Name: protein-trna agarose gel retardation assays for the analysis of the n6-threonylcarbamoyladenosine tcda function
Uploaded: 2017-06-21T12:30:00.000+00:00
Duration: 8 min 3 s
Description: Watch this Scientific Journal Video about Protein-tRNA Agarose Gel Retardation Assays for the Analysis of the N6-threonylcarbamoyladenosine TcdA Function at JoVE.com

MCV是CIB校内计划"更好生命的分子机器"（MACBET）的成员。导致这些结果的研究已经获得了西班牙萨洛德卡洛斯III研究所（PI12 / 01667至MCV）的资助，西班牙经济贸易部长（CTQ2015-66206-C2-2-R和SAF2015-72961-EXP至MCV） ），马德里区域政府（S2010 / BD-2316至MCV）和欧盟委员会（框架计划7（FP7））项目ComplexINC（MCV合同号279039）。资助者在研究设计，数据收集和分析，决定出版或准备稿件方面没有任何作用。

注意:使用前请咨询所有相关的材料安全数据表（MSDS）。本协议中使用的几种化学物质是有毒和腐蚀性的。使用苯酚进行tRNA提取时，请使用适当的做法，包括使用通风橱和个人防护装备（安全眼镜，手套，实验室外套，全长裤，闭式脚趾鞋等 ）。该方案使用无毒的核酸染色。使用替代污渍可能需要额外的预防措施，并且如果有毒和/或致癌（ 例如溴化乙锭），则染色剂的专门处置。 琼脂糖凝胶的制备<ol><li>称量2 g琼脂糖，并加入玻璃瓶中制备2％w / v琼脂糖凝胶。 </li><li>向含琼脂糖的瓶子中加入100毫升1x三硼酸盐 - 乙二胺四乙酸（EDTA）（TBE）运行缓冲液。通过在微波炉中加热熔化。以30秒的间隔旋转内容物进行混合并重复此步骤，直到琼脂糖完全溶解。使琼脂糖溶液冷却至约50-60℃。 </li><li>粘贴凝胶托盘的开口边缘以产生模具，放置适当的梳子以产生孔并将熔融的琼脂糖投入其中。避免气泡形成，使其在室温下固化。 </li><li>一旦凝固，将凝胶托盘放在电泳单元中，并用TBE缓冲液填充，直到凝胶完全被覆盖。 </li></ol> 2.制备tRNA <ol><li> 在大肠杆菌中表达 tRNA（UUU） <ol><li>早晨，使用用表达载体pET23d-EcUUU2（含有编码大肠杆菌 tRNA（UUU）的基因）转化的冷冻大肠杆菌 BL21（DE3）小瓶，连续制备低盐Luria Broth（LB）板补充100μg/ mL氨苄青霉素。倒置板并将其置于37℃的培养箱中，直到菌落出现（晚期）OON）。 </li><li>接种在5 mL LB加100μg/ mL氨苄青霉素中的一个良好生长的单个菌落，并在37℃下以220 rpm生长过夜。 </li><li>第二天早上，细胞沉淀（6,500 xg，4℃）10分钟，用5 mL新鲜LB加100μg/ mL氨苄西林替代培养基，并重新悬浮。使用该悬浮液接种200 mL LB加100μg/ mL氨苄青霉素。在37℃下以220rpm生长5小时。 </li><li>当590nm（OD 590 ）培养物的光密度达到0.6-0.8时，向培养物中加入1mM IPTG以触发tRNA（UUU）基因的表达。在37℃孵育3小时。 </li><li>通过在4℃下以6,500×g离心培养10分钟来收获细胞。 </li></ol></li><li> 裂解和提取 <ol><li>将细胞沉淀重悬于5mL裂解缓冲液（0.3M乙酸钠，10mM EDTA）中。从此以后，使用高压灭菌的缓冲液并将所有含tRNA的样品保持在4℃以防止tRNA降解。 </li><li>将1体积的酸性苯酚（pH 4.3）加入通风橱中的悬浮细胞沉淀。通过倒置混合1分钟以裂解细胞并以10,000xg（10分钟，4℃）离心。 </li><li>使用移液管收集含有可溶性tRNA（UUU）（和较小浓度的其他tRNA库）的上层水相，注意不要抽吸有机（底部）相。将底层和由有机相和细胞碎片组成的沉淀物丢弃到足够的容器中。 </li><li>通过在4℃下倒置1小时，将可溶（水）相与2.5体积的100％v / v乙醇充分混合，沉淀出tRNA。以15,000 xg（30分钟，4℃）离心混合物。 </li><li>仔细倾倒上清液，并将富含tRNA的沉淀重悬于4 mL凝胶过滤缓冲液（20 mM磷酸钠或磷酸钾，pH 7.4，0.1 mM EDTA）中。在2％w / v琼脂糖凝胶上运行5μL重悬浮的tRNA库。 注意:质量好的tRNA表现为单一条带（分子大小在50-100bp之间）。 </li></ol></li><li> 纯化tRNA（UUU） <ol><li>按照标准色谱实践12 ，将重悬浮的tRNA（UUU）加载到先前在凝胶过滤缓冲液中平衡的高分辨率制备型凝胶过滤柱（尺寸:16×600mm，床体积:120mL，分辨率范围:1,000-70,000Da） （流动相）。将流速设置为1 mL / min以洗脱样品。 注意:tRNA（UUU）峰的洗脱大约为75.5 mL。通常，可以获得培养物的0.5-1.0mg / L tRNA的产量。 </li><li>通过在2％w / v琼脂糖凝胶上电泳每个样品5 - 10μL，分析样品的代表性洗脱体积。 </li></ol></li></ol> 3.样品制备<ol><li>根据López-Estepa et al 。表达和纯化TcdA。 2 。 注意:最高可达250μMTcdA可用于研究。 </li><li>将相应量的TcdA根据表1移取到适当标记的1.5 mL离心管中。加入1.6mM 三 （2-羧乙基）膦（TCEP）（终浓度），并使用移液管轻轻混合。关闭盖子并在室温下孵育混合物5分钟。 </li><li>加入10μM三磷酸腺苷（ATP）和50mM MgCl 2 （终浓度）。用移液管混合，并在室温下孵育混合物5分钟。 </li><li>加入纯化的tRNA（UUU）（第2.3节），如表1所示 ，用移液管混合，室温孵育5分钟。 </li><li>加入最终达100μL的最终体积的磷酸盐缓冲盐水（PBS）。混合均匀并加入甘油至终浓度为10％v / v。 </li><li>旋转样品并短暂地将管内容物（10,000 x g，1 min，4°C）旋下。 </li></ol>凝胶加载和电泳发展<ol><li>将电泳单元放入装有碎冰的托盘中，以便在电泳过程中将室维持在4℃。 </li><li>小心地，将5μL每个样品移液到相应的孔中。添加合适的DNA大小标记。 </li><li>将电极插入电源单元的相应插槽。打开电源单元并将电压设置为100 V，并运行凝胶90分钟。 </li></ol> 5.凝胶染色观察tRNA蛋白质相互作用<ol><li>通过将50 mL TBE与1×合适的DNA染色液混合来制备染色溶液。通过用铝箔覆盖染色容器，避免将染色溶液暴露在阳光下。 注意:DNA污渍通常存储为10,000或20,000x浓缩的库存。 </li><li>电泳90分钟后，小心地从托盘中取出凝胶，并将其放入带有染色溶液的容器中。在室温下以低摇摆速度将其放置在摇杆上ure 30分钟</li><li>从染色容器中取出琼脂糖凝胶，小心点在纤维素组织或滤纸上，以除去多余的液体，并将其直接放在透照器上。打开紫外光以使含有tRNA的条带可视化。拍摄凝胶照片。 </li><li> 蛋白质染色（可选）。 <ol><li>放弃DNA染色溶液（根据安全程序），并用50 mL考马斯亮蓝（CBB）溶液代替。将托盘放置在室温摇杆上，过夜（&gt; 12 h）。丢弃CBB染色溶液，并用50 mL PBS替换，以除去多余的染料。在摇滚乐上消失1小时。 </li></ol></li><li>在光透照下可视化含蛋白质的tRNA复合物，并拍摄凝胶照片以与tRNA UV凝胶图片进行比较。 </li></ol>

<ol>
	<li>Scott, V., Clark, A. R., Docherty, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+gel+retardation+assay.">The gel retardation assay.</a> Methods Mol Biol. 31, 339-347 (1994).</li><li>L&#243;pez-Estepa, 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=The+crystal+structure+and+small-angle+X-ray+analysis+of+CsdL/TcdA+reveal+a+new+tRNA+binding+motif+in+the+MoeB/E1+superfamily.">The crystal structure and small-angle X-ray analysis of CsdL/TcdA reveal a new tRNA binding motif in the MoeB/E1 superfamily.</a> Plos One. 10 (4), e0118606 (2015).</li><li>Miyauchi, K., Kimura, S., Suzuki, 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+cyclic+form+of+N6-threonylcarbamoyladenosine+as+a+widely+distributed+tRNA+hypermodification.">A cyclic form of N6-threonylcarbamoyladenosine as a widely distributed tRNA hypermodification.</a> Nat Chem Biol. 9 (2), 105-111 (2013).</li><li>Bolstad, H. M., Botelho, D. J., Wood, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteomic+analysis+of+protein-protein+interactions+within+the+Cysteine+Sulfinate+Desulfinase+Fe-S+cluster+biogenesis+system.">Proteomic analysis of protein-protein interactions within the Cysteine Sulfinate Desulfinase Fe-S cluster biogenesis system.</a> J Proteome Res. 9 (10), 5358-5369 (2010).</li><li>Loiseau, L., Ollagnier-de Choudens, S., Lascoux, D., Forest, E., Fontecave, M., Barras, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+heteromeric+CsdA-CsdE+cysteine+desulfurase,+assisting+Fe-S+cluster+biogenesis+in+Escherichia+coli.">Analysis of the heteromeric CsdA-CsdE cysteine desulfurase, assisting Fe-S cluster biogenesis in Escherichia coli.</a> J Biol Chem. 280 (29), 26760-26769 (2005).</li><li>Fried, M. G., Crothers, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Equilibrium+studies+of+the+cyclic+AMP+receptor+protein-DNA+interaction.">Equilibrium studies of the cyclic AMP receptor protein-DNA interaction.</a> J Mol Biol. 172 (3), 241-262 (1984).</li><li>Garner, M. M., Revzin, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+gel+electrophoresis+method+for+quantifying+the+binding+of+proteins+to+specific+DNA+regions:+application+to+components+of+the+Escherichia+coli+lactose+operon+regulatory+system.">A gel electrophoresis method for quantifying the binding of proteins to specific DNA regions: application to components of the Escherichia coli lactose operon regulatory system.</a> Nucleic Acids Res. 9 (13), 3047-3060 (1981).</li><li>Rio, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophoretic+mobility+shift+assays+for+RNA-protein+complexes.">Electrophoretic mobility shift assays for RNA-protein complexes.</a> Cold Spring Harb Protoc. 2014 (4), 435-440 (2014).</li><li>Ryder, S. P., Recht, M. I., Williamson, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+analysis+of+protein-RNA+interactions+by+gel+mobility+shift.">Quantitative analysis of protein-RNA interactions by gel mobility shift.</a> Methods Mol Biol. 488, 99-115 (2008).</li><li>Yakhnin, A. V., Yakhnin, H., Babitzke, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gel+mobility+shift+assays+to+detect+protein-RNA+interactions.">Gel mobility shift assays to detect protein-RNA interactions.</a> Methods Mol Biol. 905, 201-211 (2012).</li><li>Ream, J. A., Lewis, L. K., Lewis, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+agarose+gel+electrophoretic+mobility+shift+assay+for+quantitating+protein:+RNA+interactions.">Rapid agarose gel electrophoretic mobility shift assay for quantitating protein: RNA interactions.</a> Anal Biochem. 511, 36-41 (2016).</li><li>Hagel, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gel-filtration+chromatography.">Gel-filtration chromatography.</a> Curr Protoc Mol Biol. , (2001).</li></ol>

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本文描述的蛋白质-TRNA琼脂糖凝胶阻滞测定可以以多种方式进行修饰。首先，可以减少凝胶中琼脂糖的百分比，以使蛋白质tRNA复合物的分离和可视化显着大于本文分析的（120 kDa）。第二，如果目标蛋白是不耐热的，则必须采取额外的预防措施，以确保通过将电泳装置移动到冷藏室或使用电泳室内的冰袋将温度保持在最高可接受温度以下，以立即消散产生的热量在运行期间。如果需要或可接受的样...

<html>凝胶阻滞测定1 （也称为电泳迁移率变动测定，EMSA）是设计用于研究和表征蛋白质 - 核酸相互作用的电泳方法。它允许使用纯化的组分或蛋白质（ 例如细胞裂解物）或核酸的复杂混合物（ 例如 ，tRNA）来分析蛋白质-DNA以及蛋白质 - RNA相互作用，特别是tRNA和tRNA结合蛋白质之间的相互作用池）。我们已经将凝胶阻滞测定法应用于纯化的tRNA（UUU）和TcdA（N6-磺酰基氨基甲酰基腺苷（t6A）脱水酶）之间相互作用的研究，该脱水酶使连接于A30的苏木糖氨基甲酰侧链在反密码子茎环（ASL）中环化，的tRNA到循环t 6 （ct 6 A） 2,3 。 TcdA也被称为CsdL 3 ，tcdA / csdL基因与csdA和csdE基因5形成簇，其编码半胱氨酸脱硫酶和半胱氨酸亚硫酸盐脱硫酸盐（CSD）系统的硫受体，并需要在体内维持TcdA功能3 。 凝胶阻滞测定的基本原理是，尽管游离核酸分子由于其大的负电荷而快速迁移到丙烯酰胺或琼脂糖凝胶的前部，但是相同核酸的蛋白质复合物的电泳迁移率显着降低。迁移率的降低可视化为核酸 - 蛋白质复合物中的"转移"，其作为离散条带解决。带正电荷的和较大的核酸 - 蛋白质复合物在凝胶上显示出更大的移动或降低迁移率。 由于复合体的电荷中和是普遍现象对于蛋白质 - 核酸复合物，凝胶阻滞测定可以应用于广泛的复合物和核酸类型。该方法简单，价格便宜，可在实验室内以最少的设备进行。它只需要少量的蛋白质和tRNA。这比替代生物物理技术有一个优势，通常消耗较大量的样品。 凝胶阻滞测定已广泛用于转录因子的研究。该测定已被用于分析许多不同DNA序列的转录因子的结合动力学，强度和特异性。 EMSA在这个领域确实是第一次开发6,7 。 RNA 8,9,10,11和tRNA分子的凝胶阻滞测定也用于核糖体研究并且像我们这里所说的那样分析在转录后修饰tRNA核苷的酶。 许多不同的参数影响凝胶阻滞测定的结果，例如温度，蛋白质和tRNA样品的质量以及结合强度。仔细规划和执行实验对于释放游离核酸和蛋白质结合物种的结果至关重要。在这里，我们使用编码tRNA（UUU）的合成基因克隆到启动子缺乏Shine-Dalgarno核糖体结合位点的表达载体中，导致大量tRNA2的合成。该详细方案旨在提供执行tRNA凝胶阻滞实验的明确指导，同时避免常见错误。

<table><tbody><tr><td>&lt;em&gt;E. coli&lt;/em&gt; BL21(DE3)</td><td>Novagen</td><td>70235</td><td>DE3 lysogen contains T7 polymerase upon IPTG induction.</td></tr><tr><td>pET23d</td><td>Novagen</td><td>69748-3</td><td>pET23d confers resistance to ampicillin; T7 promoter.</td></tr><tr><td>LB Broth, Low Salt (Lennox L Broth), Granulated</td><td>Melford</td><td>GL1703</td><td>Conventional LB Broth, High Salt, can also be used.</td></tr><tr><td>Ampicillin</td><td>Sigma-Aldrich</td><td>10419313</td><td></td></tr><tr><td>Incubator Shaker (Thermostated)</td><td>NBS</td><td>Excella E24&amp;nbsp;</td><td>Any shaker incubator with temperature control can be used.</td></tr><tr><td>Isopropyl-beta-D-thiogalactopyranoside (IPTG), &gt;=99%</td><td>Acros Organics</td><td>BP1755</td><td></td></tr><tr><td>Sodium acetate, anhydrous, &gt;99%</td><td>Melford</td><td>B4017</td><td></td></tr><tr><td>Ethylenediaminetetraacetic acid (EDTA), Disodium salt, &gt;99%</td><td>Acros Organics</td><td>AC327205000</td><td>Harmful if inhaled.</td></tr><tr><td>Centrifuge (refrigerated)</td><td>Eppendorf</td><td>5430</td><td></td></tr><tr><td>Centrifuge (refrigerated) rotor</td><td>Eppendorf</td><td>5430/5430P</td><td></td></tr><tr><td>Centrifuge</td><td>Sorvall</td><td>RC5C</td><td></td></tr><tr><td>Centrifuge rotor</td><td>Sorvall</td><td>SLA-3000</td><td></td></tr><tr><td>Phenol solution, Saturated with 0.1 M citrate buffer, pH 4.3 &amp;plusmn; 0.2</td><td>Sigma-Aldrich</td><td>P4682</td><td>Acute toxicity (oral, dermal, inhalation), corrosive</td></tr><tr><td>Ethanol absolute for analysis, 100% v/v</td><td>Merck Millipore</td><td>100983</td><td></td></tr><tr><td>Sodium phosphate dibasic dihydrate, Na&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt;, &gt;=99%</td><td>Sigma-Aldrich</td><td>71643</td><td></td></tr><tr><td>Potassium dihydrogen phosphate, KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;</td><td>Merck</td><td>48,730,250</td><td></td></tr><tr><td>HiLoad 16/60 Superdex 75&amp;nbsp;</td><td>GE Healthcare</td><td>28989333</td><td></td></tr><tr><td>Agarose</td><td>Melford</td><td>MB1200</td><td></td></tr><tr><td>Tris [Tris(hydroxymethyl) aminomethane HCl]</td><td>Melford</td><td>T1513</td><td></td></tr><tr><td>Boric Acid</td><td>Melford</td><td>B0503</td><td></td></tr><tr><td>Microwave</td><td>Haier</td><td>HDA-2070M</td><td></td></tr><tr><td>TCEP [Tris(2-carboxyethyl)phosphine hydrochloride]</td><td>Sigma-Aldrich</td><td>C4706</td><td>Corrosive to metals and skin.</td></tr><tr><td>ATP [Adenosine 5&amp;prime;-triphosphate disodium salt hydrate], Grade I, &gt;=99%</td><td>Sigma-Aldrich</td><td>A2383</td><td></td></tr><tr><td>Magnesium chloride (MgCl&lt;sub&gt;2&lt;/sub&gt;), anhydrous, &gt;=98%</td><td>Sigma-Aldrich</td><td>M8266</td><td></td></tr><tr><td>Sodium chloride (NaCl), &gt;99%</td><td>Fisher Bioreagents</td><td>BP358</td><td></td></tr><tr><td>Potassium chloride (KCl), &gt;99%</td><td>Melford</td><td>P0515</td><td></td></tr><tr><td>NZYDNA Ladder VI</td><td>NZYtech</td><td>MB8901</td><td></td></tr><tr><td>Power supply</td><td>Consort</td><td>EV261</td><td></td></tr><tr><td>Electrophoresis unit</td><td>Real Laboratory</td><td>RELSMINI10</td><td></td></tr><tr><td>Real Safe nucleic acid staining</td><td>Real Laboratory</td><td>RBMSAFE</td><td>20,000X stock</td></tr><tr><td>UV Transilluminator (G:Box/EF)</td><td>Syngene</td><td>2216498</td><td></td></tr><tr><td>Coomassie Brilliant Blue G</td><td>Sigma-Aldrich</td><td>B0770</td><td></td></tr><tr><td>Rocker (Gyro-Rocker)</td><td>Stuart</td><td>SSL3</td><td></td></tr><tr><td>Mixer Vortex&amp;nbsp;</td><td>Fisher brand</td><td>13214789</td><td></td></tr></tbody></table>

protein-trna agarose gel retardation assays for the analysis of the n6-threonylcarbamoyladenosine tcda function

我们展示了在大肠杆菌中表达和纯化tRNA（UUU）的方法，并且通过凝胶阻滞测定法分析tRNA（UUU）与TcdA（ N 6 -苏氨酰氨基甲酰氨基腺苷（t6A）脱水酶）的结合的分析，其使苏氨酰氨基甲酰基侧链连接到tRNA的反密码子茎环（ASL）中的A37到循环t 6 A（ct 6 A）。在具有1mM异丙基β-D-1-硫代吡喃半乳糖苷（IPTG）的大肠杆菌中诱导编码tRNA（UUU）的合成基因的转录，诱导后24小时收获含有tRNA的细胞。使用酸性酚提取法纯化RNA级分。通过凝胶过滤色谱法获得纯tRNA，其有效地将小尺寸tRNA分子与较大的完整或片段化的核酸分离。为了分析与tRNA（UUU）结合的TcdA，将TcdA与tRNA（UUU）混合，并在4℃下在天然琼脂糖凝胶上分离。游离tRNA（UUU）迁移更快，而TcdA-tRNA（UUU）复合物经历了在凝胶染色时可观察到的移动性延迟。我们证明TcdA是一种tRNA（UUU）结合酶。这种凝胶阻滞测定可用于研究TcdA突变体以及添加剂和其他蛋白质对结合的影响。

通过在强诱导型T7启动子的控制下在大肠杆菌中表达tRNA基因可以获得大量的tRNA（UUU）。表达的tRNA（UUU）积累在细胞质中，并且在天然丰富的tRNA库中富集。使用由捕获/提取步骤和凝胶过滤/抛光步骤组成的两步​​纯化方法获得EMSA级tRNA。捕获/提取步骤使用pH 4.3苯酚来实现蛋白质，细胞碎片，DNA的同时沉淀和tRNA（和其他RNA分子）的提取。在该步骤中，可以通过在2％...

Watch this Scientific Journal Video about Protein-tRNA Agarose Gel Retardation Assays for the Analysis of the N6-threonylcarbamoyladenosine TcdA Function at JoVE.com

Protein-tRNA Agarose Gel Retardation Assays for the Analysis of the N6-threonylcarbamoyladenosine TcdA Function

介绍了通过琼脂糖凝胶阻滞测定技术生产tRNA（UUU）和tDNA（UUU）与酶TcdA复合物的分析方案。

蛋白质tRNA琼脂糖凝胶延迟测定分析<em&gt;ñ</em<sup&gt; 6</sup&gt; - 磺酰氨基甲酰腺苷TcdA功能

We demonstrate methods for the expression and purification of tRNA(UUU) in Escherichia coli and the analysis by gel retardation assays of the binding of ...

protein-trna-agarose-gel-retardation-assays-for-analysis-n6

Research

JoVE Journal

Biochemistry

Protein-tRNA Agarose Gel Retardation Assays for the Analysis of the N6-threonylcarbamoyladenosine TcdA Function

9.7K 次观看.  Spanish National Research Council (CSIC). 介绍了通过琼脂糖凝胶阻滞测定技术生产tRNA（UUU）和tDNA（UUU）与酶TcdA复合物的分析方案。 

视频: Protein-tRNA Agarose Gel Retardation Assays for the Analysis of the N6-threonylcarbamoyladenosine TcdA Function

Preparation and In Vivo Use of an Activity-based Probe for N-acylethanolamine Acid Amidase

Activity-based protein profiling (ABPP) is a method for the identification of an enzyme of interest in a complex proteome through the use of a chemical probe that targets the enzyme&#39;s active sites. A reporter tag introduced into the probe allows for the detection of the labeled enzyme by in-gel fluorescence scanning, protein blot, fluorescence microscopy, or liquid chromatography-mass spectrometry. Here, we describe the preparation and use of the compound ARN14686, a click chemistry activity-based probe (CC-ABP) that selectively recognizes the enzyme N-acylethanolamine acid amidase (NAAA). NAAA is a cysteine hydrolase that promotes inflammation by deactivating endogenous peroxisome proliferator-activated receptor (PPAR)-alpha agonists such as palmitoylethanolamide (PEA) and oleoylethanolamide (OEA). NAAA is synthesized as an inactive full-length proenzyme, which is activated by autoproteolysis in the acidic pH of the lysosome. Localization studies have shown that NAAA is predominantly expressed in macrophages and other monocyte-derived cells, as well as in B-lymphocytes. We provide examples of how ARN14686 can be used to detect and quantify active NAAA ex vivo in rodent tissues by protein blot and fluorescence microscopy.

Preparation and In Vivo Use of an Activity-based Probe for N-acylethanolamine Acid Amidase

Here, we describe the preparation and use of an activity-based probe (ARN14686, undec-10-ynyl-N-[(3S)-2-oxoazetidin-3-yl]carbamate) that allows for the detection and quantification of the active form of the proinflammatory enzyme N-acylethanolamine acid amidase (NAAA), both in vitro and ex vivo.

制备及<em&gt;在体内</em&gt;使用基于活动的探针对<em&gt;ñ</em&gt; -acylethanolamine酸酰胺酶

Activity-based protein profiling (ABPP) is a method for the identification of an enzyme of interest in a complex proteome through the use of a chemical ...

科研

生物化学

In vitro tRNA Methylation Assay with the Entamoeba histolytica DNA and tRNA Methyltransferase Dnmt2 (Ehmeth) Enzyme

Protozoan parasites are among the most devastating infectious agents of humans responsible for a variety of diseases including amebiasis, which is one of the three most common causes of death from parasitic disease. The agent of amebiasis is the amoeba parasite Entamoeba histolytica that exists under two stages: the infective cyst found in food or water and the invasive trophozoite living in the intestine. The clinical manifestations of amebiasis range from being asymptomatic to colitis, dysentery or liver abscesses. E. histolytica is one of the rare unicellular parasite with 5-methylcytosine (5mC) in its genome. 1, 2 It contains a single DNA methyltransferase, Ehmeth, that belongs to the Dnmt2 family. 2 A role for Dnmt2 in the control of repetitive elements has been established in E. histolytica, 3 Dictyostelium discoideum 4,5 and Drosophila. 6 Our recent work has shown that Ehmeth methylates tRNAAsp, and this finding indicates that this enzyme has a dual DNA/tRNAAsp methyltransferase activity. 7 This observation is in agreement with the dual activity that has been reported for D. discoideum and D. melanogaster. 8 The functional significance of the DNA/tRNA specificity of Dnmt2 enzymes is still unknown. To address this question, a method to determine the tRNA methyltransferase activity of Dnmt2 proteins was established. In this video, we describe a straightforward approach to prepare an adequate tRNA substrate for Dnmt2 and a method to measure its tRNA methyltransferase activity.

In vitro tRNA Methylation Assay with the Entamoeba histolytica DNA and tRNA Methyltransferase Dnmt2 Ehmeth Enzyme

This protocol describes the preparation of a synthetic tRNA substrate for the Entamoeba histolytica DNA/tRNA methyltransferase 2 (Dnmt2) homolog Ehmeth and the measure of its methyltransferase activity. This experimental approach can be used for investigating the activity of other Dnmt2 proteins.

在体外的tRNA与阿米巴 DNA和tRNA甲基Dnmt2（Ehmeth）酶甲基化含量

Protozoan parasites are among the most devastating infectious agents of humans responsible for a variety of diseases including amebiasis, which is one of ...

免疫与感染

Semi-quantitative Detection of RNA-dependent RNA Polymerase Activity of Human Telomerase Reverse Transcriptase Protein

Human telomerase reverse transcriptase (TERT) is the catalytic subunit of telomerase, and it elongates telomere through RNA-dependent DNA polymerase activity. Although TERT is named as a reverse transcriptase, structural and phylogenetic analyses of TERT demonstrate that TERT is a member of right-handed polymerases, and relates to viral RNA-dependent RNA polymerases (RdRPs) as well as viral reverse transcriptase. We firstly identified RdRP activity of human TERT that generates complementary RNA stand to a template non-coding RNA and contributes to RNA silencing in cancer cells. To analyze this non-canonical enzymatic activity, we developed RdRP assay with recombinant TERT in 2009, thereafter established in vitro RdRP assay for endogenous TERT. In this manuscript, we describe the latter method. Briefly, TERT immune complexes are isolated from cells, and incubated with template RNA and rNTPs including radioactive rNTP for RdRP reaction. To eliminate single-stranded RNA, reaction products are treated with RNase I, and the final products are analyzed with polyacrylamide gel electrophoresis. Radiolabeled RdRP products can be detected by autoradiography after overnight exposure.

Human telomerase reverse transcriptase (TERT) synthesizes not only telomeric DNA but also double-stranded RNA through RNA-dependent RNA polymerase activity. Here, we describe a newly established assay to detect RNA-dependent RNA polymerase activity of endogenous TERT.

人端粒酶逆转录蛋白 rna 依赖性 rna 聚合酶活性的半定量检测

Human telomerase reverse transcriptase (TERT) is the catalytic subunit of telomerase, and it elongates telomere through RNA-dependent DNA polymerase ...

遗传学

Efficient Purification and LC-MS/MS-based Assay Development for Ten-Eleven Translocation-2 5-Methylcytosine Dioxygenase

The epigenetic transcription regulation mediated by 5-methylcytosine (5mC) has played a critical role in eukaryotic development. Demethylation of these epigenetic marks is accomplished by sequential oxidation by ten-eleven translocation dioxygenases (TET1-3), followed by the thymine-DNA glycosylase-dependent base excision repair. Inactivation of the TET2 gene due to genetic mutations or by other epigenetic mechanisms is associated with a poor prognosis in patients with diverse cancers, especially hematopoietic malignancies. Here, we describe an efficient single step purification of enzymatically active untagged human TET2 dioxygenase using cation exchange chromatography. We further provide a liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach that can separate and quantify the four normal DNA bases (A, T, G, and C), as well as the four modified cytosine bases (5-methyl, 5-hydroxymethyl, 5-formyl, and 5-carboxyl). This assay can be used to evaluate the activity of wild type and mutant TET2 dioxygenases.

Here, we present a protocol for an efficient single step purification of the active untagged human ten-eleven translocation-2 (TET2) 5-methylcytosine dioxygenase using ion-exchange chromatography and its assay using a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based approach.

高效纯化和基于 LC ms/ms 的十-十一 Translocation-2 5-甲基胞嘧啶酶的检测开发

The epigenetic transcription regulation mediated by 5-methylcytosine (5mC) has played a critical role in eukaryotic development. Demethylation of these ...

An In Vitro Assay to Detect tRNA-Isopentenyl Transferase Activity

N6-isopentenyladenosine RNA modifications are functionally diverse and highly conserved among prokaryotes and eukaryotes. One of the most highly conserved N6-isopentenyladenosine modifications occurs at the A37 position in a subset of tRNAs. This modification improves translation efficiency and fidelity by increasing the affinity of the tRNA for the ribosome. Mutation of enzymes responsible for this modification in eukaryotes are associated with several disease states, including mitochondrial dysfunction and cancer. Therefore, understanding the substrate specificity and biochemical activities of these enzymes is important for understanding of normal and pathologic eukaryotic biology. A diverse array of methods has been employed to characterize i6A modifications. Herein is described a direct approach for the detection of isopentenylation by Mod5. This method utilizes incubation of RNAs with a recombinant isopentenyl transferase, followed by RNase T1 digestion, and 1-dimensional gel electrophoresis analysis to detect i6A modifications. In addition, the potential adaptability of this protocol to characterize other RNA-modifying enzymes is discussed.

An In Vitro Assay to Detect tRNA-Isopentenyl Transferase Activity

Here, we describe a protocol for the biochemical characterization of the yeast RNA-modifying enzyme, Mod5, and discuss how this protocol could be applied to other RNA-modifying enzymes.

体外检测 tRNA-Isopentenyl 转移酶活性的实验研究

N6-isopentenyladenosine RNA modifications are functionally diverse and highly conserved among prokaryotes and eukaryotes. One of the most highly conserved ...

Antibody-Free Assay for RNA Methyltransferase Activity Analysis

There are more than 100 chemically distinct modifications of RNA, two thirds of which consist of methylations. Interest in RNA modifications, and especially methylations, has re-emerged due to the important roles played by the enzymes that write and erase them in biological processes relevant to disease and cancer. Here, a sensitive in vitro assay for accurate analysis of RNA methylation writer activity on synthetic or in vitro transcribed RNAs is provided. This assay uses a tritiated form of S-adenosyl-methionine, resulting in direct labeling of methylated RNA with tritium. The low energy of tritium radiation makes the method safe, and pre-existing methods of tritium signal amplification, make it possible to quantify and to visualize the methylated RNA without the use of antibodies, which are commonly prone to artifacts. While this method is written for RNA methylation, few tweaks make it applicable to the study of other RNA modifications that can be radioactively labeled, such as RNA acetylation with 14C acetyl coenzyme A. Overall, this assay allows to quickly assess RNA methylation conditions, inhibition with small molecule inhibitors, or the effect of RNA or enzyme mutants, and provides a powerful tool to validate and expand results obtained in cells.

Here, an antibody-free in vitro assay for direct analysis of methyltransferase activity on synthetic or in vitro transcribed RNA is described.

RNA甲基转移酶活性分析的无抗体测定

There are more than 100 chemically distinct modifications of RNA, two thirds of which consist of methylations. Interest in RNA modifications, and ...

An In Vitro Enzymatic Assay to Measure Transcription Inhibition by Gallium(III) and H3 5,10,15-tris(pentafluorophenyl)corroles

Chemotherapy often involves broad-spectrum cytotoxic agents with many side effects and limited targeting. Corroles are a class of tetrapyrrolic macrocycles that exhibit differential cytostatic and cytotoxic properties in specific cell lines, depending on the identities of the chelated metal and functional groups. The unique behavior of functionalized corroles towards specific cell lines introduces the possibility of targeted chemotherapy.
Many anticancer drugs are evaluated by their ability to inhibit RNA transcription. Here we present a step-by-step protocol for RNA transcription in the presence of known and potential inhibitors. The evaluation of the RNA products of the transcription reaction by gel electrophoresis and UV-Vis spectroscopy provides information on inhibitive properties of potential anticancer drug candidates and, with modifications to the assay, more about their mechanism of action.
Little is known about the molecular mechanism of action of corrole cytotoxicity. In this experiment, we consider two corrole compounds: gallium(III) 5,10,15-(tris)pentafluorophenylcorrole (Ga(tpfc)) and freebase analogue 5,10,15-(tris)pentafluorophenylcorrole (tpfc). An RNA transcription assay was used to examine the inhibitive properties of the corroles. Five transcription reactions were prepared: DNA treated with Actinomycin D, triptolide, Ga(tpfc), tpfc at a [complex]:[template DNA base] ratio of 0.01, respectively, and an untreated control.
The transcription reactions were analyzed after 4 hr using agarose gel electrophoresis and UV-Vis spectroscopy. There is clear inhibition by Ga(tpfc), Actinomycin D, and triptolide.
This RNA transcription assay can be modified to provide more mechanistic detail by varying the concentrations of the anticancer complex, DNA, or polymerase enzyme, or by incubating the DNA or polymerase with the complexes prior to RNA transcription; these modifications would differentiate between an inhibition mechanism involving the DNA or the enzyme. Adding the complex after RNA transcription can be used to test whether the complexes degrade or hydrolyze the RNA. This assay can also be used to study additional anticancer candidates.

An In Vitro Enzymatic Assay to Measure Transcription Inhibition by GalliumIII and H3 5,10,15-trispentafluorophenylcorroles

Gallium(III) 5,10,15-(tris)pentafluorophenylcorrole and its freebase analogue exhibit low micromolar cell cytotoxicity. This manuscript describes an RNA transcription reaction, imaging RNA with an ethidium bromide-stained gel, and quantifying RNA with UV-Vis spectroscopy, in order to assess transcription inhibition by corroles and demonstrates a straightforward method of evaluating anticancer candidate properties.

一个<em&gt;在体外</em&gt;酶测定来测量转录抑制作用镓（Ⅲ）和H<sub&gt; 3</sub&gt; -5,10,15-三（五氟苯基）corroles

Chemotherapy often involves broad-spectrum cytotoxic agents with many side effects and limited targeting. Corroles are a class of tetrapyrrolic ...

生物工程

Nucleocapsid Annealing-Mediated Electrophoresis (NAME) Assay Allows the Rapid Identification of HIV-1 Nucleocapsid Inhibitors

RNA or DNA folded in stable tridimensional folding are interesting targets in the development of antitumor or antiviral drugs. In the case of HIV-1, viral proteins involved in the regulation of the virus activity recognize several nucleic acids. The nucleocapsid protein NCp7 (NC) is a key protein regulating several processes during virus replication. NC is in fact a chaperone destabilizing the secondary structures of RNA and DNA and facilitating their annealing. The inactivation of NC is a new approach and an interesting target for anti-HIV therapy. The Nucleocapsid Annealing-Mediated Electrophoresis (NAME) assay was developed to identify molecules able to inhibit the melting and annealing of RNA and DNA folded in thermodynamically stable tridimensional conformations, such as hairpin structures of TAR and cTAR elements of HIV, by the nucleocapsid protein of HIV-1. The new assay employs either the recombinant or the synthetic protein, and oligonucleotides without the need of their previous labeling. The analysis of the results is achieved by standard polyacrylamide gel electrophoresis (PAGE) followed by conventional nucleic acid staining. The protocol reported in this work describes how to perform the NAME assay with the full-length protein or its truncated version lacking the basic N-terminal domain, both competent as nucleic acids chaperones, and how to assess the inhibition of NC chaperone activity by a threading intercalator. Moreover, NAME can be performed in two different modes, useful to obtain indications on the putative mechanism of action of the identified NC inhibitors.

Nucleocapsid Annealing-Mediated Electrophoresis NAME Assay Allows the Rapid Identification of HIV-1 Nucleocapsid Inhibitors

This protocol describes NAME, an assay that allows the rapid identification of molecules able to inhibit in vitro the chaperone activities of HIV-1 nucleocapsid protein.

核衣壳退火介导电泳（NAME）分析允许HIV-1核衣壳抑制剂的快速鉴定

RNA or DNA folded in stable tridimensional folding are interesting targets in the development of antitumor or antiviral drugs. In the case of HIV-1, viral ...

CD Spectroscopy to Study DNA-Protein Interactions

Circular dichroism (CD) spectroscopy is a simple and convenient method to investigate the secondary structure and interactions of biomolecules. Recent advancements in CD spectroscopy have enabled the study of DNA-protein interactions and conformational dynamics of DNA in different microenvironments in detail for a better understanding of transcriptional regulation in vivo. The area around a potential transcription zone needs to be unwound for transcription to occur. This is a complex process requiring the coordination of histone modifications, binding of the transcription factor to DNA, and other chromatin remodeling activities. Using CD spectroscopy, it is possible to study conformational changes in the promoter region caused by regulatory proteins, such as ATP-dependent chromatin remodelers, to promote transcription. The conformational changes occurring in the protein can also be monitored. In addition, queries regarding the affinity of the protein towards its target DNA and sequence specificity can be addressed by incorporating mutations in the target DNA. In short, the unique understanding of this sensitive and inexpensive method can predict changes in chromatin dynamics, thereby improving the understanding of transcriptional regulation.

The interaction of an ATP-dependent chromatin remodeler with a DNA ligand is described using CD spectroscopy. The induced conformational changes on a gene promoter analyzed by the peaks generated can be used to understand the mechanism of transcriptional regulation.

CD光谱学研究DNA-蛋白质相互作用

Circular dichroism (CD) spectroscopy is a simple and convenient method to investigate the secondary structure and interactions of biomolecules. Recent ...

Telomerase Activity in the Various Regions of Mouse Brain: Non-Radioactive Telomerase Repeat Amplification Protocol (TRAP) Assay

Telomerase, a ribonucleoprotein, is responsible for maintaining the telomere length and therefore promoting genomic integrity, proliferation, and lifespan. In addition, telomerase protects the mitochondria from oxidative stress and confers resistance to apoptosis, suggesting its possible importance for the surviving of non-mitotic, highly active cells such as neurons. We previously demonstrated the ability of novel telomerase activators to increase telomerase activity and expression in the various mouse brain regions and to protect motor neurons cells from oxidative stress. These results strengthen the notion that telomerase is involved in the protection of neurons from various lesions. To underline the role of telomerase in the brain, we here compare the activity of telomerase in male and female mouse brain and its dependence on age. TRAP assay is a standard method for detecting telomerase activity in various tissues or cell lines. Here we demonstrate the analysis of telomerase activity in three regions of the mouse brain by non-denaturing protein extraction using CHAPS lysis buffer followed by modification of the standard TRAP assay.
In this 2-step assay, endogenous telomerase elongates a specific telomerase substrate (TS primer) by adding TTAGGG 6 bp repeats (telomerase reaction). The telomerase reaction products are amplified by PCR reaction creating a DNA ladder of 6 bp increments. The analysis of the DNA ladder is made by 4.5% high resolution agarose gel electrophoresis followed by staining with highly sensitive nucleic acid stain.
Compared to the traditional TRAP assay that utilize 32P labeled radioactive dCTP&#39;s for DNA detection and polyacrylamide gel electrophoresis for resolving the DNA ladder, this protocol offers a non-toxic time saving TRAP assay for evaluating telomerase activity in the mouse brain, demonstrating the ability to detect differences in telomerase activity in the various female and male mouse brain region.

Telomerase Activity in the Various Regions of Mouse Brain: Non-Radioactive Telomerase Repeat Amplification Protocol TRAP Assay

Telomerase is expressed in the neonatal brain and also in distinct regions of the adult brain. We present a non-toxic time saving TRAP assay for the analysis of telomerase activity in various regions of the mouse brain and detection of differences in telomerase activity between male and female mouse brains.

蛋白质tRNA琼脂糖凝胶延迟测定分析

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