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Zhang X, Wang Z, Xu Q, Chen Y, Liu W, Zhong T, Li H, Quan C, Zhang L, Cui CP. Splicing factor Srsf5 deletion disrupts alternative splicing and causes noncompaction of ventricular myocardium. iScience 2021; 24:103097. [PMID: 34622152 PMCID: PMC8482499 DOI: 10.1016/j.isci.2021.103097] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 07/17/2021] [Accepted: 09/06/2021] [Indexed: 11/21/2022] Open
Abstract
The serine/arginine-rich (SR) family of splicing factors plays important roles in mRNA splicing activation, repression, export, stabilization, and translation. SR-splicing factor 5 (SRSF5) is a glucose-inducible protein that promotes tumor cell growth. However, the functional role of SRSF5 in tissue development and disease remains unknown. Here, Srsf5 knockout (Srsf5−/−) mice were generated using CRISPR-Cas9. Mutant mice were perinatally lethal and exhibited cardiac dysfunction with noncompaction of the ventricular myocardium. The left ventricular internal diameter and volume were increased in Srsf5−/− mice during systole. Null mice had abnormal electrocardiogram patterns, indicative of a light atrioventricular block. Mechanistically, Srsf5 promoted the alternative splicing of Myom1 (myomesin-1), a protein that crosslinks myosin filaments to the sarcomeric M-line. The switch between embryonic and adult isoforms of Myom1 could not be completed in Srsf5-deficient heart. These findings indicate that Srsf5-regulated alternative splicing plays a critical role during heart development. Systemic loss of Srsf5 causes perinatal lethality in mice Srsf5 deficiency leads to cardiac dysfunction Alternative splicing of Myom1 in the heart around birth is regulated by Srsf5
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Affiliation(s)
- Xiaoli Zhang
- The Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, 126 Xinmin Avenue, Changchun, Jilin 130021, China.,State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 27 Taiping Road, Beijing 100850, China
| | - Ze Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 27 Taiping Road, Beijing 100850, China
| | - Qing Xu
- Core Facilities Centre, Capital Medical University, Beijing 100069, China
| | - Yuhan Chen
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 27 Taiping Road, Beijing 100850, China
| | - Wen Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 27 Taiping Road, Beijing 100850, China
| | - Tong Zhong
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 27 Taiping Road, Beijing 100850, China
| | - Hongchang Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 27 Taiping Road, Beijing 100850, China
| | - Chengshi Quan
- The Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, 126 Xinmin Avenue, Changchun, Jilin 130021, China
| | - Lingqiang Zhang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 27 Taiping Road, Beijing 100850, China
| | - Chun-Ping Cui
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 27 Taiping Road, Beijing 100850, China
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2
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Palmieri B, Vadalà M, Laurino C. Review of the molecular mechanisms in wound healing: new therapeutic targets? J Wound Care 2019; 26:765-775. [PMID: 29244975 DOI: 10.12968/jowc.2017.26.12.765] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The restoration of the skin barrier in acute and chronic wounds is controlled by several molecular mechanisms that synergistically regulate cell kinetics, enzymatic functions, and neurovascular activation. These pathways include genetic and epigenetic activation, which modulate physiological wound healing. Our review describes the genetic background of skin repair, namely transcription-independent diffusible damage signals, individual variability, epigenetic mechanism, controlled qualitative traits, post-translational mechanisms, antioxidants, nutrients, DNA modifications, bacteria activation, mitochondrial activity, and oxidative stress. The DNA background modulating skin restoration could be used to plan new diagnostics and therapeutics.
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Affiliation(s)
- B Palmieri
- Associated Professor, Dipartimento Chirurgico, Medico, Odontoiatrico e di Scienze Morfologiche con Interesse Trapiantologico, Oncologico e di Medicina Rigenerativa, Università degli Studi di Modena e Reggio Emilia, Modena, Italy; Network del Secondo Parere, Modena (MO), Italy
| | - M Vadalà
- Biologist Researcher, Dipartimento Chirurgico, Medico, Odontoiatrico e di Scienze Morfologiche con Interesse Trapiantologico, Oncologico e di Medicina Rigenerativa, Università degli Studi di Modena e Reggio Emilia, Modena, Italy; Network del Secondo Parere, Modena (MO), Italy
| | - C Laurino
- Biologist Researcher, Dipartimento Chirurgico, Medico, Odontoiatrico e di Scienze Morfologiche con Interesse Trapiantologico, Oncologico e di Medicina Rigenerativa, Università degli Studi di Modena e Reggio Emilia, Modena, Italy; Network del Secondo Parere, Modena (MO), Italy
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3
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Phanish MK, Heidebrecht F, Nabi ME, Shah N, Niculescu-Duvaz I, Dockrell MEC. The Regulation of TGFβ1 Induced Fibronectin EDA Exon Alternative Splicing in Human Renal Proximal Tubule Epithelial Cells. J Cell Physiol 2015; 230:286-95. [PMID: 24962218 DOI: 10.1002/jcp.24703] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 06/20/2014] [Indexed: 11/08/2022]
Abstract
The EDA+ splice variant of fibronectin (Fn) is an early and important component of the extracellular matrix in renal fibrosis. In this work, we investigate cellular mechanisms of EDA+Fn production in human primary proximal tubule epithelial cells (PTECs). TGFβ1-induced EDA+Fn production was assessed by immunocytochemistry, PCR, and Western blotting. SRp40 knockdown was achieved by siRNA. The role of the PI3 kinase-AKT signalling and splicing regulatory protein SRp40 in the production of EDA+Fn was studied by using the chemical inhibitor LY294002 and siRNA targeted to SRp40 respectively. Interaction between PI3 kinase-AKT signalling and SRp40 were assessed by immunofluorescence and immunoprecipitation. To assess the specificity of SRp40 in regulating the splicing of EDA+ exon, we studied the effect of SRp40 knockdown on TGFβ1 induced splicing of FGF receptor 2. Primary human PTECs expressed EDA+ and EDA- Fn. TGFβ1 treatment resulted in increases in the production and deposition of EDA+ Fn as well as an increase in the ratio of EDA+/EDA- Fn mRNA. The TGFβ1 induced EDA+ production was dependent on PI3 kinase-AKT signalling and SRp40 expression. Immunoprecipitation experiments demonstrated direct binding between AKT and SRp40 with an increase in the amount of SRp40 bound to AKT upon TGFβ1 treatment. TGFβ1 treatment resulted in reduction in the FGF receptor2 IIIb splice variant which was unaffected by SRp40 knockdown. In this work, we have presented the first evidence for the regulation of Fn pre-mRNA splicing by PI3 kinase-AKT signalling and SRp40 in human PTECs. Targeting the splicing of Fn pre-mRNA to skip the EDA exon is an attractive option to combat fibrosis.
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Affiliation(s)
- Mysore Keshavmurthy Phanish
- The South West Thames Institute for Renal Research, St. Helier Hospital, Wrythe Lane Carshalton, Surrey, SM5 1AA, UK
| | - Felicia Heidebrecht
- The South West Thames Institute for Renal Research, St. Helier Hospital, Wrythe Lane Carshalton, Surrey, SM5 1AA, UK
| | - Mohammad E Nabi
- The South West Thames Institute for Renal Research, St. Helier Hospital, Wrythe Lane Carshalton, Surrey, SM5 1AA, UK
| | - Nileshkumar Shah
- The South West Thames Institute for Renal Research, St. Helier Hospital, Wrythe Lane Carshalton, Surrey, SM5 1AA, UK
| | - Ioana Niculescu-Duvaz
- The South West Thames Institute for Renal Research, St. Helier Hospital, Wrythe Lane Carshalton, Surrey, SM5 1AA, UK
| | - Mark Edward Carl Dockrell
- The South West Thames Institute for Renal Research, St. Helier Hospital, Wrythe Lane Carshalton, Surrey, SM5 1AA, UK
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He X, Zhang P. Serine/arginine-rich splicing factor 3 (SRSF3) regulates homologous recombination-mediated DNA repair. Mol Cancer 2015; 14:158. [PMID: 26282282 PMCID: PMC4539922 DOI: 10.1186/s12943-015-0422-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 07/28/2015] [Indexed: 12/20/2022] Open
Abstract
Background Our previous work found that serine/arginine-rich splicing factor 3 (SRSF3) was overexpressed in human ovarian cancer and the overexpression of SRSF3 was required for ovarian cancer cell growth and survival. The mechanism underlying the role of SRSF3 in ovarian cancer remains to be addressed. Methods We conducted microarray analysis to profile the gene expression and splicing in SRSF3-knockdown cells and employed quantitative PCR and western blotting to validate the profiling results. We used chromatin immunoprecipitation to study transcription and the direct repeat green fluorescent protein reporter assay to study homologous recombination-mediated DNA repair (HRR). Results We identified 687 genes with altered expression and 807 genes with altered splicing in SRSF3-knockdown cells. Among expression-altered genes, those involved in HRR, including BRCA1, BRIP1 and RAD51, were enriched and were all downregulated. We demonstrated that the downregulation of BRCA1, BRIP1 and RAD51 expression was caused by decreased transcription and not due to increased nonsense-mediated mRNA decay. Further, we found that SRSF3 knockdown impaired HRR activity in the cell and increased the level of γ-H2AX, a biomarker for double-strand DNA breaks. Finally, we observed that SRSF3 knockdown changed splicing pattern of KMT2C, a H3K4-specific histone methyltransferase, and reduced the levels of mono- and trimethylated H3K4. Conclusion These results suggest that SRSF3 is a new regulator of HRR process, which possibly regulates the expression of HRR-related genes indirectly through an epigenetic pathway. This new function of SRSF3 not only explains why overexpression of SRSF3 is required for ovarian cancer cell growth and survival but also offers a new insight into the mechanism of the neoplastic transformation. Electronic supplementary material The online version of this article (doi:10.1186/s12943-015-0422-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiaolong He
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago-Rockford Campus, 1601 Parkview Avenue, Room N308, Rockford, IL, 61107, USA. .,University of Illinois Cancer Center, University of Illinois at Chicago, Chicago, IL, USA.
| | - Pei Zhang
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago-Rockford Campus, 1601 Parkview Avenue, Room N308, Rockford, IL, 61107, USA.
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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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Lopez-Mejia IC, De Toledo M, Della Seta F, Fafet P, Rebouissou C, Deleuze V, Blanchard JM, Jorgensen C, Tazi J, Vignais ML. Tissue-specific and SRSF1-dependent splicing of fibronectin, a matrix protein that controls host cell invasion. Mol Biol Cell 2013; 24:3164-76. [PMID: 23966470 PMCID: PMC3806663 DOI: 10.1091/mbc.e13-03-0142] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Matching sets of human primary fibroblasts cocultured with placenta explants are used to compare tissue capacities to support trophoblast invasion. Substituting endometrium with dermis dramatically reduces EVCT interstitial invasion, a phenomenon related to the ECM fibronectin content, FN alternative splicing, and expression of the SR protein SRSF1. Cell invasion targets specific tissues in physiological placental implantation and pathological metastasis, which raises questions about how this process is controlled. We compare dermis and endometrium capacities to support trophoblast invasion, using matching sets of human primary fibroblasts in a coculture assay with human placental explants. Substituting endometrium, the natural trophoblast target, with dermis dramatically reduces trophoblast interstitial invasion. Our data reveal that endometrium expresses a higher rate of the fibronectin (FN) extra type III domain A+ (EDA+) splicing isoform, which displays stronger matrix incorporation capacity. We demonstrate that the high FN content of the endometrium matrix, and not specifically the EDA domain, supports trophoblast invasion by showing that forced incorporation of plasma FN (EDA–) promotes efficient trophoblast invasion. We further show that the serine/arginine-rich protein serine/arginine-rich splicing factor 1 (SRSF1) is more highly expressed in endometrium and, using RNA interference, that it is involved in the higher EDA exon inclusion rate in endometrium. Our data therefore show a mechanism by which tissues can be distinguished, for their capacity to support invasion, by their different rates of EDA inclusion, linked to their SRSF1 protein levels. In the broader context of cancer pathology, the results suggest that SRSF1 might play a central role not only in the tumor cells, but also in the surrounding stroma.
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Affiliation(s)
- Isabel Cristina Lopez-Mejia
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR 5535/IFR122, Universities of Montpellier 1 and Montpellier 2, 34293 Montpellier Cedex 5, France Département de Physiologie, Université de Lausanne, CH-1015 Lausanne, Switzerland INSERM U844, Institut des Neurosciences de Montpellier, Centre Hospitalier Universitaire Saint Eloi, Université Montpellier 1, 34295 Montpellier Cedex 5, France Service Immuno-Rhumatologie, Centre Hospitalier Universitaire Lapeyronie, 34093 Montpellier Cedex, France
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Hallgren O, Malmström J, Malmström L, Andersson-Sjöland A, Wildt M, Tufvesson E, Juhasz P, Marko-Varga G, Westergren-Thorsson G. Splicosomal and serine and arginine-rich splicing factors as targets for TGF-β. FIBROGENESIS & TISSUE REPAIR 2012; 5:6. [PMID: 22541002 PMCID: PMC3472233 DOI: 10.1186/1755-1536-5-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 04/28/2012] [Indexed: 11/29/2022]
Abstract
Background Transforming growth factor-β1 (TGF-β1) is a potent regulator of cell growth and differentiation. TGF-β1 has been shown to be a key player in tissue remodeling processes in a number of disease states by inducing expression of extracellular matrix proteins. In this study a quantitative proteomic analysis was undertaken to investigate if TGF-β1 contributes to tissue remodeling by mediating mRNA splicing and production of alternative isoforms of proteins. Methodology/Principal findings The expression of proteins involved in mRNA splicing from TGF-β1-stimulated lung fibroblasts was compared to non-stimulated cells by employing isotope coded affinity tag (ICATTM) reagent labeling and tandem mass spectrometry. A total of 1733 proteins were identified and quantified with a relative standard deviation of 11% +/− 8 from enriched nuclear fractions. Seventy-six of these proteins were associated with mRNA splicing, including 22 proteins involved in splice site selection. In addition, TGF-β1 was observed to alter the relative expression of splicing proteins that may be important for alternative splicing of fibronectin. Specifically, TGF-β1 significantly induced expression of SRp20, and reduced the expression of SRp30C, which has been suggested to be a prerequisite for generation of alternatively spliced fibronectin. The induction of SRp20 was further confirmed by western blot and immunofluorescence. Conclusions The results show that TGF-β1 induces the expression of proteins involved in mRNA splicing and RNA processing in human lung fibroblasts. This may have an impact on the production of alternative isoforms of matrix proteins and can therefore be an important factor in tissue remodeling and disease progression.
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Affiliation(s)
- Oskar Hallgren
- Department of Experimental Medical Science, Lund University, Lund, Sweden.
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Kozyrev SV, Bernal-Quirós M, Alarcón-Riquelme ME, Castillejo-López C. The dual effect of the lupus-associated polymorphism rs10516487 on BANK1 gene expression and protein localization. Genes Immun 2011; 13:129-38. [PMID: 21900951 DOI: 10.1038/gene.2011.62] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Numerous loci have been found genetically associated with complex diseases, but only in a few cases has the functional variant and the molecular mechanism behind it been identified. Recently, the association of the BANK1 gene with systemic lupus erythematosus (SLE) was described. Here, we investigated the role of the associated polymorphisms on gene function and found that SNP rs17266594 located in the branch point consensus sequence has negligible effect on splicing or gene expression. The non-synonymous SNP rs10516487 located in exon 2 influenced splicing efficiency by creating an exonic splicing enhancer site for the SRp40 factor. Further, this same SNP generates protein isoforms with differential and measurable self-association properties. The full-length protein isoform containing the R61 variant forms larger protein scaffold complexes in the cell cytoplasm compared with the protective BANK1-61H variant. We also observed that, contrary to the full-length isoforms, the short Δ2 isoform of BANK1 displays a homogeneous cytoplasmic distribution, underscoring the potential role of the exon 2-coded protein domain in the scaffolding function of BANK1. We provide evidence that the non-synonymous SNP rs10516487 (G>A; R61H) shows a dual nature by first, influencing mRNA splicing and consequently the quantity of protein, and, second, by producing a risk variant-containing protein isoform with increased potential for multimerization.
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Affiliation(s)
- S V Kozyrev
- Department of Medical Biochemistry and Microbiology, BMC, Uppsala University, Uppsala, Sweden
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Differences between the early and advanced stages of rheumatoid arthritis in the expression of EDA-containing fibronectin. Rheumatol Int 2009; 29:1397-401. [DOI: 10.1007/s00296-009-0866-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 01/09/2009] [Indexed: 11/25/2022]
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10
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Liang H, Tuan RS, Norton PA. Overexpression of SR proteins and splice variants modulates chondrogenesis. Exp Cell Res 2007; 313:1509-17. [PMID: 16140295 DOI: 10.1016/j.yexcr.2005.07.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Revised: 07/26/2005] [Accepted: 07/26/2005] [Indexed: 11/19/2022]
Abstract
Fibronectin alternative exon EIIIA is largely included in undifferentiated mesenchymal cells of the developing limb bud, whereas the exon is excluded in differentiated chondrocytes. Inclusion of exon EIIIA in chondrocytic cells is increased by overexpression of SRp40, and, to a lesser extent, SRp75, but not SRp55. RT-PCR analysis using real-time PCR revealed that the levels of the mRNAs for these three proteins did not vary significantly in chick chondrocytes versus mesenchymal cells of the developing limb bud. However, a variant spliced form of SRp40, termed, SRp40LF, is detected preferentially in chondrocytes and in chondrifying mesenchymal cells. Forced overexpression of SRp40 or SRp75, but not SRp55, enhanced chondrogenic differentiation of chick limb mesenchymal cells in a high-density micromass assay. Overexpression of SRp40LF, which produces a truncated form of SRp40, also was strongly pro-chondrogenic. In a HeLa cell-based assay, SRp40LF fails to substitute for SRp40 in mediating an increase in exon EIIIA inclusion, suggesting that the latter event is not essential for the pro-chondrogenic effect. These results demonstrate the ability of these highly conserved splicing factors to modulate chondrogenesis and are consistent with earlier results that implicated exon EIIIA-containing isoforms of fibronectin in formation of chondrogenic condensations.
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Affiliation(s)
- Hongyan Liang
- Department of Biochemistry and Molecular Pharmacology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Han F, Gilbert JR, Harrison G, Adams CS, Freeman T, Tao Z, Zaka R, Liang H, Williams C, Tuan RS, Norton PA, Hickok NJ. Transforming growth factor-beta1 regulates fibronectin isoform expression and splicing factor SRp40 expression during ATDC5 chondrogenic maturation. Exp Cell Res 2007; 313:1518-32. [PMID: 17391668 PMCID: PMC1920702 DOI: 10.1016/j.yexcr.2007.01.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2005] [Revised: 01/09/2007] [Accepted: 01/17/2007] [Indexed: 11/28/2022]
Abstract
Fibronectin (FN) isoform expression is altered during chondrocyte commitment and maturation, with cartilage favoring expression of FN isoforms that includes the type II repeat extra domain B (EDB) but excludes extra domain A (EDA). We and others have hypothesized that the regulated splicing of FN mRNAs is necessary for the progression of chondrogenesis. To test this, we treated the pre-chondrogenic cell line ATDC5 with transforming growth factor-beta1, which has been shown to modulate expression of the EDA and EDB exons, as well as the late markers of chondrocyte maturation; it also slightly accelerates the early acquisition of a sulfated proteoglycan matrix without affecting cell proliferation. When chondrocytes are treated with TGF-beta1, the EDA exon is preferentially excluded at all times whereas the EDB exon is relatively depleted at early times. This regulated alternative splicing of FN correlates with the regulation of alternative splicing of SRp40, a splicing factor facilitating inclusion of the EDA exon. To determine if overexpression of the SRp40 isoforms altered FN and FN EDA organization, cDNAs encoding these isoforms were overexpressed in ATDC5 cells. Overexpression of the long-form of SRp40 yielded an FN organization similar to TGF-beta1 treatment; whereas overexpression of the short form of SRp40 (which facilitates EDA inclusion) increased formation of long-thick FN fibrils. Therefore, we conclude that the effects of TGF-beta1 on FN splicing during chondrogenesis may be largely dependent on its effect on SRp40 isoform expression.
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Affiliation(s)
- Fei Han
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - James R. Gilbert
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Gerald Harrison
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Christopher S. Adams
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Theresa Freeman
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Zhuliang Tao
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Raihana Zaka
- Division of Rheumatology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Hongyan Liang
- Department of Biochemistry & Molecular Pharmacology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Charlene Williams
- Department of Biochemistry & Molecular Pharmacology, Thomas Jefferson University, Philadelphia, Pennsylvania
- Division of Rheumatology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Rocky S. Tuan
- Cartilage Biology and Orthopaedics Branch, NIAMS, NIH, Bethesda, MD
| | - Pamela A. Norton
- Department of Biochemistry & Molecular Pharmacology, Thomas Jefferson University, Philadelphia, Pennsylvania
- Jefferson Center for Biomedical Research, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Noreen J. Hickok
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania
- ‡ To Whom Correspondence Should be Addressed: Noreen J. Hickok, Ph.D., Department of Orthopaedic Surgery, Thomas Jefferson University, 1015 Walnut St., Suite 501, Philadelphia, PA 19107, Tel: 215-955-6979, Fax: 215-955-4317, e-mail:
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Massiello A, Chalfant CE. SRp30a (ASF/SF2) regulates the alternative splicing of caspase-9 pre-mRNA and is required for ceramide-responsiveness. J Lipid Res 2006; 47:892-7. [PMID: 16505493 DOI: 10.1194/jlr.c600003-jlr200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Two splice variants are derived from the caspase-9 gene, proapoptotic caspase-9a and antiapoptotic caspase-9b, by either the inclusion or exclusion of an exon 3, 4, 5, and 6 cassette. Previous studies from our laboratory have shown that the alternative splicing of caspase-9 and the phosphorylation status of SR proteins, a conserved family of splicing factors, are regulated by chemotherapy and ceramide via the action of protein phosphatase-1. In this study, a link between ceramide, SR proteins, and the alternative splicing of caspase-9 was established. The downregulation of SRp30a in A549 cells by RNA interference technology resulted in an increase in the caspase-9b splice variant, with a concomitant decrease in the caspase-9a splice variant, thereby significantly decreasing the caspase-9a/9b ratio from 1.67 +/- 0.11 to 0.56 +/- 0.08 (P < 0.005). The specific downregulation of SRp30a also inhibited the ability of exogenous ceramide treatment to induce the inclusion of the exon 3, 4, 5, and 6 cassette. Therefore, we have identified SRp30a as an RNA trans-acting factor that functions as a major regulator of caspase-9 pre-mRNA processing and is required for ceramide to mediate the alternative splicing of caspase-9.
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Affiliation(s)
- Autumn Massiello
- Department of Biochemistry, Virginia Commonwealth University, Richmond, 23298, USA
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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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Han F, Adams CS, Tao Z, Williams CJ, Zaka R, Tuan RS, Norton PA, Hickok NJ. Transforming growth factor-β1 (TGF-β1) regulates ATDC5 chondrogenic differentiation and fibronectin isoform expression. J Cell Biochem 2005; 95:750-62. [PMID: 15832361 DOI: 10.1002/jcb.20427] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Regulated splicing of fibronectin (FN) occurs during the mesenchymal to chondrocyte transition and ultimately results in the relative enrichment of an extra domain B (EDB) exon-containing FN isoform with the suggestion that FN isoforms may play a functional role in chondrogenesis. Promotion of chondrogenesis can also be achieved by treatment with transforming growth factor-beta (TGF-beta), which also regulates FN isoform expression. We have examined the effects of TGF-beta treatment on the assumption of the chondrogenic phenotype in the teratoma-derived cell line ATDC5 and tested whether these effects on chondrogenesis are paralleled by appropriate changes in FN isoform expression. ATDC5 cells were maintained in a pre-chondrogenic state and, in this state, treated with 10 ng/ml TGF-beta. The cells started to elaborate a matrix rich in sulfated proteoglycans, such that within the first 12 days of culture, TGF-beta1 treatment appeared to slightly accelerate early acquisition of an Alcian blue-stained matrix, and caused a dose- and time-dependent decrease in collagen type I expression; changes in collagen type II expression were variable. At later times, cells treated with TGF-beta became indistinguishable from those of the controls. Interestingly, TGF-beta treatment caused a significant dose- and time-dependent decrease in the proportion of FN containing the extra domain A (EDA) and the EDB exons. These data suggest that TGF-beta induces the early stages of chondrogenic maturation in this pre-chondrogenic line and that TGF-beta treatment increases expression of FN isoforms that lack the EDA and EDB exons.
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Affiliation(s)
- Fei Han
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Flanagan M, Liang H, Norton PA. Alternative splicing of fibronectin mRNAs in chondrosarcoma cells: role of far upstream intron sequences. J Cell Biochem 2004; 90:709-18. [PMID: 14587027 DOI: 10.1002/jcb.10687] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The fibronectin (FN) gene encodes multiple mRNAs through the process of alternative splicing, and production of certain isoforms is characteristic of a given cell type. Chondrocytes produce FNs that completely lack alternative exon EIIIA, and loss of inclusion of the exon is tightly linked to chondrogenic condensation of mesenchymal cells. The inclusion of a second exon, EIIIB, is high in embryonic cartilage, but declines with age. Multiple exons are omitted to produce the (V + C)-form that is highly specific for cartilage and chondrocytes. A rat chondrosarcoma cell line, RCS, was identified that preserves key features of the cartilage-specific splicing phenotype. RCS cells, which exclude exon EIIIA, and HeLa cells, which include exon EIIIA similar to mesenchymal cells, were used to assess the contribution of intron sequences flanking exon EIIIA to splicing regulation. Deletion of most of the intron downstream of the exon had little effect on splicing in either cell type. However, deletions within upstream intron 32-A reduced inclusion of the alternative exon in both cell types. The sequences involved lie more than 200 nucleotides away from the exon, but could not be localized to a single region by deletion mapping. These intronic sequences contribute to the efficiency of exon EIIIA recognition, but not to cell-type specific regulation. The normally inhibitory factor polypyrimidine tract binding protein promotes exon EIIIA inclusion in a manner that is partially dependent on the regulatory sequences within intron 32-A.
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Affiliation(s)
- Matthew Flanagan
- Jefferson Center for Biomedical Research and Department of Biochemistry and Molecular Pharmacology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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Buratti E, Muro AF, Giombi M, Gherbassi D, Iaconcig A, Baralle FE. RNA folding affects the recruitment of SR proteins by mouse and human polypurinic enhancer elements in the fibronectin EDA exon. Mol Cell Biol 2004; 24:1387-400. [PMID: 14729981 PMCID: PMC321440 DOI: 10.1128/mcb.24.3.1387-1400.2004] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In humans, inclusion or exclusion of the fibronectin EDA exon is mainly regulated by a polypurinic enhancer element (exonic splicing enhancer [ESE]) and a nearby silencer element (exonic splicing silencer [ESS]). While human and mouse ESEs behave identically, mutations introduced into the homologous mouse ESS sequence result either in no change in splicing efficiency or in complete exclusion of the exon. Here, we show that this apparently contradictory behavior cannot be simply accounted for by a localized sequence variation between the two species. Rather, the nucleotide differences as a whole determine several changes in the respective RNA secondary structures. By comparing how the two different structures respond to homologous deletions in their putative ESS sequences, we show that changes in splicing behavior can be accounted for by a differential ESE display in the two RNAs. This is confirmed by RNA-protein interaction analysis of levels of SR protein binding to each exon. The immunoprecipitation patterns show the presence of complex multi-SR protein-RNA interactions that are lost with secondary-structure variations after the introduction of ESE and ESS variations. Taken together, our results demonstrate that the sequence context, in addition to the primary sequence identity, can heavily contribute to the making of functional units capable of influencing pre-mRNA splicing.
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Affiliation(s)
- Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology, I-34012 Trieste, Italy
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McAlinden A, Havlioglu N, Sandell LJ. Regulation of protein diversity by alternative pre-mRNA splicing with specific focus on chondrogenesis. ACTA ACUST UNITED AC 2004; 72:51-68. [PMID: 15054904 DOI: 10.1002/bdrc.20004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Analysis of the human genome has dramatically demonstrated that the majority of protein diversity is generated by alternative splicing of pre-mRNA. This powerful and versatile mechanism controls the synthesis of functionally different protein isoforms that may be required during specific stages of development from a single gene. Consequently, ubiquitous and/or tissue-specific RNA splicing factors that regulate this splicing mechanism provide the basis for defining phenotypic characteristics of cells during differentiation. In this review, we will introduce the basic mechanisms of pre-mRNA alternative splicing, describe how this process is regulated by specific RNA splicing factors, and relate this to various systems of cell differentiation. Chondrogenesis, a well-defined differentiation pathway necessary for skeletogenesis, will be discussed in detail, with focus on some of the alternatively-spliced proteins known to be expressed during cartilage development. We propose a heuristic view that, ultimately, it is the regulation of these RNA splicing factors that determines the differentiation status of a cell. Studying regulation at the level of pre-mRNA alternative splicing will provide invaluable insights into how many developmental mechanisms are controlled, thus enabling us to manipulate a system to select for a specific differentiation pathway.
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Affiliation(s)
- Audrey McAlinden
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri, USA
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Xu Q, Leung DYM, Kisich KO. Serine-arginine-rich protein p30 directs alternative splicing of glucocorticoid receptor pre-mRNA to glucocorticoid receptor beta in neutrophils. J Biol Chem 2003; 278:27112-8. [PMID: 12738786 DOI: 10.1074/jbc.m300824200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glucocorticoid (GC) insensitivity is a major clinical challenge in the treatment of many inflammatory diseases. It has been shown previously that GC insensitivity, in several inflammatory cell types, is due to an overabundance of the beta isoform of the glucocorticoid receptor (GCRbeta) relative to the ligand binding isoform, GCRalpha. GCRbeta functions as a dominant inhibitor of GCRalpha action. A number of GCR isoforms are created from the same pre-mRNA transcript via alternative splicing, and the factor or factors that control alternative splicing of GCR pre-mRNA are of great importance. In the current study, we have identified the predominant alternative splicing factor present in human neutrophils, which is known to be exceptionally GC-insensitive. The predominant alternative splicing factor in neutrophils is SRp30c, which is one of several highly conserved serine-arginine-rich (SR) proteins that are involved in both constitutive and alternative splicing in eukaryotic cells. Inhibition of SRp30c expression with antisense oligonucleotide strongly inhibited expression of GCRbeta and stimulated expression of GCRalpha. Antisense molecules targeted to other SR proteins had no effect. Our data indicate that SRp30c is necessary for alternative splicing of the GCR pre-mRNA to create mRNA encoding GCRbeta.
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Affiliation(s)
- Qing Xu
- Division of Pediatric Allergy/Immunology, National Jewish Medical and Research Center, Department of Pediatrics, Denver, Colorado 80206, USA
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Jagiello P, Hammans C, Wieczorek S, Arning L, Stefanski A, Strehl H, Epplen JT, Gencik M. A novel splice site mutation in the TRIM37 gene causes mulibrey nanism in a Turkish family with phenotypic heterogeneity. Hum Mutat 2003; 21:630-5. [PMID: 12754710 DOI: 10.1002/humu.10220] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mulibrey nanism (muscle-liver-brain-eye nanism; MUL) is an autosomal recessively transmitted disease characterized by severe growth delays of prenatal onset caused by mutations in the TRIM37 gene. Recent studies on the subcellular localization revealed that the TRIM37 (KIAA0898) protein is located in peroxisomes. Therefore, MUL has been classified as a new peroxisomal disorder. Up to now, four mutations have been reported, all of which lead to frameshifts and truncated proteins. In this study, mutation screening was performed for the coding region of the TRIM37 gene in a Turkish family by means of RT-PCR and direct cDNA sequencing. We have identified a novel mutation resulting in a frameshift cosegregating within the family. Finally, we report on the presence of novel splice variants observed in lymphoblastoid cells and muscle tissue of normal subjects and patients.
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Affiliation(s)
- P Jagiello
- Human Genetics, Ruhr-University, Bochum, Germany.
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