1
|
Jiang T, Qu R, Liu X, Hou Y, Wang L, Hua Y. HnRNPR strongly represses splicing of a critical exon associated with spinal muscular atrophy through binding to an exonic AU-rich element. J Med Genet 2023; 60:1105-1115. [PMID: 37225410 DOI: 10.1136/jmg-2023-109186] [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: 01/27/2023] [Accepted: 05/08/2023] [Indexed: 05/26/2023]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a motor neuron disease caused by mutations of survival of motor neuron 1 (SMN1) gene, which encodes the SMN protein. SMN2, a nearly identical copy of SMN1, with several single-nucleotide substitutions leading to predominant skipping of its exon 7, is insufficient to compensate for loss of SMN1. Heterogeneous nuclear ribonucleoprotein R (hnRNPR) has been previously shown to interact with SMN in the 7SK complex in motoneuron axons and is implicated in the pathogenesis of SMA. Here, we show that hnRNPR also interacts with SMN1/2 pre-mRNAs and potently inhibits exon 7 inclusion. METHODS In this study, to examine the mechanism that hnRNPR regulates SMN1/2 splicing, deletion analysis in an SMN2 minigene system, RNA-affinity chromatography, co-overexpression analysis and tethering assay were performed. We screened antisense oligonucleotides (ASOs) in a minigene system and identified a few that markedly promoted SMN2 exon 7 splicing. RESULTS We pinpointed an AU-rich element located towards the 3' end of the exon that mediates splicing repression by hnRNPR. We uncovered that both hnRNPR and Sam68 bind to the element in a competitive manner, and the inhibitory effect of hnRNPR is much stronger than Sam68. Moreover, we found that, among the four hnRNPR splicing isoforms, the exon 5-skipped one has the minimal inhibitory effect, and ASOs inducing hnRNPR exon 5 skipping also promote SMN2 exon 7 inclusion. CONCLUSION We identified a novel mechanism that contributes to mis-splicing of SMN2 exon 7.
Collapse
Affiliation(s)
- Tao Jiang
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
- Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - Ruobing Qu
- Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
- College of Chemistry Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu, China
| | - Xuan Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University College of Life Sciences, Nanjing, Jiangsu, China
| | - Yanjun Hou
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University College of Life Sciences, Nanjing, Jiangsu, China
| | - Li Wang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University College of Life Sciences, Nanjing, Jiangsu, China
| | - Yimin Hua
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University College of Life Sciences, Nanjing, Jiangsu, China
| |
Collapse
|
2
|
Choi K, Yang A, Baek J, Jeong H, Kang Y, Baek W, Kim JC, Kang M, Choi M, Ham Y, Son MJ, Han SB, Kim J, Jang JH, Ahn JS, Shen H, Woo SH, Kim JH, Cho S. Regulation of Survival Motor Neuron Gene Expression by Calcium Signaling. Int J Mol Sci 2021; 22:ijms221910234. [PMID: 34638572 PMCID: PMC8508836 DOI: 10.3390/ijms221910234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/07/2021] [Accepted: 09/16/2021] [Indexed: 11/21/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous survival of motor neurons 1 (SMN1) gene deletion, leaving a duplicate gene, SMN2, as the sole source of SMN protein. However, a defect in SMN2 splicing, involving exon 7 skipping, results in a low level of functional SMN protein. Therefore, the upregulation of SMN protein expression from the SMN2 gene is generally considered to be one of the best therapeutic strategies to treat SMA. Most of the SMA drug discovery is based on synthetic compounds, and very few natural compounds have been explored thus far. Here, we performed an unbiased mechanism-independent and image-based screen of a library of microbial metabolites in SMA fibroblasts using an SMN-specific immunoassay. In doing so, we identified brefeldin A (BFA), a well-known inhibitor of ER-Golgi protein trafficking, as a strong inducer of SMN protein. The profound increase in SMN protein was attributed to, in part, the rescue of the SMN2 pre-mRNA splicing defect. Intriguingly, BFA increased the intracellular calcium concentration, and the BFA-induced exon 7 inclusion of SMN2 splicing, was abrogated by the depletion of intracellular calcium and by the pharmacological inhibition of calcium/calmodulin-dependent kinases (CaMKs). Moreover, BFA considerably reduced the expression of Tra2-β and SRSF9 proteins in SMA fibroblasts and enhanced the binding of PSF and hnRNP M to an exonic splicing enhancer (ESE) of exon 7. Together, our results demonstrate a significant role for calcium and its signaling on the regulation of SMN splicing, probably through modulating the expression/activity of splicing factors.
Collapse
Affiliation(s)
- Kwangman Choi
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Medical Biotechnology, SoonChunHyang University, Asan 31538, Korea
| | - Ansook Yang
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Jiyeon Baek
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Hyejeong Jeong
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Yura Kang
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
| | - Woosun Baek
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
| | - Joon-Chul Kim
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
| | - Mingu Kang
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Miri Choi
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Youngwook Ham
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
| | - Min-Jeong Son
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
| | - Sang-Bae Han
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Janghwan Kim
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea;
| | - Jae-Hyuk Jang
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Anticancer Agent Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea
| | - Jong Seog Ahn
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Anticancer Agent Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea
| | - Haihong Shen
- Gwangju Institute of Science and Technology, School of life Sciences, Gwangju 61005, Korea;
| | - Sun-Hee Woo
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
| | - Jong Heon Kim
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
| | - Sungchan Cho
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
| |
Collapse
|
3
|
Katano-Toki A, Yoshino S, Nakajima Y, Tomaru T, Nishikido A, Ishida E, Horiguchi K, Saito T, Ozawa A, Satoh T, Yamada M. SFPQ associated with a co-activator for PPARγ, HELZ2, regulates key nuclear factors for adipocyte differentiation. Biochem Biophys Res Commun 2021; 562:139-145. [PMID: 34052659 DOI: 10.1016/j.bbrc.2021.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 05/06/2021] [Indexed: 12/14/2022]
Abstract
We recently isolated a novel co-activator of peroxisome proliferator-activated receptor γ, helicase with zinc finger 2 (HELZ2). HELZ2 null mice were resistant to diet-induced obesity and NAFFL/NASH, and HELZ2 was phosphorylated at tyrosine residues. In order to find a factor related to HELZ2, we analyzed products co-immunoprecipitated with phosphorylated HELZ2 by mass spectrometry analyses. We identified proline- and glutamine-rich (SFPQ) as a protein associating with tyrosine-phosphorylated HELZ2. The knockdown of SFPQ in 3T3-L1 cells downregulated mRNA levels of transcription factors including Krox20, Cebpβ, and Cebpδ: key factors for early-stage adipocyte differentiation. In addition, knockdown of SFPQ inhibited 3T3-L1 cell differentiation to mature adipocytes. These findings demonstrated that SFPQ associating with HELZ2 is an important novel transcriptional regulator of adipocyte differentiation.
Collapse
Affiliation(s)
- Akiko Katano-Toki
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan.
| | - Satoshi Yoshino
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Yasuyo Nakajima
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Takuya Tomaru
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Ayaka Nishikido
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Emi Ishida
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Kazuhiko Horiguchi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Tsugumichi Saito
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Atsushi Ozawa
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Tetsurou Satoh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Masanobu Yamada
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| |
Collapse
|
4
|
Gong M, Zhang X, Wang Y, Mao G, Ou Y, Wei C, Hu X, Xiang S. DDX21 interacts with nuclear AGO2 and regulates the alternative splicing of SMN2. Biosci Biotechnol Biochem 2021; 85:272-279. [PMID: 33604619 DOI: 10.1093/bbb/zbaa029] [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: 06/30/2020] [Accepted: 08/17/2020] [Indexed: 01/30/2023]
Abstract
AGO2 is the only member of mammalian Ago protein family that possesses the catalytic activity and plays a central role in gene silencing. Recently researches reported that multiple gene silencing factors, including AGO2, function in the nuclei. The molecular mechanisms of the gene silencing factors functioning in nuclei are conducive to comprehend the roles of gene silencing in pretranslational regulation of gene expression. Here, we report that AGO2 interacts with DDX21 indirectly in an RNA-dependent manner by Co-IP and GST-Pulldown assays and the 2 proteins present nuclei foci in the immunofluorescence experiments. We found that DDX21 up-regulated the protein level of AGO2 and participated in target gene, SNM2, alternative splicing involved in AGO2 by the indirect interaction with AGO2, which produced different transcripts of SMN2 in discrepant expression level. This study laid important experiment foundation for the further analysis of the nuclear functions of gene silencing components.
Collapse
Affiliation(s)
- Mengting Gong
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China.,College of Physical Education, Hunan University of Finance and Economics, Changsha, China
| | - Xi Zhang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Yaru Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Guiyan Mao
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Yangqi Ou
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Chenxi Wei
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Xiang Hu
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Shuanglin Xiang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| |
Collapse
|
5
|
Ottesen EW, Singh RN. Characteristics of circular RNAs generated by human Survival Motor Neuron genes. Cell Signal 2020; 73:109696. [PMID: 32553550 PMCID: PMC7387165 DOI: 10.1016/j.cellsig.2020.109696] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 06/12/2020] [Indexed: 02/06/2023]
Abstract
Circular RNAs (circRNAs) belong to a diverse class of stable RNAs expressed in all cell types. Their proposed functions include sponging of microRNAs (miRNAs), sequestration and trafficking of proteins, assembly of multimeric complexes, production of peptides, and regulation of transcription. Backsplicing due to RNA structures formed by an exceptionally high number of Alu repeats lead to the production of a vast repertoire of circRNAs by human Survival Motor Neuron genes, SMN1 and SMN2, that code for SMN, an essential multifunctional protein. Low levels of SMN due to deletion or mutation of SMN1 result in spinal muscular atrophy (SMA), a major genetic disease of infants and children. Mild SMA is also recorded in adult population, expanding the spectrum of the disease. Here we review SMN circRNAs with respect to their biogenesis, sequence features, and potential functions. We also discuss how SMN circRNAs could be exploited for diagnostic and therapeutic purposes.
Collapse
Affiliation(s)
- Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States of America
| | - Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States of America.
| |
Collapse
|
6
|
Murine Long Noncoding RNA Morrbid Contributes in the Regulation of NRAS Splicing in Hepatocytes In Vitro. Int J Mol Sci 2020; 21:ijms21165605. [PMID: 32764370 PMCID: PMC7460575 DOI: 10.3390/ijms21165605] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 07/31/2020] [Accepted: 08/01/2020] [Indexed: 12/19/2022] Open
Abstract
The coupling of alternative splicing with the nonsense-mediated decay (NMD) pathway maintains quality control of the transcriptome in eukaryotes by eliminating transcripts with premature termination codons (PTC) and fine-tunes gene expression. Long noncoding RNA (lncRNA) can regulate multiple cellular processes, including alternative splicing. Previously, murine Morrbid (myeloid RNA repressor of Bcl2l11 induced death) lncRNA was described as a locus-specific controller of the lifespan of short-living myeloid cells via transcription regulation of the apoptosis-related Bcl2l11 protein. Here, we report that murine Morrbid lncRNA in hepatocytes participates in the regulation of proto-oncogene NRAS (neuroblastoma RAS viral oncogene homolog) splicing, including the formation of the isoform with PTC. We observed a significant increase of the NRAS isoform with PTC in hepatocytes with depleted Morrbid lncRNA. We demonstrated that the NRAS isoform with PTC is degraded via the NMD pathway. This transcript is presented almost only in the nucleus and has a half-life ~four times lower than other NRAS transcripts. Additionally, in UPF1 knockdown hepatocytes (the key NMD factor), we observed a significant increase of the NRAS isoform with PTC. By a modified capture hybridization (CHART) analysis of the protein targets, we uncovered interactions of Morrbid lncRNA with the SFPQ (splicing factor proline and glutamine rich)-NONO (non-POU domain-containing octamer-binding protein) splicing complex. Finally, we propose the regulation mechanism of NRAS splicing in murine hepatocytes by alternative splicing coupled with the NMD pathway with the input of Morrbid lncRNA.
Collapse
|
7
|
Takeuchi A, Iida K, Tsubota T, Hosokawa M, Denawa M, Brown JB, Ninomiya K, Ito M, Kimura H, Abe T, Kiyonari H, Ohno K, Hagiwara M. Loss of Sfpq Causes Long-Gene Transcriptopathy in the Brain. Cell Rep 2019; 23:1326-1341. [PMID: 29719248 DOI: 10.1016/j.celrep.2018.03.141] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/19/2018] [Accepted: 03/30/2018] [Indexed: 12/13/2022] Open
Abstract
Genes specifically expressed in neurons contain members with extended long introns. Longer genes present a problem with respect to fulfilment of gene length transcription, and evidence suggests that dysregulation of long genes is a mechanism underlying neurodegenerative and psychiatric disorders. Here, we report the discovery that RNA-binding protein Sfpq is a critical factor for maintaining transcriptional elongation of long genes. We demonstrate that Sfpq co-transcriptionally binds to long introns and is required for sustaining long-gene transcription by RNA polymerase II through mediating the interaction of cyclin-dependent kinase 9 with the elongation complex. Phenotypically, Sfpq disruption caused neuronal apoptosis in developing mouse brains. Expression analysis of Sfpq-regulated genes revealed specific downregulation of developmentally essential neuronal genes longer than 100 kb in Sfpq-disrupted brains; those genes are enriched in associations with neurodegenerative and psychiatric diseases. The identified molecular machinery yields directions for targeted investigations of the association between long-gene transcriptopathy and neuronal diseases.
Collapse
Affiliation(s)
- Akihide Takeuchi
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
| | - Kei Iida
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan; Medical Research Support Center, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Toshiaki Tsubota
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Motoyasu Hosokawa
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Masatsugu Denawa
- Medical Research Support Center, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - J B Brown
- Laboratory for Molecular Biosciences, Life Science Informatics Research Unit, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kensuke Ninomiya
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Mikako Ito
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Hiroshi Kimura
- Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Takaya Abe
- Genetic Engineering Team, RIKEN Center for Life Science Technologies, Kobe 650-0047, Japan
| | - Hiroshi Kiyonari
- Genetic Engineering Team, RIKEN Center for Life Science Technologies, Kobe 650-0047, Japan; Animal Resource Development Unit, R IKEN Center for Life Science Technologies, Kobe 650-0047, Japan
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Masatoshi Hagiwara
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
| |
Collapse
|
8
|
Activation of Cryptic 3' Splice-Sites by SRSF2 Contributes to Cassette Exon Skipping. Cells 2019; 8:cells8070696. [PMID: 31295920 PMCID: PMC6678912 DOI: 10.3390/cells8070696] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/05/2019] [Accepted: 07/09/2019] [Indexed: 11/21/2022] Open
Abstract
Here we show that the serine/arginine rich splicing factor 2 (SRSF2) promotes cryptic 3′ splice-site (3′AG′) usage during cassette exon exclusion in survival of motor neuron (SMN2) minigenes. Deletion of the 3′AG′ (3′AG′1), its associated branch point (BP′) and polypyrimidine tract (PPT′) sequences directs SRSF2 to promote a second 3′AG′ (3′AG′2) with less conserved associated region for intron splicing. Furthermore, deletion of both 3′AG′1 and 3′AG′2 and their associated sequences triggered usage of a third 3′AG′3 that has very weak associated sequences. Interestingly, when intron splicing was directed to the 3′AG′ cryptic splice-sites, intron splicing from the canonical 3′AG splice-site was reduced along with a decrease in cassette exon inclusion. Moreover, multiple SRSF2 binding sites within the intron are responsible for 3′AG′ activation. We conclude that SRSF2 facilitates exon exclusion by activating a cryptic 3′AG′ and inhibiting downstream intron splicing.
Collapse
|
9
|
Souček P, Réblová K, Kramárek M, Radová L, Grymová T, Hujová P, Kováčová T, Lexa M, Grodecká L, Freiberger T. High-throughput analysis revealed mutations' diverging effects on SMN1 exon 7 splicing. RNA Biol 2019; 16:1364-1376. [PMID: 31213135 DOI: 10.1080/15476286.2019.1630796] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Splicing-affecting mutations can disrupt gene function by altering the transcript assembly. To ascertain splicing dysregulation principles, we modified a minigene assay for the parallel high-throughput evaluation of different mutations by next-generation sequencing. In our model system, all exonic and six intronic positions of the SMN1 gene's exon 7 were mutated to all possible nucleotide variants, which amounted to 180 unique single-nucleotide mutants and 470 double mutants. The mutations resulted in a wide range of splicing aberrations. Exonic splicing-affecting mutations resulted either in substantial exon skipping, supposedly driven by predicted exonic splicing silencer or cryptic donor splice site (5'ss) and de novo 5'ss strengthening and use. On the other hand, a single disruption of exonic splicing enhancer was not sufficient to cause major exon skipping, suggesting these elements can be substituted during exon recognition. While disrupting the acceptor splice site led only to exon skipping, some 5'ss mutations potentiated the use of three different cryptic 5'ss. Generally, single mutations supporting cryptic 5'ss use displayed better pre-mRNA/U1 snRNA duplex stability and increased splicing regulatory element strength across the original 5'ss. Analyzing double mutants supported the predominating splicing regulatory elements' effect, but U1 snRNA binding could contribute to the global balance of splicing isoforms. Based on these findings, we suggest that creating a new splicing enhancer across the mutated 5'ss can be one of the main factors driving cryptic 5'ss use.
Collapse
Affiliation(s)
- Přemysl Souček
- Medical Genomics RG, Central European Institute of Technology, Masaryk University , Brno , Czech Republic.,Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation , Brno , Czech Republic
| | - Kamila Réblová
- Medical Genomics RG, Central European Institute of Technology, Masaryk University , Brno , Czech Republic
| | - Michal Kramárek
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation , Brno , Czech Republic
| | - Lenka Radová
- Medical Genomics RG, Central European Institute of Technology, Masaryk University , Brno , Czech Republic
| | - Tereza Grymová
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation , Brno , Czech Republic
| | - Pavla Hujová
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation , Brno , Czech Republic
| | - Tatiana Kováčová
- Medical Genomics RG, Central European Institute of Technology, Masaryk University , Brno , Czech Republic
| | - Matej Lexa
- Faculty of Informatics, Masaryk University , Brno , Czech Republic
| | - Lucie Grodecká
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation , Brno , Czech Republic
| | - Tomáš Freiberger
- Medical Genomics RG, Central European Institute of Technology, Masaryk University , Brno , Czech Republic.,Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation , Brno , Czech Republic.,Faculty of Medicine, Masaryk University , Brno , Czech Republic
| |
Collapse
|
10
|
Flather D, Nguyen JHC, Semler BL, Gershon PD. Exploitation of nuclear functions by human rhinovirus, a cytoplasmic RNA virus. PLoS Pathog 2018; 14:e1007277. [PMID: 30142213 PMCID: PMC6126879 DOI: 10.1371/journal.ppat.1007277] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 09/06/2018] [Accepted: 08/11/2018] [Indexed: 12/17/2022] Open
Abstract
Protein production, genomic RNA replication, and virion assembly during infection by picornaviruses like human rhinovirus and poliovirus take place in the cytoplasm of infected human cells, making them the quintessential cytoplasmic pathogens. However, a growing body of evidence suggests that picornavirus replication is promoted by a number of host proteins localized normally within the host cell nucleus. To systematically identify such nuclear proteins, we focused on those that appear to re-equilibrate from the nucleus to the cytoplasm during infection of HeLa cells with human rhinovirus via quantitative protein mass spectrometry. Our analysis revealed a highly selective re-equilibration of proteins with known mRNA splicing and transport-related functions over nuclear proteins of all other functional classes. The multifunctional splicing factor proline and glutamine rich (SFPQ) was identified as one such protein. We found that SFPQ is targeted for proteolysis within the nucleus by viral proteinase 3CD/3C, and a fragment of SFPQ was shown to migrate to the cytoplasm at mid-to-late times of infection. Cells knocked down for SFPQ expression showed significantly reduced rhinovirus titers, viral protein production, and viral RNA accumulation, consistent with SFPQ being a pro-viral factor. The SFPQ fragment that moved into the cytoplasm was able to bind rhinovirus RNA either directly or indirectly. We propose that the truncated form of SFPQ promotes viral RNA stability or replication, or virion morphogenesis. More broadly, our findings reveal dramatic changes in protein compartmentalization during human rhinovirus infection, allowing the virus to systematically hijack the functions of proteins not normally found at its cytoplasmic site of replication. We explored the dynamics of host cell protein relocalization from the nucleus to the cytoplasm during an infection by human rhinovirus using quantitative mass spectrometry, confocal imaging, and Western blot analysis. We discovered a highly selective re-equilibration of proteins with known mRNA splicing and transport-related functions, including splicing factor proline and glutamine rich (SFPQ). Using RNAi experiments and viral replication assays, we demonstrated that SFPQ is a pro-viral factor required for rhinovirus growth. Our studies provide new insights into how this cytoplasmic RNA virus is able to alter and hijack the functions of host proteins that normally reside in the nucleus.
Collapse
Affiliation(s)
- Dylan Flather
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, California, United States of America
- Center for Virus Research, University of California, Irvine, California, United States of America
| | - Joseph H. C. Nguyen
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, California, United States of America
- Center for Virus Research, University of California, Irvine, California, United States of America
| | - Bert L. Semler
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, California, United States of America
- Center for Virus Research, University of California, Irvine, California, United States of America
- * E-mail: (BLS); (PDG)
| | - Paul D. Gershon
- Center for Virus Research, University of California, Irvine, California, United States of America
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California, United States of America
- * E-mail: (BLS); (PDG)
| |
Collapse
|
11
|
Singh G, Rife BD, Seufzer B, Salemi M, Rendahl A, Boris-Lawrie K. Identification of conserved, primary sequence motifs that direct retrovirus RNA fate. Nucleic Acids Res 2018; 46:7366-7378. [PMID: 29846681 PMCID: PMC6101577 DOI: 10.1093/nar/gky369] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 04/20/2018] [Accepted: 05/16/2018] [Indexed: 12/16/2022] Open
Abstract
Precise stoichiometry of genome-length transcripts and alternatively spliced mRNAs is a hallmark of retroviruses. We discovered short, guanosine and adenosine sequence motifs in the 5'untranslated region of several retroviruses and ascertained the reasons for their conservation using a representative lentivirus and genetically simpler retrovirus. We conducted site-directed mutagenesis of the GA-motifs in HIV molecular clones and observed steep replication delays in T-cells. Quantitative RNA analyses demonstrate the GA-motifs are necessary to retain unspliced viral transcripts from alternative splicing. Mutagenesis of the GA-motifs in a C-type retrovirus validate the similar downregulation of unspliced transcripts and virion structural protein. The evidence from cell-based co-precipitation studies shows the GA-motifs in the 5'untranslated region confer binding by SFPQ/PSF, a protein co-regulated with T-cell activation. Diminished SFPQ/PSF or mutation of either GA-motif attenuates the replication of HIV. The interaction of SFPQ/PSF with both GA-motifs is crucial for maintaining the stoichiometry of the viral transcripts and does not affect packaging of HIV RNA. Our results demonstrate the conserved GA-motifs direct the fate of retrovirus RNA. These findings have exposed an RNA-based molecular target to attenuate retrovirus replication.
Collapse
Affiliation(s)
- Gatikrushna Singh
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA
| | - Brittany D Rife
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Bradley Seufzer
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA
| | - Marco Salemi
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Aaron Rendahl
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA
| | - Kathleen Boris-Lawrie
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA
| |
Collapse
|
12
|
Singh RN, Singh NN. Mechanism of Splicing Regulation of Spinal Muscular Atrophy Genes. ADVANCES IN NEUROBIOLOGY 2018; 20:31-61. [PMID: 29916015 DOI: 10.1007/978-3-319-89689-2_2] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) is one of the major genetic disorders associated with infant mortality. More than 90% cases of SMA result from deletions or mutations of Survival Motor Neuron 1 (SMN1) gene. SMN2, a nearly identical copy of SMN1, does not compensate for the loss of SMN1 due to predominant skipping of exon 7. However, correction of SMN2 exon 7 splicing has proven to confer therapeutic benefits in SMA patients. The only approved drug for SMA is an antisense oligonucleotide (Spinraza™/Nusinersen), which corrects SMN2 exon 7 splicing by blocking intronic splicing silencer N1 (ISS-N1) located immediately downstream of exon 7. ISS-N1 is a complex regulatory element encompassing overlapping negative motifs and sequestering a cryptic splice site. More than 40 protein factors have been implicated in the regulation of SMN exon 7 splicing. There is evidence to support that multiple exons of SMN are alternatively spliced during oxidative stress, which is associated with a growing number of pathological conditions. Here, we provide the most up to date account of the mechanism of splicing regulation of the SMN genes.
Collapse
Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA.
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| |
Collapse
|
13
|
Sbarrato T, Spriggs RV, Wilson L, Jones C, Dudek K, Bastide A, Pichon X, Pöyry T, Willis AE. An improved analysis methodology for translational profiling by microarray. RNA (NEW YORK, N.Y.) 2017; 23:1601-1613. [PMID: 28842509 PMCID: PMC5648029 DOI: 10.1261/rna.060525.116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 07/27/2017] [Indexed: 06/07/2023]
Abstract
Translational regulation plays a central role in the global gene expression of a cell, and detection of such regulation has allowed deciphering of critical biological mechanisms. Genome-wide studies of the regulation of translation (translatome) performed on microarrays represent a substantial proportion of studies, alongside with recent advances in deep-sequencing methods. However, there has been a lack of development in specific processing methodologies that deal with the distinct nature of translatome array data. In this study, we confirm that polysome profiling yields skewed data and thus violates the conventional transcriptome analysis assumptions. Using a comprehensive simulation of translatome array data varying the percentage and symmetry of deregulation, we show that conventional analysis methods (Quantile and LOESS normalizations) and statistical tests failed, respectively, to correctly normalize the data and to identify correctly deregulated genes (DEGs). We thus propose a novel analysis methodology available as a CRAN package; Internal Control Analysis of Translatome (INCATome) based on a normalization tied to a group of invariant controls. We confirm that INCATome outperforms the other normalization methods and allows a stringent identification of DEGs. More importantly, INCATome implementation on a biological translatome data set (cells silenced for splicing factor PSF) resulted in the best normalization performance and an improved validation concordance for identification of true positive DEGs. Finally, we provide evidence that INCATome is able to infer novel biological pathways with superior discovery potential, thus confirming the benefits for researchers of implementing INCATome for future translatome studies as well as for existing data sets to generate novel avenues for research.
Collapse
Affiliation(s)
- Thomas Sbarrato
- Medical Research Council Toxicology Unit, Leicester LE1 9HN, United Kingdom
- Aix Marseille Université, LAI UM 61, Marseille F-13288, France
- Inserm, UMR_S 1067, Marseille F-13288, France
- CNRS, UMR 7333, Marseille F-13288, France
| | - Ruth V Spriggs
- Medical Research Council Toxicology Unit, Leicester LE1 9HN, United Kingdom
| | - Lindsay Wilson
- Medical Research Council Toxicology Unit, Leicester LE1 9HN, United Kingdom
| | - Carolyn Jones
- Medical Research Council Toxicology Unit, Leicester LE1 9HN, United Kingdom
| | - Kate Dudek
- Medical Research Council Toxicology Unit, Leicester LE1 9HN, United Kingdom
| | - Amandine Bastide
- Medical Research Council Toxicology Unit, Leicester LE1 9HN, United Kingdom
| | - Xavier Pichon
- Medical Research Council Toxicology Unit, Leicester LE1 9HN, United Kingdom
| | - Tuija Pöyry
- Medical Research Council Toxicology Unit, Leicester LE1 9HN, United Kingdom
| | - Anne E Willis
- Medical Research Council Toxicology Unit, Leicester LE1 9HN, United Kingdom
| |
Collapse
|
14
|
Sutherland LC, Thibault P, Durand M, Lapointe E, Knee JM, Beauvais A, Kalatskaya I, Hunt SC, Loiselle JJ, Roy JG, Tessier SJ, Ybazeta G, Stein L, Kothary R, Klinck R, Chabot B. Splicing arrays reveal novel RBM10 targets, including SMN2 pre-mRNA. BMC Mol Biol 2017; 18:19. [PMID: 28728573 PMCID: PMC5520337 DOI: 10.1186/s12867-017-0096-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/14/2017] [Indexed: 12/18/2022] Open
Abstract
Background RBM10 is an RNA binding protein involved in message stabilization and alternative splicing regulation. The objective of the research described herein was to identify novel targets of RBM10-regulated splicing. To accomplish this, we downregulated RBM10 in human cell lines, using small interfering RNAs, then monitored alternative splicing, using a reverse transcription-PCR screening platform. Results RBM10 knockdown (KD) provoked alterations in splicing events in 10–20% of the pre-mRNAs, most of which had not been previously identified as RBM10 targets. Hierarchical clustering of the genes affected by RBM10 KD revealed good conservation of alternative exon inclusion or exclusion across cell lines. Pathway annotation showed RAS signaling to be most affected by RBM10 KD. Of particular interest was the finding that splicing of SMN pre-mRNA, encoding the survival of motor neuron (SMN) protein, was influenced by RBM10 KD. Inhibition of RBM10 resulted in preferential expression of the full-length, exon 7 retaining, SMN transcript in four cancer cell lines and one normal skin fibroblast cell line. SMN protein is expressed from two genes, SMN1 and SMN2, but the SMN1 gene is homozygously disrupted in people with spinal muscular atrophy; as a consequence, all of the SMN that is expressed in people with this disease is from the SMN2 gene. Expression analyses using primary fibroblasts from control, carrier and spinal muscle atrophy donors demonstrated that RBM10 KD resulted in preferential expression of the full-length, exon 7 retaining, SMN2 transcript. At the protein level, upregulation of the full-length SMN2 was also observed. Re-expression of RBM10, in a stable RBM10 KD cancer cell line, correlated with a reversion of the KD effect, demonstrating specificity. Conclusion Our work has not only expanded the number of pre-mRNA targets for RBM10, but identified RBM10 as a novel regulator of SMN2 alternative inclusion. Electronic supplementary material The online version of this article (doi:10.1186/s12867-017-0096-x) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Leslie C Sutherland
- Health Sciences North Research Institute, Sudbury, ON, P3E 5J1, Canada. .,Biomolecular Sciences Program, Laurentian University, Sudbury, ON, P3E 2C6, Canada. .,Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, P3E 2C6, Canada.
| | - Philippe Thibault
- RNomics Platform of Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Mathieu Durand
- RNomics Platform of Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Elvy Lapointe
- RNomics Platform of Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Jose M Knee
- Health Sciences North Research Institute, Sudbury, ON, P3E 5J1, Canada
| | - Ariane Beauvais
- Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
| | - Irina Kalatskaya
- Ontario Institute for Cancer Research, MaRS Centre, Toronto, ON, M5G 0A3, Canada
| | - Sarah C Hunt
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Julie J Loiselle
- Biomolecular Sciences Program, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Justin G Roy
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Sarah J Tessier
- Health Sciences North Research Institute, Sudbury, ON, P3E 5J1, Canada
| | - Gustavo Ybazeta
- Health Sciences North Research Institute, Sudbury, ON, P3E 5J1, Canada
| | - Lincoln Stein
- Ontario Institute for Cancer Research, MaRS Centre, Toronto, ON, M5G 0A3, Canada
| | - Rashmi Kothary
- Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada.,Departments of Medicine and of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Roscoe Klinck
- RNomics Platform of Université de Sherbrooke, Sherbrooke, QC, Canada.,Département de Microbiologie et d'infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Benoit Chabot
- Département de Microbiologie et d'infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| |
Collapse
|
15
|
Tu WY, Simpson JE, Highley JR, Heath PR. Spinal muscular atrophy: Factors that modulate motor neurone vulnerability. Neurobiol Dis 2017; 102:11-20. [PMID: 28161391 DOI: 10.1016/j.nbd.2017.01.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 01/10/2017] [Accepted: 01/31/2017] [Indexed: 01/07/2023] Open
Abstract
Spinal muscular atrophy (SMA), a leading genetic cause of infant death, is a neurodegenerative disease characterised by the selective loss of particular groups of motor neurones in the anterior horn of the spinal cord with concomitant muscle weakness. To date, no effective treatment is available, however, there are ongoing clinical trials are in place which promise much for the future. However, there remains an ongoing problem in trying to link a single gene loss to motor neurone degeneration. Fortunately, given successful disease models that have been established and intensive studies on SMN functions in the past ten years, we are fast approaching the stage of identifying the underlying mechanisms of SMA pathogenesis Here we discuss potential disease modifying factors on motor neurone vulnerability, in the belief that these factors give insight into the pathological mechanisms of SMA and therefore possible therapeutic targets.
Collapse
Affiliation(s)
- Wen-Yo Tu
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Julie E Simpson
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - J Robin Highley
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Paul R Heath
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK.
| |
Collapse
|
16
|
Qu YJ, Bai JL, Cao YY, Zhang WH, Wang H, Jin YW, Song F. A rare variant (c.863G>T) in exon 7 of SMN1 disrupts mRNA splicing and is responsible for spinal muscular atrophy. Eur J Hum Genet 2016; 24:864-70. [PMID: 26419278 PMCID: PMC4867452 DOI: 10.1038/ejhg.2015.213] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 08/10/2015] [Accepted: 08/25/2015] [Indexed: 11/08/2022] Open
Abstract
Proximal spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by deletion or mutation of SMN1 (survival motor neuron 1). SMN exon 7 splicing is regulated by a number of exonic and intronic regulatory sequences and the trans-factors that bind them. Variants located in or near these regulated regions should be evaluated to determine their effect on splicing. We identified the rare variant c.863G>T (r.835_*3del, p.Gly279Glufs*5) in exon 7 of SMN1 in three patients affected with type I or type II SMA. Most of the SMN1 transcripts exhibited complete loss of exon 7 in vivo. The ex vivo splicing assay demonstrated that the variant disrupts inclusion of exon 7 (~85%) in the SMN1 mRNA; replacement with various bases yielded a variety of splicing effects in SMN1 and SMN2 pre-mRNA. The c.863G>T (r.835_*3del, p.Gly279Glufs*5) variant is located in a region that includes binding sites for multiple splicing factors including Tra2β1. Thus, the variant disrupts Tra2β1 binding, but does not affect binding of hnRNP A1. These findings demonstrate how rare variants influence pre-mRNA splicing of SMN and reveal the functional influence of c.863G>T (r.835_*3del, p.Gly279Glufs*5) variant in patients with SMA.
Collapse
Affiliation(s)
- Yu-jin Qu
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Jin-li Bai
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Yan-yan Cao
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Wen-hui Zhang
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Hong Wang
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Yu-wei Jin
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Fang Song
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, P.R. China
| |
Collapse
|
17
|
Knott GJ, Bond CS, Fox AH. The DBHS proteins SFPQ, NONO and PSPC1: a multipurpose molecular scaffold. Nucleic Acids Res 2016; 44:3989-4004. [PMID: 27084935 PMCID: PMC4872119 DOI: 10.1093/nar/gkw271] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 04/05/2016] [Indexed: 12/23/2022] Open
Abstract
Nuclear proteins are often given a concise title that captures their function, such as 'transcription factor,' 'polymerase' or 'nuclear-receptor.' However, for members of the Drosophila behavior/human splicing (DBHS) protein family, no such clean-cut title exists. DBHS proteins are frequently identified engaging in almost every step of gene regulation, including but not limited to, transcriptional regulation, RNA processing and transport, and DNA repair. Herein, we present a coherent picture of DBHS proteins, integrating recent structural insights on dimerization, nucleic acid binding modalities and oligomerization propensity with biological function. The emerging paradigm describes a family of dynamic proteins mediating a wide range of protein-protein and protein-nucleic acid interactions, on the whole acting as a multipurpose molecular scaffold. Overall, significant steps toward appreciating the role of DBHS proteins have been made, but we are only beginning to understand the complexity and broader importance of this family in cellular biology.
Collapse
Affiliation(s)
- Gavin J Knott
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, WA 6009, Australia
| | - Charles S Bond
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, WA 6009, Australia
| | - Archa H Fox
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, WA 6009, Australia Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA 6009, Australia
| |
Collapse
|
18
|
Zheng X, Cho S, Moon H, Loh TJ, Jang HN, Shen H. Detecting RNA-Protein Interaction Using End-Labeled Biotinylated RNA Oligonucleotides and Immunoblotting. Methods Mol Biol 2016; 1421:35-44. [PMID: 26965255 DOI: 10.1007/978-1-4939-3591-8_4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
RNA-protein interaction can be detected by RNA pull-down and immunoblotting methods. Here, we describe a method to detect RNA-protein interaction using RNA pull down and to identify the proteins that are pulled-down by the RNA using immunoblotting. In this protocol, RNAs with specific sequences are biotinylated and immobilized onto Streptavidin beads, which are then used to pull down interacting proteins from cellular extracts. The presence of a specific protein is subsequently verified by SDS- polyacrylamide gel electrophoresis and immunoblotting with antibodies. Interactions between the SMN RNA and the PSF protein and between the caspase-2 RNA and the SRSF3 protein (SRp20) in nuclear extract prepared from HeLa cells are illustrated as examples.
Collapse
Affiliation(s)
- Xuexiu Zheng
- School of Life Science, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro (Oryong-dong), Buk-gu, Gwangju, 500-712, South Korea
| | - Sunghee Cho
- School of Life Science, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro (Oryong-dong), Buk-gu, Gwangju, 500-712, South Korea
| | - Heegyum Moon
- School of Life Science, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro (Oryong-dong), Buk-gu, Gwangju, 500-712, South Korea
| | - Tiing Jen Loh
- School of Life Science, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro (Oryong-dong), Buk-gu, Gwangju, 500-712, South Korea
| | - Ha Na Jang
- School of Life Science, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro (Oryong-dong), Buk-gu, Gwangju, 500-712, South Korea
| | - Haihong Shen
- School of Life Science, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro (Oryong-dong), Buk-gu, Gwangju, 500-712, South Korea.
| |
Collapse
|
19
|
Moon H, Zheng X, Loh TJ, Jang HN, Liu Y, Jung DW, Williams DR, Shen H. Identification of Regulatory-RNAs for Alternative Splicing of Ron Proto-Oncogene. J Cancer 2015; 6:1346-51. [PMID: 26640595 PMCID: PMC4643091 DOI: 10.7150/jca.13361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 09/07/2015] [Indexed: 12/02/2022] Open
Abstract
RON receptor tyrosine kinase is a proto-oncogene that induces cell migration and matrix invasion. RONΔ160 protein, which is produced by exclusion of exon 5 and 6, promotes cell migration, matrix invasion and protection from apoptosis. Alternative splicing regulation of exon 5 and 6 is not well understood. In this manuscript, we identified several new RNA regulatory elements for alternative splicing of Ron proto-oncogene. Firstly, we demonstrated that RNA sequences from EcoRI cleavage sites regulate alternative splicing of Ron exon 5 and 6. Secondly, we showed that the ~30 nt RNA at upstream end of exon 4 and the ~33 nt RNA at downstream end of exon 7 also modulate splicing of exon 5 and 6. Thirdly, our results indicate that the RNA sequences of the ends in exon 4 and 7 are required for the regulatory functions of the RNA from restriction enzyme cleavage sites. Our results provide a new insight for regulation of alternative splicing of Ron proto-oncogene.
Collapse
Affiliation(s)
- Heegyum Moon
- 1These authors contributed equally to this manuscript
| | - Xuexiu Zheng
- 1These authors contributed equally to this manuscript
| | - Tiing Jen Loh
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Ha Na Jang
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Yongchao Liu
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Da-Woon Jung
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Darren R Williams
- 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
| |
Collapse
|
20
|
Knott GJ, Lee M, Passon DM, Fox AH, Bond CS. Caenorhabditis elegans NONO-1: Insights into DBHS protein structure, architecture, and function. Protein Sci 2015; 24:2033-43. [PMID: 26435036 DOI: 10.1002/pro.2816] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 09/24/2015] [Indexed: 12/14/2022]
Abstract
Members of the Drosophila behavior/human splicing (DBHS) protein family have been characterized in the vertebrates Homo sapiens and Mus musculus, and the invertebrates Drosophila melanogaster and Chironomus tentans. Collectively, both vertebrate and invertebrate DBHS proteins function throughout gene regulation, largely but not always, within the nucleus. In this study, we report a structural and bioinformatic analysis of the DBHS protein family to guide future studies into DBHS protein function. To explore the structural plasticity of the family, we describe the 2.4 Å crystal structure of Caenorhabditis elegans non-POU domain-containing octamer-binding protein 1 (NONO-1). The structure is dimeric, with a domain arrangement consistent with mammalian DBHS proteins. Comparison with the DBHS structures available from H. sapiens reveals that there is inherent domain flexibility within the homologous DBHS region. Mapping amino acid similarity within the family to the NONO-1 dimer highlights the dimer interface, coiled-coil oligomerization motif, and putative RNA binding surfaces. Surprisingly, the interior surface of RNA recognition motif 2 (RRM2) that faces a large internal void is highly variable, but the external β2-β3 loops of RRM2 show remarkable preservation. Overall, the DBHS region is under strong purifying selection, whereas the sequences N- and C-terminal to the DBHS region are less constrained. The findings described in this study provide a molecular basis for further investigation into the mechanistic function of the DBHS protein family in biology.
Collapse
Affiliation(s)
- Gavin J Knott
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Mihwa Lee
- Department of Biochemistry and Genetics, La Trobe University, Melbourne, Victoria, Australia
| | - Daniel M Passon
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, 6009, Australia.,European Molecular Biology Laboratories, Hamburg, 22761, Germany
| | - Archa H Fox
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Charles S Bond
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| |
Collapse
|
21
|
Yarosh CA, Iacona JR, Lutz CS, Lynch KW. PSF: nuclear busy-body or nuclear facilitator? WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 6:351-67. [PMID: 25832716 PMCID: PMC4478221 DOI: 10.1002/wrna.1280] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 02/28/2015] [Accepted: 03/02/2015] [Indexed: 01/25/2023]
Abstract
PTB-associated splicing factor (PSF) is an abundant and essential nucleic acid-binding protein that participates in a wide range of gene regulatory processes and cellular response pathways. At the protein level, PSF consists of multiple domains, many of which remain poorly characterized. Although grouped in a family with the proteins p54nrb/NONO and PSPC1 based on sequence homology, PSF contains additional protein sequence not included in other family members. Consistently, PSF has also been implicated in functions not ascribed to p54nrb/NONO or PSPC1. Here, we provide a review of the cellular activities in which PSF has been implicated and what is known regarding the mechanisms by which PSF functions in each case. We propose that the complex domain arrangement of PSF allows for its diversity of function and integration of activities. Finally, we discuss recent evidence that individual activities of PSF can be regulated independently from one another through the activity of domain-specific co-factors.
Collapse
Affiliation(s)
- Christopher A Yarosh
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph R Iacona
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers Biomedical and Health Sciences-New Jersey Medical School, Newark, NJ, USA
| | - Carol S Lutz
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers Biomedical and Health Sciences-New Jersey Medical School, Newark, NJ, USA
| | - Kristen W Lynch
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
22
|
Singh NN, Lee BM, Singh RN. Splicing regulation in spinal muscular atrophy by an RNA structure formed by long-distance interactions. Ann N Y Acad Sci 2015; 1341:176-87. [PMID: 25727246 PMCID: PMC4651915 DOI: 10.1111/nyas.12727] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Humans carry two copies of the survival motor neuron gene: SMN1 and SMN2. Loss of SMN1 coupled with skipping of SMN2 exon 7 causes spinal muscular atrophy (SMA), a leading genetic disease associated with infant mortality. Our discovery of intronic splicing silencer N1 (ISS-N1) is a promising target, currently in a phase III clinical trial, for an antisense oligonucleotide-mediated splicing correction in SMA. We have recently shown that the first residue of ISS-N1 is locked in a unique RNA structure that we term ISTL1 (internal stem through long-distance interaction-1). Complementary strands of ISTL1 are separated from each other by 279 nucleotides. Using site-specific mutations and chemical structure probing, we confirmed the formation and functional significance of ISTL1. Located in the middle of intron 7, the 3' strand of ISTL1 falls within an inhibitory region that we term ISS-N2. We demonstrate that an antisense oligonucleotide-mediated sequestration of ISS-N2 fully corrects SMN2 exon 7 splicing and restores high levels of SMN in SMA patient cells. These results underscore the therapeutic potential of the regulatory information present in a secondary and high-order RNA structure of a human intron.
Collapse
Affiliation(s)
- Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa
| | | | | |
Collapse
|
23
|
Walsh MJ, Cooper-Knock J, Dodd JE, Stopford MJ, Mihaylov SR, Kirby J, Shaw PJ, Hautbergue GM. Invited review: decoding the pathophysiological mechanisms that underlie RNA dysregulation in neurodegenerative disorders: a review of the current state of the art. Neuropathol Appl Neurobiol 2015; 41:109-34. [PMID: 25319671 PMCID: PMC4329338 DOI: 10.1111/nan.12187] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 10/07/2014] [Indexed: 12/12/2022]
Abstract
Altered RNA metabolism is a key pathophysiological component causing several neurodegenerative diseases. Genetic mutations causing neurodegeneration occur in coding and noncoding regions of seemingly unrelated genes whose products do not always contribute to the gene expression process. Several pathogenic mechanisms may coexist within a single neuronal cell, including RNA/protein toxic gain-of-function and/or protein loss-of-function. Genetic mutations that cause neurodegenerative disorders disrupt healthy gene expression at diverse levels, from chromatin remodelling, transcription, splicing, through to axonal transport and repeat-associated non-ATG (RAN) translation. We address neurodegeneration in repeat expansion disorders [Huntington's disease, spinocerebellar ataxias, C9ORF72-related amyotrophic lateral sclerosis (ALS)] and in diseases caused by deletions or point mutations (spinal muscular atrophy, most subtypes of familial ALS). Some neurodegenerative disorders exhibit broad dysregulation of gene expression with the synthesis of hundreds to thousands of abnormal messenger RNA (mRNA) molecules. However, the number and identity of aberrant mRNAs that are translated into proteins - and how these lead to neurodegeneration - remain unknown. The field of RNA biology research faces the challenge of identifying pathophysiological events of dysregulated gene expression. In conclusion, we discuss current research limitations and future directions to improve our characterization of pathological mechanisms that trigger disease onset and progression.
Collapse
Affiliation(s)
- M J Walsh
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - J Cooper-Knock
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - J E Dodd
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - M J Stopford
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - S R Mihaylov
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - J Kirby
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - P J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - G M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| |
Collapse
|
24
|
Wee CD, Havens MA, Jodelka FM, Hastings ML. Targeting SR proteins improves SMN expression in spinal muscular atrophy cells. PLoS One 2014; 9:e115205. [PMID: 25506695 PMCID: PMC4266657 DOI: 10.1371/journal.pone.0115205] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 11/19/2014] [Indexed: 12/19/2022] Open
Abstract
Spinal muscular atrophy (SMA) is one of the most common inherited causes of pediatric mortality. SMA is caused by deletions or mutations in the survival of motor neuron 1 (SMN1) gene, which results in SMN protein deficiency. Humans have a centromeric copy of the survival of motor neuron gene, SMN2, which is nearly identical to SMN1. However, SMN2 cannot compensate for the loss of SMN1 because SMN2 has a single-nucleotide difference in exon 7, which negatively affects splicing of the exon. As a result, most mRNA produced from SMN2 lacks exon 7. SMN2 mRNA lacking exon 7 encodes a truncated protein with reduced functionality. Improving SMN2 exon 7 inclusion is a goal of many SMA therapeutic strategies. The identification of regulators of exon 7 inclusion may provide additional therapeutic targets or improve the design of existing strategies. Although a number of regulators of exon 7 inclusion have been identified, the function of most splicing proteins in exon 7 inclusion is unknown. Here, we test the role of SR proteins and hnRNP proteins in SMN2 exon 7 inclusion. Knockdown and overexpression studies reveal that SRSF1, SRSF2, SRSF3, SRSF4, SRSF5, SRSF6, SRSF7, SRSF11, hnRNPA1/B1 and hnRNP U can inhibit exon 7 inclusion. Depletion of two of the most potent inhibitors of exon 7 inclusion, SRSF2 or SRSF3, in cell lines derived from SMA patients, increased SMN2 exon 7 inclusion and SMN protein. Our results identify novel regulators of SMN2 exon 7 inclusion, revealing potential targets for SMA therapeutics.
Collapse
Affiliation(s)
- Claribel D. Wee
- Department of Cell Biology and Anatomy, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Mallory A. Havens
- Department of Cell Biology and Anatomy, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Francine M. Jodelka
- Department of Cell Biology and Anatomy, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Michelle L. Hastings
- Department of Cell Biology and Anatomy, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
- * E-mail:
| |
Collapse
|