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Jia R, Zheng ZM. Oncogenic SRSF3 in health and diseases. Int J Biol Sci 2023; 19:3057-3076. [PMID: 37416784 PMCID: PMC10321290 DOI: 10.7150/ijbs.83368] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 05/30/2023] [Indexed: 07/08/2023] Open
Abstract
Serine/arginine rich splicing factor 3 (SRSF3) is an important multi-functional splicing factor, and has attracted increasing attentions in the past thirty years. The importance of SRSF3 is evidenced by its impressively conserved protein sequences in all animals and alternative exon 4 which represents an autoregulatory mechanism to maintain its proper cellular expression level. New functions of SRSF3 have been continuously discovered recently, especially its oncogenic function. SRSF3 plays essential roles in many cellular processes by regulating almost all aspects of RNA biogenesis and processing of many target genes, and thus, contributes to tumorigenesis when overexpressed or disregulated. This review updates and highlights the gene, mRNA, and protein structure of SRSF3, the regulatory mechanisms of SRSF3 expression, and the characteristics of SRSF3 targets and binding sequences that contribute to SRSF3's diverse molecular and cellular functions in tumorigenesis and human diseases.
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Affiliation(s)
- Rong Jia
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
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2
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Yu L, Majerciak V, Jia R, Zheng ZM. Revisiting and corrections to the annotated SRSF3 (SRp20) gene structure and RefSeq sequences from the human and mouse genomes. CELL INSIGHT 2023; 2:100089. [PMID: 37193066 PMCID: PMC10134197 DOI: 10.1016/j.cellin.2023.100089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/14/2023] [Accepted: 02/18/2023] [Indexed: 05/18/2023]
Abstract
SRSF3 (SRp20) is the smallest member of the serine/arginine (SR)-rich protein family. We found the annotated human SRSF3 and mouse Srsf3 RefSeq sequences are much larger than the detected SRSF3/Srsf3 RNA size by Northern blot. Mapping of RNA-seq reads from various human and mouse cell lines to the annotated SRSF3/Srsf3 gene illustrated only a partial coverage of its terminal exon 7. By 5' RACE and 3' RACE, we determined that SRSF3 gene spanning over 8422 bases and Srsf3 gene spanning over 9423 bases. SRSF3/Srsf3 gene has seven exons with exon 7 bearing two alternative polyadenylation signals (PAS). Through alternative PAS selection and exon 4 exclusion/inclusion by alternative RNA splicing, SRSF3/Srsf3 gene expresses four RNA isoforms. The major SRSF3 mRNA isoform with exon 4 exclusion by using a favorable distal PAS to encode a full-length protein is 1411 nt long (not annotated 4228 nt) and the same major mouse Srsf3 mRNA isoform is only 1295 nt (not annotated 2585 nt). The difference from the redefined RNA size of SRSF3/Srsf3 to the corresponding RefSeq sequence is at the 3' UTR region. Collectively, the redefined SRSF3/Srsf3 gene structure and expression will allow better understanding of SRSF3 functions and its regulations in health and diseases.
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Affiliation(s)
- Lulu Yu
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Vladimir Majerciak
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Rong Jia
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST), Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
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3
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Cooperative Binding of SRSF3 to Structured 3'ss-α Exon RNA during α Exon Inclusion in the ZO-1 mRNA. Curr Issues Mol Biol 2023; 45:593-603. [PMID: 36661525 PMCID: PMC9857539 DOI: 10.3390/cimb45010039] [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: 12/07/2022] [Revised: 12/28/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
ZO-1α+ and ZO-1α- proteins are expressed in hermetic and leaky tight junctions, respectively. Two cis-acting distant exonic elements partly activate the 240 nucleotide-long α exon producing the ZO-1α+ isoform. However, the elements within and around the α exon and their respective factors involved in its splicing are unknown. To study the dynamic interaction between SRSF3 and its bioinformatically predicted target sites around the 3'ss upstream of the α exon during its activation, we performed EMSA, crosslinking, and in vivo splicing assays by ZO-1 minigene expression and siRNA-mediated silencing in transfected cells. Using V1 RNase, we probed the possible formation of a hairpin RNA structure between the intronic and proximal exonic SRSF3 binding sites. The hairpin sufficed for complex formations in the EMSA. The interaction of SRSF3 with the intronic site promoted the cooperative binding of SRSF3 to the exonic site. Finally, SRSF3 restored α exon activation in SRSF3 knockdown transfectants. Altogether, our results show that SRSF3-hairpin RNA interaction is crucial in the early recognition of 3'ss for α exon activation. It remains to be explored whether SRSF3 recruits or stabilizes the binding of other factors or brings separate splice sites into proximity.
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4
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Li Z, Huang H, Wu X, Yu T, Xiao F, Zhou H, Shang A, Yang Y. SRSF3 Expression Serves as a Potential Biomarker for Prognostic and Immune Response in Pan-Cancer. Front Oncol 2022; 12:808530. [PMID: 35494088 PMCID: PMC9047863 DOI: 10.3389/fonc.2022.808530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 03/15/2022] [Indexed: 11/13/2022] Open
Abstract
Serine-rich splicing factor3 (SRSF3) plays an essential role in cell proliferation and inducing and maintaining of cancers as a proto-oncogene. However, the mechanisms of SRSF3 in pan-cancers are still unknown. In our study, a visualized prognostic landscape of SRSF3 in pan-cancer was investigated and the relationship between SRSF3 expression and immune infiltration was also investigated. The expression pattern and prognostic worth of SRSF3 among pan-cancers were explored through different databases, namely, the TCGA and Kaplan–Meier Plotter. Moreover, the survival analysis including Kaplan-Meier method for evaluating between groups was conducted. Further analyses including the correlation between expression SRSF expression and immune infiltration including tumor mutation burden (TMB), microsatellite instability (MSI) was investigated using Spearman test. In ACC, KIRP and UCEC cancer, upregulated expression of SRSF3 was associated with worse disease-free interval (DFI), representing a mechanism in promoting progression of tumor. Our results showed that SRSF3 expression was positively correlated immune cell infiltration, TMB, MSI in certain cancer types, indicating SRSF3 expression to potential value of therapy response. Additionally, we explored the functional characteristics of SRSF in vitro through western blot detecting the expression level of the apoptosis-related proteins in SW480 and 786-O cells. SRSF3 expression was upregulated in pan-cancer tissue compared with normal tissue, which confirmed by immunohistochemistry and its expression indicated poor overall survival and death-specific survival. Therefore, SRSF3 was found to be a possible biomarker for prognostic and therapeutic assessment through bioinformatic analysis. SRSF3 is expressed in various cancers and its high expression correlated to poor survival and disease progression. In summary, SRSF3 expression can be considered as a prognostic biomarker in pan-cancer and therapeutic evaluation.
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Affiliation(s)
- Zihua Li
- Department of Orthopedics, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Orthopedics, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Hui Huang
- Department of Orthopedics, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Xinbo Wu
- Department of Orthopedics, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Orthopedics, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Tao Yu
- Department of Orthopedics, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Fajiao Xiao
- Department of Orthopedics, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Haichao Zhou
- Department of Orthopedics, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Anquan Shang
- Department of Laboratory Medicine, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
- *Correspondence: Anquan Shang, ; Yunfeng Yang,
| | - Yunfeng Yang
- Department of Orthopedics, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
- *Correspondence: Anquan Shang, ; Yunfeng Yang,
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5
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Resistance Mechanisms in Pediatric B-Cell Acute Lymphoblastic Leukemia. Int J Mol Sci 2022; 23:ijms23063067. [PMID: 35328487 PMCID: PMC8950780 DOI: 10.3390/ijms23063067] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/09/2022] [Accepted: 03/10/2022] [Indexed: 02/01/2023] Open
Abstract
Despite the rapid development of medicine, even nowadays, acute lymphoblastic leukemia (ALL) is still a problem for pediatric clinicians. Modern medicine has reached a limit of curability even though the recovery rate exceeds 90%. Relapse occurs in around 20% of treated patients and, regrettably, 10% of diagnosed ALL patients are still incurable. In this article, we would like to focus on the treatment resistance and disease relapse of patients with B-cell leukemia in the context of prognostic factors of ALL. We demonstrate the mechanisms of the resistance to steroid therapy and Tyrosine Kinase Inhibitors and assess the impact of genetic factors on the treatment resistance, especially TCF3::HLF translocation. We compare therapeutic protocols and decipher how cancer cells become resistant to innovative treatments—including CAR-T-cell therapies and monoclonal antibodies. The comparisons made in our article help to bring closer the main factors of resistance in hematologic malignancies in the context of ALL.
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6
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Heazlewood SY, Ahmad T, Mohenska M, Guo BB, Gangatirkar P, Josefsson EC, Ellis SL, Ratnadiwakara M, Cao H, Cao B, Heazlewood CK, Williams B, Fulton M, White JF, Ramialison M, Nilsson SK, Änkö ML. The RNA-binding protein SRSF3 has an essential role in megakaryocyte maturation and platelet production. Blood 2022; 139:1359-1373. [PMID: 34852174 PMCID: PMC8900270 DOI: 10.1182/blood.2021013826] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/06/2021] [Indexed: 11/20/2022] Open
Abstract
RNA processing is increasingly recognized as a critical control point in the regulation of different hematopoietic lineages including megakaryocytes responsible for the production of platelets. Platelets are anucleate cytoplasts that contain a rich repertoire of RNAs encoding proteins with essential platelet functions derived from the parent megakaryocyte. It is largely unknown how RNA binding proteins contribute to the development and functions of megakaryocytes and platelets. We show that serine-arginine-rich splicing factor 3 (SRSF3) is essential for megakaryocyte maturation and generation of functional platelets. Megakaryocyte-specific deletion of Srsf3 in mice led to macrothrombocytopenia characterized by megakaryocyte maturation arrest, dramatically reduced platelet counts, and abnormally large functionally compromised platelets. SRSF3 deficient megakaryocytes failed to reprogram their transcriptome during maturation and to load platelets with RNAs required for normal platelet function. SRSF3 depletion led to nuclear accumulation of megakaryocyte mRNAs, demonstrating that SRSF3 deploys similar RNA regulatory mechanisms in megakaryocytes as in other cell types. Our study further suggests that SRSF3 plays a role in sorting cytoplasmic megakaryocyte RNAs into platelets and demonstrates how SRSF3-mediated RNA processing forms a central part of megakaryocyte gene regulation. Understanding SRSF3 functions in megakaryocytes and platelets provides key insights into normal thrombopoiesis and platelet pathologies as SRSF3 RNA targets in megakaryocytes are associated with platelet diseases.
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Affiliation(s)
- Shen Y Heazlewood
- Biomedical Manufacturing CSIRO, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
| | - Tanveer Ahmad
- Biomedical Manufacturing CSIRO, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
| | - Monika Mohenska
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
| | - Belinda B Guo
- School of Biomedical Sciences, Pathology and Laboratory Science, University of Western Australia, WA, Australia
| | | | - Emma C Josefsson
- Walter and Eliza Hall Institute of Medical Research, VIC, Australia
- Department of Medical Biology, The University of Melbourne, VIC, Australia
| | - Sarah L Ellis
- Peter MacCallum Cancer Centre, and Sir Peter MacCallum Department of Oncology, University of Melbourne, VIC, Australia
- Olivia Newton-John Cancer Research Institute, Microscopy Facility and School of Cancer Medicine, La Trobe University, VIC, Australia
| | - Madara Ratnadiwakara
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
- Hudson Institute of Medical Research, VIC, Australia; and
- Department of Molecular and Translational Sciences, Monash University, VIC, Australia
| | - Huimin Cao
- Biomedical Manufacturing CSIRO, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
| | - Benjamin Cao
- Biomedical Manufacturing CSIRO, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
| | - Chad K Heazlewood
- Biomedical Manufacturing CSIRO, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
| | - Brenda Williams
- Biomedical Manufacturing CSIRO, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
| | - Madeline Fulton
- Biomedical Manufacturing CSIRO, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
| | | | - Mirana Ramialison
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
| | - Susan K Nilsson
- Biomedical Manufacturing CSIRO, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
| | - Minna-Liisa Änkö
- Australian Regenerative Medicine Institute, Monash University, VIC, Australia
- Hudson Institute of Medical Research, VIC, Australia; and
- Department of Molecular and Translational Sciences, Monash University, VIC, Australia
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7
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Xiong J, Chen Y, Wang W, Sun J. Biological function and molecular mechanism of SRSF3 in cancer and beyond. Oncol Lett 2021; 23:21. [PMID: 34858525 PMCID: PMC8617561 DOI: 10.3892/ol.2021.13139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/07/2021] [Indexed: 12/15/2022] Open
Abstract
Serine/arginine-rich splicing factor 3 (SRSF3; also known as SRp20), an important member of the family of SRSFs, is abnormally expressed in tumors, resulting in aberrant splicing of hub genes, such as CD44, HER2, MDM4, Rac family small GTPase 1 and tumor protein p53. Under normal conditions, the splicing and expression of SRSF3 are strictly regulated. However, the splicing, expression and phosphorylation of SRSF3 are abnormal in tumors. SRSF3 plays important roles in the occurrence and development of tumors, including the promotion of tumorigenesis, cellular proliferation, the cell cycle and metastasis, as well as inhibition of cell senescence, apoptosis and autophagy. SRSF3-knockdown significantly inhibits the proliferation and metastatic characteristics of tumor cells. Therefore, SRSF3 may be suggested as a novel anti-tumor target. The other biological functions of SRSF3 and its regulatory mechanisms are also summarized in the current review.
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Affiliation(s)
- Jian Xiong
- Institute of Medical Biotechnology, Suzhou Vocational Health College, Suzhou, Jiangsu 215009, P.R. China
| | - Yinshuang Chen
- Center for Drug Metabolism and Pharmacokinetics, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Weipeng Wang
- Center for Drug Metabolism and Pharmacokinetics, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Jing Sun
- Institute of Medical Biotechnology, Suzhou Vocational Health College, Suzhou, Jiangsu 215009, P.R. China
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8
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Identification of SRSF3 target mRNAs using inducible TRIBE. Biochem Biophys Res Commun 2021; 578:21-27. [PMID: 34534741 DOI: 10.1016/j.bbrc.2021.09.019] [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: 08/10/2021] [Revised: 09/06/2021] [Accepted: 09/08/2021] [Indexed: 11/22/2022]
Abstract
Serine and arginine-rich splicing factor 3 (SRSF3), the smallest member of the Ser/Arg-rich (SR) RNA-binding protein family, regulates multiple aspects of post-transcriptional gene expression program. Although SRSF3 is essential for early embryo development, reprogramming, and pluripotency maintenance, the RNA targets and specificity of RNA recognition of SRSF3 are not well understood in human pluripotent stem cells. In this study, we used inducible TRIBE (targets of RNA binding sites by editing) to identify RNA targets and binding motifs of SRSF3 in human embryonic stem cells (hESCs). We identified 3888 confident binding sites of SRSF3, corresponding to 1222 gene targets. Our results showed that nearly half of the binding sites were distributed in exons, reflecting the alternative splicing function of SRSF3. Motif analysis demonstrated that two of the SRSF3 recognition sequences were the same as the motifs identified in mouse embryonic stem cells, suggesting the recognition sequences of SRSF3 may be conserved in mammals. Overall, our analyses revealed the RNA targets of SRSF3 and uncovered its RNA recognition specificity, providing a valuable resource for understanding the function of SRSF3 in human embryonic stem cells.
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9
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Yan JM, Zhang WK, Li F, Zhou CM, Yu XJ. Integrated transcriptome profiling in THP-1 macrophages infected with bunyavirus SFTSV. Virus Res 2021; 306:198594. [PMID: 34637813 DOI: 10.1016/j.virusres.2021.198594] [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: 06/05/2021] [Revised: 09/10/2021] [Accepted: 10/06/2021] [Indexed: 10/20/2022]
Abstract
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tick-borne bunyavirus that causes an emerging hemorrhagic fever termed SFTS with high mortality. However, knowledge of SFTSV-host interactions is largely limited. Here, we performed a global transcriptome analysis of mRNAs and lncRNAs in THP-1 macrophages infected with SFTSV for 24 and 48 h. A total of 2,334 differentially expressed mRNAs and 154 differentially expressed lncRNAs were identified with 577 mRNAs and 31 lncRNAs commonly changed at both time points. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that differentially expressed mRNAs were mainly associated with innate immune, cytokine signaling, systemic lupus erythematosus, and alcoholism. Differentially expressed lncRNAs were enriched in systemic lupus erythematosus, alcoholism, and ribosome. Bioinformatic analysis also revealed hub regulatory mRNAs including IL6, TNF, UBA52, SRC, IL10, CXCL10, and CDK1 and core regulatory lncRNAs including XLOC_083027 and XLOC_113317. Transcription factor analysis of the differentially expressed mRNAs revealed that IRF1, SPI1, SPIB, ELF5, and FEV were enriched during SFTSV infection. Taken together, our studies illustrate the complex interaction between THP-1 macrophages and SFTSV.
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Affiliation(s)
- Jia-Min Yan
- State Key Laboratory of Virology, School of Health Sciences, Wuhan University, Wuhan, 430071, China
| | - Wen-Kang Zhang
- State Key Laboratory of Virology, School of Health Sciences, Wuhan University, Wuhan, 430071, China
| | - Fei Li
- School of Public Health, Shandong University, Jinan, Shandong 250012, China
| | - Chuan-Min Zhou
- State Key Laboratory of Virology, School of Health Sciences, Wuhan University, Wuhan, 430071, China; Zhongnan hospital of Wuhan University, Wuhan, 430071, China.
| | - Xue-Jie Yu
- State Key Laboratory of Virology, School of Health Sciences, Wuhan University, Wuhan, 430071, China.
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10
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Wang H, Jiang Y. SRp20: A potential therapeutic target for human tumors. Pathol Res Pract 2021; 224:153444. [PMID: 34126370 DOI: 10.1016/j.prp.2021.153444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 04/11/2021] [Accepted: 04/11/2021] [Indexed: 12/12/2022]
Abstract
As an important member of SR protein family, SRp20 plays a crucial role in alternative splicing. It not only participates in cell cycle regulation, export of mRNA, cleaving of primary microRNAs, homologous recombination-mediated DNA repair, cellular senescence and apoptosis, but also gets involved in the integrity and pluripotency of genome. Alternative splicing maintains a strict balance in the body to ensure the normal physiological function of cells. Once the balance is broken, diseases, even tumors, will follow. Through the analysis of SRp20-related articles, we found that Alzheimer's disease, glaucoma, bipolar disorder and other diseases have a certain relationship with SRp20. More importantly, SRp20 is closely related to the occurrence, proliferation, invasion and metastasis of various tumors, as well as chemotherapy resistance. Some SRp20 inhibitors have shown significant anticancer efficacy, suggesting a potential therapeutic strategy for tumors.
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Affiliation(s)
- Han Wang
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, China
| | - Yanxia Jiang
- Department of Pathology, The Affiliated Hospital of Qingdao University, Qingdao, China.
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11
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More DA, Kumar A. SRSF3: Newly discovered functions and roles in human health and diseases. Eur J Cell Biol 2020; 99:151099. [PMID: 32800280 DOI: 10.1016/j.ejcb.2020.151099] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/15/2020] [Accepted: 06/29/2020] [Indexed: 12/21/2022] Open
Abstract
The serine/arginine rich proteins (SR proteins) are members of a family of RNA binding proteins involved in regulating various features of RNA metabolism, including pre-mRNA constitutive and alternative splicing. In humans, a total of 12 SR splicing factors (SRSFs) namely SRSF1-SRSF12 have been reported. SRSF3, the smallest member of the SR family and the focus of this review, regulates critical steps in mRNA metabolism and has been shown to have mRNA-independent functions as well. Recent studies on SRSF3 have uncovered its role in a wide array of complex biological processes. We have also reviewed the involvement of SRSF3 in disease conditions like cancer, ageing, neurological and cardiac disorders. Finally, we have discussed in detail the autoregulation of SRSF3 and its implications in cancer and commented on the potential of SRSF3 as a therapeutic target, especially in the context of cancer.
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Affiliation(s)
- Dhanashree Anil More
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560012, India
| | - Arun Kumar
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560012, India.
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12
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Jiménez M, Urtasun R, Elizalde M, Azkona M, Latasa MU, Uriarte I, Arechederra M, Alignani D, Bárcena-Varela M, Álvarez-Sola G, Colyn L, Santamaría E, Sangro B, Rodriguez-Ortigosa C, Fernández-Barrena MG, Ávila MA, Berasain C. Splicing events in the control of genome integrity: role of SLU7 and truncated SRSF3 proteins. Nucleic Acids Res 2019; 47:3450-3466. [PMID: 30657957 PMCID: PMC6468163 DOI: 10.1093/nar/gkz014] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 11/21/2018] [Accepted: 01/08/2019] [Indexed: 12/13/2022] Open
Abstract
Genome instability is related to disease development and carcinogenesis. DNA lesions are caused by genotoxic compounds but also by the dysregulation of fundamental processes like transcription, DNA replication and mitosis. Recent evidence indicates that impaired expression of RNA-binding proteins results in mitotic aberrations and the formation of transcription-associated RNA-DNA hybrids (R-loops), events strongly associated with DNA injury. We identify the splicing regulator SLU7 as a key mediator of genome stability. SLU7 knockdown results in R-loops formation, DNA damage, cell-cycle arrest and severe mitotic derangements with loss of sister chromatid cohesion (SCC). We define a molecular pathway through which SLU7 keeps in check the generation of truncated forms of the splicing factor SRSF3 (SRp20) (SRSF3-TR). Behaving as dominant negative, or by gain-of-function, SRSF3-TR impair the correct splicing and expression of the splicing regulator SRSF1 (ASF/SF2) and the crucial SCC protein sororin. This unique function of SLU7 was found in cancer cells of different tissue origin and also in the normal mouse liver, demonstrating a conserved and fundamental role of SLU7 in the preservation of genome integrity. Therefore, the dowregulation of SLU7 and the alterations of this pathway that we observe in the cirrhotic liver could be involved in the process of hepatocarcinogenesis.
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Affiliation(s)
- Maddalen Jiménez
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain
| | - Raquel Urtasun
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain.,Instituto de Investigaciones Sanitarias de Navarra-IdiSNA, Pamplona 31008, Spain
| | - María Elizalde
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain
| | - María Azkona
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain
| | - M Ujue Latasa
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain
| | - Iker Uriarte
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - María Arechederra
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain
| | - Diego Alignani
- Instituto de Investigaciones Sanitarias de Navarra-IdiSNA, Pamplona 31008, Spain.,Cytometry Unit, CIMA, University of Navarra, Pamplona 31008, Spain
| | | | - Gloria Álvarez-Sola
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Leticia Colyn
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain
| | - Eva Santamaría
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Bruno Sangro
- Instituto de Investigaciones Sanitarias de Navarra-IdiSNA, Pamplona 31008, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid 28029, Spain.,Hepatology Unit, Navarra University Clinic, Pamplona 31008, Spain
| | - Carlos Rodriguez-Ortigosa
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain.,Instituto de Investigaciones Sanitarias de Navarra-IdiSNA, Pamplona 31008, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Maite G Fernández-Barrena
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain.,Instituto de Investigaciones Sanitarias de Navarra-IdiSNA, Pamplona 31008, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Matías A Ávila
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain.,Instituto de Investigaciones Sanitarias de Navarra-IdiSNA, Pamplona 31008, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Carmen Berasain
- Hepatology Program, CIMA, University of Navarra, Pamplona 31008, Spain.,Instituto de Investigaciones Sanitarias de Navarra-IdiSNA, Pamplona 31008, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid 28029, Spain
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13
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Kumar D, Das M, Sauceda C, Ellies LG, Kuo K, Parwal P, Kaur M, Jih L, Bandyopadhyay GK, Burton D, Loomba R, Osborn O, Webster NJ. Degradation of splicing factor SRSF3 contributes to progressive liver disease. J Clin Invest 2019; 129:4477-4491. [PMID: 31393851 DOI: 10.1172/jci127374] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Serine rich splicing factor 3 (SRSF3) plays a critical role in liver function and its loss promotes chronic liver damage and regeneration. As a consequence, genetic deletion of SRSF3 in hepatocytes caused progressive liver disease and ultimately led to hepatocellular carcinoma. Here we show that SRSF3 is decreased in human liver samples with non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), or cirrhosis that was associated with alterations in RNA splicing of known SRSF3 target genes. Hepatic SRSF3 expression was similarly decreased and RNA splicing dysregulated in mouse models of NAFLD and NASH. We showed that palmitic acid-induced oxidative stress caused conjugation of the ubiquitin like NEDD8 protein to SRSF3 and proteasome mediated degradation. SRSF3 was selectively neddylated at lysine11 and mutation of this residue (SRSF3-K11R) was sufficient to prevent both SRSF3 degradation and alterations in RNA splicing. Finally prevention of SRSF3 degradation in vivo partially protected mice from hepatic steatosis, fibrosis and inflammation. These results highlight a neddylation-dependent mechanism regulating gene expression in the liver that is disrupted in early metabolic liver disease and may contribute to the progression to NASH, cirrhosis and ultimately hepatocellular carcinoma.
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Affiliation(s)
- Deepak Kumar
- VA San Diego Healthcare System, San Diego, California, USA.,Department of Medicine
| | | | - Consuelo Sauceda
- VA San Diego Healthcare System, San Diego, California, USA.,Department of Medicine
| | - Lesley G Ellies
- Department of Pathology, and.,Moores Cancer Center, UCSD, La Jolla, California, USA
| | | | | | | | - Lily Jih
- VA San Diego Healthcare System, San Diego, California, USA
| | | | - Douglas Burton
- VA San Diego Healthcare System, San Diego, California, USA
| | - Rohit Loomba
- Department of Medicine.,Moores Cancer Center, UCSD, La Jolla, California, USA
| | | | - Nicholas Jg Webster
- VA San Diego Healthcare System, San Diego, California, USA.,Department of Medicine.,Moores Cancer Center, UCSD, La Jolla, California, USA
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14
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Ruiz JC, Hunter OV, Conrad NK. Kaposi's sarcoma-associated herpesvirus ORF57 protein protects viral transcripts from specific nuclear RNA decay pathways by preventing hMTR4 recruitment. PLoS Pathog 2019; 15:e1007596. [PMID: 30785952 PMCID: PMC6398867 DOI: 10.1371/journal.ppat.1007596] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/04/2019] [Accepted: 01/25/2019] [Indexed: 12/15/2022] Open
Abstract
Nuclear RNAs are subject to a number of RNA decay pathways that serve quality control and regulatory functions. As a result, any virus that expresses its genes in the nucleus must have evolved mechanisms that avoid these pathways, but the how viruses evade nuclear RNA decay remains largely unknown. The multifunctional Kaposi’s sarcoma-associated herpesvirus (KSHV) ORF57 (Mta) protein is required for the nuclear stability of viral transcripts. In the absence of ORF57, we show that viral transcripts are subject to degradation by two specific nuclear RNA decay pathways, PABPN1 and PAPα/γ-mediated RNA decay (PPD) in which decay factors are recruited through poly(A) tails, and an ARS2-mediated RNA decay pathway dependent on the 5ʹ RNA cap. In transcription pulse chase assays, ORF57 appears to act primarily by inhibiting the ARS2-mediated RNA decay pathway. In the context of viral infection in cultured cells, inactivation of both decay pathways by RNAi is necessary for the restoration of ORF57-dependent viral genes produced from an ORF57-null bacmid. Mechanistically, we demonstrate that ORF57 protects viral transcripts by preventing the recruitment of the exosome co-factor hMTR4. In addition, our data suggest that ORF57 recruitment of ALYREF inhibits hMTR4 association with some viral RNAs, whereas other KSHV transcripts are stabilized by ORF57 in an ALYREF-independent fashion. In conclusion, our studies show that KSHV RNAs are subject to nuclear degradation by two specific host pathways, PPD and ARS2-mediated decay, and ORF57 protects viral transcripts from decay by inhibiting hMTR4 recruitment. Eukaryotic cells contain numerous nuclear RNA quality control (QC) systems that ensure transcriptome fidelity by detecting and degrading aberrant RNAs. Some viral RNAs are also predicted to be degraded by these RNA QC systems, so viruses have evolved mechanisms that counter host RNA QC pathways. Previous studies showed that the Kaposi’s sarcoma-associated herpesvirus (KSHV) expresses the ORF57 protein to protect its RNAs from nuclear decay. However, neither the specific host pathways that degrade KSHV RNAs nor the mechanisms describing ORF57 protection of viral RNAs were known. Our data suggest that ORF57 protects viral RNAs from two different nuclear RNA QC pathways, PABPN1 and PAPα/γ-mediated RNA decay (PPD) and an ARS2-mediated RNA decay pathway. Mechanistically, we show that ORF57 binds directly to viral RNAs and prevents the recruitment of hMTR4, a cellular factor whose function is to recruit the exosome, the complex responsible for RNA decay, to the transcript. We conclude that by preventing hMTR4 recruitment, ORF57 protects viral RNAs from degradation resulting in robust expression of viral genes.
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Affiliation(s)
- Julio C. Ruiz
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Olga V. Hunter
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Nicholas K. Conrad
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
- * E-mail:
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15
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Nguyen HM, Nguyen TD, Nguyen TL, Nguyen TA. Orientation of Human Microprocessor on Primary MicroRNAs. Biochemistry 2018; 58:189-198. [DOI: 10.1021/acs.biochem.8b00944] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Huong Minh Nguyen
- Laboratory of Molecular Microbiology, Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Trung Duc Nguyen
- Division of Life Science, Hong Kong University of Science & Technology, Hong Kong, China
| | - Thuy Linh Nguyen
- Division of Life Science, Hong Kong University of Science & Technology, Hong Kong, China
| | - Tuan Anh Nguyen
- Division of Life Science, Hong Kong University of Science & Technology, Hong Kong, China
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16
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Epstein-Barr Virus-Induced Nodules on Viral Replication Compartments Contain RNA Processing Proteins and a Viral Long Noncoding RNA. J Virol 2018; 92:JVI.01254-18. [PMID: 30068640 DOI: 10.1128/jvi.01254-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 11/20/2022] Open
Abstract
Profound alterations in host cell nuclear architecture accompany the lytic phase of Epstein-Barr virus (EBV) infection. Viral replication compartments assemble, host chromatin marginalizes to the nuclear periphery, cytoplasmic poly(A)-binding protein translocates to the nucleus, and polyadenylated mRNAs are sequestered within the nucleus. Virus-induced changes to nuclear architecture that contribute to viral host shutoff (VHS) must accommodate selective processing and export of viral mRNAs. Here we describe additional previously unrecognized nuclear alterations during EBV lytic infection in which viral and cellular factors that function in pre-mRNA processing and mRNA export are redistributed. Early during lytic infection, before formation of viral replication compartments, two cellular pre-mRNA splicing factors, SC35 and SON, were dispersed from interchromatin granule clusters, and three mRNA export factors, Y14, ALY, and NXF1, were depleted from the nucleus. During late lytic infection, virus-induced nodular structures (VINORCs) formed at the periphery of viral replication compartments. VINORCs were composed of viral (BMLF1 and BGLF5) and cellular (SC35, SON, SRp20, and NXF1) proteins that mediate pre-mRNA processing and mRNA export. BHLF1 long noncoding RNA was invariably found in VINORCs. VINORCs did not contain other nodular nuclear cellular proteins (PML or coilin), nor did they contain viral proteins (BRLF1 or BMRF1) found exclusively within replication compartments. VINORCs are novel EBV-induced nuclear structures. We propose that EBV-induced dispersal and depletion of pre-mRNA processing and mRNA export factors during early lytic infection contribute to VHS; subsequent relocalization of these pre-mRNA processing and mRNA export proteins to VINORCs and viral replication compartments facilitates selective processing and export of viral mRNAs.IMPORTANCE In order to make protein, mRNA transcribed from DNA in the nucleus must enter the cytoplasm. Nuclear export of mRNA requires correct processing of mRNAs by enzymes that function in splicing and nuclear export. During the Epstein-Barr virus (EBV) lytic cycle, nuclear export of cellular mRNAs is blocked, yet export of viral mRNAs is facilitated. Here we report the dispersal and dramatic reorganization of cellular (SC35, SON, SRp20, Y14, ALY, and NXF1) and viral (BMLF1 and BGLF5) proteins that play key roles in pre-mRNA processing and export of mRNA. These virus-induced nuclear changes culminate in formation of VINORCs, novel nodular structures composed of viral and cellular RNA splicing and export factors. VINORCs localize to the periphery of viral replication compartments, where viral mRNAs reside. These EBV-induced changes in nuclear organization may contribute to blockade of nuclear export of host mRNA, while enabling selective processing and export of viral mRNA.
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17
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Yang S, Jia R, Bian Z. SRSF5 functions as a novel oncogenic splicing factor and is upregulated by oncogene SRSF3 in oral squamous cell carcinoma. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1161-1172. [DOI: 10.1016/j.bbamcr.2018.05.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/25/2018] [Accepted: 05/26/2018] [Indexed: 10/25/2022]
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18
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Kim K, Nguyen TD, Li S, Nguyen TA. SRSF3 recruits DROSHA to the basal junction of primary microRNAs. RNA (NEW YORK, N.Y.) 2018; 24:892-898. [PMID: 29615481 PMCID: PMC6004053 DOI: 10.1261/rna.065862.118] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 03/29/2018] [Indexed: 05/22/2023]
Abstract
The Microprocessor complex, consisting of an RNase III DROSHA and the DGCR8 dimer, cleaves primary microRNA transcripts (pri-miRNAs) to initiate microRNA (miRNA) maturation. Pri-miRNAs are stem-loop RNAs, and ∼79% of them contain at least one of the three major and conserved RNA motifs, UG, UGU, and CNNC. We recently demonstrated that the basal UG and apical UGU motifs of pri-miRNAs interact with DROSHA and DGCR8, respectively. They help orient Microprocessor on pri-miRNA in a proper direction in which DROSHA and DGCR8 localize to the basal and apical pri-miRNA junctions, respectively. In addition, CNNC, located at ∼17 nucleotides (nt) from the Microprocessor cleavage site, interacts with SRSF3 (SRp20) to stimulate Microprocessor to process pri-miRNAs. The mechanism underlying this stimulation, however, is unknown. In this study, we discovered that SRSF3 recruits DROSHA to the basal junction in a CNNC-dependent manner, thereby enhancing Microprocessor activity. Furthermore, by generating various pri-miRNA substrates containing CNNC at different locations, we demonstrated that such stimulation only occurs when CNNC is located at ∼17 nt from the Microprocessor cleavage site. Our findings reveal the molecular mechanism of SRSF3 in pri-miRNA processing and support the previously proposed explanation for the highly conserved position of CNNC in SRSF3-enhanced pri-miRNA processing.
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Affiliation(s)
- Kijun Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Trung Duc Nguyen
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
- HKUST Shenzhen Research Institute, Shenzhen 518057, China
| | - Shaohua Li
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Tuan Anh Nguyen
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
- HKUST Shenzhen Research Institute, Shenzhen 518057, China
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19
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Ratnadiwakara M, Archer SK, Dent CI, Ruiz De Los Mozos I, Beilharz TH, Knaupp AS, Nefzger CM, Polo JM, Anko ML. SRSF3 promotes pluripotency through Nanog mRNA export and coordination of the pluripotency gene expression program. eLife 2018; 7:37419. [PMID: 29741478 PMCID: PMC5963917 DOI: 10.7554/elife.37419] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/05/2018] [Indexed: 12/28/2022] Open
Abstract
The establishment and maintenance of pluripotency depend on precise coordination of gene expression. We establish serine-arginine-rich splicing factor 3 (SRSF3) as an essential regulator of RNAs encoding key components of the mouse pluripotency circuitry, SRSF3 ablation resulting in the loss of pluripotency and its overexpression enhancing reprogramming. Strikingly, SRSF3 binds to the core pluripotency transcription factor Nanog mRNA to facilitate its nucleo-cytoplasmic export independent of splicing. In the absence of SRSF3 binding, Nanog mRNA is sequestered in the nucleus and protein levels are severely downregulated. Moreover, SRSF3 controls the alternative splicing of the export factor Nxf1 and RNA regulators with established roles in pluripotency, and the steady-state levels of mRNAs encoding chromatin modifiers. Our investigation links molecular events to cellular functions by demonstrating how SRSF3 regulates the pluripotency genes and uncovers SRSF3-RNA interactions as a critical means to coordinate gene expression during reprogramming, stem cell self-renewal and early development.
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Affiliation(s)
- Madara Ratnadiwakara
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Stuart K Archer
- Bioinformatics Platform, Monash University, Clayton, Australia
| | - Craig I Dent
- School of Biological Sciences, Monash University, Melbourne, Australia
| | | | - Traude H Beilharz
- Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia
| | - Anja S Knaupp
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Christian M Nefzger
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Jose M Polo
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Minna-Liisa Anko
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
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20
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The High Level of Aberrant Splicing of ISCU in Slow-Twitch Muscle May Involve the Splicing Factor SRSF3. PLoS One 2016; 11:e0165453. [PMID: 27783661 PMCID: PMC5081167 DOI: 10.1371/journal.pone.0165453] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 10/12/2016] [Indexed: 01/08/2023] Open
Abstract
Hereditary myopathy with lactic acidosis (HML) is an autosomal recessive disease caused by an intronic one-base mutation in the iron-sulfur cluster assembly (ISCU) gene, resulting in aberrant splicing. The incorrectly spliced transcripts contain a 100 or 86 bp intron sequence encoding a non-functional ISCU protein, which leads to defects in several Fe-S containing proteins in the respiratory chain and the TCA cycle. The symptoms in HML are restricted to skeletal muscle, and it has been proposed that this effect is due to higher levels of incorrectly spliced ISCU in skeletal muscle compared with other energy-demanding tissues. In this study, we confirm that skeletal muscle contains the highest levels of incorrect ISCU splice variants compared with heart, brain, liver and kidney using a transgenic mouse model expressing human HML mutated ISCU. We also show that incorrect splicing occurs to a significantly higher extent in the slow-twitch soleus muscle compared with the gastrocnemius and quadriceps. The splicing factor serine/arginine-rich splicing factor 3 (SRSF3) was identified as a potential candidate for the slow fiber specific regulation of ISCU splicing since this factor was expressed at higher levels in the soleus compared to the gastrocnemius and quadriceps. We identified an interaction between SRSF3 and the ISCU transcript, and by overexpressing SRSF3 in human myoblasts we observed increased levels of incorrectly spliced ISCU, while knockdown of SRSF3 resulted in decreased levels. We therefore suggest that SRSF3 may participate in the regulation of the incorrect splicing of mutant ISCU and may, at least partially, explain the muscle-specific symptoms of HML.
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21
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SRSF3 represses the expression of PDCD4 protein by coordinated regulation of alternative splicing, export and translation. Biochem Biophys Res Commun 2016; 470:431-438. [DOI: 10.1016/j.bbrc.2016.01.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 01/05/2016] [Indexed: 02/04/2023]
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22
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Ajiro M, Jia R, Yang Y, Zhu J, Zheng ZM. A genome landscape of SRSF3-regulated splicing events and gene expression in human osteosarcoma U2OS cells. Nucleic Acids Res 2015; 44:1854-70. [PMID: 26704980 PMCID: PMC4770227 DOI: 10.1093/nar/gkv1500] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 12/11/2015] [Indexed: 02/07/2023] Open
Abstract
Alternative RNA splicing is an essential process to yield proteomic diversity in eukaryotic cells, and aberrant splicing is often associated with numerous human diseases and cancers. We recently described serine/arginine-rich splicing factor 3 (SRSF3 or SRp20) being a proto-oncogene. However, the SRSF3-regulated splicing events responsible for its oncogenic activities remain largely unknown. By global profiling of the SRSF3-regulated splicing events in human osteosarcoma U2OS cells, we found that SRSF3 regulates the expression of 60 genes including ERRFI1, ANXA1 and TGFB2, and 182 splicing events in 164 genes, including EP300, PUS3, CLINT1, PKP4, KIF23, CHK1, SMC2, CKLF, MAP4, MBNL1, MELK, DDX5, PABPC1, MAP4K4, Sp1 and SRSF1, which are primarily associated with cell proliferation or cell cycle. Two SRSF3-binding motifs, CCAGC(G)C and A(G)CAGCA, are enriched to the alternative exons. An SRSF3-binding site in the EP300 exon 14 is essential for exon 14 inclusion. We found that the expression of SRSF1 and SRSF3 are mutually dependent and coexpressed in normal and tumor tissues/cells. SRSF3 also significantly regulates the expression of at least 20 miRNAs, including a subset of oncogenic or tumor suppressive miRNAs. These data indicate that SRSF3 affects a global change of gene expression to maintain cell homeostasis.
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Affiliation(s)
- Masahiko Ajiro
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Rong Jia
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Yanqin Yang
- DNA Sequencing and Genomics Core, System Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jun Zhu
- DNA Sequencing and Genomics Core, System Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
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23
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Sen S, Langiewicz M, Jumaa H, Webster NJ. Deletion of serine/arginine-rich splicing factor 3 in hepatocytes predisposes to hepatocellular carcinoma in mice. Hepatology 2015; 61:171-83. [PMID: 25132062 PMCID: PMC4280350 DOI: 10.1002/hep.27380] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 08/13/2014] [Indexed: 12/17/2022]
Abstract
UNLABELLED Alterations in RNA splicing are associated with cancer, but it is not clear whether they result from malignant transformation or have a causative role. We show here that hepatocyte-specific deletion of serine/arginine-rich splicing factor 3 (SRSF3) impairs hepatocyte maturation and metabolism in early adult life, and mice develop spontaneous hepatocellular carcinoma (HCC) with aging. Tumor development is preceded by chronic liver disease with progressive steatosis and fibrosis. SRSF3 protects mice against CCl4 -induced fibrosis and carcinogenesis and suppresses inclusion of the profibrogenic EDA exon in fibronectin 1. Loss of SRSF3 increases expression of insulin-like growth factor 2 and the A-isoform of the insulin receptor, allowing aberrant activation of mitogenic signaling, promotes aberrant splicing and expression of epithelial to mesenchymal transition (EMT) genes, and activates Wnt/β-catenin signaling leading to c-Myc induction. Finally, SRSF3 expression is either decreased or the protein mislocalized in human HCC. CONCLUSION Our data suggest a potential role for SRSF3 in preventing hepatic carcinogenesis by regulating splicing to suppress fibrosis, mitogenic splicing, and EMT. Thus, these mice may provide an attractive model to discover the pathogenic mechanisms linking aberrant pre-messenger RNA splicing with liver damage, fibrosis, and HCC.
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Affiliation(s)
- Supriya Sen
- Medical Research Service, VA San Diego Healthcare System, San Diego, CA 92161, USA
- Department of Medicine, Division of Endocrinology and Metabolism, University of California San Diego, La Jolla, CA 92093, USA
| | - Magda Langiewicz
- Medical Research Service, VA San Diego Healthcare System, San Diego, CA 92161, USA
| | - Hassan Jumaa
- Center for Biological Signaling Studies BIOSS, Albert-Ludwigs Universität, Freiburg 79098, Germany
| | - Nicholas J.G. Webster
- Medical Research Service, VA San Diego Healthcare System, San Diego, CA 92161, USA
- Department of Medicine, Division of Endocrinology and Metabolism, University of California San Diego, La Jolla, CA 92093, USA
- Moores Cancer Center, University of California San Diego, La Jolla, CA 92093, USA
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24
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Kano S, Nishida K, Kurebe H, Nishiyama C, Kita K, Akaike Y, Kajita K, Kurokawa K, Masuda K, Kuwano Y, Tanahashi T, Rokutan K. Oxidative stress-inducible truncated serine/arginine-rich splicing factor 3 regulates interleukin-8 production in human colon cancer cells. Am J Physiol Cell Physiol 2014; 306:C250-62. [DOI: 10.1152/ajpcell.00091.2013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Serine/arginine-rich splicing factor 3 (SRSF3) is a member of the SR protein family and plays wide-ranging roles in gene expression. The human SRSF3 gene generates two alternative splice transcripts, a major mRNA isoform ( SRSF3-FL) encoding functional full-length protein and a premature termination codon (PTC)-containing isoform ( SRSF3-PTC). The latter is degraded through nonsense-mediated mRNA decay (NMD). Treatment of a human colon cancer cell line (HCT116) with 100 μM sodium arsenite increased SRSF3-PTC mRNA levels without changing SRSF3-FL mRNA levels. A chemiluminescence-based NMD reporter assay system demonstrated that arsenite treatment inhibited NMD activity and increased SRSF3-PTC mRNA levels in the cytoplasm, facilitating translation of a truncated SRSF3 protein (SRSF3-TR) from SRSF3-PTC mRNA. SRSF3-TR lacked two-thirds of the Arg/Ser-rich (RS) domain whose phosphorylation state is known to be crucial for subcellular distribution. SRSF3-FL was localized in the nucleus, while overexpressed SRSF3-TR was diffusely distributed in the cytoplasm and the nucleus. A part of SRSF3-TR was also associated with stress granules in the cytoplasm. Interestingly, treatment of HCT116 cells with a small interference RNA specifically targeting SRSF3-PTC mRNA significantly attenuated arsenite-stimulated induction of c-JUN protein, its binding activity to the AP-1 binding site (−126 to 120 bp) in the interleukin (IL)-8 gene promoter, and AP-1 promoter activity, resulting in significant reduction of arsenite-stimulated IL-8 production. Our results suggest that SRSF3-TR may function as a positive regulator of oxidative stress-initiated inflammatory responses in colon cancer cells.
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Affiliation(s)
- Shizuka Kano
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Kensei Nishida
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Hiroyuki Kurebe
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Chihiro Nishiyama
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Kentaro Kita
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Yoko Akaike
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Keisuke Kajita
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Ken Kurokawa
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Kiyoshi Masuda
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Yuki Kuwano
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Toshihito Tanahashi
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Kazuhito Rokutan
- Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
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25
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Jang HN, Lee M, Loh TJ, Choi SW, Oh HK, Moon H, Cho S, Hong SE, Kim DH, Sheng Z, Green MR, Park D, Zheng X, Shen H. Exon 9 skipping of apoptotic caspase-2 pre-mRNA is promoted by SRSF3 through interaction with exon 8. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1839:25-32. [PMID: 24321384 DOI: 10.1016/j.bbagrm.2013.11.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 11/14/2013] [Accepted: 11/26/2013] [Indexed: 01/24/2023]
Abstract
Alternative splicing plays an important role in gene expression by producing different proteins from a gene. Caspase-2 pre-mRNA produces anti-apoptotic Casp-2S and pro-apoptotic Casp-2L proteins through exon 9 inclusion or skipping. However, the molecular mechanisms of exon 9 splicing are not well understood. Here we show that knockdown of SRSF3 (also known as SRp20) with siRNA induced significant increase of endogenous exon 9 inclusion. In addition, overexpression of SRSF3 promoted exon 9 skipping. Thus we conclude that SRSF3 promotes exon 9 skipping. In order to understand the functional target of SRSF3 on caspase-2 pre-mRNA, we performed substitution and deletion mutagenesis on the potential SRSF3 binding sites that were predicted from previous reports. We demonstrate that substitution mutagenesis of the potential SRSF3 binding site on exon 8 severely disrupted the effects of SRSF3 on exon 9 skipping. Furthermore, with the approach of RNA pulldown and immunoblotting analysis we show that SRSF3 interacts with the potential SRSF3 binding RNA sequence on exon 8 but not with the mutant RNA sequence. In addition, we show that a deletion of 26nt RNA from 5' end of exon 8, a 33nt RNA from 3' end of exon 10 and a 2225nt RNA from intron 9 did not compromise the function of SRSF3 on exon 9 splicing. Therefore we conclude that SRSF3 promotes exon 9 skipping of caspase-2 pre-mRNA by interacting with exon 8. Our results reveal a novel mechanism of caspase-2 pre-mRNA splicing.
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Affiliation(s)
- Ha Na Jang
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Minho Lee
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Tiing Jen Loh
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Seung-Woo Choi
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Hyun Kyung Oh
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Heegyum Moon
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Sunghee Cho
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Seong-Eui Hong
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Do Han Kim
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Zhi Sheng
- Virginia Tech Carilion Research Institute, Roanoke, VA, 24016, USA; Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Michael R Green
- Howard Hughes Medical Institute and Programs in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Daeho Park
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Xuexiu Zheng
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Haihong Shen
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Follo MY, Faenza I, Piazzi M, Blalock WL, Manzoli L, McCubrey JA, Cocco L. Nuclear PI-PLCβ1: an appraisal on targets and pathology. Adv Biol Regul 2013; 54:2-11. [PMID: 24296032 DOI: 10.1016/j.jbior.2013.11.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 11/08/2013] [Indexed: 11/16/2022]
Abstract
Lipid signalling molecules are essential components of the processes that allow one extracellular signal to be transferred inside the nucleus, where specific lipid second messengers elicit reactions capable of regulating gene transcription, DNA replication or repair and DNA cleavage, eventually resulting in cell growth, differentiation, apoptosis or many other cell functions. Nuclear inositides are independently regulated, suggesting that the nucleus constitutes a functionally distinct compartment of inositol lipids metabolism. Indeed, nuclear inositol lipids themselves can modulate nuclear processes, such as transcription and pre-mRNA splicing, growth, proliferation, cell cycle regulation and differentiation. Nuclear PI-PLCβ1 is a key molecule for nuclear inositide signalling, where it plays a role in cell cycle progression, proliferation and differentiation. Here we review the targets and possible involvement of nuclear PI-PLCβ1 in human physiology and pathology.
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Affiliation(s)
- Matilde Y Follo
- Department of Biomedical and Neuromotor Sciences, Cellular Signalling Laboratory, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy.
| | - Irene Faenza
- Department of Biomedical and Neuromotor Sciences, Cellular Signalling Laboratory, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Manuela Piazzi
- Department of Biomedical and Neuromotor Sciences, Cellular Signalling Laboratory, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - William L Blalock
- CNR - Consiglio Nazionale delle Ricerche, Istituto di Genetica Molecolare and SC Laboratorio di Biologia Cellulare Muscoloscheletrica, IOR, Bologna, Italy
| | - Lucia Manzoli
- Department of Biomedical and Neuromotor Sciences, Cellular Signalling Laboratory, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - James A McCubrey
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, NC, USA
| | - Lucio Cocco
- Department of Biomedical and Neuromotor Sciences, Cellular Signalling Laboratory, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy.
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27
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Corbo C, Orrù S, Salvatore F. SRp20: an overview of its role in human diseases. Biochem Biophys Res Commun 2013; 436:1-5. [PMID: 23685143 DOI: 10.1016/j.bbrc.2013.05.027] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 10/26/2022]
Abstract
Alternative splicing in mRNA maturation has emerged as a major field of study also because of its implications in various diseases. The SR proteins play an important role in the regulation of this process. Evidence indicates that SRp20 (SFSR3), the smallest member of the SR protein family, is involved in numerous biological processes. Here we review the state-of-the-art of knowledge about the SR proteins, in particular SRp20, in terms of its function and misregulation in human diseases including cancer also in view of its potential as a therapeutic target.
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Kano S, Nishida K, Nishiyama C, Akaike Y, Kajita K, Kurokawa K, Masuda K, Kuwano Y, Tanahashi T, Rokutan K. Truncated serine/arginine-rich splicing factor 3 accelerates cell growth through up-regulating c-Jun expression. THE JOURNAL OF MEDICAL INVESTIGATION 2013; 60:228-35. [DOI: 10.2152/jmi.60.228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Shizuka Kano
- Department of Stress Science, Institute of Health Biosciences, the University of Tokushima Graduate School
- Student Lab, the University of Tokushima Faculty of Medicine
| | - Kensei Nishida
- Department of Stress Science, Institute of Health Biosciences, the University of Tokushima Graduate School
| | | | - Yoko Akaike
- Department of Stress Science, Institute of Health Biosciences, the University of Tokushima Graduate School
| | - Keisuke Kajita
- Department of Stress Science, Institute of Health Biosciences, the University of Tokushima Graduate School
| | - Ken Kurokawa
- Department of Stress Science, Institute of Health Biosciences, the University of Tokushima Graduate School
| | - Kiyoshi Masuda
- Department of Stress Science, Institute of Health Biosciences, the University of Tokushima Graduate School
| | - Yuki Kuwano
- Department of Stress Science, Institute of Health Biosciences, the University of Tokushima Graduate School
| | - Toshihito Tanahashi
- Department of Stress Science, Institute of Health Biosciences, the University of Tokushima Graduate School
| | - Kazuhito Rokutan
- Department of Stress Science, Institute of Health Biosciences, the University of Tokushima Graduate School
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29
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Kosti I, Radivojac P, Mandel-Gutfreund Y. An integrated regulatory network reveals pervasive cross-regulation among transcription and splicing factors. PLoS Comput Biol 2012; 8:e1002603. [PMID: 22844237 PMCID: PMC3405991 DOI: 10.1371/journal.pcbi.1002603] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 05/24/2012] [Indexed: 11/19/2022] Open
Abstract
Traditionally the gene expression pathway has been regarded as being comprised of independent steps, from RNA transcription to protein translation. To date there is increasing evidence of coupling between the different processes of the pathway, specifically between transcription and splicing. To study the interplay between these processes we derived a transcription-splicing integrated network. The nodes of the network included experimentally verified human proteins belonging to three groups of regulators: transcription factors, splicing factors and kinases. The nodes were wired by instances of predicted transcriptional and alternative splicing regulation. Analysis of the network indicated a pervasive cross-regulation among the nodes; specifically, splicing factors are significantly more connected by alternative splicing regulatory edges relative to the two other subgroups, while transcription factors are more extensively controlled by transcriptional regulation. Furthermore, we found that splicing factors are the most regulated of the three regulatory groups and are subject to extensive combinatorial control by alternative splicing and transcriptional regulation. Consistent with the network results, our bioinformatics analyses showed that the subgroup of kinases have the highest density of predicted phosphorylation sites. Overall, our systematic study reveals that an organizing principle in the logic of integrated networks favor the regulation of regulatory proteins by the specific regulation they conduct. Based on these results, we propose a new regulatory paradigm postulating that gene expression regulation of the master regulators in the cell is predominantly achieved by cross-regulation.
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Affiliation(s)
- Idit Kosti
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Predrag Radivojac
- School of Informatics and Computing, Indiana University, Bloomington, Indiana, United States of America
| | - Yael Mandel-Gutfreund
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa, Israel
- * E-mail:
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30
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Tang Y, Horikawa I, Ajiro M, Robles AI, Fujita K, Mondal AM, Stauffer JK, Zheng ZM, Harris CC. Downregulation of splicing factor SRSF3 induces p53β, an alternatively spliced isoform of p53 that promotes cellular senescence. Oncogene 2012; 32:2792-8. [PMID: 22777358 DOI: 10.1038/onc.2012.288] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Most human pre-mRNA transcripts are alternatively spliced, but the significance and fine-tuning of alternative splicing in different biological processes is only starting to be understood. SRSF3 (SRp20) is a member of a highly conserved family of splicing factors that have critical roles in key biological processes, including tumor progression. Here, we show that SRSF3 regulates cellular senescence, a p53-mediated process to suppress tumorigenesis, through TP53 alternative splicing. Downregulation of SRSF3 was observed in normal human fibroblasts undergoing replicative senescence, and was associated with the upregulation of p53β, an alternatively spliced isoform of p53 that promotes p53-mediated senescence. Knockdown of SRSF3 by short interfering RNA (siRNA) in early-passage fibroblasts induced senescence, which was associated with elevated expression of p53β at mRNA and protein levels. Knockdown of p53 partially rescued SRSF3-knockdown-induced senescence, suggesting that SRSF3 acts on p53-mediated cellular senescence. RNA pulldown assays demonstrated that SRSF3 binds to an alternatively spliced exon uniquely included in p53β mRNA through the consensus SRSF3-binding sequences. RNA crosslinking and immunoprecipitation assays (CLIP) also showed that SRSF3 in vivo binds to endogenous p53 pre-mRNA at the region containing the p53β-unique exon. Splicing assays using a transfected TP53 minigene in combination with siRNA knockdown of SRSF3 showed that SRSF3 functions to inhibit the inclusion of the p53β-unique exon in splicing of p53 pre-mRNA. These data suggest that downregulation of SRSF3 represents an endogenous mechanism for cellular senescence that directly regulates the TP53 alternative splicing to generate p53β. This study uncovers the role for general splicing machinery in tumorigenesis, and suggests that SRSF3 is a direct regulator of p53.
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Affiliation(s)
- Y Tang
- Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4258, USA
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31
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Mukherjee A, Reisdorph N, Guda B, Pandey S, Roy SK. Changes in ovarian protein expression during primordial follicle formation in the hamster. Mol Cell Endocrinol 2012; 348:87-94. [PMID: 21821096 PMCID: PMC3418795 DOI: 10.1016/j.mce.2011.07.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 07/19/2011] [Accepted: 07/20/2011] [Indexed: 01/01/2023]
Abstract
Although many proteins have been shown to affect the transition of primordial follicles to the primary stage, factors regulating the formation of primordial follicles remains sketchy at best. Differentiation of somatic cells into early granulosa cells during ovarian morphogenesis is the hallmark of primordial follicle formation; hence, critical changes are expected in protein expression. We wanted to identify proteins, the expression of which would correlate with the formation of primordial follicles as a first step to determine their biological function in folliculogenesis. Proteins were extracted from embryonic (E15) and 8-day-old (P8) hamster ovaries and fractionated by two-dimensional gel electrophoresis. Gels were stained with Proteosilver, and images of protein profiles corresponding to E15 and P8 ovaries were overlayed to identify protein spots showing altered expression. Some of the protein spots were extracted from SyproRuby-stained preparative gels, digested with trypsin, and analyzed by mass spectrometry. Both E15 and P8 ovaries had high molecular weight proteins at acidic, basic, and neutral ranges; however, we focused on small molecular weight proteins at 4-7 pH range. Many of those spots might represent post-translational modification. Mass spectrometric analysis revealed the identity of these proteins. The formation of primordial follicles on P8 correlated with many differentially and newly expressed proteins. Whereas Ebp1 expression was downregulated in ovarian somatic cells, Sfrs3 expression was specifically upregulated in newly formed granulosa cells of primordial follicles on P8. The results show for the first time that the morphogenesis of primordial follicles in the hamster coincides with altered and novel expression of proteins involved in cell proliferation, transcriptional regulation, and metabolism. Therefore, formation of primordial follicles is an active process requiring differentiation of somatic cells into early granulosa cells and their interaction with the oocytes.
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Affiliation(s)
- Anindit Mukherjee
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center 984515 Nebraska Medical Center, Omaha, NE 68198-4515
| | - Nichole Reisdorph
- Department of Immunology, National Jewish Medical and Research Center, 1400 Jackson St, K924, Denver, CO 80206
| | - Babu Guda
- Department of Genetics, Cell Biology and Anatomy, and Center for Bioinformatics and System Biology, University of Nebraska Medical Center 984515 Nebraska Medical Center, Omaha, NE 68198-4515
| | - Sanjit Pandey
- Department of Genetics, Cell Biology and Anatomy, and Center for Bioinformatics and System Biology, University of Nebraska Medical Center 984515 Nebraska Medical Center, Omaha, NE 68198-4515
| | - Shyamal K Roy
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center 984515 Nebraska Medical Center, Omaha, NE 68198-4515
- Department of Cellular and Integrative Physiology, Department of OB/GYN and Olson Center for Women's Health, and Eppley Institute for Cancer Research, University of Nebraska Medical Center 984515 Nebraska Medical Center, Omaha, NE 68198-4515
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32
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Tarallo R, Bamundo A, Nassa G, Nola E, Paris O, Ambrosino C, Facchiano A, Baumann M, Nyman TA, Weisz A. Identification of proteins associated with ligand-activated estrogen receptor α in human breast cancer cell nuclei by tandem affinity purification and nano LC-MS/MS. Proteomics 2010; 11:172-9. [PMID: 21182205 DOI: 10.1002/pmic.201000217] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 08/03/2010] [Accepted: 10/04/2010] [Indexed: 01/14/2023]
Abstract
Estrogen receptor α (ER-α) is a key mediator of estrogen actions in breast cancer (BC) cells. Understanding the effects of ligand-activated ER-α in target cells requires identification of the molecular partners acting in concert with this nuclear receptor to transduce the hormonal signal. We applied tandem affinity purification (TAP), glycerol gradient centrifugation and MS analysis to isolate and identify proteins interacting with ligand-activated ER-α in MCF-7 cell nuclei. This led to the identification of 264 ER-associated proteins, whose functions highlight the hinge role of ER-α in the coordination of multiple hormone-regulated nuclear processes in BC cells.
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Affiliation(s)
- Roberta Tarallo
- Department of General Pathology, Second University of Naples, Napoli, Italy
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33
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Abstract
Low-density lipoprotein receptor (LDLR) is a major apolipoprotein E (APOE) receptor and thereby is critical to cholesterol homeostasis and, possibly, Alzheimer disease (AD) development. We previously identified a single nucleotide polymorphism (SNP), rs688:C>T, that modulates LDLR exon 12 splicing and is associated with cholesterol levels in premenopausal women and with Alzheimer disease in men. To gain additional insights into LDLR splicing regulation, we seek to identify splicing factors that modulate LDLR splicing efficiency. By using an in vitro minigene study, we first found that ectopic expression of SFRS3 (SRp20), SFRS13A (SRp38), SFRS13A-2 (SRp38-2), and RBMX (hnRNP G) robustly decreased LDLR splicing efficiency. Although SFRS3 and SFRS13A specifically increased the LDLR transcript lacking exon 11, SFRS13A-2 and RBMX primarily increased the LDLR isoform lacking both exons 11 and 12. When we evaluated the relationship between the expression of these splicing factors and LDLR splicing in human brain and liver specimens, we found that overall SFRS13A expression was significantly associated with LDLR splicing efficiency in vivo. We interpret these results as suggesting that SFRS13A regulates LDLR splicing efficiency and may therefore emerge as a modulator of cholesterol homeostasis.
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Affiliation(s)
- I-Fang Ling
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky 40536-0230, USA
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34
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Ivanov AV, Parakhnevitch NM, Malygin AA, Karpova GG. Human ribosomal protein S16 inhibits excision of the first intron from its own pre-mRNA. Mol Biol 2010. [DOI: 10.1134/s0026893310010115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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35
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Kanka J, Kepková K, Nemcová L. Gene expression during minor genome activation in preimplantation bovine development. Theriogenology 2009; 72:572-83. [PMID: 19501393 DOI: 10.1016/j.theriogenology.2009.04.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 04/01/2009] [Accepted: 04/03/2009] [Indexed: 11/30/2022]
Abstract
The main goal of this study was to identify mRNA transcripts whose content increases during bovine minor embryonic genome activation. We compared the gene expression profile of the bovine 4-cell-stage embryo and MII oocyte using the technique of suppression subtractive hybridization. Differentially expressed amplicons were subcloned, and 60 of them were sequenced. The resulting DNA sequences were compared with GenBank databases using BLAST search. The expression of five differentially expressed genes with an apparent function in cell cycle progression, chromatin remodeling, and splicing or translation initiation was further characterized by a real-time RT-PCR. Centromere protein F, 350/400ka (CENPF), and splicing factor arginine/serine-rich 3 (SRFS3) show an increase in mRNA content during the 2- to 4-cell and late 8-cell stages. For the high mobility group nucleosomal binding domain 2 (HMGN2), the level of mRNA increases in 2- to 4-cell and morula embryos. The transcription of splicing factor SRFS3 is alpha-amanitin sensitive both during 4-cell and late 8-cell stages. The transcription of CENPF and HMGN2 is alpha-amanitin sensitive only at late 8-cell stage and morula, respectively. SRFS3 represents the first described gene with an important function in preimplantation development, which is also expressed during bovine minor genome activation, and it is alpha-amanitin sensitive during this period. All described genes can play an important role in the preimplantation development of bovine embryos.
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Affiliation(s)
- J Kanka
- Institute of Animal Physiology and Genetics, Laboratory of Developmental Biology, Academy of Sciences of the Czech Republic v.v.i., 277 21 Libechov, Czech Republic.
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36
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Many pathways to apoptosis: E2F1 regulates splicing of apoptotic genes. Cell Death Differ 2008; 15:1813-4. [DOI: 10.1038/cdd.2008.155] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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37
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Palusa SG, Ali GS, Reddy ASN. Alternative splicing of pre-mRNAs of Arabidopsis serine/arginine-rich proteins: regulation by hormones and stresses. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 49:1091-107. [PMID: 17319848 DOI: 10.1111/j.1365-313x.2006.03020.x] [Citation(s) in RCA: 283] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Precursor mRNAs with introns can undergo alternative splicing (AS) to produce structurally and functionally different proteins from the same gene. Here, we show that the pre-mRNAs of Arabidopsis genes that encode serine/arginine-rich (SR) proteins, a conserved family of splicing regulators in eukaryotes, are extensively alternatively spliced. Remarkably about 95 transcripts are produced from only 15 genes, thereby increasing the complexity of the SR gene family transcriptome by six-fold. The AS of some SR genes is controlled in a developmental and tissue-specific manner. Interestingly, among the various hormones and abiotic stresses tested, temperature stress (cold and heat) dramatically altered the AS of pre-mRNAs of several SR genes, whereas hormones altered the splicing of only three SR genes. These results indicate that abiotic stresses regulate the AS of the pre-mRNAs of SR genes to produce different isoforms of SR proteins that are likely to have altered function(s) in pre-mRNA splicing. Sequence analysis of splice variants revealed that predicted proteins from a majority of these variants either lack one or more modular domains or contain truncated domains. Because of the modular nature of the various domains in SR proteins, the proteins produced from splice variants are likely to have distinct functions. Together our results indicate that Arabidopsis SR genes generate surprisingly large transcriptome complexity, which is altered by stresses and hormones.
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38
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Bavelloni A, Faenza I, Cioffi G, Piazzi M, Parisi D, Matic I, Maraldi NM, Cocco L. Proteomic-based analysis of nuclear signaling: PLCbeta1 affects the expression of the splicing factor SRp20 in Friend erythroleukemia cells. Proteomics 2007; 6:5725-34. [PMID: 17022104 DOI: 10.1002/pmic.200600318] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
An extensive body of evidence links inositide-specific phospholipase C (PLC) to the nucleus and the main isoform located in the nucleus is PLCbeta(1). Constitutive overexpression of nuclear PLCbeta(1) has been previously shown to inhibit Friend erythroleukemia cells differentiation and to induce cell cycle progression targeting cyclin D3. The aim of this study was to identify new proteins regulated by PLCbeta(1) overexpression, given the role exerted by its signaling in the nucleus during cell growth and differentiation. To identify novel downstream effectors of nuclear PLCbeta(1)-dependent signaling in Friend erythroleukemia cells, we performed the high-resolution 2-DE-based proteomic analysis. Using a proteomic approach we found that SRp20, a member of the highly conserved SR family of splicing regulators, was down-regulated in cells overexpressing nuclear PLCbeta(1) as compared with wild-type cells. Reduction in SRp20 was confirmed by 2-D Western blotting. Moreover, we have shown that nuclear PLCbeta(1) is bound to the SRp20 splicing factor. Indeed, by immunoprecipitation and subcellular fractioning, we have demonstrated that endogenous PLCbeta(1) and SRp20 physically interact in the nucleus. Here we show the existence of a PLCbeta(1)-specific target, the splicing factor SRp20, whose expression is specifically down-regulated by the nuclear signaling evoked by PLCbeta(1).
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MESH Headings
- Animals
- Blotting, Western
- Cell Nucleus/metabolism
- Cells, Cultured
- Down-Regulation
- Electrophoresis, Gel, Two-Dimensional
- Fluorescein-5-isothiocyanate
- Fluorescent Antibody Technique, Direct
- Fluorescent Dyes
- Gene Expression Regulation, Neoplastic
- Isoelectric Focusing
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Leukemia, Erythroblastic, Acute/metabolism
- Leukemia, Erythroblastic, Acute/pathology
- Mice
- Microscopy, Fluorescence
- Peptide Mapping
- Phospholipase C beta
- Precipitin Tests
- Proteomics/methods
- RNA-Binding Proteins/metabolism
- RNA-Binding Proteins/physiology
- Serine-Arginine Splicing Factors
- Signal Transduction
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Subcellular Fractions/metabolism
- Type C Phospholipases/genetics
- Type C Phospholipases/metabolism
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Affiliation(s)
- Alberto Bavelloni
- Laboratory of Cell Biology and Electron Microscopy, IOR, Bologna Italy
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39
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Cocco L, Follo MY, Faenza I, Bavelloni A, Billi AM, Martelli AM, Manzoli L. Nuclear inositide signaling: An appraisal of phospholipase C β1 behavior in myelodysplastic and leukemia cells. ACTA ACUST UNITED AC 2007; 47:2-9. [PMID: 17335878 DOI: 10.1016/j.advenzreg.2006.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Lucio Cocco
- Cellular Signalling Laboratory, Department of Anatomical Sciences, University of Bologna, via Irnerio 48, 40126 Bologna, Italy.
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40
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Lin S, Fu XD. SR proteins and related factors in alternative splicing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 623:107-22. [PMID: 18380343 DOI: 10.1007/978-0-387-77374-2_7] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
SR proteins are a family of RNA binding proteins that contain a signature RS domain enriched with serine/arginine repeats. The RS domain is also found in many other proteins, which are collectively referred to as SR-related proteins. Several prototypical SR proteins are essential splicing factors, but the majority of RS domain-containing factors are characterized by their ability to alter splice site selection in vitro or in transfected cells. SR proteins and SR-related proteins are generally believed to modulate splice site selection via RNA recognition motif-mediated binding to exonic splicing enhancers and RS domain-mediated protein-protein and protein-RNA interactions during spliceosome assembly. However, the biological function of individual RS domain-containing splicing regulators is complex because of redundant as well as competitive functions, context-dependent effects and regulation by cotranscriptional and post-translational events. This chapter will focus on our current mechanistic understanding of alternative splicing regulation by SR proteins and SR-related proteins and will discuss some of the questions that remain to be addressed in future research.
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Affiliation(s)
- Shengrong Lin
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA
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Kalyna M, Lopato S, Voronin V, Barta A. Evolutionary conservation and regulation of particular alternative splicing events in plant SR proteins. Nucleic Acids Res 2006; 34:4395-405. [PMID: 16936312 PMCID: PMC1636356 DOI: 10.1093/nar/gkl570] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Alternative splicing is an important mechanism for fine tuning of gene expression at the post-transcriptional level. SR proteins govern splice site selection and spliceosome assembly. The Arabidopsis genome encodes 19 SR proteins, several of which have no orthologues in metazoan. Three of the plant specific subfamilies are characterized by the presence of a relatively long alternatively spliced intron located in their first RNA recognition motif, which potentially results in an extremely truncated protein. In atRSZ33, a member of the RS2Z subfamily, this alternative splicing event was shown to be autoregulated. Here we show that atRSp31, a member of the RS subfamily, does not autoregulate alternative splicing of its similarily positioned intron. Interestingly, this alternative splicing event is regulated by atRSZ33. We demonstrate that the positions of these long introns and their capability for alternative splicing are conserved from green algae to flowering plants. Moreover, in particular alternative splicing events the splicing signals are embedded into highly conserved sequences. In different taxa, these conserved sequences occur in at least one gene within a subfamily. The evolutionary preservation of alternative splice forms together with highly conserved intron features argues for additional functions hidden in the genes of these plant-specific SR proteins.
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Affiliation(s)
- Maria Kalyna
- Correspondence may also be addressed to Maria Kalyna. Tel: +43 1 4277 61642; Fax: +43 1 4277 9616;
| | | | | | - Andrea Barta
- To whom correspondence should be addressed. Tel: +43 1 4277 61640; Fax: +43 1 4277 9616;
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Dong H, Ying T, Li T, Cao T, Wang J, Yuan J, Feng E, Han B, Hua F, Yang Y, Yuan J, Wang H, Xu C. Comparative proteomic analysis of apoptosis induced by sodium selenite in human acute promyelocytic leukemia NB4 cells. J Cell Biochem 2006; 98:1495-506. [PMID: 16552729 DOI: 10.1002/jcb.20755] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Selenium (Se) is an essential trace element possessing anticarcinogenic properties. Sodium selenite (Na2SeO3) induced apoptosis in human acute promyelocytic leukemia (APL) cell line NB4 with dose and time dependency. In this study, proteomic techniques were used to study the apoptosis of NB4 cells induced by sodium selenite. Twenty-six downregulated and four upregulated proteins were identified, which exhibited a 1.5-fold change or greater. The identified proteins included key regulators of signal transduction such as Rho GDP dissociation inhibitor (Rho GDI) alpha and beta members of the MAPK family, and proteins involved in the regulation of c-fos or c-myc expression. Importantly, the identified proteins, hnRNP D0B and Rho GDI beta, which were related with the regulation of c-myc, c-fos, and c-jun, were determined by reverse transcription-polymerase chain reaction (RT-PCR) to confirm their downregulation in proteomic study. Western blot analysis and RT-PCR were then performed on three associated proteins: c-Myc, c-Fos, and c-Jun, and their expression were observed to be significantly downregulated. Results showed that certain regulation involved in c-myc, c-fos, and c-jun was present in the apoptosis, and the c-Myc dependent-on and Jun N-terminal kinase (JNK) pathway also play roles.
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Affiliation(s)
- Hua Dong
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
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43
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Li-Korotky HS, Hebda PA, Kelly LA, Lo CY, Dohar JE. Identification of a pre-mRNA splicing factor, arginine/serine-rich 3 (Sfrs3), and its co-expression with fibronectin in fetal and postnatal rabbit airway mucosal and skin wounds. Biochim Biophys Acta Mol Basis Dis 2006; 1762:34-45. [PMID: 16168628 DOI: 10.1016/j.bbadis.2005.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 06/28/2005] [Accepted: 08/09/2005] [Indexed: 10/25/2022]
Abstract
Fibronectin (FN) is a multi-functional, adhesion protein and involved in multi-steps of the wound healing process. Strong evidence suggests that FN protein diversity is controlled by alternative RNA splicing; a coordinated transcription and RNA processing that is development-, age-, and tissue/cell type-regulated. We previously demonstrated that fetal rabbit airway mucosal healing is regenerative and scarless. Expression, regulation, and biological function of the FN gene and various spliced forms in this model are unknown. Airway and skin incisional wounds were made in fetal (gestation days 21-23), weanling (4-6 weeks) and adult (>6 months) rabbits. Non-wounded and wounded tissues were collected at 12 h (all age groups), 24 h and 48 h (weanling only) post-wounding. Expression profiles were obtained using mRNA differential display and cDNAs of interest were cloned, sequenced and validated by real-time PCR. Here, we report two rabbit cDNAs that showed similar expression patterns after wounding. One encodes a rabbit fibronectin gene, Fn1, and another shares a high sequence homology to a human pre-mRNA splicing factor, arginine/serine-rich 3 (Sfrs3), coding for a RNA binding protein, SRp20. Both Fn1 and Sfrs3 mRNAs were suppressed in fetal wounds but induced in postnatal wounds 12 h post-wounding. The increased levels of both Fn1 and Sfrs3 transcripts were sustained up to 48 h in weanling airway mucosal wounds. The augmentations of the two genes in postnatal airway mucosal wounds were more prominent than that in skin wounds, indicating that the involvement of Sfrs3 and Fn1 genes in postnatal airway mucosal wounds is tissue-specific. Literature provides evidence that SRp20 is indeed involved in the alternative splicing of FN and that the embryonic FN variants reappear during adult wound healing. A connection between the enhanced molecular activity of Sfrs3 and the regulation of the FN gene expression through alternative splicing during the early events of postnatal airway mucosal wound repair was proposed.
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Affiliation(s)
- Ha-Sheng Li-Korotky
- Division of Pediatric Otolaryngology, Children's Hospital of Pittsburgh, Pittsburgh, PA 15213, USA.
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Tarapore P, Shinmura K, Suzuki H, Tokuyama Y, Kim SH, Mayeda A, Fukasawa K. Thr199phosphorylation targets nucleophosmin to nuclear speckles and represses pre-mRNA processing. FEBS Lett 2005; 580:399-409. [PMID: 16376875 DOI: 10.1016/j.febslet.2005.12.022] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Revised: 12/05/2005] [Accepted: 12/07/2005] [Indexed: 11/29/2022]
Abstract
Nucleophosmin (NPM) is a multifunctional phosphoprotein, being involved in ribosome assembly, pre-ribosomal RNA processing, DNA duplication, nucleocytoplasmic protein trafficking, and centrosome duplication. NPM is phosphorylated by several kinases, including nuclear kinase II, casein kinase 2, Polo-like kinase 1 and cyclin-dependent kinases (CDK1 and 2), and these phosphorylations modulate the activity and function of NPM. We have previously identified Thr(199) as the major phosphorylation site of NPM mediated by CDK2/cyclin E (and A), and this phosphorylation is involved in the regulation of centrosome duplication. In this study, we further examined the effect of CDK2-mediated phosphorylation of NPM by using the antibody that specifically recognizes NPM phosphorylated on Thr(199). We found that the phospho-Thr(199) NPM localized to dynamic sub-nuclear structures known as nuclear speckles, which are believed to be the sites of storage and/or assembly of pre-mRNA splicing factors. Phosphorylation on Thr(199) by CDK2/cyclin E (and A) targets NPM to nuclear speckles, and enhances the RNA-binding activity of NPM. Moreover, phospho-Thr(199) NPM, but not unphosphorylated NPM, effectively represses pre-mRNA splicing. These findings indicate the involvement of NPM in the regulation of pre-mRNA processing, and its activity is controlled by CDK2-mediated phosphorylation on Thr(199).
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Affiliation(s)
- Pheruza Tarapore
- Department of Cell Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
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45
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Saeki K, Yasugi E, Okuma E, Breit SN, Nakamura M, Toda T, Kaburagi Y, Yuo A. Proteomic analysis on insulin signaling in human hematopoietic cells: identification of CLIC1 and SRp20 as novel downstream effectors of insulin. Am J Physiol Endocrinol Metab 2005; 289:E419-28. [PMID: 15827065 DOI: 10.1152/ajpendo.00512.2004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin/IGF-I-dependent signals play important roles for the regulation of proliferation, differentiation, metabolism, and autophagy in various cells, including hematopoietic cells. Although the early protein kinase activation cascade has been intensively studied, the whole picture of intracellular signaling events has not yet been clarified. To identify novel downstream effectors of insulin-dependent signals in relatively early phases, we performed high-resolution two-dimensional electrophoresis (2-DE)-based proteomic analysis using human hematopoietic cells 1 h after insulin stimulation. We identified SRp20, a splicing factor, and CLIC1, an intracellular chloride ion channel, as novel downstream effectors besides previously reported effectors of Rho-guanine nucleotide dissociation inhibitor 2 and glutathione S-transferase-pi. Reduction in SRp20 was confirmed by one-dimensional Western blotting. Moreover, MG-132, a proteasome inhibitor, prevented this reduction. By contrast, upregulation of CLIC1 was not observed in one-dimensional Western blotting, unlike the 2-DE results. As hydrophilic proteins were predominantly recovered in 2-DE, the discrepancy between the 1-DE and 2-DE results may indicate a certain qualitative change of the protein. Indeed, the nuclear localization pattern of CLIC1 was remarkably changed by insulin stimulation. Thus insulin induces the proteasome-dependent degradation of SRp20 as well as the subnuclear relocalization of CLIC1.
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Affiliation(s)
- Kumiko Saeki
- Department of Hematology, Research Institute, International Medical Center of Japan, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
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Bao B, Yang G, Liu Z, Li S, Wang Z, Ren D. Isolation of SFRS3 gene and its differential expression during metamorphosis involving eye migration of Japanese flounder Paralichthys olivaceus. Biochim Biophys Acta Gen Subj 2005; 1725:64-70. [PMID: 15950387 DOI: 10.1016/j.bbagen.2005.04.032] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2004] [Revised: 03/31/2005] [Accepted: 04/27/2005] [Indexed: 11/30/2022]
Abstract
Both eyes of flatfishes are located on one side of the body due to asymmetrical eye migration. The molecular mechanisms underlying such asymmetry is poorly understood. As an initial step, we have adopted suppression subtractive hybridization for the identification of upregulated genes during metamorphosis involving eye migration in Japanese flounder, Paralichthys olicaceus. One of the upregulated genes was identified as the splicing factor arginine/serine rich-3 (SFRS3). Sequence analysis of SFRS3 revealed that it encodes a protein of 168 amino acids containing the typical eukaryotic RNA recognition motif (RRM) and an arginine/serine-rich region. The overall amino acid sequences of the Japanese flounder SFRS3 was highly conserved with that of other organisms. The expression of flounder SFRS3 gene increased sharply from the beginning of metamorphosis and reached a high level of expression at stage H of metamorphosis 43 days after hatching. The SFRS3 gene upregulation was mainly limited to the head region, particularly in the rapidly proliferative tissues, the lateral ethmoid and "skin thickness" on blind side, which are thought as two proliferative tissues to push the eye movement. In spite of the upregulated expression of SFRS3 during metamorphosis, its role in metamorphosis involving eye migration requires further studies.
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Affiliation(s)
- Baolong Bao
- The State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433, China.
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47
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Pacheco TR, Gomes AQ, Barbosa-Morais NL, Benes V, Ansorge W, Wollerton M, Smith CW, Valcárcel J, Carmo-Fonseca M. Diversity of vertebrate splicing factor U2AF35: identification of alternatively spliced U2AF1 mRNAS. J Biol Chem 2004; 279:27039-49. [PMID: 15096518 DOI: 10.1074/jbc.m402136200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
U2 small nuclear ribonucleoprotein auxiliary factor small subunit (U2AF(35)) is encoded by a conserved gene designated U2AF1. Here we provide evidence for the existence of alternative vertebrate transcripts encoding different U2AF(35) isoforms. Three mRNA isoforms (termed U2AF(35)a-c) were produced by alternative splicing of the human U2AF1 gene. U2AF(35)c contains a premature stop codon that targets the resulting mRNA to nonsense-mediated mRNA decay. U2AF(35)b differs from the previously described U2AF(35)a isoform in 7 amino acids located at the atypical RNA Recognition Motif involved in dimerization with U2AF(65). Biochemical experiments indicate that isoform U2AF(35)b, which has been highly conserved from fish to man, maintains the ability to interact with U2AF(65), stimulates U2AF(65) binding to a pre-mRNA, and promotes U2AF splicing activity in vitro. Real time, quantitative PCR analysis indicates that U2AF(35)a is the most abundant isoform expressed in murine tissues, although the ratio between U2AF(35)a and U2AF(35)b varies from 10-fold in the brain to 20-fold in skeletal muscle. We propose that post-transcriptional regulation of U2AF1 gene expression may provide a mechanism by which the relative cellular concentration and availability of U2AF(35) protein isoforms are modulated, thus contributing to the finely tuned control of splicing events in different tissues.
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Affiliation(s)
- Teresa R Pacheco
- Institute of Molecular Medicine, Faculty of Medicine, University of Lisbon, 1649-028 Lisbon, Portugal
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48
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Wollerton MC, Gooding C, Wagner EJ, Garcia-Blanco MA, Smith CWJ. Autoregulation of Polypyrimidine Tract Binding Protein by Alternative Splicing Leading to Nonsense-Mediated Decay. Mol Cell 2004; 13:91-100. [PMID: 14731397 DOI: 10.1016/s1097-2765(03)00502-1] [Citation(s) in RCA: 305] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polypyrimdine tract binding protein (PTB) is a regulator of alternative splicing, mRNA 3' end formation, mRNA stability and localization, and IRES-mediated translation. Transient overexpression of PTB can influence alternative splicing, sometimes resulting in nonphysiological splicing patterns. Here, we show that alternative skipping of PTB exon 11 leads to an mRNA that is removed by NMD and that this pathway consumes at least 20% of the PTB mRNA in HeLa cells. We also show that exon 11 skipping is itself promoted by PTB in a negative feedback loop. This autoregulation may serve both to prevent disruptively high levels of PTB expression and to restore nuclear levels when PTB is mobilized to the cytoplasm. Our findings suggest that alternative splicing can act not only to generate protein isoform diversity but also to quantitatively control gene expression and complement recent bioinformatic analyses, indicating a high prevalence of human alternative splicing leading to NMD.
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Affiliation(s)
- Matthew C Wollerton
- Department of Biochemistry, 80 Tennis Court Road, University of Cambridge, Cambridge CB2 1GA, United Kingdom
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Bourgeois CF, Lejeune F, Stévenin J. Broad specificity of SR (serine/arginine) proteins in the regulation of alternative splicing of pre-messenger RNA. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2004; 78:37-88. [PMID: 15210328 DOI: 10.1016/s0079-6603(04)78002-2] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Alternative splicing of pre-messenger RNA (pre-mRNA) is a highly regulated process that allows expansion of the potential of expression of the genome in higher eukaryotes and involves many factors. Among them, the family of the serine- and arginine-rich proteins (SR proteins) plays a pivotal role: it has essential functions during spliceosome assembly and also interacts with RNA regulatory sequences on the pre-mRNA as well as with multiple cofactors. Collectively, SR proteins, because of their capacity to recognize multiple RNA sequences with a broad specificity, are at the heart of the regulation pathways that lead to the choice of alternative splice sites. Moreover, a growing body of evidence shows that the mechanisms of splicing regulation are not limited to the basic involvement of cis- and trans-acting factors at the pre-mRNA level, but result from intricate pathways, initiated sometimes by stimuli that are external to the cell and integrate SR proteins (and other factors) within an extremely sophisticated network of molecular machines associated with one another. This review focuses on the molecular aspects of the functions of SR proteins. In particular, we discuss the different ways in which SR proteins manage to achieve a high level of specificity in splicing regulation, even though they are also involved in the constitutive reaction.
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Affiliation(s)
- Cyril F Bourgeois
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, 67404 Illkirch, C.U. Strasbourg, France
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Li J, Hawkins IC, Harvey CD, Jennings JL, Link AJ, Patton JG. Regulation of alternative splicing by SRrp86 and its interacting proteins. Mol Cell Biol 2003; 23:7437-47. [PMID: 14559993 PMCID: PMC207616 DOI: 10.1128/mcb.23.21.7437-7447.2003] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SRrp86 is a unique member of the SR protein superfamily containing one RNA recognition motif and two serine-arginine (SR)-rich domains separated by an unusual glutamic acid-lysine (EK)-rich region. Previously, we showed that SRrp86 could regulate alternative splicing by both positively and negatively modulating the activity of other SR proteins and that the unique EK domain could inhibit both constitutive and alternative splicing. These functions were most consistent with the model in which SRrp86 functions by interacting with and thereby modulating the activity of target proteins. To identify the specific proteins that interact with SRrp86, we used a yeast two-hybrid library screen and immunoprecipitation coupled to mass spectrometry. We show that SRrp86 interacts with all of the core SR proteins, as well as a subset of other splicing regulatory proteins, including SAF-B, hnRNP G, YB-1, and p72. In contrast to previous results that showed activation of SRp20 by SRrp86, we now show that SAF-B, hnRNP G, and 9G8 all antagonize the activity of SRrp86. Overall, we conclude that not only does SRrp86 regulate SR protein activity but that it is, in turn, regulated by other splicing factors to control alternative splice site selection.
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Affiliation(s)
- Jun Li
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, USA
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