Detecção de splicing alternativo Durante epitelial-mesenquimal Transição
Summary
Alternative splicing regulation has been shown to contribute to the epithelial-mesenchymal transition (EMT), an essential cellular program in various physiological and pathological processes. Here we describe a method utilizing an inducible EMT model for the detection of alternative splicing during EMT.
Abstract
Alternative splicing plays a critical role in the epithelial-mesenchymal transition (EMT), an essential cellular program that occurs in various physiological and pathological processes. Here we describe a strategy to detect alternative splicing during EMT using an inducible EMT model by expressing the transcription repressor Twist. EMT is monitored by changes in cell morphology, loss of E-cadherin localization at cell-cell junctions, and the switched expression of EMT markers, such as loss of epithelial markers E-cadherin and γ-catenin and gain of mesenchymal markers N-cadherin and vimentin. Using isoform-specific primer sets, the alternative splicing of interested mRNAs are analyzed by quantitative RT-PCR. The production of corresponding protein isoforms is validated by immunoblotting assays. The method of detecting splice isoforms described here is also suitable for the study of alternative splicing in other biological processes.
Introduction
A transição epitelial-mesenquimal (EMT) é um programa de desenvolvimento que impulsiona a morfogênese de órgãos e remodelação do tecido durante a embriogênese. Quando activados anormalmente, EMT promove a metástase do tumor e órgão fibrose 1,2. Obrigando estudos descreveram a importância da regulação da transcrição durante o processo de EMT, definida por vários factores de transcrição, tais como torção, Snail, e ZEB, que reprimem a expressão da proteína de junção aderente E-caderina, que resultam na perda de um cobble- pedra, como morfologia epitelial e ganho de um fenótipo mesenquimal fusiforme 3-8. Estudos recentes por meio de análise de todo o genoma de ARN revelou que existe um grupo de genes cujos padrões de splicing estão associadas quer epiteliais ou mesenquimais fenótipos 9,10. Trabalho de nosso laboratório de funcionalmente ligados splicing alternativo e EMT. Ao estudar a molécula de adesão de superfície celular CD44, foi demonstrado que CD44 alternative splicing é rigidamente controlado durante a EMT, e mais importante, que isoforma CD44 emenda comutação causalmente contribui para EMT 11.
O splicing alternativo representa um modelo disseminado e conservada da regulação de genes, tal como até 95% de genes de multi-exões humanos são de splicing alternativo 12-14. Através da produção de vários produtos de proteínas a partir de um único gene, o splicing alternativo constitui um mecanismo essencial para a diversidade de proteínas, a adição de uma outra camada de complexidade para o genoma humano. Como tal, a desregulação de splicing alternativo pode potencialmente levar a profundos efeitos biológicos que causam doenças humanas. Na verdade, o splicing alternativo aberrante em doenças tem sido documentada por mais de uma década de 15-25, incluindo as recentes descobertas de que as mutações em genes que codificam a maquinaria spliceosome são comumente encontrados em síndromes mielodisplásicas 26-28. Portanto, o desenvolvimento de métodos confiáveis para a detecção de i de splicing alternativosoforms é de grande importância no estudo de processos biológicos diversos, incluindo EMT.
Aqui nós fornecemos um protocolo para detectar mudanças no splicing alternativo utilizando um modelo EMT induzida. Os métodos para a concepção de iniciadores de PCR e detectar as isoformas de splicing são adequadas não apenas para o estudo de splicing alternativo durante EMT, mas também para o estudo de splicing alternativo em outros processos biológicos. Investigando splicing alternativo durante EMT é imprescindível, a fim de compreender melhor os mecanismos da EMT ea metástase do tumor, facilitando, assim, o desenvolvimento de estratégias eficazes para tratar a metástase do câncer.
Protocol
Representative Results
Discussion
O processo aqui descrito permite a detecção de splicing alternativo de um modelo de EMT indutível. Como tal, as alterações dinâmicas de emenda de expressão da isoforma pode ser captado em todo o curso de tempo de EMT. Este método tem vantagens sobre o uso de diferentes epithelial- ou linhas de células-representando mesenquimais para a comparação de splicing alternativo, porque origens genéticas distintas de linhas celulares relacionadas un poderia influenciar indevidamente splicing alternativo. No entanto, a…
Declarações
The authors have nothing to disclose.
Acknowledgements
The authors would like to acknowledge Wensheng Liu for invaluable help with cell imaging. This work was supported by grants from the US National Institutes of Health (R01 CA182467), American Cancer Society (RSG-09-252-01-RMC), Lynn Sage Foundation, and A Sister’s Hope Foundation.
Materials
| Name of the reagent | Company | Catalogue number | Comments (optional) |
| 4-hydroxytamoxifen | Sigma | H7904 | Make stock solution by dissolving in ethanol to 200μM, and keep at -20℃ protected from light. |
| E.Z.N.A. Total RNA Isolation kit | Omega Bio-Tek | R6731 | Total RNA isolation kit |
| GoScript Reverse Transcription System | Promega | A5001 | Reagent for qRT-PCR assay |
| GoTaq qPCR Master Mix | Promega | A6002 | Reagent for qRT-PCR assay |
| LightCycler 480 Real-Time PCR System | Roche | Equipment for qRT-PCR assay | |
| CD44 antibody | R&D Systems | BBA10 | 1:1000 dilution |
| E-cadherin antibody | Cell Signaling Technology | 4065 | 1:2500 dilution for immunoblotting; 1:50 dilution for immunofluorescence |
| γ-catenin antibody | Cell Signaling Technology | 2309 | 1:1000 dilution |
| occludin antibody | Santa Cruz Biotechnology Inc. | sc-5562 | 1:500 dilution |
| fibronectin antibody | BD Transduction Laboratories | 610077 | 1:5000 dilution |
| N-cadherin antibody | BD Transduction Laboratories | 610920 | 1:2000 dilution |
| vimentin antibody | NeoMarkers | MS-129-p1 | 1:500 dilution |
| GAPDH antibody | Millipore Corporation | MAB374 | 1:10000 dilution |
| Amasham ECL Western blotting detection reagent | GE Health Life Science | RPN2209 | Chemiluminescence system |
Referências
- Thiery, J. P., Sleeman, J. P. Complex networks orchestrate epithelial-mesenchymal transitions. Nat Rev Mol Cell Biol. 7, 131-142 (2006).
- Yang, J., Weinberg, R. A. Epithelial-mesenchymal transition at the crossroads of development and tumor metastasis. Dev Cell. 14, 818-829 (2008).
- Yang, J., et al. a master regulator of morphogenesis, plays an essential role in tumor metastasis. Cell. 117, 927-939 (2004).
- Batlle, E., et al. The transcription factor snail is a repressor of E-cadherin gene expression in epithelial tumour cells. Nat Cell Biol. 2, 84-89 (2000).
- Cano, A., et al. The transcription factor snail controls epithelial-mesenchymal transitions by repressing E-cadherin expression. Nat Cell Biol. 2, 76-83 (2000).
- Comijn, J., et al. The two-handed E box binding zinc finger protein SIP1 downregulates E-cadherin and induces invasion. Mol Cell. 7, 1267-1278 (2001).
- Bolos, V., et al. The transcription factor Slug represses E-cadherin expression and induces epithelial to mesenchymal transitions: a comparison with Snail and E47 repressors. J Cell Sci. 116, 499-511 (2003).
- Eger, A., et al. DeltaEF1 is a transcriptional repressor of E-cadherin and regulates epithelial plasticity in breast cancer cells. Oncogene. 24, 2375-2385 (2005).
- Shapiro, I. M., et al. An EMT-driven alternative splicing program occurs in human breast cancer and modulates cellular phenotype. PLoS Genet. 7, e1002218 (2011).
- Warzecha, C. C., et al. An ESRP-regulated splicing programme is abrogated during the epithelial-mesenchymal transition. EMBO J. 29, 3286-3300 (2010).
- Brown, R. L., et al. CD44 splice isoform switching in human and mouse epithelium is essential for epithelial-mesenchymal transition and breast cancer progression. J Clin Invest. 121, 1064-1074 (2011).
- Wang, E. T., et al. Alternative isoform regulation in human tissue transcriptomes. Nature. 456, 470-476 (2008).
- Pan, Q., Shai, O., Lee, L. J., Frey, B. J., Blencowe, B. J. Deep surveying of alternative splicing complexity in the human transcriptome by high-throughput sequencing. Nat Genet. 40, 1413-1415 (2008).
- Liu, S., Cheng, C. Alternative RNA splicing and cancer. Wiley Interdiscip Rev RNA. 4, 547-566 (2013).
- Shtivelman, E., Lifshitz, B., Gale, R. P., Roe, B. A., Canaani, E. Alternative splicing of RNAs transcribed from the human abl gene and from the bcr-abl fused gene. Cell. 47, 277-284 (1986).
- Krangel, M. S. Secretion of HLA-A and -B antigens via an alternative RNA splicing pathway. J Exp Med. 163, 1173-1190 (1986).
- Brickell, P. M., Latchman, D. S., Murphy, D., Willison, K., Rigby, P. W. Activation of a Qa/Tla class I major histocompatibility antigen gene is a general feature of oncogenesis in the mouse. Nature. 306, 756-760 (1983).
- Barbaux, S., et al. Donor splice-site mutations in WT1 are responsible for Frasier syndrome. Nat Genet. 17, 467-470 (1997).
- Charlet, B. N., et al. Loss of the muscle-specific chloride channel in type 1 myotonic dystrophy due to misregulated alternative splicing. Mol Cell. 10, 45-53 (2002).
- Hutton, M., et al. Association of missense and 5′-splice-site mutations in tau with the inherited dementia FTDP-17. Nature. 393, 702-705 (1998).
- Kohsaka, T., et al. Exon 9 mutations in the WT1 gene, without influencing KTS splice isoforms, are also responsible for Frasier syndrome. Hum Mutat. 14, 466-470 (1999).
- Philips, A. V., Timchenko, L. T., Cooper, T. A. Disruption of splicing regulated by a CUG-binding protein in myotonic dystrophy. Science. 280, 737-741 (1998).
- Savkur, R. S., Philips, A. V., Cooper, T. A. Aberrant regulation of insulin receptor alternative splicing is associated with insulin resistance in myotonic dystrophy. Nat Genet. 29, 40-47 (2001).
- Spillantini, M. G., et al. Mutation in the tau gene in familial multiple system tauopathy with presenile dementia. Proc Natl Acad Sci USA. 95, 7737-7741 (1998).
- Wang, J., et al. Myotonic dystrophy evidence for a possible dominant-negative RNA mutation. Hum Mol Genet. 4, 599-606 (1995).
- Graubert, T. A., et al. Recurrent mutations in the U2AF1 splicing factor in myelodysplastic syndromes. Nat Genet. 44, 53-57 (2012).
- Papaemmanuil, E., et al. Somatic SF3B1 mutation in myelodysplasia with ring sideroblasts. N Engl J Med. 365, 1384-1395 (2011).
- Yoshida, K., et al. Frequent pathway mutations of splicing machinery in myelodysplasia. Nature. 478, 64-69 (2011).
- Mani, S. A., et al. The epithelial-mesenchymal transition generates cells with properties of stem cells. Cell. 133, 704-715 (2008).
- Reinke, L. M., Xu, Y., Cheng, C. Snail represses the splicing regulator epithelial splicing regulatory protein 1 to promote epithelial-mesenchymal transition. J Biol Chem. 287, 36435-36442 (2012).
- Serini, G., Gabbiani, G. Mechanisms of myofibroblast activity and phenotypic modulation. Exp Cell Res. 250, 273-283 (1999).
- Zavadil, J., Bottinger, E. P. TGF-beta and epithelial-to-mesenchymal transitions. Oncogene. 24, 5764-5774 (2005).
- Pfaffl, M. W. A new mathematical model for relative quantification in real-time RT-PCR. Nucleic Acids Res. 29, e45 (2001).
- Hellemans, J., Mortier, G., De Paepe, A., Speleman, F., Vandesompele, J. qBase relative quantification framework and software for management and automated analysis of real-time quantitative PCR data. Genome Biol. 8, R19 (2007).
- Boutz, P. L., et al. A post-transcriptional regulatory switch in polypyrimidine tract-binding proteins reprograms alternative splicing in developing neurons. Genes Dev. 21, 1636-1652 (2007).
- Salomonis, N., et al. Alternative splicing regulates mouse embryonic stem cell pluripotency and differentiation. Proc Natl Acad Sci USA. 107, 10514-10519 (2010).
- Calarco, J. A., et al. Regulation of vertebrate nervous system alternative splicing and development by an SR-related protein. Cell. 138, 898-910 (2009).
- Grabowski, P. Alternative splicing takes shape during neuronal development. Curr Opin Genet Dev. 21, 388-394 (2011).
- Seol, D. W., Billiar, T. R. A caspase-9 variant missing the catalytic site is an endogenous inhibitor of apoptosis. J Biol Chem. 274, 2072-2076 (1999).
- Srinivasula, S. M., et al. Identification of an endogenous dominant-negative short isoform of caspase-9 that can regulate apoptosis. Cancer Res. 59, 999-1002 (1999).
- Akgul, C., Moulding, D. A., Edwards, S. W. Alternative splicing of Bcl-2-related genes functional consequences and potential therapeutic applications. Cell Mol Life Sci. 61, 2189-2199 (2004).
- Cooper, T. A. Use of minigene systems to dissect alternative splicing elements. Methods. 37, 331-340 (2005).
- Cheng, C., Sharp, P. A. Regulation of CD44 alternative splicing by SRm160 and its potential role in tumor cell invasion. Mol Cell Biol. 26, 362-370 (2006).
