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Das R, Panigrahi GK. Messenger RNA Surveillance: Current Understanding, Regulatory Mechanisms, and Future Implications. Mol Biotechnol 2024:10.1007/s12033-024-01062-4. [PMID: 38411790 DOI: 10.1007/s12033-024-01062-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/02/2024] [Indexed: 02/28/2024]
Abstract
Nonsense-mediated mRNA decay (NMD) is an evolutionarily conserved surveillance mechanism in eukaryotes primarily deployed to ensure RNA quality control by eliminating aberrant transcripts and also involved in modulating the expression of several physiological transcripts. NMD, the mRNA surveillance pathway, is a major form of gene regulation in eukaryotes. NMD serves as one of the most significant quality control mechanisms as it primarily scans the newly synthesized transcripts and differentiates the aberrant and non-aberrant transcripts. The synthesis of truncated proteins is restricted, which would otherwise lead to cellular dysfunctions. The up-frameshift factors (UPFs) play a central role in executing the NMD event, largely by recognizing and recruiting multiple protein factors that result in the decay of non-physiological mRNAs. NMD exhibits astounding variability in its ability across eukaryotes in an array of pathological and physiological contexts. The detailed understanding of NMD and the underlying molecular mechanisms remains blurred. This review outlines our current understanding of NMD, in regulating multifaceted cellular events during development and disease. It also attempts to identify unanswered questions that deserve further investigation.
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Affiliation(s)
- Rutupurna Das
- Department of Zoology, School of Applied Sciences, Centurion University of Technology and Management, Jatni, Khordha, Odisha, India
| | - Gagan Kumar Panigrahi
- Department of Zoology, School of Applied Sciences, Centurion University of Technology and Management, Jatni, Khordha, Odisha, India.
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2
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Llorca-Cardenosa MJ, Aronson LI, Krastev DB, Nieminuszczy J, Alexander J, Song F, Dylewska M, Broderick R, Brough R, Zimmermann A, Zenke FT, Gurel B, Riisnaes R, Ferreira A, Roumeliotis T, Choudhary J, Pettitt SJ, de Bono J, Cervantes A, Haider S, Niedzwiedz W, Lord CJ, Chong IY. SMG8/SMG9 Heterodimer Loss Modulates SMG1 Kinase to Drive ATR Inhibitor Resistance. Cancer Res 2022; 82:3962-3973. [PMID: 36273494 PMCID: PMC9627126 DOI: 10.1158/0008-5472.can-21-4339] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 07/19/2022] [Accepted: 08/26/2022] [Indexed: 01/07/2023]
Abstract
Gastric cancer represents the third leading cause of global cancer mortality and an area of unmet clinical need. Drugs that target the DNA damage response, including ATR inhibitors (ATRi), have been proposed as novel targeted agents in gastric cancer. Here, we sought to evaluate the efficacy of ATRi in preclinical models of gastric cancer and to understand how ATRi resistance might emerge as a means to identify predictors of ATRi response. A positive selection genome-wide CRISPR-Cas9 screen identified candidate regulators of ATRi resistance in gastric cancer. Loss-of-function mutations in either SMG8 or SMG9 caused ATRi resistance by an SMG1-mediated mechanism. Although ATRi still impaired ATR/CHK1 signaling in SMG8/9-defective cells, other characteristic responses to ATRi exposure were not seen, such as changes in ATM/CHK2, γH2AX, phospho-RPA, or 53BP1 status or changes in the proportions of cells in S- or G2-M-phases of the cell cycle. Transcription/replication conflicts (TRC) elicited by ATRi exposure are a likely cause of ATRi sensitivity, and SMG8/9-defective cells exhibited a reduced level of ATRi-induced TRCs, which could contribute to ATRi resistance. These observations suggest ATRi elicits antitumor efficacy in gastric cancer but that drug resistance could emerge via alterations in the SMG8/9/1 pathway. SIGNIFICANCE These findings reveal how cancer cells acquire resistance to ATRi and identify pathways that could be targeted to enhance the overall effectiveness of these inhibitors.
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Affiliation(s)
| | | | - Dragomir B. Krastev
- The CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom
- Breast Cancer Now Toby Robins Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | | | - John Alexander
- The Institute of Cancer Research, London, United Kingdom
| | - Feifei Song
- The CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom
- Breast Cancer Now Toby Robins Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | | | | | - Rachel Brough
- The CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom
- Breast Cancer Now Toby Robins Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Astrid Zimmermann
- The healthcare business of Merck KGaA, Biopharma R&D, Translational Innovation Platform Oncology, Darmstadt, Germany
| | - Frank T. Zenke
- The healthcare business of Merck KGaA, Biopharma R&D, Translational Innovation Platform Oncology, Darmstadt, Germany
| | - Bora Gurel
- The Institute of Cancer Research, London, United Kingdom
- The Royal Marsden Hospital NHS Foundation Trust, London, United Kingdom
| | - Ruth Riisnaes
- The Institute of Cancer Research, London, United Kingdom
- The Royal Marsden Hospital NHS Foundation Trust, London, United Kingdom
| | - Ana Ferreira
- The Institute of Cancer Research, London, United Kingdom
- The Royal Marsden Hospital NHS Foundation Trust, London, United Kingdom
| | | | | | - Stephen J. Pettitt
- The CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom
- Breast Cancer Now Toby Robins Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Johann de Bono
- The Institute of Cancer Research, London, United Kingdom
- The Royal Marsden Hospital NHS Foundation Trust, London, United Kingdom
| | - Andres Cervantes
- Department of Medical Oncology, INCLIVA Biomedical Research Institute, University of Valencia, Valencia, 46010, Spain
- CIBERONC, Instituto de Salud Carlos III, Madrid, Spain
| | - Syed Haider
- Breast Cancer Now Toby Robins Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | | | - Christopher J. Lord
- The CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom
- Breast Cancer Now Toby Robins Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Irene Y. Chong
- The Institute of Cancer Research, London, United Kingdom
- The Royal Marsden Hospital NHS Foundation Trust, London, United Kingdom
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Mailliot J, Vivoli-Vega M, Schaffitzel C. No-nonsense: insights into the functional interplay of nonsense-mediated mRNA decay factors. Biochem J 2022; 479:973-993. [PMID: 35551602 PMCID: PMC9162471 DOI: 10.1042/bcj20210556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/10/2022] [Accepted: 04/12/2022] [Indexed: 11/22/2022]
Abstract
Nonsense-mediated messenger RNA decay (NMD) represents one of the main surveillance pathways used by eukaryotic cells to control the quality and abundance of mRNAs and to degrade viral RNA. NMD recognises mRNAs with a premature termination codon (PTC) and targets them to decay. Markers for a mRNA with a PTC, and thus NMD, are a long a 3'-untranslated region and the presence of an exon-junction complex (EJC) downstream of the stop codon. Here, we review our structural understanding of mammalian NMD factors and their functional interplay leading to a branched network of different interconnected but specialised mRNA decay pathways. We discuss recent insights into the potential impact of EJC composition on NMD pathway choice. We highlight the coexistence and function of different isoforms of up-frameshift protein 1 (UPF1) with an emphasis of their role at the endoplasmic reticulum and during stress, and the role of the paralogs UPF3B and UPF3A, underscoring that gene regulation by mammalian NMD is tightly controlled and context-dependent being conditional on developmental stage, tissue and cell types.
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Affiliation(s)
- Justine Mailliot
- School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, U.K
| | - Mirella Vivoli-Vega
- School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, U.K
| | - Christiane Schaffitzel
- School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, U.K
- Bristol Synthetic Biology Centre BrisSynBio, 24 Tyndall Ave, Bristol BS8 1TQ, U.K
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Yang Q, Qin Z, Zhang Q, Yi S, Yi S, Luo J. Identification of a novel compound heterozygous SMG9 variants in a Chinese family with heart and brain malformation syndrome using whole exome sequencing. BMC Med Genomics 2022; 15:67. [PMID: 35321723 PMCID: PMC8943999 DOI: 10.1186/s12920-022-01217-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/17/2022] [Indexed: 11/13/2022] Open
Abstract
SMG9-deficiency syndrome, also known as heart and brain malformation syndrome, is a very rare congenital genetic disorder mainly characterized by brain, heart, and growth and developmental abnormalities. This syndrome is an autosomal recessive disease resulting from mutations in the SMG9 gene, which encodes a critical component of nonsense-mediated mRNA decay. Thus far, only twelve SMG9 deficiency patients have been reported with five novel homozygous SMG9 mutations. The most frequent characteristic features of these patients are facial dysmorphism, severe global developmental delay, intellectual disability, congenital heart disease, growth restriction, microcephaly, and brain abnormalities. Herein, whole exome sequencing was performed to identify novel compound heterozygous SMG9 variants (NM_019108.3: c.1318_1319delAG (p.Ser440*) and c.947A>G (p.His316Arg)) in the proband, who exhibited syndromic intellectual disability. Mutations were confirmed as segregating in his affected sister and other unaffected family members by Sanger sequencing. The patients we describe here have a similar dysmorphology profile associated with SMG9-deficiency syndrome. Comparing the phenotype with that of patients in published reports, our patients can walk independently and their growth parameters are normal. In addition, short stature, failure to thrive, and microcephaly were not observed. Possible residual function of the H316R SMG9 variant could explain the milder phenotype observed in our patients. Our report is the first description of a non-consanguineous Chinese pedigree with novel compound heterozygous variants in the SMG9 gene. The molecular confirmation of the patient expands the genetic spectrum of SMG9-deficiency syndrome, and the manifestation of SMG9-deficiency syndrome in the patient provides additional clinical information regarding this syndrome.
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Affiliation(s)
- Qi Yang
- Guangxi Key Laboratory of Birth Defects Research and Prevention, Guangxi Key Laboratory of Reproductive Health and Birth Defects Prevention, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, No. 59, Xiangzhu Road, Nanning, China.,Department of Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Zailong Qin
- Guangxi Key Laboratory of Birth Defects Research and Prevention, Guangxi Key Laboratory of Reproductive Health and Birth Defects Prevention, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, No. 59, Xiangzhu Road, Nanning, China.,Department of Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Qinle Zhang
- Guangxi Key Laboratory of Birth Defects Research and Prevention, Guangxi Key Laboratory of Reproductive Health and Birth Defects Prevention, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, No. 59, Xiangzhu Road, Nanning, China.,Department of Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Shang Yi
- Guangxi Key Laboratory of Birth Defects Research and Prevention, Guangxi Key Laboratory of Reproductive Health and Birth Defects Prevention, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, No. 59, Xiangzhu Road, Nanning, China.,Department of Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Sheng Yi
- Guangxi Key Laboratory of Birth Defects Research and Prevention, Guangxi Key Laboratory of Reproductive Health and Birth Defects Prevention, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, No. 59, Xiangzhu Road, Nanning, China.,Department of Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Jingsi Luo
- Guangxi Key Laboratory of Birth Defects Research and Prevention, Guangxi Key Laboratory of Reproductive Health and Birth Defects Prevention, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, No. 59, Xiangzhu Road, Nanning, China. .,Department of Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, China.
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Langer LM, Bonneau F, Gat Y, Conti E. Cryo-EM reconstructions of inhibitor-bound SMG1 kinase reveal an autoinhibitory state dependent on SMG8. eLife 2021; 10:72353. [PMID: 34698635 PMCID: PMC8592573 DOI: 10.7554/elife.72353] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/25/2021] [Indexed: 12/31/2022] Open
Abstract
The PI3K-related kinase (PIKK) SMG1 monitors the progression of metazoan nonsense-mediated mRNA decay (NMD) by phosphorylating the RNA helicase UPF1. Previous work has shown that the activity of SMG1 is impaired by small molecule inhibitors, is reduced by the SMG1 interactors SMG8 and SMG9, and is downregulated by the so-called SMG1 insertion domain. However, the molecular basis for this complex regulatory network has remained elusive. Here, we present cryo-electron microscopy reconstructions of human SMG1-9 and SMG1-8-9 complexes bound to either a SMG1 inhibitor or a non-hydrolyzable ATP analog at overall resolutions ranging from 2.8 to 3.6 Å. These structures reveal the basis with which a small molecule inhibitor preferentially targets SMG1 over other PIKKs. By comparison with our previously reported substrate-bound structure (Langer et al.,2020), we show that the SMG1 insertion domain can exert an autoinhibitory function by directly blocking the substrate-binding path as well as overall access to the SMG1 kinase active site. Together with biochemical analysis, our data indicate that SMG1 autoinhibition is stabilized by the presence of SMG8. Our results explain the specific inhibition of SMG1 by an ATP-competitive small molecule, provide insights into regulation of its kinase activity within the NMD pathway, and expand the understanding of PIKK regulatory mechanisms in general.
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Affiliation(s)
- Lukas M Langer
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Fabien Bonneau
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Yair Gat
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Elena Conti
- Max Planck Institute of Biochemistry, Martinsried, Germany
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Powers KT, Szeto JYA, Schaffitzel C. New insights into no-go, non-stop and nonsense-mediated mRNA decay complexes. Curr Opin Struct Biol 2020; 65:110-118. [PMID: 32688260 DOI: 10.1016/j.sbi.2020.06.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 06/10/2020] [Accepted: 06/18/2020] [Indexed: 11/26/2022]
Abstract
Eukaryotes possess a variety of translational control mechanisms which function in the surveillance of mRNAs, discriminating between normal and aberrant translation elongation and termination, triggering mRNA decay. The three major evolutionarily conserved eukaryotic pathways are No-Go, Non-Stop and Nonsense-Mediated mRNA Decay. Recent findings suggest that stalling of the ribosome, due to mRNA secondary structure or translation into poly(A)-stretches, leads to ribosome collisions which are detected by No-Go/Non-Stop mRNA decay factors. Subsequent ribosome ubiquitination at the interface of two collided ribosomes is considered the signal for mRNA decay. Similarly, translation termination at a premature stop codon is slower than normal, leading to recruitment and activation of nonsense-mediated mRNA decay factors, including SMG1-8-9. Here, we detail new insights into the molecular mechanisms of these pathways.
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Affiliation(s)
- Kyle T Powers
- University of Bristol, School of Biochemistry, University Walk, Bristol, BS8 1TD, United Kingdom
| | - Jenn-Yeu Alvin Szeto
- University of Bristol, School of Biochemistry, University Walk, Bristol, BS8 1TD, United Kingdom
| | - Christiane Schaffitzel
- University of Bristol, School of Biochemistry, University Walk, Bristol, BS8 1TD, United Kingdom.
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Nonsense-Mediated mRNA Decay: Pathologies and the Potential for Novel Therapeutics. Cancers (Basel) 2020; 12:cancers12030765. [PMID: 32213869 PMCID: PMC7140085 DOI: 10.3390/cancers12030765] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/19/2020] [Accepted: 03/19/2020] [Indexed: 12/22/2022] Open
Abstract
Nonsense-mediated messenger RNA (mRNA) decay (NMD) is a surveillance pathway used by cells to control the quality mRNAs and to fine-tune transcript abundance. NMD plays an important role in cell cycle regulation, cell viability, DNA damage response, while also serving as a barrier to virus infection. Disturbance of this control mechanism caused by genetic mutations or dys-regulation of the NMD pathway can lead to pathologies, including neurological disorders, immune diseases and cancers. The role of NMD in cancer development is complex, acting as both a promoter and a barrier to tumour progression. Cancer cells can exploit NMD for the downregulation of key tumour suppressor genes, or tumours adjust NMD activity to adapt to an aggressive immune microenvironment. The latter case might provide an avenue for therapeutic intervention as NMD inhibition has been shown to lead to the production of neoantigens that stimulate an immune system attack on tumours. For this reason, understanding the biology and co-option pathways of NMD is important for the development of novel therapeutic agents. Inhibitors, whose design can make use of the many structures available for NMD study, will play a crucial role in characterizing and providing diverse therapeutic options for this pathway in cancer and other diseases.
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InsP6 binding to PIKK kinases revealed by the cryo-EM structure of an SMG1–SMG8–SMG9 complex. Nat Struct Mol Biol 2019; 26:1089-1093. [DOI: 10.1038/s41594-019-0342-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 10/28/2019] [Indexed: 12/30/2022]
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Zhu L, Li L, Qi Y, Yu Z, Xu Y. Cryo-EM structure of SMG1-SMG8-SMG9 complex. Cell Res 2019; 29:1027-1034. [PMID: 31729466 DOI: 10.1038/s41422-019-0255-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 10/25/2019] [Indexed: 11/09/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) targets premature stop codon (PTC)-containing mRNAs for rapid degradation, and is essential for mammalian embryonic development, brain development and modulation of the stress response. The key event in NMD is the SMG1-mediated phosphorylation of an RNA helicase UPF1 and SMG1 kinase activity is inhibited by SMG8 and SMG9 in an unknown mechanism. Here, we determined the cryo-EM structures of human SMG1 at 3.6 Å resolution and the SMG1-SMG8-SMG9 complex at 3.4 Å resolution, respectively. SMG8 has a C-terminal kinase inhibitory domain (KID), which covers the catalytic pocket and inhibits the kinase activity of SMG1. Structural analyses suggest that GTP hydrolysis of SMG9 would lead to a dramatic conformational change of SMG8-SMG9 and the KID would move away from the inhibitory position to restore SMG1 kinase activity. Thus, our structural and biochemical analyses provide a mechanistic understanding of SMG1-SMG8-SMG9 complex assembly and the regulatory mechanism of SMG1 kinase activity.
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Affiliation(s)
- Li Zhu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Key Laboratory of Medical Epigenetics and Metabolism, Shanghai Medical College of Fudan University, Shanghai, 200032, China
| | - Liang Li
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Key Laboratory of Medical Epigenetics and Metabolism, Shanghai Medical College of Fudan University, Shanghai, 200032, China
| | - Yilun Qi
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Key Laboratory of Medical Epigenetics and Metabolism, Shanghai Medical College of Fudan University, Shanghai, 200032, China
| | - Zishuo Yu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Key Laboratory of Medical Epigenetics and Metabolism, Shanghai Medical College of Fudan University, Shanghai, 200032, China
| | - Yanhui Xu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Key Laboratory of Medical Epigenetics and Metabolism, Shanghai Medical College of Fudan University, Shanghai, 200032, China. .,Key Laboratory of Molecular Medicine, Ministry of Education, Department of Systems Biology for Medicine, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, 200032, China. .,Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, 200433, China. .,CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China.
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