graham
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road NW, New Research Building E316, Washington, DC 20007, USA
| | - Brittany Griffin
- Department of Microbiology and Immunology, Georgetown University Medical Center, SW 309 Med-Dent, Washington, DC 20007, USA
| | - Sergey Chasovskikh
- Department of Radiation Medicine, Georgetown University Medical Center, 3970 Reservoir Road NW, New Research Building E220, Washington, DC 20007, USA
| | - Sarah E Youbi
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road NW, New Research Building E316, Washington, DC 20007, USA
| | - Abraham Kallarakal
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road NW, New Research Building E316, Washington, DC 20007, USA
| | - Maksymilian Chruszcz
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, SC 29208, USA
| | - Radhakrishnan Padmanabhan
- Department of Microbiology and Immunology, Georgetown University Medical Center, SW 309 Med-Dent, Washington, DC 20007, USA
| | - John L Casey
- Department of Microbiology and Immunology, Georgetown University Medical Center, SW 309 Med-Dent, Washington, DC 20007, USA
| | - Aykut Üren
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road NW, New Research Building E316, Washington, DC 20007, USA
| | - Jeffrey A Toretsky
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road NW, New Research Building E316, Washington, DC 20007, USA
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30
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Umate P, Tuteja N, Tuteja R. Genome-wide comprehensive analysis of human helicases. Commun Integr Biol 2014. [DOI: 10.4161/cib.13844] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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31
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Lee T, Di Paola D, Malina A, Mills JR, Kreps A, Grosse F, Tang H, Zannis-Hadjopoulos M, Larsson O, Pelletier J. Suppression of the DHX9 helicase induces premature senescence in human diploid fibroblasts in a p53-dependent manner. J Biol Chem 2014; 289:22798-22814. [PMID: 24990949 PMCID: PMC4132785 DOI: 10.1074/jbc.m114.568535] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 07/02/2014] [Indexed: 12/28/2022] Open
Abstract
DHX9 is an ATP-dependent DEXH box helicase with a multitude of cellular functions. Its ability to unwind both DNA and RNA, as well as aberrant, noncanonical polynucleotide structures, has implicated it in transcriptional and translational regulation, DNA replication and repair, and maintenance of genome stability. We report that loss of DHX9 in primary human fibroblasts results in premature senescence, a state of irreversible growth arrest. This is accompanied by morphological defects, elevation of senescence-associated β-galactosidase levels, and changes in gene expression closely resembling those encountered during replicative (telomere-dependent) senescence. Activation of the p53 signaling pathway was found to be essential to this process. ChIP analysis and investigation of nascent DNA levels revealed that DHX9 is associated with origins of replication and that its suppression leads to a reduction of DNA replication. Our results demonstrate an essential role of DHX9 in DNA replication and normal cell cycle progression.
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Affiliation(s)
- Teresa Lee
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Domenic Di Paola
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Abba Malina
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - John R Mills
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Amina Kreps
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Frank Grosse
- Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena D-07745, Germany
| | - Hengli Tang
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306
| | - Maria Zannis-Hadjopoulos
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada,; Department of Oncology, McGill University, Montreal, Quebec H3A 1A3, Canada; The Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec H3A 1A3, Canada, and
| | - Ola Larsson
- Department of Oncology-Pathology, Karolinska Institute, Stockholm 171 77, Sweden
| | - Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada,; Department of Oncology, McGill University, Montreal, Quebec H3A 1A3, Canada; The Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec H3A 1A3, Canada, and.
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32
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Kassavetis GA, Kadonaga JT. The annealing helicase and branch migration activities of Drosophila HARP. PLoS One 2014; 9:e98173. [PMID: 24866343 PMCID: PMC4035279 DOI: 10.1371/journal.pone.0098173] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 04/29/2014] [Indexed: 01/25/2023] Open
Abstract
HARP (SMARCAL1, MARCAL1) is an annealing helicase that functions in the repair and restart of damaged DNA replication forks through its DNA branch migration and replication fork regression activities. HARP is conserved among metazoans. HARP from invertebrates differs by the absence of one of the two HARP-specific domain repeats found in vertebrates. The annealing helicase and branch migration activity of invertebrate HARP has not been documented. We found that HARP from Drosophila melanogaster retains the annealing helicase activity of human HARP, the ability to disrupt D-loops and to branch migrate Holliday junctions, but fails to regress model DNA replication fork structures. A comparison of human and Drosophila HARP on additional substrates revealed that both HARPs are competent in branch migrating a bidirectional replication bubble composed of either DNA:DNA or RNA:DNA hybrid. Human, but not Drosophila, HARP is also capable of regressing a replication fork structure containing a highly stable poly rG:dC hybrid. Persistent RNA:DNA hybrids in vivo can lead to replication fork arrest and genome instability. The ability of HARP to strand transfer hybrids may signify a hybrid removal function for this enzyme, in vivo.
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Affiliation(s)
- George A. Kassavetis
- Section of Molecular Biology, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
| | - James T. Kadonaga
- Section of Molecular Biology, University of California San Diego, La Jolla, California, United States of America
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Jain A, Bacolla A, Del Mundo IM, Zhao J, Wang G, Vasquez KM. DHX9 helicase is involved in preventing genomic instability induced by alternatively structured DNA in human cells. Nucleic Acids Res 2013; 41:10345-57. [PMID: 24049074 PMCID: PMC3905860 DOI: 10.1093/nar/gkt804] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Sequences that have the capacity to adopt alternative (i.e. non-B) DNA structures in the human genome have been implicated in stimulating genomic instability. Previously, we found that a naturally occurring intra-molecular triplex (H-DNA) caused genetic instability in mammals largely in the form of DNA double-strand breaks. Thus, it is of interest to determine the mechanism(s) involved in processing H-DNA. Recently, we demonstrated that human DHX9 helicase preferentially unwinds inter-molecular triplex DNA in vitro. Herein, we used a mutation-reporter system containing H-DNA to examine the relevance of DHX9 activity on naturally occurring H-DNA structures in human cells. We found that H-DNA significantly increased mutagenesis in small-interfering siRNA-treated, DHX9-depleted cells, affecting mostly deletions. Moreover, DHX9 associated with H-DNA in the context of supercoiled plasmids. To further investigate the role of DHX9 in the recognition/processing of H-DNA, we performed binding assays in vitro and chromatin immunoprecipitation assays in U2OS cells. DHX9 recognized H-DNA, as evidenced by its binding to the H-DNA structure and enrichment at the H-DNA region compared with a control region in human cells. These composite data implicate DHX9 in processing H-DNA structures in vivo and support its role in the overall maintenance of genomic stability at sites of alternatively structured DNA.
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Affiliation(s)
- Aklank Jain
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd. Austin, TX 78723, USA
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RNAi screening uncovers Dhx9 as a modifier of ABT-737 resistance in an Eμ-myc/Bcl-2 mouse model. Blood 2013; 121:3402-12. [PMID: 23440244 DOI: 10.1182/blood-2012-06-434365] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
ABT-737 is a promising chemotherapeutic agent that promotes apoptosis by acting as a selective BH3 mimetic to neutralize Bcl-2-like family members. One shortcoming with its use is that Mcl-1, a member of the Bcl-2 family, is poorly inhibited by ABT-737 and thus is a major cause of resistance. We performed a short hairpin RNA (shRNA)-based drop-out screen to identify novel genes and pathways that could reverse resistance to ABT-737 treatment in Eµ-myc/Bcl-2 lymphoma cells engineered to rely on endogenous Mcl-1 for survival. Several drug-sensitive shRNAs were identified that were selectively depleted in the presence of ABT-737. Of these, 2 independent shRNAs targeting the RNA/DNA helicase Dhx9 were found to sensitize lymphomas to ABT-737 to an extent comparable to control Mcl-1 shRNAs. Although Dhx9 suppression sensitized both mouse and human cells to ABT-737 treatment, it did so without altering MCL-1 levels. Rather, loss of Dhx9 appeared to activate a p53-dependent apoptotic program, through aggravation of replicative stress, which was found to be both necessary and sufficient for the ABT-737-shDhx9 synthetic lethal relationship.
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35
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Structure and Mechanisms of SF1 DNA Helicases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 767:17-46. [PMID: 23161005 DOI: 10.1007/978-1-4614-5037-5_2] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Superfamily I is a large and diverse group of monomeric and dimeric helicases defined by a set of conserved sequence motifs. Members of this class are involved in essential processes in both DNA and RNA metabolism in all organisms. In addition to conserved amino acid sequences, they also share a common structure containing two RecA-like motifs involved in ATP binding and hydrolysis and nucleic acid binding and unwinding. Unwinding is facilitated by a "pin" structure which serves to split the incoming duplex. This activity has been measured using both ensemble and single-molecule conditions. SF1 helicase activity is modulated through interactions with other proteins.
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36
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Lorgeoux RP, Guo F, Liang C. From promoting to inhibiting: diverse roles of helicases in HIV-1 Replication. Retrovirology 2012; 9:79. [PMID: 23020886 PMCID: PMC3484045 DOI: 10.1186/1742-4690-9-79] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 09/22/2012] [Indexed: 01/09/2023] Open
Abstract
Helicases hydrolyze nucleotide triphosphates (NTPs) and use the energy to modify the structures of nucleic acids. They are key players in every cellular process involving RNA or DNA. Human immunodeficiency virus type 1 (HIV-1) does not encode a helicase, thus it has to exploit cellular helicases in order to efficiently replicate its RNA genome. Indeed, several helicases have been found to specifically associate with HIV-1 and promote viral replication. However, studies have also revealed a couple of helicases that inhibit HIV-1 replication; these findings suggest that HIV-1 can either benefit from the function of cellular helicases or become curtailed by these enzymes. In this review, we focus on what is known about how a specific helicase associates with HIV-1 and how a distinct step of HIV-1 replication is affected. Despite many helicases having demonstrated roles in HIV-1 replication and dozens of other helicase candidates awaiting to be tested, a deeper appreciation of their involvement in the HIV-1 life cycle is hindered by our limited knowledge at the enzymatic and molecular levels regarding how helicases shape the conformation and structure of viral RNA-protein complexes and how these conformational changes are translated into functional outcomes in the context of viral replication.
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Affiliation(s)
- Rene-Pierre Lorgeoux
- McGill AIDS Centre, Lady Davis Institute-Jewish General Hospital, Montreal, H3T 1E2, Quebec, Canada
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Human DHX9 helicase preferentially unwinds RNA-containing displacement loops (R-loops) and G-quadruplexes. DNA Repair (Amst) 2011; 10:654-65. [PMID: 21561811 DOI: 10.1016/j.dnarep.2011.04.013] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 04/08/2011] [Accepted: 04/11/2011] [Indexed: 02/02/2023]
Abstract
Human DHX9 helicase, also known as nuclear DNA helicase II (NDH II) and RNA helicase A (RHA), belongs to the SF2 superfamily of nucleic acid unwinding enzymes. DHX9 melts simple DNA-DNA, RNA-RNA, and DNA-RNA strands with a 3'-5' polarity; despite this little is known about its substrate specificity. Here, we used partial duplex DNA consisting of M13mp18 DNA and oligonucleotide-based replication and recombination intermediates. We show that DHX9 unwinds DNA- and RNA-containing forks, DNA- and RNA-containing displacement loops (D- and R-loops), and also G-quadruplexes. With these substrates, DHX9 behaved similarly as the RecQ helicase WRN. In contrast to WRN, DHX9 melted RNA-hybrids considerably faster than the corresponding DNA-DNA strands. DHX9 preferably unwound R-loops and DNA-based G-quadruplexes indicating that these structures may be biologically relevant. DHX9 also unwound RNA-based G-quadruplexes that have been reported to occur in human transcripts. It is believed that an improper dissolution of co-transcriptionally formed D-loops, R-loops, and DNA- or RNA-based G-quadruplexes represent potential roadblocks for transcription and thereby enhance transcription associated recombination events. By unwinding these structures, DHX9 may significantly contribute to transcriptional activation and also to the maintenance of genomic stability.
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38
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Bacolla A, Wang G, Jain A, Chuzhanova NA, Cer RZ, Collins JR, Cooper DN, Bohr VA, Vasquez KM. Non-B DNA-forming sequences and WRN deficiency independently increase the frequency of base substitution in human cells. J Biol Chem 2011; 286:10017-26. [PMID: 21285356 PMCID: PMC3060453 DOI: 10.1074/jbc.m110.176636] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 01/31/2011] [Indexed: 01/01/2023] Open
Abstract
Although alternative DNA secondary structures (non-B DNA) can induce genomic rearrangements, their associated mutational spectra remain largely unknown. The helicase activity of WRN, which is absent in the human progeroid Werner syndrome, is thought to counteract this genomic instability. We determined non-B DNA-induced mutation frequencies and spectra in human U2OS osteosarcoma cells and assessed the role of WRN in isogenic knockdown (WRN-KD) cells using a supF gene mutation reporter system flanked by triplex- or Z-DNA-forming sequences. Although both non-B DNA and WRN-KD served to increase the mutation frequency, the increase afforded by WRN-KD was independent of DNA structure despite the fact that purified WRN helicase was found to resolve these structures in vitro. In U2OS cells, ∼70% of mutations comprised single-base substitutions, mostly at G·C base-pairs, with the remaining ∼30% being microdeletions. The number of mutations at G·C base-pairs in the context of NGNN/NNCN sequences correlated well with predicted free energies of base stacking and ionization potentials, suggesting a possible origin via oxidation reactions involving electron loss and subsequent electron transfer (hole migration) between neighboring bases. A set of ∼40,000 somatic mutations at G·C base pairs identified in a lung cancer genome exhibited similar correlations, implying that hole migration may also be involved. We conclude that alternative DNA conformations, WRN deficiency and lung tumorigenesis may all serve to increase the mutation rate by promoting, through diverse pathways, oxidation reactions that perturb the electron orbitals of neighboring bases. It follows that such "hole migration" is likely to play a much more widespread role in mutagenesis than previously anticipated.
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Affiliation(s)
- Albino Bacolla
- From the Department of Molecular Carcinogenesis, Science Park-Research Division, The University of Texas, M. D. Anderson Cancer Center, Smithville, Texas 78957
| | - Guliang Wang
- From the Department of Molecular Carcinogenesis, Science Park-Research Division, The University of Texas, M. D. Anderson Cancer Center, Smithville, Texas 78957
| | - Aklank Jain
- From the Department of Molecular Carcinogenesis, Science Park-Research Division, The University of Texas, M. D. Anderson Cancer Center, Smithville, Texas 78957
| | - Nadia A. Chuzhanova
- the School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, United Kingdom
| | - Regina Z. Cer
- the Advanced Biomedical Computing Center, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702
| | - Jack R. Collins
- the Advanced Biomedical Computing Center, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702
| | - David N. Cooper
- the Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, CF14 4XN, United Kingdom, and
| | - Vilhelm A. Bohr
- the Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224
| | - Karen M. Vasquez
- From the Department of Molecular Carcinogenesis, Science Park-Research Division, The University of Texas, M. D. Anderson Cancer Center, Smithville, Texas 78957
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Lachapelle S, Gagné JP, Garand C, Desbiens M, Coulombe Y, Bohr VA, Hendzel MJ, Masson JY, Poirier GG, Lebel M. Proteome-wide identification of WRN-interacting proteins in untreated and nuclease-treated samples. J Proteome Res 2011; 10:1216-27. [PMID: 21210717 DOI: 10.1021/pr100990s] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Werner syndrome (WS) is characterized by the premature onset of several age-associated pathologies. The protein defective in WS patients (WRN) is a helicase/exonuclease involved in DNA repair, replication, telomere maintenance, and transcription. Here, we present the results of a large-scale proteome analysis to determine protein partners of WRN. We expressed fluorescent tagged-WRN (eYFP-WRN) in human 293 embryonic kidney cells and detected interacting proteins by co-immunoprecipitation from cell extract. We identified by mass spectrometry 220 nuclear proteins that complexed with WRN. This number was reduced to 40 when broad-spectrum nucleases were added to the lysate. We consider these 40 proteins as directly interacting with WRN. Some of these proteins have previously been shown to interact with WRN, whereas most are new partners. Among the top 15 hits, we find the new interactors TMPO, HNRNPU, RPS3, RALY, RPS9 DDX21, and HNRNPM. These proteins are likely important components in understanding the function of WRN in preventing premature aging and deserve further investigation. We have confirmed endogenous WRN interaction with endogenous RPS3, a ribosomal protein with endonuclease activities involved in oxidative DNA damage recognition. Our results suggest that the use of nucleases during cell lysis severely restricts interacting protein partners and thus enhances specificity.
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Affiliation(s)
- Sophie Lachapelle
- Centre de Recherche en Cancérologie de l'Université Laval, Hôpital Hôtel-Dieu de Québec, Québec City, Québec, G1R 2J6, Canada
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Umate P, Tuteja N, Tuteja R. Genome-wide comprehensive analysis of human helicases. Commun Integr Biol 2011; 4:118-37. [PMID: 21509200 PMCID: PMC3073292 DOI: 10.4161/cib.4.1.13844] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 10/03/2010] [Indexed: 12/20/2022] Open
Abstract
Helicases are motor proteins that catalyze the unwinding of duplex nucleic acids in an ATP-dependent manner. They are involved in almost all the nucleic acid transactions. In the present study, we report a comprehensive analysis of helicase gene family in human and its comparison with homologs in model organisms. The human genome encodes for 95 non-redundant helicase proteins, of which 64 are RNA helicases and 31 are DNA helicases. 57 RNA helicases are validated based on annotations and occurrence of conserved helicase signature motifs. These include 14 DExH and 37 DExD subfamily members, six other members such as U5.snRNP, ATR-X, Suv3, FANCJ, and two of superkiller viralicidic activity 2-like helicases. 31 DNA helicases are also identified, which include RecQ, MCM and RuvB-like helicases. Finding a set of helicases in human and almost similar sequences in model organisms suggests that the "core" members of helicase gene family are highly conserved throughout evolution. The present study gives an overview of members of RNA and DNA helicases encoded by the human genome along with their conserved motifs, phylogeny and homologs in model organisms. The study on comparing these homologs will spread light on the organization and complexity of helicase gene family in model organisms. The comprehensive analysis of human helicases presented in this study will further provide an invaluable resource for elaborate biological research on these helicases.
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Affiliation(s)
- Pavan Umate
- International Center for Genetic Engineering and Biotechnology; Aruna Asaf Ali Marg; New Delhi, India
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Human RECQ helicases: roles in DNA metabolism, mutagenesis and cancer biology. Semin Cancer Biol 2010; 20:329-39. [PMID: 20934517 DOI: 10.1016/j.semcancer.2010.10.002] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 10/01/2010] [Indexed: 12/13/2022]
Abstract
Helicases use the energy of ATP hydrolysis to separate double-stranded nucleic acids to facilitate essential processes such as replication, recombination, transcription and repair. This article focuses on the human RECQ helicase gene and protein family. Loss of function of three different members has been shown to cause Bloom syndrome (BS), Werner syndrome (WS) and Rothmund-Thomson syndrome (RTS). This article outlines clinical and cellular features of these cancer predisposition syndromes, and discusses their pathogenesis in light of our understanding of RECQ helicase biochemical activities and in vivo functions. I also discuss the emerging role for RECQ helicases as predictors of disease risk and the response to therapy.
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Jain A, Bacolla A, Chakraborty P, Grosse F, Vasquez KM. Human DHX9 helicase unwinds triple-helical DNA structures. Biochemistry 2010; 49:6992-9. [PMID: 20669935 DOI: 10.1021/bi100795m] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Naturally occurring poly(purine.pyrimidine) rich regions in the human genome are prone to adopting non-canonical DNA structures such as intramolecular triplexes (i.e., H-DNA). Such structure-forming sequences are abundant and can regulate the expression of several disease-linked genes. In addition, the use of triplex-forming oligonucleotides (TFOs) to modulate gene structure and function has potential as an approach to targeted gene therapy. Previously, we found that endogenous H-DNA structures can induce DNA double-strand breaks and promote genomic rearrangements. Herein, we find that the DHX9 helicase co-immunoprecipitates with triplex DNA structures in mammalian cells, suggesting a role in the maintenance of genome stability. We tested this postulate by assessing the helicase activity of purified human DHX9 on various duplex and triplex DNA substrates in vitro. DHX9 displaced the third strand from a specific triplex DNA structure and catalyzed the unwinding with a 3' --> 5' polarity with respect to the displaced third strand. Helicase activity required a 3'-single-stranded overhang on the third strand and was dependent on ATP hydrolysis. The reaction kinetics consisted of a pre-steady-state burst phase followed by a linear, steady-state pseudo-zero-order reaction. In contrast, very little if any helicase activity was detected on blunt triplexes, triplexes with 5'-overhangs, blunt duplexes, duplexes with overhangs, or forked duplex substrates. Thus, triplex structures containing a 3'-overhang represent preferred substrates for DHX9, where it removes the strand with Hoogsteen hydrogen-bonded bases. Our results suggest the involvement of DHX9 in maintaining genome integrity by unwinding mutagenic triplex DNA structures.
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Affiliation(s)
- Aklank Jain
- Department of Carcinogenesis, Science Park-Research Division, The University of Texas M. D. Anderson Cancer Center, Smithville, Texas 78957, USA
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