Name: rna-seq analysis of differential gene expression in electroporated chick embryonic spinal cord
Uploaded: 2014-11-01T14:00:00.000+00:00
Duration: 11 min 13 s
Description: Watch this Scientific Journal Video about RNA-Seq Analysis of Differential Gene Expression in Electroporated Chick Embryonic Spinal Cord at JoVE.com

CYIY is supported by FAPESP (2012/14421-5) and FMV is supported by a fellowship from FAPESP (2009/53695-0). We thank the DNA Technologies Core at University of California, Davis for preparation and sequencing of the RNA-Seq libraries used in this work, the Galaxy team for providing an excellent and free interface for high-throughput sequencing data analysis tools and Dr. Marianne Bronner for allowing us to film in her laboratory space.

1. electroporate do construto de interesse nos tubos neurais da HH12-13 frango embriões no ovo Usar um repórter fluorescente, de preferência, em uma transcrição bicistrï¿½ica ou fundido com a proteína de interesse com um péptido intercalante 2a viral 11, para permitir uma rápida identificação de indivíduos com níveis satisfatórios de transfecção. NOTA: O tempo de incubação típico para esta fase é de cerca de 48 horas a 37,8 ° C. <ol><li> Abrir uma pequena janela em que os ovos após a remoção de 3 ml de albumina com uma seringa acoplada a um 18 G x 1 1/2 agulha. Para melhorar a visualização do embrião, injetar uma pequena quantidade de tinta nanquim diluída 1:50 em solução de Ringer estéril sob o embrião 1-4. </li><li> Depois de cobrir o embrião com a solução estéril de Ringer, injectar uma solução de 10 mM Tris-HCl, pH 8,2 e 0,1% Corante Alimentar (F, D e C) contendo 2,5 mg / mL de ADN através da extremidade posterior do tubo neural, até que preenchaaté a região hindbrain. Para electroporate, eletrodos de platina posição (0,5 milímetros de diâmetro) separados por quatro milímetros ao longo de uma região do flanco e entregar cinco pulsos de 50 ms e 20 V com um intervalo de 100 ms entre eles 4. </li><li> Após eletroporação, incubar os embriões manipulados por 48 horas mais até atingirem estágio HH23 e identificar indivíduos com alto nível de transfecção na região flanco sob microscópio estereoscópico fluorescente. NOTA: A duração da incubação após a electroporação depende do objectivo da experiência. Os plasmídeos eletroporados pode gerar níveis de expressão significativa após 2 horas 2. Assim, se o interesse reside nos genes de início precoce do período de incubação pós-electroporação pode ser reduzida. </li></ol> 2. Colheita sucesso Transfected Embriões e dissecar as Metades Medula Espinhal electroporados NOTA: Este procedimento dura 2-3 horas para cada 10 embriões e rendimentos 1-2 Ug de RNA total por embrião. A dissecção de tubos neurais requer movimentos finos e algumas sessões de prática pode ser necessária antes de aplicá-lo a amostras experimentais. <ol><li> Descontaminar instrumentos de dissecação metálicas com solução de descontaminação de RNase ou por cozedura a 150 ° C durante 4 h 12 e preparar tratada com DEPC PBS. Use somente novo plasticware livre de RNase certificado. NOTA: Após a colheita, é importante seguir o tratamento padrão para evitar a contaminação RNase durante a dissecção. </li><li> Colher os embriões usando um par de tesouras de dissecação multa e uma colher coleção peneirada. Manter os embriões no frio tratada com DEPC PBS numa placa de Petri de 100 milímetros. </li><li> Com um par de pinças finas, cortar a região do flanco inteiro (entre o limite posterior do broto de membro anterior eo limite anterior do broto de membro posterior) e transfira esta seção para um novo prato contendo frio tratados com DEPC PBS. </li><li> Use duas agulhas de vidro finos para perfurar em três diferentesaponta em cada lado dorsolateral do embrião entre o tubo neural e da mesoderme paraxial. </li><li> Introduzir as duas agulhas de vidro na perfuração central e mover-se lentamente uma delas distância ao longo do tubo do eixo ântero-posterior neural. Repita esse procedimento para as perfurações que não foram alcançados pelos primeiros movimentos. Retire a mesoderme paraxial isolada com um par de pinças finas. </li><li> Ligue o embrião lateralmente, inserir as pontas das pinças entre o tubo neural e da notocorda e deslizá-los em sentidos opostos ao longo do eixo ântero-posterior para separar as duas estruturas. NOTA: Este também deve remover a maior parte da mesoderme ainda ligado ao tubo neural. </li><li> Se necessário, retire todos os pedaços maiores de tecido mesodérmica que permanecem ligados puxando com um par de pinças, enquanto levemente segurando o tubo neural com outro par de pinças. Quando terminar, gentilmente transferir o tubo neural para outro prato contendo frio tratados com DEPC PBS usando umLivre de RNase pipeta de Pasteur de vidro acoplado a uma bomba de pipeta manual e manter em gelo até que todos os tubos são dissecados. </li><li> Dividir os tubos neurais em duas metades. Para isso, insira a ponta afiada de um par de pinças fechado na luz e abrir a placa de telhado movendo a pinça para fora através dele. Após isso, separar as metades cortando a placa de piso com as pontas pinças. </li><li> Ordenar electroporadas a partir de metades não-electroporado sob um escopo de dissecação fluorescente e transferir para um tubo de 1,5 ml cheio com gelado tratada com DEPC PBS. Se necessário, os microtubos agite suavemente para libertar qualquer tecido ligado às paredes de plástico e para promover a sedimentação dos tubos. </li><li> Rotação a 100 xg por 3 segundos e remover muito lentamente, tanto PBS possível com uma micropipeta de 1 ml. Faça isso enquanto olha para uma fonte de luz que brilha através do microtubo para monitorar se qualquer material embrionário é sugado para a ponta da pipeta; se isso acontecer, lentamente descarregar e repita a centrifugação. </li><li> Adicionar 70 ml de solução de lise para extração de RNA por tubo neural metade e apertar o tubo para misturar o conteúdo. Incubar à temperatura ambiente durante 5 min e vórtex vigorosamente. Repetir a 5 min de incubação e vórtex mais duas vezes. Armazenar a -80 ° C. </li><li> Recolher pelo menos oito metades do tubo neural por amostra para garantir um rendimento adequado para o passo seguinte. Piscina amostras menores se várias sessões de eletroporação / dissecação são obrigados a acumular número suficiente de tubos neurais. Armazenar amostras suficientes para duplicatas ou triplicatas para cada condição. </li></ol> 3. Purify RNA e Prepare Bibliotecas para Illumina Sequencing <ol><li> Retirar amostras de -80 ° C de armazenamento e colocar no gelo por 15-30 min. Retomar o descongelamento à temperatura ambiente até estar completa. </li><li> Vortex bem e deixe em temperatura ambiente por 5 min. Vortex e centrifuga-se novamente a 15000 xg durante 1 min para sedimentar o material insolúvel. </li><li> Transferir o sobrenadante para um novo tuboe proceder à extração de RNA de acordo com as instruções de isolamento de RNA total de manuais kit. Eluir no volume mínimo recomendado para aumentar a concentração. NOTA: tratamento DNase após clean-up é recomendado, a fim de evitar a contaminação potencial de sequências genômicas de DNA em RNA-Seq conjuntos de dados. </li><li> Flick o tubo para misturar o conteúdo e remover 5 mL para análise de controle de qualidade. Armazenar o restante amostra a -80 ° C até à preparação da biblioteca; estas amostras devem ser descongeladas apenas uma vez para evitar a degradação do RNA. </li><li> Executar RNA purificado em um instrumento Bioanalyzer usando o kit RNA 6000 Nano; RIN valor deve ser, pelo menos, acima de 7 para prosseguir. </li><li> Gerar bibliotecas usando um kit de preparação biblioteca RNA-Seq compatível Illumina e multiplexar até quatro bibliotecas em uma pista de um instrumento HiSeq definido para gerar 100 pb única lê. Se possível, inclua todas as amostras no mesmo prazo para minimizar potenciais artefatos técnicos. NOTA: Este deve produzir até 50 milhões de rEADS por exemplo, que é mais do que suficiente para obter cobertura para a maioria dos genes 13. </li></ol> 4. Compare os conjuntos de dados de RNA-Seq no Servidor Público Galaxy 10. NOTA: o espaço de armazenamento do servidor é limitado e experimentos comparando muitas amostras podem requerer a exclusão de arquivos intermediários gerados nas etapas de filtragem. <ol><li> Criar uma conta de usuário no servidor público Galaxy ( <a href="https://usegalaxy.org/">https://usegalaxy.org</a> ) e FTP upload dos conjuntos de dados Illumina em formato fastq. </li><li> Prepare os arquivos enviados com a ferramenta FastqGroomer 14 do NGS: menu de QC e manipulação; se os índices de qualidade já são codificados em Phred + 33 (Sanger), ignore esta etapa, simplesmente mudando o tipo de arquivo para fastqsanger sob os atributos para cada conjunto de dados. </li><li> Analisar a qualidade geral de cada conjunto de dados usando a ferramenta FastQC sob a NGS: QC e manipulação menu. NOTA: Deve ser dada especial atenção aos gráficos resultantes para o conteúdo sequência de bases por qualidade sequência de bases e por, como estes irão fornecer estimativas para os parâmetros usados ​​para aparar as extremidades da lê. </li><li> Aparar lê descartar 3 &#39;com dados de baixa qualidade, utilizando a ferramenta FASTQ Qualidade Trimmer 14 do NGS: menu de QC e manipulação. Definir a ferramenta para processar apenas 3 &#39;para o índice de qualidade inferior a 20. </li><li> Remover seqüências adaptadoras de lê usando a ferramenta Clip ( <a href="http://hannonlab.cshl.edu/fastx_toolkit/">http://hannonlab.cshl.edu/fastx_toolkit/</a> ) sob a NGS: menu de QC e manipulação. Definir a ferramenta para descartar leituras com menos do que 45 bp para a esquerda, a sequência de entrada do adaptador usado e escolher a saída de modo a incluir ambas as sequências cortadas e não-cortadas. Além disso, optar por não descartar sequências com bases desconhecidos pois a maioria das bases de baixa qualidade já foram removidos na última etapa. </lEu&gt; <li> Usando a ferramenta de sequências de guarnição ( <a href="http://hannonlab.cshl.edu/fastx_toolkit/">http://hannonlab.cshl.edu/fastx_toolkit/</a> ), sob a NGS: QC e menu de manipulação, apare as primeiras bases da lê para remover 5 &#39;viés seqüência detectada por FastQC (normalmente 10). NOTA: Neste ponto, é uma boa idéia para executar FastQC novamente e comparar com a análise anterior para determinar se a qualidade do conjunto de dados foi melhorada. </li><li> Baixe e descompacte o mais recente montagem do genoma da galinha para o navegador genoma UCSC de Illumina iGenomes ( <a href="http://support.illumina.com/sequencing/sequencing_software/igenome.ilmn">http://support.illumina.com/sequencing/sequencing_software/igenome.ilmn</a> ) e fazer o upload de todo o arquivo de formato genoma fasta eo arquivo de formato GTF anotação genes para a história da galáxia utilizando a ferramenta de upload de arquivos no menu Obter dados. </li><li> Mapa lê para cada amostra para o genoma de galinha utilizando o alinhador TopHat2 15 sobos NGS: menu de Análise RNA. Escolha usar um genoma de História (selecione o arquivo fasta carregado no passo 4.7). </li><li> Construir um transcriptoma previsto para cada amostra usando abotoaduras 16 sob as NGS: menu de Análise RNA. Escolha usar anotação de referência como guia (selecione o arquivo GTF carregado no passo 4.7) e ativar as opções de realizar correção de viés (de História, arquivo fasta do passo 4.7) e usar multi-leitura correta. </li><li> Mesclar transcriptomes previstos para todas as amostras usando Cuffmerge 16 sob a NGS: Menu Análise de RNA. Escolha usar anotação de referência (arquivo GTF do passo 4.7) e dados de sequências (de História, arquivo fasta do passo 4.7). </li><li> Compare arquivos BAM gerados por TopHat2 para cada amostra usando Cuffdiff 16 sob a NGS: Menu Análise RNA. Nas transcrições de campo, selecione a metranscriptoma rged gerado pelo Cuffmerge e ativar as opções de realizar correção de viés (de História, arquivo fasta do passo 4.7) e usar multi-leitura correta. </li><li> Ordenar expressão diferencial testar tabelas numericamente ascensão na coluna 13 (valor q) usando o Sort ferramenta sob o menu Filtro e classificar. NOTA: Genes / transcrições mostrando expressão diferencial significativa entre as condições experimentais serão apresentados os valores de q menores. </li><li> Para verificar os resultados visualmente com gráficos de cobertura, primeiro converter arquivos para o formato BAM bedGraph utilizando a ferramenta Criar um BedGraph de cobertura do genoma 17 sob o menu BEDTools. Desativar relatório de regiões sem cobertura, escolha para tratar entradas emendados como intervalos distintos e dimensionar a cobertura por um fator que normaliza profundidade sequenciamento para todos os conjuntos de dados que estão sendo comparados. </li><li> Converter o arquivo para o formato bedGraph resultando figurão usando oferramenta peruca / BedGraph-a-mandachuva ( <a href="http://www.genome.ucsc.edu/">http://www.genome.ucsc.edu/</a> ) no menu Formatos converter. Faça o upload dos arquivos bigwig como faixas personalizadas no navegador UCSC genoma ( <a href="http://www.genome.ucsc.edu/">http://www.genome.ucsc.edu/</a> ) para a montagem galGal4 e procurar um gene de interesse para visualizar a cobertura nos conjuntos de dados. </li></ol>

<ol>
	<li>Itasaki, N., Bel-Vialar, S., Krumlauf, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shocking'+developments+in+chick+embryology:+electroporation+and+in+ovo+gene+expression.">Shocking' developments in chick embryology: electroporation and in ovo gene expression.</a> Nat. Cell Biol. 1 (8), 207-20 (1999).</li><li>Krull, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+primer+on+using+in+ovo+electroporation+to+analyze+gene+function.">A primer on using in ovo electroporation to analyze gene function.</a> Dev. Dyn. 229 (3), 433-439 (2004).</li><li>Blank, M. C., Chizhikov, V., Millen, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+ovo+electroporations+of+HH+stage+10+chicken+embryos.">In ovo electroporations of HH stage 10 chicken embryos.</a> J. Vis. Exp. (9), 10-3791 (2007).</li><li>Sauka-Spengler, T., Barembaum, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gain-+and+loss-of-function+approaches+in+the+chick+embryo.">Gain- and loss-of-function approaches in the chick embryo.</a> Methods Cell Biol. 87, 237-256 (2008).</li><li>Ghadge, G. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Truncated+wild-type+SOD1+and+FALS-linked+mutant+SOD1+cause+neural+cell+death+in+the+chick+embryo+spinal+cord.">Truncated wild-type SOD1 and FALS-linked mutant SOD1 cause neural cell death in the chick embryo spinal cord.</a> Neurobiol. Dis. 21 (1), 205-20 (2006).</li><li>Megason, S. G., McMahon, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+mitogen+gradient+of+dorsal+midline+Wnts+organizes+growth+in+the+CNS.">A mitogen gradient of dorsal midline Wnts organizes growth in the CNS.</a> Development. 129 (9), 2087-2098 .</li><li>Swartz, M., Eberhart, J., Mastick, G. S., Krull, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sparking+new+frontiers:+using+in+vivo+electroporation+for+genetic+manipulations.">Sparking new frontiers: using in vivo electroporation for genetic manipulations.</a> Dev. Biol. 233 (1), 13-21 (2001).</li><li>Cloonan, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stem+cell+transcriptome+profiling+via+massive-scale+mRNA+sequencing.">Stem cell transcriptome profiling via massive-scale mRNA sequencing.</a> Nat. Methods. 5 (7), 613-619 (2008).</li><li>Mortazavi, A., Williams, B. A., McCue, K., Schaeffer, L., Wold, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mapping+and+quantifying+mammalian+transcriptomes+by+RNA-Seq.">Mapping and quantifying mammalian transcriptomes by RNA-Seq.</a> Nat. Methods. 5 (7), 621-628 (2008).</li><li>Goecks, J., Nekrutenko, A., Taylor, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Galaxy+Team.+Galaxy:+a+comprehensive+approach+for+supporting+accessible,+reproducible,+and+transparent+computational+research+in+the+life+sciences.">Galaxy Team. Galaxy: a comprehensive approach for supporting accessible, reproducible, and transparent computational research in the life sciences.</a> Genome Biol. 11 (8), 86 (2010).</li><li>Trichas, G., Begbie, J., Srinivas, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+the+viral+2A+peptide+for+bicistronic+expression+in+transgenic+mice.">Use of the viral 2A peptide for bicistronic expression in transgenic mice.</a> BMC Biol. 6, 40 (2008).</li><li>Maniatis, T., Fritsch, E. F., Sambrook, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Molecular cloning. A laboratory manual. , (1982).</li><li>Wang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+the+coverage+and+depth+of+transcriptome+by+RNA-Seq+in+chickens.">Evaluation of the coverage and depth of transcriptome by RNA-Seq in chickens.</a> BMC Bioinformatics. 12, 10-1186 (2011).</li><li>Blankenberg, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Manipulation+of+FASTQ+data+with+Galaxy.">Manipulation of FASTQ data with Galaxy.</a> Bioinformatics. 26 (14), 1783-1785 (2010).</li><li>Kim, D., Pertea, G., Trapnell, C., Pimentel, H., Kelley, R., Salzberg, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TopHat2:+accurate+alignment+of+transcriptomes+in+the+presence+of+insertions,+deletions+and+gene+fusions.">TopHat2: accurate alignment of transcriptomes in the presence of insertions, deletions and gene fusions.</a> Genome Biol. 14 (4), 36 (2013).</li><li>Trapnell, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcript+assembly+and+quantification+by+RNA-Seq+reveals+unannotated+transcripts+and+isoform+switching+during+cell+differentiation.">Transcript assembly and quantification by RNA-Seq reveals unannotated transcripts and isoform switching during cell differentiation.</a> Nat Biotechnol. 28 (5), 511-515 (2010).</li><li>Quinlan, A. R., Hall, I. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BEDTools:+a+flexible+suite+of+utilities+for+comparing+genomic+features.">BEDTools: a flexible suite of utilities for comparing genomic features.</a> Bioinformatics. 26 (6), 841-842 (2010).</li><li>Vieceli, F. M., Sim&#245;es-Costa, M., Turri, J. A., Kanno, T., Bronner, M., Yan, C. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+transcription+factor+chicken+Scratch2+is+expressed+in+a+subset+of+early+postmitotic+neural+progenitors.">The transcription factor chicken Scratch2 is expressed in a subset of early postmitotic neural progenitors.</a> Gene Expr. Patterns. 13 (5-6), 189-196 (2013).</li><li>Chesnutt, C., Niswander, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasmid-based+short-hairpin+RNA+interference+in+the+chicken+embryo.">Plasmid-based short-hairpin RNA interference in the chicken embryo.</a> Genesis. 39 (2), 73-78 (2004).</li><li>Katahira, T., Nakamura, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+silencing+in+chick+embryos+with+a+vector-based+small+interfering+RNA+system.">Gene silencing in chick embryos with a vector-based small interfering RNA system.</a> Dev. Growth. Differ. 45 (4), 361-367 (2003).</li><li>Rao, M., Baraban, J. H., Rajaii, F., Sockanathan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+comparative+study+of+RNAi+methodologies+by+in+ovo+electroporation+in+the+chick+embryo.">In vivo comparative study of RNAi methodologies by in ovo electroporation in the chick embryo.</a> Dev. Dyn. 231 (3), 592-600 (2004).</li><li>Lu, Y., Lin, C., Wang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PiggyBac+transgenic+strategies+in+the+developing+chicken+spinal+cord.">PiggyBac transgenic strategies in the developing chicken spinal cord.</a> Nucleic Acids Res. 37 (21), 141 (2009).</li><li>Sim&#245;es-Costa, M., Tan-Cabugao, J., Antoshechkin, I., Sauka-Spengler, T., Bronner, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcriptome+analysis+reveals+novel+players+in+the+cranial+neural+crest+gene+regulatory+network.">Transcriptome analysis reveals novel players in the cranial neural crest gene regulatory network.</a> Genome Res. 24 (2), 281-290 (2014).</li><li>Trapnell, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+gene+and+transcript+expression+analysis+of+RNA-seq+experiments+with+TopHat+and+Cufflinks.">Differential gene and transcript expression analysis of RNA-seq experiments with TopHat and Cufflinks.</a> Nat. Protoc. 7 (3), 562-578 (2012).</li></ol>

The authors have nothing to disclose.

Aqui nós fornecemos orientações para a análise dos efeitos após a eletroporação do frango medula espinhal. Embora eletroporação de vetores de DNA é mais freqüentemente usado para superexpressão de um gene de interesse, pode-se também usar construções que codificam negativos dominantes, proteínas quimeric ou precursores de siRNAs para gerar condições de função do gene knock-down 19-21. Na verdade, a comparação de perfis de transcriptoma resultantes de ambos gain- e análise por perda de f...

Estudos genéticos sobre os organismos vivos utilizam frequentemente o embrião de galinha como modelo porque em eletroporação in ovo representa uma forma rápida e barata para transf parcialmente estruturas embrionárias in vivo com DNA constrói 1-5. Vectores de expressão bicistrónicos que codificam um transcrito contendo um repórter fluorescente em conjunto com o gene de interesse, tais como PCIG 6 ou 7 PMES, permitir a verificação rápida da qualidade transfecção na região desejada sob um microscópio estereoscópico antes de processar os embriões para análise a jusante. Com os recentes avanços na sequenciação de ADN, é agora possível obter perfis de expressão transcriptoma digitais inteiras a partir de amostras de ARN utilizando ARN-8,9 Seq. Portanto, em vez de métodos demorados que permitem a análise de apenas alguns produtos de genes em paralelo, tais como hibridação in situ, imuno-histoquímica e qPCR, preparação de bibliotecas de cDNA parade alto rendimento seqüenciamento pode fornecer informações de todo o transcriptoma. Observação dos efeitos experimentais sobre os níveis de cada gene único de expressão podem, por sua vez fornecem insights poderosos sobre os percursos alterados pela construção usado. Isto é particularmente fácil, se uma montagem genómico para o organismo utilizado, está disponível, assim, o embrião de galinha é novamente um modelo adequado. Se o usuário tem acesso a um centro de sequenciamento do genoma de confiança, a questão principal é a obtenção de amostras de RNA de alta qualidade. Este trabalho demonstra um método para a obtenção de amostras de ARN a partir de tubos neurais transfectadas adequadas para a RNA-Seq, bem como os passos a jusante para a análise in silico dos conjuntos de dados resultantes. Após eletroporação em HH12-13 seguido de 48 horas de incubação, tronco transfectadas metades da medula espinhal foram dissecados em condições livres de ribonuclease, imediatamente lisadas e mais protegida da degradação por ultra-baixo de congelamento até purificação RNA e biblioteca preparatião. O servidor público Galaxy 10 fornece acesso a recursos livres para análise de dados de sequenciamento de alto rendimento. A quantidade de espaço oferecido para usuários registrados é suficiente para pequenos experimentos, eliminando assim a necessidade de infra-estrutura computacional local. A análise de dados de RNA-Seq inclui filtragem, alinhamento e quantificação / Comparação da expressão do gene. Embora existam diretrizes gerais para a análise de dados de RNA-Seq, parâmetros de filtragem dependerá em grande parte a qualidade do sequenciamento e deve ser determinada após a análise dos dados brutos de controle de qualidade. Este protocolo descreve os passos para obter e comparar os perfis de RNA-Seq de frango embrionário medulas espinhais transfectadas in vivo. Como um resultado representativo, a comparação de conjuntos de dados obtidos a partir de duas amostras de controlo independentes transfectadas com um vector vazio mostraram que o método é reprodutível e deve permitir a identificação de expres diferencialmentetranscrições sed em amostras experimentais. Portanto, a aplicação deste método tem o potencial para aumentar grandemente o número de descobertas após uma única experiência e, assim, proporcionar um grande conjunto de dados para investigação posterior.

<table><tbody><tr><td>Indian ink</td><td>Any supplier</td><td></td><td></td></tr><tr><td>18G x 1 1/2 needle</td><td>BD</td><td>305196</td><td></td></tr><tr><td>3 ml syringe</td><td>BD</td><td>309657</td><td></td></tr><tr><td>Tris</td><td>MP Biomedicals</td><td>819620</td><td></td></tr><tr><td>F D &amp;amp; C Blue 1</td><td>Spectra Colors Corporation</td><td>5.FC.0010P0</td><td>Food Dye used to visualize DNA injection</td></tr><tr><td>Ringer&#039;s solution (1 L)</td><td></td><td></td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - 7.2 g NaCl</td><td>Sigma-Aldrich</td><td>S-9888</td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - 0.37 g KCl</td><td>Sigma-Aldrich</td><td>P-4504</td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - 0.225 g CaCl&lt;sub&gt;2&lt;/sub&gt;&amp;#8226;2H&lt;sub&gt;2&lt;/sub&gt;O</td><td>Fisher Scientific</td><td>10043-52-4</td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - 0.217 g Na&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt;.7H&lt;sub&gt;2&lt;/sub&gt;O</td><td>Sigma-Aldrich</td><td>S-9390</td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - 0.02 g KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;</td><td>Sigma-Aldrich</td><td>P-5379</td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - ddH&lt;sub&gt;2&lt;/sub&gt;O to 800 ml and adjust pH to 7.4</td><td></td><td></td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - ddH&lt;sub&gt;2&lt;/sub&gt;O to 1 L</td><td></td><td></td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - Filter and autoclave</td><td></td><td></td><td></td></tr><tr><td>PBS (Phosphate Buffered Solution) (1 L)</td><td></td><td></td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - 8 g NaCl</td><td>Sigma-Aldrich</td><td>S-9888</td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - 0.2 g KCl</td><td>Sigma-Aldrich</td><td>P-4504</td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - 1.15 g Na&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt;&amp;#8226;7H&lt;sub&gt;2&lt;/sub&gt;O</td><td>Sigma-Aldrich</td><td>S-9390</td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - 0.2 g KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;</td><td>Sigma-Aldrich</td><td>P-5379</td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - ddH&lt;sub&gt;2&lt;/sub&gt;O to 800 ml and adjust pH to 7.2</td><td></td><td></td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - ddH&lt;sub&gt;2&lt;/sub&gt;O to 1 L and filter</td><td></td><td></td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - 1 ml DEPC (Diethylpyrocarbonate)</td><td>Sigma-Aldrich</td><td>D-5758</td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - Shake vigorously and let stand overnight at room temperature</td><td></td><td></td><td></td></tr><tr><td>&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; - Autoclave</td><td></td><td></td><td></td></tr><tr><td>Sieved spoon</td><td>Any supplier</td><td></td><td></td></tr><tr><td>Sterile 60 x 15 mm polystirene Petri dishes</td><td>Corning Life Sciences</td><td>351007</td><td></td></tr><tr><td>RNaseZap RNase decontamination solution</td><td>Life Technologies</td><td>AM9780</td><td></td></tr><tr><td>Fine point surgical scissors</td><td>Any supplier</td><td></td><td></td></tr><tr><td>Straight fine point tweezers</td><td>Any supplier</td><td></td><td></td></tr><tr><td>Pulled glass needle made from 1.1 x 75 mm glass capillary tubes</td><td>Kimble Chase</td><td>40A502</td><td></td></tr><tr><td>9&#039;&#039; glass Pasteur pipette</td><td>Any supplier</td><td></td><td></td></tr><tr><td>Manual pipette pump</td><td>Any supplier</td><td></td><td></td></tr><tr><td>Clear 1.5 ml microcentrifuge polypropilene tubes</td><td>Corning Life Sciences</td><td>MCT-150-C</td><td></td></tr><tr><td>Microcentrifuge</td><td>Any supplier</td><td></td><td></td></tr><tr><td>RNAlater solution for RNA stabilization</td><td>Life Technologies</td><td>AM7020</td><td></td></tr><tr><td>RNAqueous total RNA isolation kit</td><td>Life Technologies</td><td>AM1912</td><td></td></tr><tr><td>Molecular Biology Grade Ethanol</td><td>Any supplier</td><td></td><td></td></tr><tr><td>RNA 6000 Nano Kit</td><td>Agilent Technologies</td><td>5067-1511</td><td></td></tr><tr><td>2100 Electrophoresis Bioanalyzer Instrument</td><td>Agilent Technologies</td><td>G2939AA</td><td></td></tr><tr><td>Truseq RNA Sample Preparation Kit v2</td><td>Illumina</td><td>RS-122-2001/RS-122-2002</td><td></td></tr></tbody></table>

rna-seq analysis of differential gene expression in electroporated chick embryonic spinal cord

In ovo electroporation of the chick neural tube is a fast and inexpensive method for identification of gene function during neural development. Genome wide analysis of differentially expressed transcripts after such an experimental manipulation has the potential to uncover an almost complete picture of the downstream effects caused by the transfected construct. This work describes a simple method for comparing transcriptomes from samples of transfected embryonic spinal cords comprising all steps between electroporation and identification of differentially expressed transcripts. The first stage consists of guidelines for electroporation and instructions for dissection of transfected spinal cord halves from HH23 embryos in ribonuclease-free environment and extraction of high-quality RNA samples suitable for transcriptome sequencing. The next stage is that of bioinformatic analysis with general guidelines for filtering and comparison of RNA-Seq datasets in the Galaxy public server, which eliminates the need of a local computational structure for small to medium scale experiments. The representative results show that the dissection methods generate high quality RNA samples and that the transcriptomes obtained from two control samples are essentially the same, an important requirement for detection of differential expression genes in experimental samples. Furthermore, one example is provided where experimental overexpression of a DNA construct can be visually verified after comparison with control samples. The application of this method may be a powerful tool to facilitate new discoveries on the function of neural factors involved in spinal cord early development.

Para validar o método descrito, duas amostras de controlo foram gerados a partir de embriões electroporadas com as PMEs de vetores vazios 7 e uma amostra a partir de embriões transfectadas com o mesmo vector contendo a inserção construir SCRT2-ZnF, que codifica os domínios dedo-de-zinco de frango SCRT2 18. As amostras de RNA total produzindo 11-22 g cada foram obtidos a partir de misturas de 8 a 12 embriões. Todas as três amostras teve um valor óptimo RIN em 10 de um controlo de qualidade ...

Watch this Scientific Journal Video about RNA-Seq Analysis of Differential Gene Expression in Electroporated Chick Embryonic Spinal Cord at JoVE.com

RNA-Seq Analysis of Differential Gene Expression in Electroporated Chick Embryonic Spinal Cord

This video shows the basic steps for performing whole transcriptome analysis on dissected chick embryonic spinal cord samples after transfection with in ovo electroporation.

RNA-Seq Análise de Gene Expression Diferencial em electroporados Pintainho Embryonic Medular

In ovo electroporation of the chick neural tube is a fast and inexpensive method for identification of gene function during neural development. Genome ...

rna-seq-analysis-differential-gene-expression-electroporated-chick

Universidad de Cartagena UDEC

Research

JoVE Journal

Neuroscience

14.5K visualizações.  Universidade de São Paulo. This video shows the basic steps for performing whole transcriptome analysis on dissected chick embryonic spinal cord samples after transfection with in ovo electroporation.

Vídeo: RNA-Seq Analysis of Differential Gene Expression in Electroporated Chick Embryonic Spinal Cord

Chromatin Immunoprecipitation (ChIP) Protocol for Low-abundance Embryonic Samples

Chromatin immunoprecipitation (ChIP) is a widely-used technique for mapping the localization of post-translationally modified histones, histone variants, transcription factors, or chromatin-modifying enzymes at a given locus or on a genome-wide scale. The combination of ChIP assays with next-generation sequencing (i.e., ChIP-Seq) is a powerful approach to globally uncover gene regulatory networks and to improve the functional annotation of genomes, especially of non-coding regulatory sequences. ChIP protocols normally require large amounts of cellular material, thus precluding the applicability of this method to investigating rare cell types or small tissue biopsies. In order to make the ChIP assay compatible with the amount of biological material that can typically be obtained in vivo during early vertebrate embryogenesis, we describe here a simplified ChIP protocol in which the number of steps required to complete the assay were reduced to minimize sample loss. This ChIP protocol has been successfully used to investigate different histone modifications in various embryonic chicken and adult mouse tissues using low to medium cell numbers (5 x 104 - 5 x 105 cells). Importantly, this protocol is compatible with ChIP-seq technology using standard library preparation methods, thus providing global epigenomic maps in highly relevant embryonic tissues.

Chromatin Immunoprecipitation ChIP Protocol for Low-abundance Embryonic Samples

Here, we describe a chromatin immunoprecipitation (ChIP) and ChIP-seq library preparation protocol to generate global epigenomic profiles from low-abundance chicken embryonic samples.

Cromatina (ChIP) imunoprecipitação para baixo-abundância embrionárias amostras

Chromatin immunoprecipitation (ChIP) is a widely-used technique for mapping the localization of post-translationally modified histones, histone variants, ...

Genética

Analysis of Retinoic Acid-induced Neural Differentiation of Mouse Embryonic Stem Cells in Two and Three-dimensional Embryoid Bodies

Mouse embryonic stem cells (ESCs) isolated from the inner mass of the blastocyst (typically at day E3.5), can be used as in vitro model system for studying early embryonic development. In the absence of leukemia inhibitory factor (LIF), ESCs differentiate by default into neural precursor cells. They can be amassed into a three dimensional (3D) spherical aggregate termed embryoid body (EB) due to its similarity to the early stage embryo. EBs can be seeded on fibronectin-coated coverslips, where they expand by growing two dimensional (2D) extensions, or implanted in 3D collagen matrices where they continue growing as spheroids, and differentiate into the three germ layers: endodermal, mesodermal, and ectodermal. The 3D collagen culture mimics the in vivo environment more closely than the 2D EBs. The 2D EB culture facilitates analysis by immunofluorescence and immunoblotting to track differentiation. We have developed a two-step neural differentiation protocol. In the first step, EBs are generated by the hanging-drop technique, and, simultaneously, are induced to differentiate by exposure to retinoic acid (RA). In the second step, neural differentiation proceeds in a 2D or 3D format in the absence of RA.

We describe a technique for using murine embryonic stem cells for generating two or three dimensional embryoid bodies. We then explain how to induce neural differentiation of the embryoid body cells by retinoic acid, and how to analyze their state of differentiation by progenitor cell marker immunofluorescence and immunoblotting.

Análise do induzida por ácido retinóico Neural diferenciação de células estaminais embrionárias rato em corpos embrióides Dois e tridimensionais

Mouse embryonic stem cells (ESCs) isolated from the inner mass of the blastocyst (typically at day E3.5), can be used as in vitro model system for ...

Biologia do Desenvolvimento

Direct Gene Knock-out of Axolotl Spinal Cord Neural Stem Cells via Electroporation of CAS9 Protein-gRNA Complexes

The axolotl has the unique ability to fully regenerate its spinal cord. This is largely due to the ependymal cells remaining as neural stem cells (NSCs) throughout life, which proliferate to reform the ependymal tube and differentiate into lost neurons after spinal cord injury. Deciphering how these NSCs retain pluripotency post-development and proliferate upon spinal cord injury to reform the exact pre-injury structure can provide valuable insight into how mammalian spinal cords may regenerate as well as potential treatment options. Performing gene knock-outs in specific subsets of NSCs within a restricted time period will allow study of the molecular mechanisms behind these regenerative processes, without being confounded by development perturbing effects. Described here is a method to perform gene knock-out in axolotl spinal cord NSCs using the CRISPR-Cas9 system. By injecting the CAS9-gRNA complex into the spinal cord central canal followed by electroporation, target genes are knocked out in NSCs within specific regions of the spinal cord at a desired timepoint, allowing for molecular studies of spinal cord NSCs during regeneration.

Presented here is a protocol to perform time- and space-restricted gene knock-out in axolotl spinal cords by injecting CAS9-gRNA complex into the spinal cord central canal followed by electroporation.

Gene direto knock-out de células-tronco neurais da medula espinhal Axolotl via eletroporação de complexos de proteína-gRNA CAS9

The axolotl has the unique ability to fully regenerate its spinal cord. This is largely due to the ependymal cells remaining as neural stem cells (NSCs) ...

In ovo Electroporation of miRNA-based Plasmids in the Developing Neural Tube and Assessment of Phenotypes by DiI Injection in Open-book Preparations

Commissural dI1 neurons have been extensively studied to elucidate the mechanisms underlying axon guidance during development1,2. These neurons are located in the dorsal spinal cord and send their axons along stereotyped trajectories. Commissural axons initially project ventrally towards and then across the floorplate. After crossing the midline, these axons make a sharp rostral turn and project longitudinally towards the brain. Each of these steps is regulated by the coordinated activities of attractive and repulsive guidance cues. The correct interpretation of these cues is crucial to the guidance of axons along their demarcated pathway. Thus, the physiological contribution of a particular molecule to commissural axon guidance is ideally investigated in the context of the living embryo. Accordingly, gene knockdown in vivo must be precisely controlled in order to carefully distinguish axon guidance activities of genes that may play multiple roles during development.
Here, we describe a method to knockdown gene expression in the chicken neural tube in a cell type-specific, traceable manner. We use novel plasmid vectors3 harboring cell type-specific promoters/enhancers that drive the expression of a fluorescent protein marker, followed directly by a miR30-RNAi transcript4 (located within the 3'-UTR of the cDNA encoding the fluorescent protein) (Figure 1). When electroporated into the developing neural tube, these vectors elicit efficient downregulation of gene expression and express bright fluorescent marker proteins to enable direct tracing of the cells experiencing knockdown3. Mixing different RNAi vectors prior to electroporation allows the simultaneous knockdown of two or more genes in independent regions of the spinal cord. This permits complex cellular and molecular interactions to be examined during development, in a manner that is fast, simple, precise and inexpensive. In combination with DiI tracing of commissural axon trajectories in open-book preparations5, this method is a useful tool for in vivo studies of the cellular and molecular mechanisms of commissural axon growth and guidance. In principle, any promoter/enhancer could be used, potentially making the technique more widely applicable for in vivo studies of gene function during development6.
This video first demonstrates how to handle and window eggs, the injection of DNA plasmids into the neural tube and the electroporation procedure. To investigate commissural axon guidance, the spinal cord is removed from the embryo as an open-book preparation, fixed, and injected with DiI to enable axon pathways to be traced. The spinal cord is mounted between coverslips and visualized using confocal microscopy.

In ovo Electroporation of miRNA-based Plasmids in the Developing Neural Tube and Assessment of Phenotypes by DiI Injection in Open-book Preparations

A method by which gene expression in the neural tube can be downregulated in a cell type-specific, traceable manner is described. We demonstrate how in ovo electroporation of microRNA-based plasmids that elicit spatiotemporally controlled RNA interference can be used to investigate commissural axon guidance in the developing neural tube.

Em Eletroporação ovo de miRNA-base de plasmídeos no Tubo Neural Desenvolvimento e Avaliação de Fenótipos por Dil Injeção em livro aberto Preparações

Commissural dI1 neurons have been extensively studied to elucidate the mechanisms underlying axon guidance during development1,2. These neurons are ...

Neurociência

Electroporation of the Hindbrain to Trace Axonal Trajectories and Synaptic Targets in the Chick Embryo

Electroporation of the chick embryonic neural tube has many advantages such as being quick and efficient for the expression of foreign genes into neuronal cells. In this manuscript we provide a method that demonstrates uniquely how to electroporate DNA into the avian hindbrain at E2.75 in order to specifically label a subset of neuronal progenitors, and how to follow their axonal projections and synaptic targets at much advanced stages of development, up to E14.5. We have utilized novel genetic tools including specific enhancer elements, Cre/Lox - based plasmids and the PiggyBac-mediated DNA transposition system to drive GFP expression in a subtype of hindbrain cells (the dorsal most subgroup of interneurons, dA1). Axonal trajectories and targets of dA1 axons are followed at early and late embryonic stages at various brainstem regions. This strategy contributes advanced techniques for targeting cells of interest in the embryonic hindbrain and for tracing circuit formation at multiple stages of development.

How neuronal networks are established in the embryonic brain is a fundamental question in developmental neurobiology. Here we combined an electroporation technique with novel genetic tools, such as Cre/Lox&#x2013;plasmids and PiggyBac-mediated DNA transposition system in the avian hindbrain to label dorsal interneurons and track their axonal projections and synaptic targets at various developmental stages.

Eletroporação do rombencéfalo rastrear Trajetórias axonal e Metas Synaptic no embrião de galinha

Electroporation of  the chick embryonic neural tube has many advantages such as being quick and efficient  for the expression of foreign genes into ...

Deciphering Axonal Pathways of Genetically Defined Groups of Neurons in the Chick Neural Tube Utilizing in ovo Electroporation

Employment of enhancer elements to drive expression of reporter genes in neurons is a widely used paradigm for tracking axonal projection. For tracking axonal projection of spinal interneurons in vertebrates, germ line-targeted reporter genes yield bilaterally symmetric labeling. Therefore, it is hard to distinguish between the ipsi- and contra-laterally projecting axons. Unilateral electroporation into the chick neural tube provides a useful means to restrict expression of a reporter gene to one side of the central nervous system, and to follow axonal projection on both sides 1 ,2-5. This video demonstrates first how to handle the eggs prior to injection. At HH stage 18-20, DNA is injected into the sacral level of the neural tube, then tungsten electrodes are placed parallel to the embryo and short electrical pulses are administered with a pulse generator. The egg is sealed with tape and placed back into an incubator for further development. Three days later (E6) the spinal cord is removed as an open book preparation from embryo, fixed, and processed for whole mount antibody staining. The stained spinal cord is mounted on slide and visualized using confocal microscopy.

Deciphering Axonal Pathways of Genetically Defined Groups of Neurons in the Chick Neural Tube Utilizing in ovo Electroporation

This video demonstrates how to visualize axonal pathways of genetically defined groups of neurons in the embryonic chick spinal cord utilizing in ovo electroporation of reporter genes under the control of specific enhancer elements.

Decifrando Pathways Axonal dos Grupos geneticamente definidos de neurônios no tubo Neural Utilizando Pintainho In ovo Eletroporação

Employment of enhancer elements to drive expression of reporter genes in neurons is a widely used paradigm for tracking axonal projection. For tracking ...

Biologia

Differentiation and Characterization of Neural Progenitors and Neurons from Mouse Embryonic Stem Cells

We describe the step-by-step procedure for culturing and differentiating mouse embryonic stem cells into neuronal lineages, followed by a series of assays to characterize the differentiated cells. The E14 mouse embryonic stem cells were used to form embryoid bodies through the hanging drop method, and then induced to differentiate into neural progenitor cells by retinoic acid, and finally differentiated into neurons. Quantitative&#160;reverse transcription&#160;polymerase chain reaction (RT-qPCR) and immunofluorescence experiments revealed that the neural progenitors and neurons exhibit corresponding markers (nestin for neural progenitors and neurofilament for neurons) at day 8 and 12 post-differentiation, respectively. Flow cytometry experiments on an E14 line expressing a Sox1 promoter-driven GFP reporter showed that about 60% of cells at day 8 are GFP positive, indicating the successful differentiation of neural progenitor cells at this stage. Finally, RNA-seq analysis was used to profile the global transcriptomic changes. These methods are useful for analyzing the involvement of specific genes and pathways in regulating the cell identity transition during neuronal differentiation.

We describe the procedure for the in vitro differentiation of mouse embryonic stem cells into neuronal cells using the hanging drop method. Furthermore, we perform a comprehensive phenotypic analysis through RT-qPCR, immunofluorescence, RNA-seq, and flow cytometry.

Diferenciação e caracterização de progenitores neurais e neurônios de células-tronco embrionárias do rato

We describe the step-by-step procedure for culturing and differentiating mouse embryonic stem cells into neuronal lineages, followed by a series of assays ...

Cell-Lineage Guided Mass Spectrometry Proteomics in the Developing (Frog) Embryo

Characterization of molecular events as cells give rise to tissues and organs raises a potential to better understand normal development and design efficient remedies for diseases. Technologies enabling accurate identification and quantification of diverse types and large numbers of proteins would provide still missing information on molecular mechanisms orchestrating tissue and organism development in space and time. Here, we present a mass spectrometry-based protocol that enables the measurement of thousands of proteins in identified cell lineages in Xenopus laevis (frog) embryos. The approach builds on reproducible cell-fate maps and established methods to identify, fluorescently label, track, and sample cells and their progeny (clones) from this model of vertebrate development. After collecting cellular contents using microsampling or isolating cells by dissection or fluorescence-activated cell sorting, proteins are extracted and processed for bottom-up proteomic analysis. Liquid chromatography and capillary electrophoresis are used to provide scalable separation for protein detection and quantification with high-resolution mass spectrometry (HRMS). Representative examples are provided for the proteomic characterization of neural-tissue fated cells. Cell-lineage-guided HRMS proteomics is adaptable to different tissues and organisms. It is sufficiently sensitive, specific, and quantitative to peer into the spatio-temporal dynamics of the proteome during vertebrate development.

Cell-Lineage Guided Mass Spectrometry Proteomics in the Developing Frog Embryo

Here we describe a mass spectrometry-based proteomic characterization of cell lineages with known tissue fates in the vertebrate Xenopus laevis embryo.

Proteômica por Espectrometria de Massas Guiada por Linhagem Celular no Embrião em Desenvolvimento (Rã)

Characterization of molecular events as cells give rise to tissues and organs raises a potential to better understand normal development and design ...

Química

Chromatin Immunoprecipitation Assay for Tissue-specific Genes using Early-stage Mouse Embryos

Chromatin immunoprecipitation (ChIP) is a powerful tool to identify protein:chromatin interactions that occur in the context of living cells 1-3. This technique has been widely exploited in tissue culture cells, and to a lesser extent, in primary tissue. The application of ChIP to rodent embryonic tissue, especially at early times of development, is complicated by the limited amount of tissue and the heterogeneity of cell and tissue types in the embryo. Here we present a method to perform ChIP using a dissociated embryonic day 8.5 (E8.5) embryo. Sheared chromatin from a single E8.5 embryo can be divided into up to five aliquots, which allows the investigator sufficient material for controls and for investigation of specific protein:chromatin interactions.
We have utilized this technique to begin to document protein:chromatin interactions during the specification of tissue-specific gene expression programs. The heterogeneity of cell types in an embryo necessarily restricts the application of this technique because the result is the detection of protein:chromatin interactions without distinguishing whether the interactions occur in all, a subset of, or a single cell type(s). However, examination of tissue-specific genes during or following the onset of tissue-specific gene expression is feasible for two reasons. First, immunoprecipitation of tissue specific factors necessarily isolates chromatin from the cell type where the factor is expressed. Second, immunoprecipitation of coactivators and histones containing post-translational modifications that are associated with gene activation should only be found at genes and gene regulatory sequences in the cell type where the gene is being or has been activated. The technique should be applicable to the study of most tissue-specific gene activation events.
In the example described below, we utilized E8.5 and E9.5 mouse embryos to examine factor binding at a skeletal muscle specific gene promoter. Somites, which are the precursor tissues from which the skeletal muscles of the trunk and limbs will form, are present at E8.5-9.54,5. Myogenin is a regulatory factor required for skeletal muscle differentiation 6-9. The data demonstrate that myogenin is associated with its own promoter in E8.5 and E9.5 embryos. Because myogenin is only expressed in somites at this stage of development 6,10, the data indicate that myogenin interactions with its own promoter have already occurred in skeletal muscle precursor cells in E8.5 embryos.

We demonstrate a chromatin immunoprecipitation (ChIP) method to identify factor interactions at tissue-specific genes during or after the onset of tissue-specific gene expression in mouse embryonic tissue. This protocol should be widely applicable for the study of tissue-specific gene activation as it occurs during normal embryonic development.

Ensaio para imunoprecipitação da cromatina Genes Tissue-específicos usando embriões em início de carreira do rato

Chromatin immunoprecipitation (ChIP) is a powerful tool to identify protein:chromatin interactions that occur in the context of living cells 1-3. This ...

Profiling Individual Human Embryonic Stem Cells by Quantitative RT-PCR

Heterogeneity of stem cell population hampers detailed understanding of stem cell biology, such as their differentiation propensity toward different lineages. A single cell transcriptome assay can be a new approach for dissecting individual variation. We have developed the single cell qRT-PCR method, and confirmed that this method works well in several gene expression profiles. In single cell level, each human embryonic stem cell, sorted by OCT4::EGFP positive cells, has high expression in OCT4, but a different level of NANOG expression. Our single cell gene expression assay should be useful to interrogate population heterogeneities.

Single cell gene expression assay is needed for understanding stem cell heterogeneities.

Profiling Individual células estaminais embrionárias humanas por RT-PCR quantitativo

Heterogeneity of stem cell population hampers detailed understanding of stem cell biology, such as their differentiation propensity toward different ...