Este trabalho foi apoiado pelo Canadá de Diabetes.

<ol>
	<li>Guh, D. 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=The+incidence+of+co-morbidities+related+to+obesity+and+overweight:+a+systematic+review+and+meta-analysis.">The incidence of co-morbidities related to obesity and overweight: a systematic review and meta-analysis.</a> BMC. Public Health. 9, 88 (2009).</li><li>Wronska, A., Kmiec, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+and+biochemical+characteristics+of+various+white+adipose+tissue+depots.">Structural and biochemical characteristics of various white adipose tissue depots.</a> Acta Physiol (Oxf). 205 (2), 194-208 (2012).</li><li>Cannon, B., Nedergaard, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brown+adipose+tissue:+function+and+physiological+significance.">Brown adipose tissue: function and physiological significance.</a> Physiol Rev. 84 (1), 277-359 (2004).</li><li>Holland, N. T., Smith, M. T., Eskenazi, B., Bastaki, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biological+sample+collection+and+processing+for+molecular+epidemiological+studies.">Biological sample collection and processing for molecular epidemiological studies.</a> Mutat Res. 543 (3), 217-234 (2003).</li><li>Ibrahim, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subcutaneous+and+visceral+adipose+tissue:+structural+and+functional+differences.">Subcutaneous and visceral adipose tissue: structural and functional differences.</a> Obes Rev. 11 (1), 11-18 (2010).</li><li>Mann, A., Thompson, A., Robbins, N., Blomkalns, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localization,+identification,+and+excision+of+murine+adipose+depots.">Localization, identification, and excision of murine adipose depots.</a> J Vis Exp. (94), (2014).</li><li>Hemmrich, K., Denecke, B., Paul, N. E., Hoffmeister, D., Pallua, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RNA+Isolation+from+Adipose+Tissue:+An+Optimized+Procedure+for+High+RNA+Yield+and+Integrity.">RNA Isolation from Adipose Tissue: An Optimized Procedure for High RNA Yield and Integrity.</a> Laboratory Medicine. 41 (2), 104-106 (2010).</li><li>Cirera, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+efficient+method+for+isolation+of+total+RNA+from+adipose+tissue.">Highly efficient method for isolation of total RNA from adipose tissue.</a> BMC Res Notes. 6, 472 (2013).</li><li>Tan, S. C., Yiap, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DNA,+RNA,+and+protein+extraction:+the+past+and+the+present.">DNA, RNA, and protein extraction: the past and the present.</a> J Biomed Biotechnol. 2009, 574398 (2009).</li><li>Sellin Jeffries, M. K., Kiss, A. J., Smith, A. W., Oris, J. 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+comparison+of+commercially-available+automated+and+manual+extraction+kits+for+the+isolation+of+total+RNA+from+small+tissue+samples.">A comparison of commercially-available automated and manual extraction kits for the isolation of total RNA from small tissue samples.</a> BMC Biotechnol. 14, 94 (2014).</li><li>Tan, 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=Impact+of+the+prorenin/renin+receptor+on+the+development+of+obesity+and+associated+cardiometabolic+risk+factors.">Impact of the prorenin/renin receptor on the development of obesity and associated cardiometabolic risk factors.</a> Obesity (Silver. Spring). 22 (10), 2201-2209 (2014).</li><li>Taylor, S., Wakem, M., Dijkman, G., Alsarraj, M., Nguyen, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+practical+approach+to+RT-qPCR-Publishing+data+that+conform+to+the+MIQE+guidelines.">A practical approach to RT-qPCR-Publishing data that conform to the MIQE guidelines.</a> Methods. 50 (4), 1-5 (2010).</li><li>Aranda, P. S., LaJoie, D. M., Jorcyk, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bleach+gel:+a+simple+agarose+gel+for+analyzing+RNA+quality.">Bleach gel: a simple agarose gel for analyzing RNA quality.</a> Electrophoresis. 33 (2), 366-369 (2012).</li><li>Mercure, C., Prescott, G., Lacombe, M. J., Silversides, D. W., Reudelhuber, T. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+increases+in+circulating+prorenin+are+not+associated+with+renal+or+cardiac+pathologies.">Chronic increases in circulating prorenin are not associated with renal or cardiac pathologies.</a> Hypertension. 53 (6), 1062-1069 (2009).</li><li>Dusaulcy, 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=Adipose-specific+disruption+of+autotaxin+enhances+nutritional+fattening+and+reduces+plasma+lysophosphatidic+acid.">Adipose-specific disruption of autotaxin enhances nutritional fattening and reduces plasma lysophosphatidic acid.</a> J. Lipid Res. 52 (6), 1247-1255 (2011).</li><li>Nakamura, K., Fuster, J. J., Walsh, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipokines:+a+link+between+obesity+and+cardiovascular+disease.">Adipokines: a link between obesity and cardiovascular disease.</a> J Cardiol. 63 (4), 250-259 (2014).</li><li>Taylor, S. C., Mrkusich, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+state+of+RT-quantitative+PCR:+firsthand+observations+of+implementation+of+minimum+information+for+the+publication+of+quantitative+real-time+PCR+experiments+(MIQE).">The state of RT-quantitative PCR: firsthand observations of implementation of minimum information for the publication of quantitative real-time PCR experiments (MIQE).</a> J Mol Microbiol Biotechnol. 24 (1), 46-52 (2014).</li><li>Hummon, A. B., Lim, S. R., Difilippantonio, M. J., Ried, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+solubilization+of+proteins+after+TRIzol+extraction+of+RNA+and+DNA+from+patient+material+following+prolonged+storage.">Isolation and solubilization of proteins after TRIzol extraction of RNA and DNA from patient material following prolonged storage.</a> Biotechniques. 42 (4), 467-470 (2007).</li></ol>

Os autores não têm nada para divulgar.

Seguir HF-dieta alimentar, ratos obesos foram encontrados para ter aumentado o corpo e os pesos de tecido adiposo branco em comparação com ratos alimentados com uma dieta de N. RNA extraído usando solução de fenol rendeu amostras com boa pureza. Leptina é uma adipokine primeiramente produzido pelo tecido adiposo e é conhecida por correlacionar-se positivamente com a massa gorda16. Como esperado, a expressão de RNAm de leptina aumentou em ratos obesos em concomitância com sua massa gorda.
Este método tem várias etapas críticas. O importante é contaminação de um depósito de tecido adiposo branco com outro como é conhecido que depósitos diferentes de tecido adiposo têm funções diferentes,2,5. Contaminação pode trazer resultados enganosos em aplicações a jusante. Além disso, como a gordura tende a secar uma vez em contacto com o ar, coletando o tecido adiposo branco em um ritmo regular e consistente entre ratos recomenda-se o peso precisa ser tomada. Caso contrário, o peso total de uma almofada de gordura pode estar incorreto. A fim de obter RNA de boa qualidade e rendimento, seguindo o recentemente publicado MIQE diretrizes é um trunfo definitivo17. Em particular, fazendo pó muito fino de amostra durante a moagem pode ajudar a maximizar o rendimento. Isso maximiza o contato entre a solução de pó e fenol de tecido durante o isolamento de RNA. Por último mas não menos importante é o isolamento da camada contendo RNA durante o isolamento de RNA (etapa 3.12). Como a gordura é menos densa que a água, ele está posicionado na parte superior da fase de interesse. Minimizar o reporte de gordura é necessário para reduzir a interferência com aplicações a jusante.
Uma limitação deste método é a habilidade necessária para executar várias etapas do procedimento, bem como a necessidade de trabalhar com reagentes prejudiciais durante o isolamento de RNA. Além disso, todo o processo é trabalhoso.
Não há muitas alternativas ao método de coleta de tecido adiposo e amostra transformação antes do isolamento do RNA, além de pequenos detalhes que normalmente são ajustados por cada usuário. No caso de isolamento de RNA, muitas opções estão disponíveis, tais como a extração fenol/clorofórmio ou kits de isolamento de RNA. Há vantagens e desvantagens de cada opção e cabe ao usuário selecionar o melhor método baseado em aplicações a jusante. Extração fenol/clorofórmio é menos cara, mas requer o uso de reagentes prejudiciais e é trabalhosa. Kits de isolamento de RNA são geralmente mais caros, mas o procedimento é mais rápido e normalmente produz amostras com boa qualidade e pureza. É importante considerar o rendimento e a pureza do RNA, porque o material é limitado em branco tecido adiposo que é composto principalmente de gordura. A principal vantagem em usar a solução de fenol para isolamento (extração fenol/clorofórmio) é a possibilidade de isolar o DNA, RNA e proteína de uma única amostra18. Este é o custo - e tempo-eficaz que reduz o número de ratos exigidas para a obtenção de material suficiente. Como mencionado anteriormente, massa gorda é limitada em alguns modelos do rato. Para estes ratos, dividindo o tecido adiposo de terra em três partes para obter separadamente o RNA, DNA e proteína não é recomendado pois isso pode levar à material insuficiente para aplicações a jusante. Para contornar esse problema, também é possível juntar semelhante depósito de tecido adiposo de vários ratos com base em critérios definidos pelo usuário, que leva a um aumento do número de animais necessários.

A obesidade é uma epidemia mundial que pode levar a complicações, tais como o tipo 2 diabetes1. Modelos animais induzida por dieta obesos e geneticamente modificados são frequentemente usados para investigação em obesidade e suas complicações associadas. Tradicionalmente, o tecido adiposo branco é conhecido como um compartimento de armazenamento para o excesso de energia e é principalmente composto de lipídios enquanto marrom tecido adiposo converte energia em calor2,3. Tecido adiposo é dinâmico e irá expandir e encolher dependendo de vários fatores tais como a ingestão de alimentos e atividade física. Portanto, para determinar os fatores que contribuem para essas alterações, manipulação e coleta adequada de tecido adiposo são necessários4.
Entre os brancos os tecidos adiposos, é geralmente aceite que os depósitos de gordura subcutâneos e viscerais possuem diferentes propriedades como localização anatômica e função2,5. Por conseguinte, para evitar resultados conflitantes ou grande variabilidade, atenção deve ser tomado para evitar a contaminação cruzada entre estes depósitos de gordura diferentes quando coletando almofadas de gordura.
Além disso, existem três grandes desafios quando isolando RNA ou proteína do tecido adiposo de ratos brancos. Primeiro, coletar almofadas de gordura em ratos obesos não é uma tarefa fácil como a fronteira que separa diferentes depósitos de gordura brancos nem sempre é clara, em contraste com outros órgãos como rins e coração6. Em segundo lugar, por causa do alto teor lipídico do tecido adiposo, durante o isolamento do RNA ou proteína, uma camada de lipídios flutua no topo e impede o acesso direto à amostra. Em terceiro lugar, em vez de marrom tecido adiposo ou outros tecidos, tecido adiposo branco tem consideravelmente mais baixo conteúdo de RNA e proteína e isso é de grande preocupação quando usando ratos jovens, ratos alimentados com uma dieta normal de (N) e ratos que deverão tem baixas gordura massas (ou seja, KO modelos, tratamento com medicamentos, exercem, treinamento, etc.) 7 , 8.
Portanto, escolher o método apropriado para isolar o RNA do tecido adiposo é crítico. Métodos alternativos para extração fenol/clorofórmio são jogos comerciais. Eles normalmente são baseados em uma etapa de extração do fenol inicial, seguida de purificação de RNA em uma coluna de9. No entanto, esses kits são tipicamente mais caros e dar amostras de rendimento mais baixo, enquanto a qualidade do RNA pode ser variável mas são menos demorados. No entanto, uma das maiores vantagens para extração de solução/clorofórmio fenol descrito aqui é a possibilidade de isolar o DNA, RNA e proteína de uma única amostra10. Desde almofadas de gordura de ratos são geralmente pequenas e dar uma quantidade pequena de RNA e proteínas (especialmente em modelos do rato magra), estes protocolos maximizam os dados um pode tirar uma pequena amostra.
O objetivo deste trabalho é descrever detalhadamente um método para garantir a coleta de amostra adequada de depósitos de tecido adiposo branco três ratos, bem como a quantidade e a qualidade da isolação do RNA. RNA obtido seguindo este protocolo pode ser usado para realizar ensaios PCR em tempo real. Este protocolo não se destina para isolamento de RNA de adipócitos primários culturas.

<table border="0" cellpadding="0" cellspacing="0" style="width:1003px;" width="1002">
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		<tr height="21">
			<td height="21" style="height:21px;width:457px;">1 mL seringes</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">1X TE solution (10 mM Tris-HCl and 1 mM EDTA&#8226;Na2. pH 8.0)</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">22 G needles</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">26 G needles</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">75% Ethanol</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Block heater (dry bath)</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Chloroform</td>
			<td>Sigma</td>
			<td>C2432-500mL</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">dATP&#160;&#160;&#160;</td>
			<td style="width:189px;">Thermo scientific</td>
			<td style="width:189px;">R0141</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">dCTP&#160;&#160;</td>
			<td style="width:189px;">Thermo scientific</td>
			<td style="width:189px;">R0151</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">dGTP&#160;&#160;</td>
			<td style="width:189px;">Thermo scientific</td>
			<td style="width:189px;">R0161</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">DNase I (1 U/&#181;l)&#160;</td>
			<td style="width:189px;">Thermo scientific</td>
			<td style="width:189px;">EN0521</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">dTTP&#160;</td>
			<td style="width:189px;">Thermo scientific</td>
			<td style="width:189px;">R0171</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Faststart Universal SYBR green Master (Rox)</td>
			<td style="width:189px;">Roche</td>
			<td style="width:189px;">4913922001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Faststart universal SYBR green master (Rox) fluorescent dye&#160;</td>
			<td style="width:189px;">Roche</td>
			<td style="width:189px;">4913914001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Filtered tips</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Forceps&#160;</td>
			<td style="width:189px;">Instrumentarium</td>
			<td>HB275</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Gauze</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Hammer</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">High fat rodent diet</td>
			<td>Bio-Serv, Frenchtown, NJ</td>
			<td style="width:189px;">F3282</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Isopropanol&#160;</td>
			<td>Laboratoire MAT</td>
			<td>IH-0101</td>
			<td></td>
		</tr>
		<tr height="39">
			<td height="39" style="height:39px;width:457px;">Leptin forward PCR primer (5&#8217;-GGGCTTCACCCCATTCTGA-3&#8217;) 10 uM</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="39">
			<td height="39" style="height:39px;width:457px;">Leptin reverse PCR primer (5&#8217;-GGCTATCTGCAGCACATTTTG-3&#8217;) 10 uM</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Liquid nitrogen</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Maxima Reverse Transcriptase (enzyme and 5x buffer)</td>
			<td style="width:189px;">Thermo scientific</td>
			<td style="width:189px;">EP0742</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Nanopure water (referred as ultrapure water)</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Nitrile examination gloves</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Nitrile gloves</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="39">
			<td height="39" style="height:39px;width:457px;">Normal rodent diet</td>
			<td style="width:189px;">Harlan Laboratories, Madison, WI</td>
			<td style="width:189px;">Harlan 2018</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">P1000 pipetman</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">P2 pipetman</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">P20 pipetman</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">P200 pipetman</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Phenol solution (TRIzol)&#160;</td>
			<td style="width:189px;">Ambion Life Technologies</td>
			<td style="width:189px;">15598018</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Pre-identified aluminium foil</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Quartz spectrophotometer cuvette</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Rack for PCR tube strips</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Racks for RT-PCR tube strips</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Random hexamers&#160;</td>
			<td style="width:189px;">Invitrogen</td>
			<td style="width:189px;">58875</td>
			<td></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:457px;">Real-time PCR Rotor Gene system&#160;</td>
			<td style="width:189px;">Corbett research</td>
			<td style="width:189px;">RG-3000 Rotor-Gene thermal cycler</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Refrigerated bench-top centrifuge</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">RiboLock RNase Inhibitor&#160;</td>
			<td style="width:189px;">Thermo scientific</td>
			<td style="width:189px;">EO0381</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">RNase-free 1.5 mL eppendorf tubes</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">RNase-free 1.5 mL screw cap tubes</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RNase-free PCR tube strips (0.2 mL) and caps</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">RNase-free water&#160;</td>
			<td style="width:189px;">Hyclone</td>
			<td style="width:189px;">SH30538.02</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">RT-PCR machine</td>
			<td style="width:189px;">Qiagen</td>
			<td style="width:189px;">Rotor-Gene Corbett 3000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">RT-PCR tube strips (0.1 mL) and caps</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="39">
			<td height="39" style="height:39px;width:457px;">S16 forward PCR primer (5&#8217;-ATCTCAAAGGCCCTGGTAGC-3&#8217;) 10 uM</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="39">
			<td height="39" style="height:39px;width:457px;">S16 reverse PCR primer (5&#8217; ACAAAGGTAAACCCCGATCG-3&#8217;) 10 uM</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Spectrophotometer</td>
			<td style="width:189px;">Biochrom</td>
			<td style="width:189px;">Ultrospec 3100 pro</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Stainless steel mortar and pestle</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="77">
			<td height="77" style="height:77px;width:457px;">Surgical pads</td>
			<td style="width:189px;">Home made a foam board wrapped in a disposable absorbent underpad</td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Surgical scissors&#160;</td>
			<td style="width:189px;">Intrumentarium</td>
			<td style="width:189px;">130.450.11</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Thermal cycler</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Thermal cycler&#160;</td>
			<td style="width:189px;">Biometra</td>
			<td style="width:189px;">Thermocycler</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Vortex mixer</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:457px;">Weighing spatula</td>
			<td style="width:189px;"></td>
			<td style="width:189px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

mouse adipose tissue collection and processing for rna analysis

Comparado a outros tecidos, tecido adiposo branco tem um teor consideravelmente menos RNA e proteína para aplicações a jusante, tais como a PCR em tempo real e Western Blot, desde que em sua maioria contém lipídios. Isolamento de RNA a partir de amostras de tecido adiposo é também um desafio como etapas adicionais são necessárias para evitar esses lipídios. Aqui, apresentamos um procedimento para coletar três anatomicamente diferentes brancos adiposo tecidos de ratos, para processar estas amostras e realizar o isolamento de RNA. Podemos descrever a síntese do cDNA e gene experimentos de expressão usando PCR em tempo real. O protocolo descrito por este meio permite a redução da contaminação de cabelo e sangue nas almofadas de gordura, bem como a contaminação cruzada entre diferentes almofadas de gordura durante a coleta de tecido do animal. Ele também foi otimizado para garantir adequada quantidade e qualidade do RNA extraído. Este protocolo pode ser amplamente aplicado a qualquer modelo de rato onde as amostras de tecido adiposo são necessárias para experimentos de rotina, tais como a PCR em tempo real, mas não deve ser isolada da cultura de células primárias de adipócitos.

Após o processo de necropsia, os três tecidos adiposo brancos foram coletados e ponderados de dois grupos de ratos (N e HF dieta-alimentou ratos). Como esperado, os ratos na dieta de HF tinham aumentado de peso final e ganho de peso em comparação com littermates dieta N (tabela 1). Estas observações foram acompanhadas por mais do que um aumento de 2 vezes no peso da PGF, PRF e SCF em ratos obesos em comparação com aqueles na dieta de N.
Antes de executar quaisquer experimentos com o RNA isolado, sua pureza foi avaliada como descrito na etapa 4.9. Para cada tecido adiposo branco, isolamento de RNA pela solução de fenol produzido amostras com qualidade adequada, como a relação OD260/OD280 foi em torno de 2.0, que é considerada como puro para o RNA (tabela 2). Dados PCR em tempo real mostram que a expressão de RNAm de leptina aumentou significativamente em PGF, PRF e SCF de ratos obesos em comparação com aqueles na dieta de N(Figura 4). Com efeito, as diferenças observadas na expressão de RNAm de leptina não eram devido a uma variação de s16, o gene de referência usado para normalizar os resultados, entre os dois grupos de ratos, como valores de Ct não foram alterados (Figura 4B). Assim, s16 pode ser confiável usado como um gene de referência para a expressão de RNAm de PGF, PRF e SCF quando dieta HF é um parâmetro em um protocolo de estudo.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57026/57026fig1.jpg"> Figura 1 . Localização anatômica do tecido adiposo branco em camundongos. Um rato masculino na dieta de N tem sido dissecado para mostrar a localização de cada depósito de tecido adiposo e glândulas adrenais. SCF (A), PGF (B), PRF (C) e glândula adrenal (D). PGF, gordura peri-gonadal; PRF, gordura peri-renal; SCF, gordura subcutânea abdominal. <a href="//cloudflare.jove.com/files/ftp_upload/57026/57026fig1large.jpg" target="_blank">Clique aqui para ver uma versão maior desta figura.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57026/57026fig2.jpg"> Figura 2 . Carta de fluxo do protocolo isolamento do RNA usando solução de fenol. Representação esquemática das etapas necessárias para isolar o RNA do aterrado tecido adiposo branco. <a href="//cloudflare.jove.com/files/ftp_upload/57026/57026fig2large.jpg" target="_blank">Clique aqui para ver uma versão maior desta figura.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57026/57026fig3.jpg"> Figura 3 . Avaliação da qualidade do RNA em gel de lixívia. 1 µ g de RNA isolado de gordura subcutânea (SCF) e gordura peri-gonadal (PGF) é separado em um gel de agarose a 1% lixívia por eletroforese. 28s e 18s rRNA são visualizados por UV-transiluminação. Em gel é RNA isolado do SCF e PGF de um rato alimentado uma dieta normal. <a href="//cloudflare.jove.com/files/ftp_upload/57026/57026fig3large.jpg" target="_blank">Clique aqui para ver uma versão maior desta figura.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57026/57026fig4.jpg"> Figura 4 . Efeito da dieta de HF na expressão de RNAm de leptina e s16 no tecido adiposo branco. Leptina (A) e s16 (B) a expressão de RNAm. Dados de leptina são normalizados para os níveis do mRNA s16 enquanto dados para s16 são mostrados como valor de Ct e ambos são apresentados como média ± SE com n = por grupo de 12-13. * p < 0.05 comparado a dieta N. N, normal; HF, alto teor de gordura; PGF, gordura peri-gonadal; PRF, gordura peri-renal; SCF, gordura subcutânea abdominal. Esta figura foi modificada de Tan, p. et al, obesidade (2014) 22, 2201-2209. <a href="//cloudflare.jove.com/files/ftp_upload/57026/57026fig4large.jpg" target="_blank">Clique aqui para ver uma versão maior desta figura.</a>
<table fo:keep-together.within-page="1"><tbody>
<tr>
<td></td>
			<td>Dieta N</td>
			<td>Dieta de HF</td>
		</tr>
<tr>
<td>Peso corporal final (g)</td>
			<td>37,5 ± 1.3</td>
			<td>46.7 ± 1.7*</td>
		</tr>
<tr>
<td>Ganho de peso (g)</td>
			<td>6,6 ± 0,7</td>
			<td>16,7 ± 1.0*</td>
		</tr>
<tr>
<td>PGF (g)</td>
			<td>1.08 ± 0,17</td>
			<td>2.19 ± 0.15*</td>
		</tr>
<tr>
<td>PRF (g)</td>
			<td>0,79 ± 0,15</td>
			<td>1,71 ± 0.06</td>
		</tr>
<tr>
<td>SCF (g)</td>
			<td>1,62 ± 0.35</td>
			<td>3,55 ± 0.20*</td>
		</tr>
</tbody></table>Tabela 1. Efeito da dieta de HF em pesos de tecido adiposo do corpo e branco. Valores são expressos como média ± SE com n = 14-15 por grupo. * p < 0.05 comparado a dieta N. N, normal; HF, alto teor de gordura; PGF, gordura peri-gonadal; PRF, gordura peri-renal; SCF, gordura subcutânea abdominal. Esta figura foi modificada de Tan, p. et al, obesidade (2014) 22, 2201-2209.
<table fo:keep-together.within-page="1"><tbody>
<tr>
<td>Amostras</td>
			<td>Relação OD260/OD280</td>
		</tr>
<tr>
<td>PGF 1</td>
			<td>2,04</td>
		</tr>
<tr>
<td>PGF 2</td>
			<td>2,04</td>
		</tr>
<tr>
<td>PGF 3</td>
			<td>2.02</td>
		</tr>
<tr>
<td>PRF 1</td>
			<td>1.95</td>
		</tr>
<tr>
<td>PRF 2</td>
			<td>2.08</td>
		</tr>
<tr>
<td>PRF 3</td>
			<td>2.08</td>
		</tr>
<tr>
<td>SCF 1</td>
			<td>2,04</td>
		</tr>
<tr>
<td>SCF 2</td>
			<td>2.02</td>
		</tr>
<tr>
<td>SCF 3</td>
			<td>2.06</td>
		</tr>
</tbody></table>Tabela 2. Pureza de RNA após isolamento branco tecido adiposo. n = 3 por tecido adiposo. PGF, gordura peri-gonadal; PRF, gordura peri-renal; SCF, gordura subcutânea abdominal.

Watch this Scientific Journal Video about Mouse Adipose Tissue Collection and Processing for RNA Analysis at JoVE.com

Mouse Adipose Tissue Collection and Processing for RNA Analysis

Coleção de tecido adiposo de mouse e processamento para análise de RNA

O objetivo deste trabalho é apresentar um procedimento passo a passo para coletar os diferentes tecidos adiposo brancos de ratos, processar as amostras de gordura e extrair o RNA.

Compared to other tissues, white adipose tissue has a considerably less RNA and protein content for downstream applications such as real-time PCR and ...

mouse-adipose-tissue-collection-and-processing-for-rna-analysis

Nanyang Technological University

Research

JoVE Journal

Biochemistry

48.1K visualizações.  Université de Montréal. O objetivo deste trabalho é apresentar um procedimento passo a passo para coletar os diferentes tecidos adiposo brancos de ratos, processar as amostras de gordura e extrair o RNA.

Vídeo: Mouse Adipose Tissue Collection and Processing for RNA Analysis

Experimental Design for Laser Microdissection RNA-Seq: Lessons from an Analysis of Maize Leaf Development

Genes with important roles in development frequently have spatially and/or temporally restricted expression patterns. Often these gene transcripts are not detected or are not identified as differentially expressed (DE) in transcriptomic analyses of whole plant organs. Laser Microdissection RNA-Seq (LM RNA-Seq) is a powerful tool to identify genes that are DE in specific developmental domains. However, the choice of cellular domains to microdissect and compare, and the accuracy of the microdissections are crucial to the success of the experiments. Here, two examples illustrate design considerations for transcriptomics experiments; a LM RNA-seq analysis to identify genes that are DE along the maize leaf proximal-distal axis, and a second experiment to identify genes that are DE in liguleless1-R (lg1-R) mutants compared to wild-type. Key elements that contributed to the success of these experiments were detailed histological and in situ hybridization analyses of the region to be analyzed, selection of leaf primordia at equivalent developmental stages, the use of morphological landmarks to select regions for microdissection, and microdissection of precisely measured domains. This paper provides a detailed protocol for the analysis of developmental domains by LM RNA-Seq. The data presented here illustrate how the region selected for microdissection will affect the results obtained.

Many developmentally important genes have cell- or tissue-specific expression patterns. This paper describes LM RNA-seq experiments to identify genes that are differentially expressed at the maize leaf blade-sheath boundary and in lg1-R mutants compared to wild-type. The experimental considerations discussed here apply to transcriptomic analyses of other developmental phenomena.

Projeto Experimental de Laser Microdissecção RNA-Seq: Lições de uma análise do desenvolvimento foliar do milho

Genes with important roles in development frequently have spatially and/or temporally restricted expression patterns. Often these gene transcripts are not ...

Bioquímica

An Efficient Method for the Isolation of Highly Purified RNA from Seeds for Use in Quantitative Transcriptome Analysis

Plant seeds accumulate large amounts of storage reserves comprising biodegradable organic matter. Humans rely on seed storage reserves for food and as industrial materials. Gene expression profiles are powerful tools for investigating metabolic regulation in plant cells. Therefore, detailed, accurate gene expression profiles during seed development are required for crop breeding. Acquiring highly purified RNA is essential for producing these profiles. Efficient methods are needed to isolate highly purified RNA from seeds. Here, we describe a method for isolating RNA from seeds containing large amounts of oils, proteins, and polyphenols, which have inhibitory effects on high-purity RNA isolation. Our method enables highly purified RNA to be obtained from seeds without the use of phenol, chloroform, or additional processes for RNA purification. This method is applicable to Arabidopsis, rapeseed, and soybean seeds. Our method will be useful for monitoring the expression patterns of low level transcripts in developing and mature seeds.

We have succeeded in establishing a method for RNA isolation from plant seeds containing large amounts of oils, proteins, and polyphenols, which have inhibitory effects on high-purity RNA isolation. Our method is suitable for monitoring the expression of genes with low level transcripts in seeds.

Um método eficiente para o isolamento de ARN altamente purificada a partir de sementes para Utilização em Análise Quantitativa do transcriptoma

Plant seeds accumulate large amounts of storage reserves comprising biodegradable organic matter. Humans rely on seed storage reserves for food and as ...

Toeprinting Analysis of Translation Initiation Complex Formation on Mammalian mRNAs

Translation initiation is the rate-limiting step of protein synthesis and represents a key point at which cells regulate their protein output. Regulation of protein synthesis is the key to cellular stress-response, and dysregulation is central to many disease states, such as cancer. For instance, although cellular stress leads to the inhibition of global translation by attenuating cap-dependent initiation, certain stress-response proteins are selectively translated in a cap-independent manner. Discreet RNA regulatory elements, such as cellular internal ribosome entry sites (IRESes), allow for the translation of these specific mRNAs. Identification of such mRNAs, and the characterization of their regulatory mechanisms, have been a key area in molecular biology. Toeprinting is a method for the study of RNA structure and function as it pertains to translation initiation. The goal of toeprinting is to assess the ability of in vitro transcribed RNA to form stable complexes with ribosomes under a variety of conditions, in order to determine which sequences, structural elements, or accessory factors are involved in ribosome binding&#8212;a pre-cursor for efficient translation initiation. Alongside other techniques, such as western analysis and polysome profiling, toeprinting allows for a robust characterization of mechanisms for the regulation of translation initiation.

Toeprinting aims to measure the ability of in vitro transcribed RNA to form translation initiation complexes with ribosomes under a variety of conditions. This protocol describes a method for toeprinting mammalian RNA and can be used to study both cap-dependent and IRES-driven translation.

Análise de Toeprinting de formação do complexo iniciação tradução de mRNAs mamíferos

Translation initiation is the rate-limiting step of protein synthesis and represents a key point at which cells regulate their protein output. Regulation ...

Capture and Identification of RNA-binding Proteins by Using Click Chemistry-assisted RNA-interactome Capture (CARIC) Strategy

A comprehensive identification of RNA-binding proteins (RBPs) is key to understanding the posttranscriptional regulatory network in cells. A widely used strategy for RBP capture exploits the polyadenylation [poly(A)] of target RNAs, which mostly occurs on eukaryotic mature mRNAs, leaving most binding proteins of non-poly(A) RNAs unidentified. Here we describe the detailed procedures of a recently reported method termed click chemistry-assisted RNA-interactome capture (CARIC), which enables the transcriptome-wide capture of both poly(A) and non-poly(A) RBPs by combining the metabolic labeling of RNAs, in vivo UV cross-linking, and bioorthogonal tagging.

Capture and Identification of RNA-binding Proteins by Using Click Chemistry-assisted RNA-interactome Capture CARIC Strategy

A detailed protocol for applying the click chemistry-assisted RNA-interactome capture (CARIC) strategy to identify proteins binding to both coding and noncoding RNAs is presented.

Captura e identificação de proteínas de ligação de RNA usando clique química assistida RNA-interactome capturam estratégia (CARIC)

A comprehensive identification of RNA-binding proteins (RBPs) is key to understanding the posttranscriptional regulatory network in cells. A widely used ...

Rapid Collection of Floral Fragrance Volatiles using a Headspace Volatile Collection Technique for GC-MS Thermal Desorption Sampling

Fragrances of many flower families have been sampled and the volatiles analyzed. Knowing the compounds that make up the fragrances can be an important step to conservation of flowers that are threatened or endangered. Because floral fragrance is critical for attracting pollinators, this method could be used to better understand or even enhance pollination. We present a protocol using a portable charcoal air filter and vacuum to collect floral fragrance volatiles, which are then analyzed by a GC-MS. By using this method, fragrance volatiles can be sampled using a non-destructive method with a machine that is easily transported. This methodology uses a rapid sampling procedure, cutting sampling time down from 2-3 hours to approximately 10 minutes. Using GC-MS, the fragrance compounds can be identified individually, based on authentic standards. The steps used for collecting fragrance and control data are presented, from material setup to collecting the data output.

Here, we present a protocol for collecting the floral fragrance volatiles from blooming flowers, using a non-destructive sampling procedure.

Coleção rápida de voláteis florais da fragrância usando uma técnica da coleção do volatile do Headspace para a amostragem térmica da desorção de GC-MS

Fragrances of many flower families have been sampled and the volatiles analyzed. Knowing the compounds that make up the fragrances can be an important ...

Studying RNA Interactors of Protein Kinase RNA-Activated during the Mammalian Cell Cycle

Protein kinase RNA-activated (PKR) is a member of the innate immune response proteins and recognizes the double-stranded secondary structure of viral RNAs. When bound to viral double-stranded RNAs (dsRNAs), PKR undergoes dimerization and subsequent autophosphorylation. Phosphorylated PKR (pPKR) becomes active and induces phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF2&#945;) to suppress global translation. Increasing evidence suggests that PKR can be activated under physiological conditions such as during the cell cycle or under various stress conditions without infection. However, our understanding of the RNA activators of PKR is limited due to the lack of a standardized experimental method to capture and analyze PKR-interacting dsRNAs. Here, we present an experimental protocol to specifically enrich and analyze PKR bound RNAs during the cell cycle using HeLa cells. We utilize the efficient crosslinking activity of formaldehyde to fix PKR-RNA complexes and isolate them via immunoprecipitation. PKR co-immunoprecipitated RNAs can then be further processed to generate a high-throughput sequencing library. One major class of PKR-interacting cellular dsRNAs is mitochondrial RNAs (mtRNAs), which can exist as intermolecular dsRNAs through complementary interaction between the heavy-strand and the light-strand RNAs. To study the strandedness of these duplex mtRNAs, we also present a protocol for strand-specific qRT-PCR. Our protocol is optimized for the analysis of PKR-bound RNAs, but it can be easily modified to study cellular dsRNAs or RNA-interactors of other dsRNA binding proteins.

We present experimental approaches for studying RNA-interactors of double-stranded RNA binding protein kinase RNA-activated (PKR) during the mammalian cell cycle using HeLa cells. This method utilizes formaldehyde to crosslink RNA-PKR complexes and immunoprecipitation to enrich PKR-bound RNAs. These RNAs can be further analyzed through high-throughput sequencing or qRT-PCR.

Estudando o RNA interactianos de proteína quinase RNA-ativado durante o ciclo celular dos mamíferos

Protein kinase RNA-activated (PKR) is a member of the innate immune response proteins and recognizes the double-stranded secondary structure of viral ...

Rapid and Cost-Effective RNA Extraction of Rat Pancreatic Tissue

Regardless of the extraction method, optimized RNA extraction of tissues and cell lines are carried out in four stages: 1) homogenization, 2) effective denaturation of proteins from RNA, 3) ribonuclease inactivation, and 4) removal of contamination from DNA, proteins, and carbohydrates. However, it is very laborious to maintain the integrity of RNA when there are high levels of RNase in the tissue. Spontaneous autolysis makes it very difficult to extract RNA from pancreatic tissue without damaging it. Thus, a practical RNA extraction method is needed to maintain the integrity of pancreatic tissues during the extraction process. An experimental and comparative study of existing protocols was carried out by obtaining 20-30 mg of rat pancreatic tissues in less than 2 minutes and extracting the RNA. The results were assessed by electrophoresis. The experiments were carried out three times for generalization of the results. Immersing pancreatic tissue in RNA stabilization reagent at -80 &#176;C for 24 h yielded high integrity RNA, when the RNA extraction reagent was used as the reagent. The results obtained were comparable to the results obtained from commercial kits with spin column bindings.

The purity and integrity of the isolated RNA is a vital step in RNA dependent assays. Here, we present a practical, rapid, and inexpensive method to extract RNA from a small quantity of undamaged pancreatic tissue.

Extração rápida e econômica do RNA do tecido pancreático de rato

Regardless of the extraction method, optimized RNA extraction of tissues and cell lines are carried out in four stages: 1) homogenization, 2) effective ...

RNA Blot Analysis for the Detection and Quantification of Plant MicroRNAs

MicroRNAs (miRNAs) are a class of endogenously expressed non-coding, ~21 nt small RNAs involved in the regulation of gene expression in both plants and animals. Most miRNAs act as negative switches of gene expression targeting key genes. In plants, primary miRNAs (pri-miRNAs) transcripts are generated by RNA polymerase II, and they form varying lengths of stable stem-loop structures called pre-miRNAs. An endonuclease, Dicer-like1, processes the pre-miRNAs into miRNA-miRNA* duplexes. One of the strands from miRNA-miRNA* duplex is selected and loaded onto Argonaute 1 protein or its homologs to mediate the cleavage of target mRNAs. Although miRNAs are key signaling molecules, their detection is often carried out by less than optimal PCR-based methods instead of a sensitive northern blot analysis. We describe a simple, reliable, and extremely sensitive northern method that is ideal for the quantification of miRNA levels with very high sensitivity, literally from any plant tissue. Additionally, this method can be used to confirm the size, stability and the abundance of miRNAs and their precursors.

This method demonstrates use of the northern hybridization technique to detect miRNAs from total RNA extract.

Análise de blot de RNA para detecção e quantificação de MicroRNAs vegetais

MicroRNAs (miRNAs) are a class of endogenously expressed non-coding, ~21 nt small RNAs involved in the regulation of gene expression in both plants and ...

Optical Tweezers to Study RNA-Protein Interactions in Translation Regulation

RNA adopts diverse structural folds, which are essential for its functions and thereby can impact diverse processes in the cell. In addition, the structure and function of an RNA can be modulated by various trans-acting factors, such as proteins, metabolites or other RNAs. Frameshifting RNA molecules, for instance, are regulatory RNAs located in coding regions, which direct translating ribosomes into an alternative open reading frame, and thereby act as gene switches. They may also adopt different folds after binding to proteins or other trans-factors. To dissect the role of RNA-binding proteins in translation and how they modulate RNA structure and stability, it is crucial to study the interplay and mechanical features of these RNA-protein complexes simultaneously.&#160;This work illustrates how to employ single-molecule-fluorescence-coupled optical tweezers to explore the conformational and thermodynamic landscape of RNA-protein complexes at a high resolution. As an example, the interaction of the SARS-CoV-2 programmed ribosomal frameshifting element with the trans-acting factor short isoform of zinc-finger antiviral protein is elaborated. In addition, fluorescence-labeled ribosomes were monitored using the confocal unit, which would ultimately enable the study of translation elongation. The fluorescence coupled OT assay can be widely applied to explore diverse RNA-protein complexes or trans-acting factors regulating translation and could facilitate studies of RNA-based gene regulation.

This protocol presents a complete experimental workflow for studying RNA-protein interactions using optical tweezers. Several possible experimental setups are outlined including the combination of optical tweezers with confocal microscopy.

Pinças ópticas para estudar interações RNA-proteína no regulamento de tradução

RNA adopts diverse structural folds, which are essential for its functions and thereby can impact diverse processes in the cell. In addition, the ...

Routine Collection of High-Resolution cryo-EM Datasets Using 200 KV Transmission Electron Microscope

Cryo-electron microscopy (cryo-EM) has been established as a routine method for protein structure determination during the past decade, taking an ever-increasing share of published structural data. Recent advances in TEM technology and automation have boosted both the speed of data collection and quality of acquired images while simultaneously decreasing the required level of expertise for obtaining cryo-EM maps at sub-3 &#197; resolutions. While most of such high-resolution structures have been obtained using state-of-the-art 300 kV cryo-TEM systems, high-resolution structures can be also obtained with 200 kV cryo-TEM systems, especially when equipped with an energy filter. Additionally, automation of microscope alignments and data collection with real-time image quality assessment reduces system complexity and assures optimal microscope settings, resulting in increased yield of high-quality images and overall throughput of data collection. This protocol demonstrates the implementation of recent technological advances and automation features on a 200 kV cryo-transmission electron microscope and shows how to collect data for the reconstruction of 3D maps that are sufficient for de novo atomic model building. We focus on best practices, critical variables, and common issues that must be considered to enable the routine collection of such high-resolution cryo-EM datasets. Particularly the following essential topics are reviewed in detail: i) automation of microscope alignments, ii) selection of suitable areas for data acquisition, iii) optimal optical parameters for high-quality, high-throughput data collection, iv) energy filter tuning for zero-loss imaging, and v) data management and quality assessment. Application of the best practices and improvement of achievable resolution using an energy filter will be demonstrated on the example of apo-ferritin that was reconstructed to 1.6 &#197;, and Thermoplasma acidophilum 20S proteasome reconstructed to 2.1-&#197; resolution using a 200 kV TEM equipped with an energy filter and a direct electron detector.

High-resolution cryo-EM maps of macromolecules can be also achieved by using 200 kV TEM microscopes. This protocol shows the best practices for setting accurate optics alignments, data acquisition schemes, and selection of imaging areas that are all essential for the successful collection of high-resolution datasets using a 200 kV TEM.