Name: use of alu element containing minigenes to analyze circular rnas
Uploaded: 2020-03-10T12:00:00
Description: Watch this Scientific Journal Video about Use of Alu Element Containing Minigenes to Analyze Circular RNAs at JoVE.com

Este trabalho foi apoiado pelo Departamento de Defesa DoD conceder AZ180075. Stefan Stamm agradece jacqueline Noonan Endowment. Anna Pawluchin foi apoiada pelo DAAD, programa alemão de intercâmbio acadêmico, Justin R. Welden recebeu o Prêmio Da Universidade de Kentucky Max Steckler.

1. Projeto das construções
<ol><li>Use o navegador de genoma UCSC24 para identificar elementos repetitivos necessários para a formação de RNA circular e incorporá-los nos construtos. É importante ressaltar que os primers para amplificação precisam estar fora dos elementos repetitivos.</li>
	<li>Cole a seqüência circular de RNA(Figura Suplementar 1 é uma seqüência de teste) em <a href="https://genome.ucsc.edu/cgi-bin/hgBlat?command=start" target="_blank">https://gen...

<ol>
	<li>Jeck, W. R., 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=Circular+RNAs+are+abundant,+conserved,+and+associated+with+ALU+repeats.">Circular RNAs are abundant, conserved, and associated with ALU repeats.</a> RNA. 19 (2), 141-157 (2013).</li><li>Zhang, X. O., 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=Complementary+sequence-mediated+exon+circularization.">Complementary sequence-mediated exon circularization.</a> Cell. 159 (1), 134-147 (2014).</li><li>Deininger, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alu+elements:+know+the+SINEs.">Alu elements: know the SINEs.</a> Genome Biology. 12 (12), 236 (2011).</li><li>Bazak, L., Levanon, E. Y., Eisenberg, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-wide+analysis+of+Alu+editability.">Genome-wide analysis of Alu editability.</a> Nucleic Acids Research. 42 (11), 6876-6884 (2014).</li><li>Levanon, E. 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=Systematic+identification+of+abundant+A-to-I+editing+sites+in+the+human+transcriptome.">Systematic identification of abundant A-to-I editing sites in the human transcriptome.</a> Nature Biotechnology. 22 (8), 1001-1005 (2004).</li><li>Hansen, T. B., 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=Natural+RNA+circles+function+as+efficient+microRNA+sponges.">Natural RNA circles function as efficient microRNA sponges.</a> Nature. 495 (7441), 384-388 (2013).</li><li>Kelly, S., Greenman, C., Cook, P. R., Papantonis, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exon+Skipping+Is+Correlated+with+Exon+Circularization.">Exon Skipping Is Correlated with Exon Circularization.</a> Journal of Molecular Biology. 427 (15), 2414-2417 (2015).</li><li>Li, Z., 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=Exon-intron+circular+RNAs+regulate+transcription+in+the+nucleus.">Exon-intron circular RNAs regulate transcription in the nucleus.</a> Nature Structural &amp; Molecular Biology. 22 (3), 256-264 (2015).</li><li>Yang, 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=Extensive+translation+of+circular+RNAs+driven+by+N(6)-methyladenosine.">Extensive translation of circular RNAs driven by N(6)-methyladenosine.</a> Cell Research. 27 (6), 626-641 (2017).</li><li>Abe, 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=Rolling+Circle+Translation+of+Circular+RNA+in+Living+Human+Cells.">Rolling Circle Translation of Circular RNA in Living Human Cells.</a> Scientific Reports. 5, 16435 (2015).</li><li>Salzman, J., Chen, R. E., Olsen, M. N., Wang, P. L., Brown, P. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell-type+specific+features+of+circular+RNA+expression.">Cell-type specific features of circular RNA expression.</a> PLOS Genetics. 9 (9), 1003777 (2013).</li><li>Ottesen, E. W., Luo, D., Seo, J., Singh, N. N., Singh, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+Survival+Motor+Neuron+genes+generate+a+vast+repertoire+of+circular+RNAs.">Human Survival Motor Neuron genes generate a vast repertoire of circular RNAs.</a> Nucleic Acids Research. 47 (6), 2884-2905 (2019).</li><li>Stoss, O., Stoilov, P., Hartmann, A. 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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+role+for+exon+sequences+in+alternative+splicing+of+the+human+fibronectin+gene.">A role for exon sequences in alternative splicing of the human fibronectin gene.</a> Nucleic Acids Research. 15, 7725-7733 (1987).</li><li>Gaildrat, P., 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=Use+of+splicing+reporter+minigene+assay+to+evaluate+the+effect+on+splicing+of+unclassified+genetic+variants.">Use of splicing reporter minigene assay to evaluate the effect on splicing of unclassified genetic variants.</a> Methods in Molecular Biology. 653, 249-257 (2010).</li><li>Cooper, T. A. <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+minigene+systems+to+dissect+alternative+splicing+elements.">Use of minigene systems to dissect alternative splicing elements.</a> Methods. 37 (4), 331-340 (2005).</li><li>Baralle, D., Baralle, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Splicing+in+action:+assessing+disease+causing+sequence+changes.">Splicing in action: assessing disease causing sequence changes.</a> Journal of Medical Genetics. 42 (10), 737-748 (2005).</li><li>Percifield, R., Murphy, D., Stoilov, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Medium+throughput+analysis+of+alternative+splicing+by+fluorescently+labeled+RT-PCR.">Medium throughput analysis of alternative splicing by fluorescently labeled RT-PCR.</a> Methods in Molecular Biology. 1126, 299-313 (2014).</li><li>Stoilov, P., Lin, C. H., Damoiseaux, R., Nikolic, J., Black, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+high-throughput+screening+strategy+identifies+cardiotonic+steroids+as+alternative+splicing+modulators.">A high-throughput screening strategy identifies cardiotonic steroids as alternative splicing modulators.</a> Proceedings of the National Academy of Sciences of the United States of America. 105 (32), 11218-11223 (2008).</li><li>Shen, M., 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=Pyrvinium+pamoate+changes+alternative+splicing+of+the+serotonin+receptor+2C+by+influencing+its+RNA+structure.">Pyrvinium pamoate changes alternative splicing of the serotonin receptor 2C by influencing its RNA structure.</a> Nucleic Acids Research. 41 (6), 3819-3832 (2013).</li><li>Noto, J. J., Schmidt, C. A., Matera, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+and+expressing+circular+RNAs+via+tRNA+splicing.">Engineering and expressing circular RNAs via tRNA splicing.</a> RNA Biology. , 1-7 (2017).</li><li>Schmidt, C. A., Noto, J. J., Filonov, G. S., Matera, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Method+for+Expressing+and+Imaging+Abundant,+Stable,+Circular+RNAs+In+Vivo+Using+tRNA+Splicing.">A Method for Expressing and Imaging Abundant, Stable, Circular RNAs In Vivo Using tRNA Splicing.</a> Methods in Enzymology. 572, 215-236 (2016).</li><li>Welden, J. R., van Doorn, J., Nelson, P. T., Stamm, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+human+MAPT+locus+generates+circular+RNAs.">The human MAPT locus generates circular RNAs.</a> Biochimica et Biophysica Acta - Molecular Basis of Disease. , 2753-2760 (2018).</li><li>Casper, J., 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=The+UCSC+Genome+Browser+database:+2018+update.">The UCSC Genome Browser database: 2018 update.</a> Nucleic Acids Research. 46, 762-769 (2018).</li><li>Grozdanov, P. N., MacDonald, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+plasmid+vectors+expressing+FLAG-tagged+proteins+under+the+regulation+of+human+elongation+factor-1alpha+promoter+using+Gibson+assembly.">Generation of plasmid vectors expressing FLAG-tagged proteins under the regulation of human elongation factor-1alpha promoter using Gibson assembly.</a> Journal of Visualized Experiments. (96), (2015).</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=A+novel+strategy+to+engineer+DNA+polymerases+for+enhanced+processivity+and+improved+performance+in+vitro.">A novel strategy to engineer DNA polymerases for enhanced processivity and improved performance in vitro.</a> Nucleic Acids Research. 32 (3), 1197-1207 (2004).</li><li>Gibson, D. G., 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=Enzymatic+assembly+of+DNA+molecules+up+to+several+hundred+kilobases.">Enzymatic assembly of DNA molecules up to several hundred kilobases.</a> Nature Methods. 6 (5), 343-345 (2009).</li><li>Conn, S. J., 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=The+RNA+binding+protein+quaking+regulates+formation+of+circRNAs.">The RNA binding protein quaking regulates formation of circRNAs.</a> Cell. 160 (6), 1125-1134 (2015).</li><li>Jeck, W. R., Sharpless, N. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detecting+and+characterizing+circular+RNAs.">Detecting and characterizing circular RNAs.</a> Nature Biotechnology. 32 (5), 453-461 (2014).</li><li>Pamudurti, N. R., 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=Translation+of+CircRNAs.">Translation of CircRNAs.</a> Molecular Cell. 66 (1), 9-21 (2017).</li><li>Kramer, M. 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=Combinatorial+control+of+Drosophila+circular+RNA+expression+by+intronic+repeats,+hnRNPs,+and+SR+proteins.">Combinatorial control of Drosophila circular RNA expression by intronic repeats, hnRNPs, and SR proteins.</a> Genes &amp; Development. 29 (20), 2168-2182 (2015).</li><li>Starke, S., 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=Exon+circularization+requires+canonical+splice+signals.">Exon circularization requires canonical splice signals.</a> Cell Reports. 10 (1), 103-111 (2015).</li><li>Suzuki, H., Tsukahara, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+view+of+pre-mRNA+splicing+from+RNase+R+resistant+RNAs.">A view of pre-mRNA splicing from RNase R resistant RNAs.</a> International Journal of Molecular Sciences. 15 (6), 9331-9342 (2014).</li><li>Zhang, X. O., 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=Diverse+alternative+back-splicing+and+alternative+splicing+landscape+of+circular+RNAs.">Diverse alternative back-splicing and alternative splicing landscape of circular RNAs.</a> Genome Research. 26 (9), 1277-1287 (2016).</li><li>Liang, D., Wilusz, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Short+intronic+repeat+sequences+facilitate+circular+RNA+production.">Short intronic repeat sequences facilitate circular RNA production.</a> Genes &amp; Development. 28 (20), 2233-2247 (2014).</li><li>Wang, Y., Mandelkow, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tau+in+physiology+and+pathology.">Tau in physiology and pathology.</a> Nature Reviews Neuroscience. 17 (1), 5-21 (2016).</li><li>Fejes-Toth, K., 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=Post-transcriptional+processing+generates+a+diversity+of+5'-modified+long+and+short+RNAs.">Post-transcriptional processing generates a diversity of 5'-modified long and short RNAs.</a> Nature. 457 (7232), 1028-1032 (2009).</li><li>Gao, Q. S., 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=Complex+regulation+of+tau+exon+10,+whose+missplicing+causes+frontotemporal+dementia.">Complex regulation of tau exon 10, whose missplicing causes frontotemporal dementia.</a> Journal of Neurochemistry. 74 (2), 490-500 (2000).</li><li>Hartmann, A. M., 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=Regulation+of+alternative+splicing+of+human+tau+exon+10+by+phosphorylation+of+splicing+factors.">Regulation of alternative splicing of human tau exon 10 by phosphorylation of splicing factors.</a> Molecular and Cellular Neuroscience. 18 (1), 80-90 (2001).</li><li>Wang, Y., Wang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+backsplicing+produces+translatable+circular+mRNAs.">Efficient backsplicing produces translatable circular mRNAs.</a> RNA. 21 (2), 172-179 (2015).</li><li>Yang, Y., Wang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Constructing+GFP-Based+Reporter+to+Study+Back+Splicing+and+Translation+of+Circular+RNA.">Constructing GFP-Based Reporter to Study Back Splicing and Translation of Circular RNA.</a> Methods in Molecular Biology. 1724, 107-118 (2018).</li><li>Zheng, Q., 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=Circular+RNA+profiling+reveals+an+abundant+circHIPK3+that+regulates+cell+growth+by+sponging+multiple+miRNAs.">Circular RNA profiling reveals an abundant circHIPK3 that regulates cell growth by sponging multiple miRNAs.</a> Nature Communications. 7, 11215 (2016).</li><li>Jia, W., Xu, B., Wu, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circular+RNA+expression+profiles+of+mouse+ovaries+during+postnatal+development+and+the+function+of+circular+RNA+epidermal+growth+factor+receptor+in+granulosa+cells.">Circular RNA expression profiles of mouse ovaries during postnatal development and the function of circular RNA epidermal growth factor receptor in granulosa cells.</a> Metabolism. 85, 192-204 (2018).</li><li>Liang, 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=The+Output+of+Protein-Coding+Genes+Shifts+to+Circular+RNAs+When+the+Pre-mRNA+Processing+Machinery+Is+Limiting.">The Output of Protein-Coding Genes Shifts to Circular RNAs When the Pre-mRNA Processing Machinery Is Limiting.</a> Molecular Cell. 68 (5), 940-954 (2017).</li><li>Legnini, I., 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=Circ-ZNF609+Is+a+Circular+RNA+that+Can+Be+Translated+and+Functions+in+Myogenesis.">Circ-ZNF609 Is a Circular RNA that Can Be Translated and Functions in Myogenesis.</a> Molecular Cell. 66 (1), 22-37 (2017).</li><li>Li, X., 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=Coordinated+circRNA+Biogenesis+and+Function+with+NF90/NF110+in+Viral+Infection.">Coordinated circRNA Biogenesis and Function with NF90/NF110 in Viral Infection.</a> Molecular Cell. 67 (2), 214-227 (2017).</li><li>Zhang, 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=The+Biogenesis+of+Nascent+Circular+RNAs.">The Biogenesis of Nascent Circular RNAs.</a> Cell Reports. 15 (3), 611-624 (2016).</li></ol>

Em geral, as RNAs circulares são baixas abundantes1, o que complica o estudo de sua função e formação. Semelhante às RNAs lineares13, o uso de minigenes repórter permite a identificação de fatores cis e trans-atuação que regulam a formação de RNAs circulares. Assim, essa abordagem gera hipóteses que podem ser ainda mais testadas usando os genes endógenos.
O passo mais crítico é o design do gene do repórter. A montagem enzimátic...

RNAs Circulares As RNAs circulares (circRNAs) são RNAs univalentemente fechadas que são expressas na maioria dos organismos. Eles são gerados juntando um site de emenda downstream 5' a um site de emendas upstream 3', um processo chamado back-splicing(Figura 1A)1. Seqüências no pré-mRNA que exibem base complementar tão curta quanto 30-40 nt trazem locais de back-splice em alinhamento adequado para formação de cirrna2. Em humanos, os elementos Alu 1, representando cerca de 11% do genoma3, formam extensas estruturas de RNA duplamente encalhadas em pré-mRNA devido à sua auto-complementaridade4,5 e, assim, promovem a formação de cirrnas1.
Atualmente, três principais funções de cirrnas foram descritas. Algumas circRNAs ligam microRNAs (miRNAs) e através de atos de sequestro como esponjas miRNA6. CircRNAs foram implicadas na regulação transcricional e pós-transcricional, por meio de competição com emenda linear7 ou modulação da atividade do fator de transcrição8. Por fim, as cirrnas contêm quadros curtos de leitura abertas e a prova de estudos de princípio mostram que podem ser traduzidos9,10. No entanto, a função da maioria das cirrnas permanece enigmática. A maioria das RNAs circulares foram detectadas usando métodos de seqüenciamento de última geração11. Análises detalhadas de genes individuais usando abordagens RT-PCR direcionadas revelam que um grande número de RNAs circulares continua a ser descoberto12.
Uso de genes de repórteres para analisar o processamento pré-mRNA A análise do mRNA derivado do DNA que o repórter constrói transfeccionado em células é um método bem estabelecido para estudar emendas alternativas pré-mRNA, que podem ser aplicadas a RNAs circulares. Em geral, o éon alternativo, seus íntrons circundantes e exons constitutivos são amplificados e clonados em um vetor de expressão eucariótica. Freqüentemente, os íntrons são encurtados. Os construtos são transfeccionados em células eucarióticas e geralmente analisados por RT-PCR13,14. Esta abordagem tem sido amplamente utilizada para mapear sites de emendas regulatórias e fatores transadores em experimentos de cofecção13,15,16,17,18. Além disso, a geração de minigenes que expressam proteínas permitiu a triagem de substâncias que alteram emendas alternativas19,20.
O método foi aplicado a RNAs circulares. Atualmente, pelo menos 12 backbones minigenes foram descritos na literatura e estão resumidos na Tabela 1. Com exceção do sistema de expressão baseado em tRNA21,22, todos eles são dependentes de promotores de polimerase II. Aqui, descrevemos um método para gerar minigenes de repórteres humanos para determinar fatores cis e transativos envolvidos na geração de RNAs circulares. Uma visão geral do método usando seqüências de um gene de repórter publicado23 é mostrada na Figura 1.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>(PEI) Hydrochloride</td>
			<td>Polysciences</td>
			<td>24765-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Builder tool</td>
			<td>NEB</td>
			<td></td>
			<td><a href="https://nebuilder.neb.com/#!/" target="_blank">https://nebuilder.neb.com/#!/</a></td>
		</tr>
		<tr>
			<td>Dark Reader Transilluminator.</td>
			<td>Clare Chemical Research</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Enzymatic DNA assembly kit</td>
			<td>NEB</td>
			<td>E2621S</td>
			<td></td>
		</tr>
		<tr>
			<td>Gel and PCR cleanup kit</td>
			<td>Promega</td>
			<td>A9282</td>
			<td></td>
		</tr>
		<tr>
			<td>Glyco Blue</td>
			<td>Thermo Fisher</td>
			<td>AM9516</td>
			<td></td>
		</tr>
		<tr>
			<td>pcDNA3.1 cloning site</td>
			<td>Polycloning site</td>
			<td></td>
			<td><a href="https://assets.thermofisher.com/TFS-Assets/LSG/manuals/pcdna3_1_man.pdf" target="_blank">https://assets.thermofisher.com/TFS-Assets/LSG/manuals/pcdna3_1_man.pdf</a></td>
		</tr>
		<tr>
			<td>Polymerase 1</td>
			<td>NEB</td>
			<td>M0491L</td>
			<td>Q5 DNA polymerase</td>
		</tr>
		<tr>
			<td>Polymerase 2</td>
			<td>Biorad</td>
			<td>1725310</td>
			<td>Long range polymerase (NEB), iproof (BioRad)</td>
		</tr>
		<tr>
			<td>Polymerase 2</td>
			<td>Qiagen</td>
			<td>206402</td>
			<td>Qiagen long range polymerase kit</td>
		</tr>
		<tr>
			<td>Reverse Transcriptase</td>
			<td>Thermo Fisher</td>
			<td>18080044</td>
			<td></td>
		</tr>
		<tr>
			<td>RNA isolation kit</td>
			<td>Life Technologies</td>
			<td>12183025</td>
			<td>Ambion by Life Technologies</td>
		</tr>
		<tr>
			<td>RNAse R</td>
			<td>Lucigen</td>
			<td>RNR07250</td>
			<td>Epicenter/Lucigen</td>
		</tr>
		<tr>
			<td>Stable competent cells</td>
			<td>NEB</td>
			<td>C3040H</td>
			<td>NEB stable cells</td>
		</tr>
		<tr>
			<td>Standard cloning bacteria</td>
			<td>NEB</td>
			<td>C2988J</td>
			<td>NEB5-alpha competent</td>
		</tr>
		<tr>
			<td>Web tool to design primers</td>
			<td>NEB</td>
			<td></td>
			<td><a href="https://nebuilder.neb.com/#!/" target="_blank">https://nebuilder.neb.com/#!/</a></td>
		</tr>
		<tr>
			<td>Web-based temperature calculations</td>
			<td>NEB</td>
			<td></td>
			<td><a href="https://tmcalculator.neb.com/#!/main" target="_blank">https://tmcalculator.neb.com/#!/main</a></td>
		</tr>
	</tbody>
</table>

use of alu element containing minigenes to analyze circular rnas

Além de mRNAs lineares, muitos genes eucaticos geram RNAs circulares. A maioria das RNAs circulares são geradas juntando-se a um site de emenda de 5' com um site de emenda upstream 3' dentro de um pré-mRNA, um processo chamado back-splicing. Essa circularização é provavelmente auxiliada por estruturas secundárias no pré-mRNA que aproximam os locais de junção. Nos genes humanos, os elementos alu são pensados para promover essas estruturas secundárias de RNA, pois os elementos alu são abundantes e exibem complementaridades de base uns com os outros quando presentes em direções opostas no pré-mRNA. Aqui, descrevemos a geração e análise de grandes elementos Alu contendo genes de repórteres que formam RNAs circulares. Através da otimização dos protocolos de clonagem, genes de repórter com comprimento de inserção de até 20 kb podem ser gerados. Sua análise em experimentos de cofecção permite a identificação de fatores regulatórios. Assim, este método pode identificar seqüências de RNA e componentes celulares envolvidos na formação de RNA circular.

Os genes dos repórteres permitem determinar fatores regulatórios que influenciam a formação circular de RNA. No entanto, esses genes de repórteres são grandes e contêm elementos repetitivos que muitas vezes tornam construções de DNA instáveis. Devido ao seu grande tamanho, muitas vezes é necessário excluir partes dos íntrons, o que é conseguido amplificando peças genômicas contendo os éons e partes menores de flanqueamento intrônico. Essas peças de DNA são montadas enzimáticamente, permitindo a const...

Watch this Scientific Journal Video about Use of Alu Element Containing Minigenes to Analyze Circular RNAs at JoVE.com

Use of Alu Element Containing Minigenes to Analyze Circular RNAs

Clonamos e analisamos genes de repórteres gerando RNAs circulares. Esses genes de repórter são maiores do que construções para analisar emendas lineares e conter elementos Alu. Para investigar os RNAs circulares, os construtos são transfeccionados em células e o RNA resultante é analisado usando RT-PCR após a remoção do RNA linear.

Uso do elemento Alu contendo Minigenes para analisar RNAs circulares

In addition to linear mRNAs, many eukaryotic genes generate circular RNAs. Most circular RNAs are generated by joining a 5&#39; splice site with an ...

Este protocolo é significativo porque permite ao usuário gerar um sistema de expressão genômica que pode sofrer emendas alternativas e, neste caso, formar RNAs circulares que podem ser testadas para sua função e associação de doenças. A principal vantagem dessa técnica é que ela abrirá caminho para que outros usem esse protocolo em biologia molecular e clonagem ao estudar emendas alternativas na formação e função circular de RNA. Meu conselho para alguém que experimente essa técnica pela primeira vez seria otimizar as condições do PCR.Execute gradientes ou realize o PCR de touchdown com diferentes temperaturas de ressarcimento e tempos de extensão. Normalmente fragmentos mais longos ao longo de seis KB estenderão um KB por ciclo e diferentes temperaturas de ressarcial precisarão ser testadas para a melhor amplificação. A demonstração desse método é fundamental porque dará aos usuários uma melhor representação visual dos aspectos mais difíceis do procedimento, especialmente a geração de primers.Para iniciar este procedimento, carregue o Navegador de Genomas ucsc e use-o para identificar elementos repetitivos necessários para a formação circular de RNA e incorporá-los nos construtos. É importante ressaltar que os primers para amplificação precisam estar fora dos elementos repetitivos. Cole a sequência circular de RNA na pesquisa blat humana e selecione o organismo certo.Envie a sequência, vá para a visualização do navegador e amplie os temporizadores de 1,5 ou conforme apropriado. Em seguida, mouse sobre os elementos repetitivos para identificar seu subtipo em uma janela flutuante. Elementos Alu estão na linha seno.Use o botão de faixas padrão sob a janela para redefinir o navegador se uma imagem incorreta for obtida. Primeiro vá ver, DNA na linha superior do Navegador de Genoma uscs para baixar a sequência de DNA mostrada na janela. Na opção de formatação de sequenciamento, selecione opções estendidas de caixa/cor.Selecione o caso padrão como menor e selecione o caso de alternância para NCBI RefSeq. Selecione sublinhar e em negrito e Itálico para RepeatMasker. Clique em enviar.Haverá exons como letras maiúsculas e introns como letras minúsculas. Verifique as fronteiras exon/intron. Se o navegador mostrar o complemento reverso, volte e selecione a caixa de complemento reverso até que as bordas exon/intron corretas sejam exibidas.Em seguida, copie o arquivo com a orientação correta em um documento de processamento de palavras e destaque os exons. Selecione os fragmentos a serem amplificados certificando-se de que o intron não comece ou termine em uma região repetitiva, pois os primers nessas regiões não amplificarão sequências específicas. Para começar, use uma ferramenta web para projetar os primers para clonagem.Para a sequência vetorial, adicione o local de inserção como o último nucleotídeo e, posteriormente, adicione os fragmentos. Como a numeração do vetor não começa com um determinado local de inserção, o local de inserção no vetor está localizado e a parte a jusante é colocada na frente da sequência upstream. Ajuste os primers se seus pontos de fusão estiverem a mais de quatro graus Celsius de distância e não funcionarem em amplificação.Neste estudo, os genes repórteres que geram RNAs circulares são clonados e analisados. Os produtos PCR otimizados são separados em um gel de 1% de agarose contendo 1X verde gel. As bandas individuais representam os produtos PCR que serão usados na montagem de DNA enzimático.Essas bandas são então cortadas do gel e purificadas. O produto PCR purificado não se aplica ao tamanho esperado com verde gel, de modo que os produtos também são separados em um gel de 1%agarose que é posteriormente manchado com brometo de etídio para garantir que os produtos sejam do tamanho correto. Para começar, prepare um kit de montagem de DNA enzimático.Combine o vetor e insira em uma relação molar de um a dois. Em seguida, adicione 10 microliters de mistura de DNA master mix. Incubar amostras por 60 minutos a 50 graus.Descongele células competentes no gelo durante a incubação. As células devem estar em um volume de 50 microliters. Em seguida, transforme células competentes com a reação total de montagem.Adicione dois microliters do produto montado refrigerado às células competentes. Misture movendo suavemente o tubo quatro a cinco vezes. Não vórtice.Coloque a mistura no gelo por 30 minutos. Aqueça a mistura a 42 graus Celsius por 30 segundos. Em seguida, colocá-lo de volta no gelo por dois minutos.Depois disso, adicione 950 microliters de mídia SOC de temperatura ambiente ao tubo. Incubar a 37 graus Celsius por 60 minutos enquanto treme a 300 RPM. Durante esta incubação, aqueça duas placas de seleção que contenham o antibiótico apropriado.Após a incubação, centrifugar o tubo de reação a 10.000 g durante 30 segundos para pelotar as células e emplacar 25% das células em uma placa de seleção e 75% na outra. Incubar essas placas durante a noite a 37 graus Celsius. Antes de começar a transfecção, verifique seu DNA por restrição de digestão.Aqui, um representante tau minigene que contém exons de nove a 12 é cortado com enzimas de restrição indicadas para descartar grandes recombinações. Para transfecção, primeiro dissolver cloridrato linear de polietileno na água a uma concentração de um miligrama por mililitro no pH dois. Use hidróxido de sódio para levar o pH até sete e filtrar a solução com um filtro de 0,22 micrômetros.Armazene a solução a quatro graus Celsius até estar pronta para uso. Em seguida, divida as células nos poços de uma placa de seis poços e deixe-as crescer durante a noite na mídia DMEM contendo 10% de FBS. No dia seguinte, aliquot um micrograma do gene relatado em um tubo estéril e adicionar 200 microliters de cloreto de sódio filtrado 150 mililitros.Misture por vórtice. Em seguida, adicione a solução de polietilenimina a esta mistura a uma proporção de três microliters de polietilenimina para cada um micrograma de DNA. Centrífuga brevemente para coletar amostras na parte inferior do tubo.Incubar as amostras em temperatura ambiente por 10 minutos. Em seguida, adicione-o diretamente às células HEK293. Incubar as células durante a noite a 37 graus Celsius com 5% de dióxido de carbono.No dia seguinte, use um kit de isolamento de RNA para isolar o RNA para RT-PCR. cDNA de duas amostras derivadas de tecidos cerebrais humanos são amplificadas com primers circulares de RNA circ tau exon 1210 reverso e circ tau exon 1211 para a frente. Enquanto a faixa esperada correspondente ao RNA circular tau é vista, as outras bandas fortes são artefatos que não combinam com o genoma humano.Este experimento é repetido com condições de PCR idênticas, mas a transcrição reversa foi realizada apenas com o primer reverso circ tau exon 1210. Apenas a banda esperada é amplificada e validada através de sequenciamento. O RNA é então tratado com RNase R que remove RNA linear.O RNA circular é detectável após o tratamento, enquanto o RNA linear não dá mais um sinal detectável. O RNA é isolado 24 horas após a transfecção e analisado pelo RT-PCR. A amplificação do tau linear mRNA mostra duas bandas devido ao splicing alternativo do exon 10.Sua proporção muda para a expressão excessiva de fatores de emenda. A amplificação do RNA circular 1210 tau mostra a dependência da expressão tau circ RNA na expressão de alguns fatores de emenda, especialmente o CLK2 de quinase semelhante ao Cdc2 e a proteína SR 9G8. A coisa mais importante a se lembrar ao tentar este procedimento é o design e a localização dos primers ao construir um minigene.O primer não deve estar em elementos repetitivos e precisará ser otimizado em diferentes condições, dependendo do fragmento ser amplificado. Após este procedimento, outros métodos que podem ser realizados serão o teste da função das RNAs circulares. Os usuários podem testar a tradução ou o sequestro de proteínas para identificar uma função para o RNA circular específico que o usuário está interessado.Essa técnica abriu caminho para a utilização de fragmentos genômicos em um sistema de minigene que pode expressar sobre as RNAs circulares permitindo que o usuário teste e identifique sua função e em alguns aspectos sua associação à doença. A implicação dessa técnica se estende para potenciais terapias e diagnósticos de uma determinada doença, por exemplo, tauopatias, doenças neurodegenerativas associadas à patologia tau. Descobrimos que a proteína associada ao microtúbulo tau, conhecida como MAPT, gera RNAs circulares que acreditamos estar contribuindo para a patologia da doença e esse método nos permite estudar plenamente essas RNAs circulares e identificar sua função e relação com a doença.Esse método poderia fornecer uma visão sobre uma melhor compreensão das RNAs circulares, quais são suas funções e o papel que podem desempenhar em certas doenças. Este método pode ser aplicado na clonagem de outros minigenes que expressam RNAs circulares entre espécies onde ele pode fornecer insights sobre sua função. A amplificação dos produtos PCR prova ser a mais difícil com fragmentos longos amplificados a partir do DNA genômico, juntamente com múltiplos elementos repetitivos dentro do fragmento.

use-of-alu-element-containing-minigenes-to-analyze-circular-rnas

Research

JoVE Journal

Biochemistry

Use of Alu Element Containing Minigenes to Analyze Circular RNAs

Combining Wet and Dry Lab Techniques to Guide the Crystallization of Large Coiled-coil Containing Proteins

Obtaining crystals for structure determination can be a difficult and time consuming proposition for any protein. Coiled-coil proteins and domains are found throughout nature, however, because of their physical properties and tendency to aggregate, they are traditionally viewed as being especially difficult to crystallize. Here, we utilize a variety of quick and simple techniques designed to identify a series of possible domain boundaries for a given coiled-coil protein, and then quickly characterize the behavior of these proteins in solution. With the addition of a strongly fluorescent tag (mRuby2), protein characterization is simple and straightforward. The target protein can be readily visualized under normal lighting and can be quantified with the use of an appropriate imager. The goal is to quickly identify candidates that can be removed from the crystallization pipeline because they are unlikely to succeed, affording more time for the best candidates and fewer funds expended on proteins that do not produce crystals. This process can be iterated to incorporate information gained from initial screening efforts, can be adapted for high-throughput expression and purification procedures, and is augmented by robotic screening for crystallization.

We describe a framework incorporating straightforward biochemical and computational analysis to guide the characterization and crystallization of large coiled-coil domains. This framework can be adapted for globular proteins or extended to incorporate a variety of high-throughput techniques.

Combinando Wet and Dry técnicas de laboratório para orientar a cristalização de grandes espiral enrolada contendo proteínas

Obtaining crystals for structure determination can be a difficult and time consuming proposition for any protein. Coiled-coil proteins and domains are ...

Bioquímica

Method to Visualize and Analyze Membrane Interacting Proteins by Transmission Electron Microscopy

Monotopic proteins exert their function when attached to a membrane surface, and such interactions depend on the specific lipid composition and on the availability of enough area to perform the function. Nanodiscs are used to provide a membrane surface of controlled size and lipid content. In the absence of bound extrinsic proteins, sodium phosphotungstate-stained nanodiscs appear as stacks of coins when viewed from the side by transmission electron microscopy (TEM). This protocol is therefore designed to intentionally promote stacking; consequently, the prevention of stacking can be interpreted as the binding of the membrane-binding protein to the nanodisc. In a further step, the TEM images of the protein-nanodisc complexes can be processed with standard single-particle methods to yield low-resolution structures as a basis for higher resolution cryoEM work. Furthermore, the nanodiscs provide samples suitable for either TEM or non-denaturing gel electrophoresis. To illustrate the method, Ca2+-induced binding of 5-lipoxygenase on nanodiscs is presented.

Many proteins perform their function when attached to membrane surfaces. The binding of extrinsic proteins on nanodisc membranes can be indirectly imaged by transmission electron microscopy. We show that the characteristic stacking (rouleau) of nanodiscs induced by the negative stain sodium phosphotungstate is prevented by the binding of extrinsic protein.

Método para visualizar e analisar proteínas de interação de membrana por microscopia eletrônica de transmissão

Monotopic proteins exert their function when attached to a membrane surface, and such interactions depend on the specific lipid composition and on the ...

Quantification of the Abundance and Charging Levels of Transfer RNAs in Escherichia coli

Transfer RNA (tRNA) is an essential part of the translational machinery in any organism. tRNAs bind and transfer amino acids to the translating ribosome. The relative levels of different tRNAs, and the ratio of aminoacylated tRNA to total tRNA, known as the charging level, are important factors in determining the accuracy and speed of translation. Therefore, the abundance and charging levels of tRNAs are important variables to measure when studying protein synthesis, for example under various stress conditions. Here, we describe a method for harvesting tRNA and directly measuring both the relative abundance and the absolute charging level of specific tRNA species in Escherichia coli. The tRNA is harvested in such a way that the labile bond between the tRNA and its amino acid is preserved. The RNA is then subjected to gel electrophoresis and Northern blotting, which results in separation of the charged and uncharged tRNAs. The levels of specific tRNAs in different samples can be compared due to the addition of spike-in cells for normalization. Prior to RNA purification, we add 5% of E. coli cells that overproduce the rare tRNAselC to each sample. The amount of the tRNA species of interest in a sample is then normalized to the amount of tRNAselC in the same sample. Addition of spike-in cells prior to RNA purification has the advantage over addition of purified spike-in RNAs that it also accounts for any differences in cell lysis efficiency between samples.

Quantification of the Abundance and Charging Levels of Transfer RNAs in Escherichia coli

Here we present a method for directly measuring transfer RNA charging levels from purified Escherichia coli RNA as well as a way to compare relative levels of transfer RNA, or any other short RNA, across different samples based on the addition of spike-in cells expressing a reference gene.

Quantificação de abundância e carregamento níveis de RNAs de transferência em Escherichia coli

Transfer RNA (tRNA) is an essential part of the translational machinery in any organism. tRNAs bind and transfer amino acids to the translating ribosome. ...

Simultaneous Measurement of Superoxide/Hydrogen Peroxide and NADH Production by Flavin-containing Mitochondrial Dehydrogenases

It has been reported that mitochondria can contain up to 12 enzymatic sources of reactive oxygen species (ROS). A majority of these sites include flavin-dependent respiratory complexes and dehydrogenases that produce a mixture of superoxide (O2&#9679;-) and hydrogen peroxide (H2O2). Accurate quantification of the ROS-producing potential of individual sites in isolated mitochondria can be challenging due to the presence of antioxidant defense systems&#160;and side reactions that also form O2&#9679;-/H2O2. Use&#160;of nonspecific inhibitors that can disrupt mitochondrial bioenergetics can also compromise measurements by altering&#160;ROS release from other sites of production. Here, we present an easy method for the simultaneous measurement of H2O2 release and nicotinamide adenine dinucleotide (NADH) production by purified flavin-linked dehydrogenases. For our purposes here, we have used purified pyruvate dehydrogenase complex (PDHC) and &#945;-ketoglutarate dehydrogenase complex (KGDHC) of porcine heart origin as examples. This method allows for an accurate measure of native H2O2 release rates by individual sites of production by eliminating other potential sources of ROS and antioxidant systems. In addition, this method allows for a direct comparison of the relationship between H2O2 release and enzyme activity and the screening of the effectiveness and selectivity of inhibitors for ROS production. Overall, this approach can allow for the in-depth assessment of native rates of ROS release for individual enzymes prior to conducting more sophisticated experiments with isolated mitochondria or permeabilized muscle fiber.

Mitochondria contain several flavin-dependent enzymes that can produce reactive oxygen species (ROS). Monitoring ROS release from individual sites in mitochondria is challenging due to unwanted side reactions. We present an easy, inexpensive method for direct assessment of native rates for ROS release using purified flavoenzymes and microplate fluorometry.

Medição simultânea de peróxido de hidrogénio superóxido e produção de NADH por desidrogenases mitocondriais contendo Flavin

It has been reported that mitochondria can contain up to 12 enzymatic sources of reactive oxygen species (ROS). A majority of these sites include ...

Use of Two Dimensional Semi-denaturing Detergent Agarose Gel Electrophoresis to Confirm Size Heterogeneity of Amyloid or Amyloid-like Fibers

Amyloid or amyloid-like fibers have been associated with many human diseases, and are now being discovered to be important for many signaling pathways. The ability to readily detect the formation of these fibers under various experimental conditions is essential for understanding their potential function. Many methods have been used to detect the fibers, but not without some drawbacks. For example, electron microscopy (EM), or staining with Congo Red or Thioflavin T often requires purification of the fibers. On the other hand, semi-denaturing detergent agarose gel electrophoresis (SDD-AGE) allows detection of the SDS-resistant amyloid-like fibers in the cell extracts without purification. In addition, it allows the comparison of the size difference of the fibers. More importantly, it can be used to identify specific proteins within the fibers by Western blotting. It is less time consuming and more easily accessible to a wider number of labs. SDD-AGE results often show variable degree of heterogeneity. It raises the question whether part of the heterogeneity results from the dissociation of the protein complex during the electrophoresis in the presence of SDS. For this reason, we have employed a second dimension of SDD-AGE to determine if the size heterogeneity seen in SDD-AGE is truly a result of fiber heterogeneity in vivo and not a result of either degradation or dissociation of some of the proteins during electrophoresis. This method allows fast, qualitative confirmation that the amyloid or amyloid-like fibers are not partially dissociating during the SDD-AGE process.

Here we use two-dimensional semi-denaturing agarose gel electrophoresis to confirm the presence of amyloid-like fibers of heterogeneous size and exclude the possibility that the size heterogeneity is due to dissociation of the amyloid fibers during the gel running process.

Utilização de eletroforese em Gel de Agarose detergente semi desnaturação Dimensional dois para confirmar a heterogeneidade de tamanho das fibras de amiloides ou Amyloid-como

Amyloid or amyloid-like fibers have been associated with many human diseases, and are now being discovered to be important for many signaling pathways. ...

Large-scale Production of Recombinant RNAs on a Circular Scaffold Using a Viroid-derived System in Escherichia coli

With increasing interest in RNA biology and the use of RNA molecules in sophisticated biotechnological applications, the methods to produce large amounts of recombinant RNAs are limited. Here, we describe a protocol to produce large amounts of recombinant RNA in Escherichia coli based on co-expression of a chimeric molecule that contains the RNA of interest in a viroid scaffold and a plant tRNA ligase. Viroids are relatively small, non-coding, highly base-paired circular RNAs that are infectious to higher plants. The host plant tRNA ligase is an enzyme recruited by viroids that belong to the family Avsunviroidae, such as Eggplant latent viroid (ELVd), to mediate RNA circularization during viroid replication. Although ELVd does not replicate in E. coli, an ELVd precursor is efficiently transcribed by the E. coli RNA polymerase and processed by the embedded hammerhead ribozymes in bacterial cells, and the resulting monomers are circularized by the co-expressed tRNA ligase reaching a remarkable concentration. The insertion of an RNA of interest into the ELVd scaffold enables the production of tens of milligrams of the recombinant RNA per liter of bacterial culture in regular laboratory conditions. A main fraction of the RNA product is circular, a feature that facilitates the purification of the recombinant RNA to virtual homogeneity. In this protocol, a complementary DNA (cDNA) corresponding to the RNA of interest is inserted in a particular position of the ELVd cDNA in an expression plasmid that is used, along the plasmid to co-express eggplant tRNA ligase, to transform E. coli. Co-expression of both molecules under the control of strong constitutive promoters leads to production of large amounts of the recombinant RNA. The recombinant RNA can be extracted from the bacterial cells and separated from the bulk of bacterial RNAs taking advantage of its circularity.

Large-scale Production of Recombinant RNAs on a Circular Scaffold Using a Viroid-derived System in Escherichia coli

Here, we present a protocol to produce large amounts of recombinant RNA in Escherichia coli by co-expressing a chimeric RNA that contains the RNA of interest in a viroid scaffold and a plant tRNA ligase. The main product is a circular molecule that facilitates purification to homogeneity.

Produção em grande escala de RNAs recombinantes em um andaime Circular usando um sistema derivado de Viroid em Escherichia coli

With increasing interest in RNA biology and the use of RNA molecules in sophisticated biotechnological applications, the methods to produce large amounts ...

Expression, Purification, Crystallization, and Enzyme Assays of Fumarylacetoacetate Hydrolase Domain-Containing Proteins

Fumarylacetoacetate hydrolase (FAH) domain-containing proteins (FAHD) are identified members of the FAH superfamily in eukaryotes. Enzymes of this superfamily generally display multi-functionality, involving mainly hydrolase and decarboxylase mechanisms. This article presents a series of consecutive methods for the expression and purification of FAHD proteins, mainly FAHD protein 1 (FAHD1) orthologues among species (human, mouse, nematodes, plants, etc.). Covered methods are protein expression in E. coli, affinity chromatography, ion exchange chromatography, preparative and analytical gel filtration, crystallization, X-ray diffraction, and photometric assays. Concentrated protein of high levels of purity (&#62;98%) may be employed for crystallization or antibody production. Proteins of similar or lower quality may be employed in enzyme assays or used as antigens in detection systems (Western-Blot, ELISA). In the discussion of this work, the identified enzymatic mechanisms of FAHD1 are outlined to describe its hydrolase and decarboxylase bi-functionality in more detail.

Expression and purification of fumarylacetoacetate hydrolase domain-containing proteins is described with examples (expression in E. coli, FPLC). Purified proteins are used for crystallization and antibody production and employed for enzyme assays. Selected photometric assays are presented to display the multi-functionality of FAHD1 as oxaloacetate decarboxylase and acylpyruvate hydrolase.

Expressão, purificação, cristalização e ensaios enzimáticos de proteínas contendo domínio de Fumarilacetoacetato de hidrolase

Fumarylacetoacetate hydrolase (FAH) domain-containing proteins (FAHD) are identified members of the FAH superfamily in eukaryotes. Enzymes of this ...

Use of Microscale Thermophoresis to Measure Protein-Lipid Interactions

The ability to determine the binding affinity of lipids to proteins is an essential part of understanding protein-lipid interactions in membrane trafficking, signal transduction and cytoskeletal remodeling. Classic tools for measuring such interactions include surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). While powerful tools, these approaches have setbacks. ITC requires large amounts of purified protein as well as lipids, which can be costly and difficult to produce. Furthermore, ITC as well as SPR are very time consuming, which could add significantly to the cost of performing these experiments. One way to bypass these restrictions is to use the relatively new technique of microscale thermophoresis (MST). MST is fast and cost effective using small amounts of sample to obtain a saturation curve for a given binding event. There currently are two types of MST systems available. One type of MST requires labeling with a fluorophore in the blue or red spectrum. The second system relies on the intrinsic fluorescence of aromatic amino acids in the UV range. Both systems detect the movement of molecules in response to localized induction of heat from an infrared laser. Each approach has its advantages and disadvantages. Label-free MST can use untagged native proteins; however, many analytes, including pharmaceuticals, fluoresce in the UV range, which can interfere with determination of accurate KD values. In comparison, labeled MST allows for a greater diversity of measurable pairwise interactions utilizing fluorescently labeled probes attached to ligands with measurable absorbances in the visible range as opposed to UV, limiting the potential for interfering signals from analytes.

Microscale thermophoresis obtains binding constants quickly at low material cost. Either labeled or label free microscale thermophoresis is commercially available; however, label free thermophoresis is not capable of the diversity of interaction measurements that can be performed using fluorescent labels. We provide a protocol for labeled thermophoresis measurements.

Uso de Termoforese microescala para medir interações proteína-lipídicas

The ability to determine the binding affinity of lipids to proteins is an essential part of understanding protein-lipid interactions in membrane ...

Ready-To-Use qPCR for Detection of DNA from Trypanosoma cruzi or Other Pathogenic Organisms

Real-time PCR (qPCR) is a remarkably sensitive and precise technique&#160;that allows for amplifying&#160;minute amounts of nucleic acid targets from a multitude of samples. It has been extensively used in many research areas and achieved industrial application in fields such as human diagnostics and trait selection in crops of genetically modified organisms (GMO) crops. However, qPCR is not an error-proof technique. Mixing all reagents into a single master mix subsequently distributed onto 96 wells of a regular qPCR plate might lead to operator mistakes such as incorrect mixing of reagents or inaccurate dispensing into the wells. Here, a technique called gelification is presented, whereby most of the water present in the master mix is substituted by reagents that form a sol-gel mixture when submitted to a vacuum. As a result, qPCR reagents are effectively preserved for a few weeks at room temperature or a few months at 2-8 oC. Details of preparing each solution are shown here along with the expected aspect of a gelified reaction designed to detect&#160;T. cruzi satellite DNA (satDNA). A similar procedure can be applied to detect other organisms. Starting a gelified qPCR run is as simple as removing the plate from the refrigerator, adding the samples to their respective wells, and starting the run, thus decreasing the setup time of a full-plate reaction to the time it takes to load the samples. Additionally, gelified PCR reactions can be produced and controlled for quality in batches, saving time and avoiding common operator mistakes while running routine PCR reactions.

Ready-To-Use qPCR for Detection of DNA from Trypanosoma cruzi or Other Pathogenic Organisms

The present work describes the steps for producing ready-to-use qPCR for T. cruzi DNA detection that can be pre-loaded on the reaction vessel and stored in the refrigerator for several months.

QPCR pronto para uso para detecção de DNA de Trypanosoma cruzi ou outros organismos patogênicos

Real-time PCR (qPCR) is a remarkably sensitive and precise technique&#160;that allows for amplifying&#160;minute amounts of nucleic acid targets from a ...

Formulation and Characterization of Bioactive Agent Containing Nanodisks

The term nanodisk refers to a discrete type of nanoparticle comprised of a bilayer forming lipid, a scaffold protein, and an integrated bioactive agent. Nanodisks are organized as a disk-shaped lipid bilayer whose perimeter is circumscribed by the scaffold protein, usually a member of the exchangeable apolipoprotein family. Numerous hydrophobic bioactive agents have been efficiently solubilized in nanodisks by their integration into the hydrophobic milieu of the particle&#39;s lipid bilayer, yielding a largely homogenous population of particles in the range of 10-20 nm in diameter. The formulation of nanodisks requires a precise ratio of individual components, an appropriate sequential addition of each component, followed by bath sonication of the formulation mixture. The amphipathic scaffold protein spontaneously contacts and reorganizes the dispersed bilayer forming lipid/bioactive agent mixture to form a discrete, homogeneous population of nanodisk&#160;particles. During this process, the reaction mixture transitions from an opaque, turbid appearance to a clarified sample that, when fully optimized, yields no precipitate upon centrifugation. Characterization studies involve the determination of bioactive agent solubilization efficiency, electron microscopy, gel filtration chromatography, ultraviolet visible (UV/Vis) absorbance spectroscopy, and/or fluorescence spectroscopy. This is normally followed by an investigation of biological activity using cultured cells or mice. In the case of nanodisks harboring an antibiotic (i.e., the macrolide polyene antibiotic amphotericin B), their ability to inhibit the growth of yeast or fungi as a function of concentration or time can be measured. The relative ease of formulation, versatility with respect to component parts, nanoscale particle size, inherent stability, and aqueous solubility permits myriad in vitro and in vivo applications of nanodisk technology. In the present article, we describe a general methodology to formulate and characterize nanodisks containing amphotericin&#160;B as the hydrophobic bioactive agent.

Here, we describe the production and characterization of bioactive agents containing nanodisks. Amphotericin B nanodisks are taken as an example to describe the protocol in a stepwise manner.

Formulação e caracterização de agentes bioativos contendo nanodiscos

The term nanodisk refers to a discrete type of nanoparticle comprised of a bilayer forming lipid, a scaffold protein, and an integrated bioactive agent. ...