SV是感谢来自美国国立卫生研究院K22AI077353和Landenberger基金会的资助。 KR感激来自美国国立卫生研究院（5SC1GM083754）承认资金。

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作者什么都没有透露。

体外前体mRNA 3&#39;裂解反应，在HeLa细胞核提取物或从这些提取物分馏裂解因素进行，使识别的核心裂解因素，其主要复合物16-21。许多与这些因素相关的更多的蛋白质最近已确定了22个，并在体外的反应可能会继续阐明这些蛋白是如何有助于反应轻。也许是因为在体内的反应似乎是cotranscriptional 23，或者是因为一些影响因素可能提取和透析过程中丢失时...

最成熟的真核生物的RNA消息（mRNA的）的生物合成需要几个转录后修饰，如封盖，剪接和多聚腺苷酸化。这些修饰通常耦合，以确保正确的处理1，并强烈增加mRNA的稳定性。 由聚（A）聚合酶（PAP）2-4 3&#39;哺乳动物预mRNA的末端形成由新生RNA，随后加入腺苷酸残基到5的内切核苷酸裂解产生&#39;裂解产物。在哺乳动物中，断裂是由多组分蛋白复合物完成约800 kDa的，是组装在特定的预RNA序列。所述聚（A）信号序列，一个高度保守的典型六核苷酸序列AAUAAA，引导切割位点在约10-30个核苷酸的下游。这个网站是专门由切割和多聚腺苷酸化特异性因子（CPSF）及73 kD的亚基确认CSPF包含内切核酸酶的活性。裂解刺激因子（CSTF）结合更加堕落GU-或U丰富的元素序列中的poly（A）位点下游。还需要裂解是哺乳动物裂解因子I（CFIM）和哺乳动物裂解因子II（CFII）。 CFIM结合上游序列中的元素（使用）的具体UGUA（N）的网站，已经被定义为一些基因，似乎参与重要的生理过程5-8。 在体外实验中 ，RNA加工反应通过使用放射性标记的RNA底物9-12常用分析。这些可以通过从噬菌体启动子的T7或SP6失控转录来合成。当研究一种多聚腺苷酸化位点尚未之前其特征在于，它需要使用的基因组DNA，而不是基因产生的RNA底物，作为重要的下游序列中可能不存在于cDNA的。设计底物，包括至少150个核苷酸upstrea米和50从上成熟的mRNA切割位点/结束nt的下游。裂解产物迁移比基材快;然而，因为其他片段可以通过非特异性核酸酶作用而生成的，该反应的特异性具有由其上的正确处理的信号序列依赖性进行验证。因此，RNA底物具有在AAUAAA序列（ 例如，AAGAAA）的点突变可作为阴性对照的裂解反应。 由于少量的放射性标记的RNA被用于裂解反应中，存在于高丰度在大多数核提取核糖核酸酶可以是有问题的，并限制对提取物的制备起始材料的选择范围。 HeLa细胞中往往含有内源性核糖核酸酶水平低，因而在这些测定中表现良好。 在RNA底物在体内和体外的信使核糖核酸是紧接着的poly（A）另外，周四S中的裂解的中间不存在可检测量。因此，研究一个特定的RNA序列或涉及的裂解反应的蛋白质，实验是在防止多聚腺苷酸化的发生条件进行。有乳沟的多聚腺苷酸化无依赖性，反之亦然，所以人能阻止多聚腺苷酸化而不伤害裂解反应。因此，ATP被替换为缺少3&#39;羟基基团，以便只有一个单核苷酸可以在多聚（A）位点被结合并可以被检测到刚切割的RNA链终止类似物。 由于复杂性和这种类型的检测的特殊性程度高，我们描述了一个详细的视频协议由前体mRNA的体外切割/聚（A）机械研究核酸内切裂解。我们描述了如何准备主管核提取物，产生放射性标记的RNA底物，进行裂解反应，并分析和解释结果ING产品。 图1显示了HIV-1的前mRNA的3&#39;末端也可以用于裂解分析法进行编码的RNA底物的例子。艾滋病毒RNA基因组的3&#39;端是由许多重要的调控序列，如聚（A）位点，一个G+ü丰富的地区，以及使用的元素，这些都是必要的病毒mRNA转录13高效成熟。在这个例子中，我们所期望的输入RNA底物为338 nt的，一经裂解237 nt的。如果多聚腺苷酸化被允许发生，产品一抹黑将237和437个核苷酸之间被观察到。

<table border="0" cellpadding="0" cellspacing="0" width="757">
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			<td height="21" style="height:21px;width:216px;">1L Celstir Flask</td>
			<td style="width:141px;">Wheaton</td>
			<td style="width:119px;">356884</td>
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			<td height="21" style="height:21px;width:216px;">4 Position Slow Speed Stirrer</td>
			<td style="width:141px;">VWR</td>
			<td style="width:119px;">12621-076</td>
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			<td height="21" style="height:21px;width:216px;">Swinging Bucket Centrifuge</td>
			<td style="width:141px;">Beckman Coulter</td>
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			<td style="width:281px;">Allegra x-15R with SX4500 Rotor</td>
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			<td height="21" style="height:21px;width:216px;">Ultra Centrifuge</td>
			<td style="width:141px;">Beckman Coulter</td>
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			<td>Optima L-100 XP Ultra with SW41 Rotor</td>
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			<td height="21" style="height:21px;width:216px;">Table Top Centrifuge 5417R</td>
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			<td>Refridgerated</td>
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			<td style="width:141px;">Eppendorf</td>
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			<td height="21" style="height:21px;width:216px;">250ml Conicle Tubes</td>
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			<td height="21" style="height:21px;width:216px;">50ml Conicle Tubes</td>
			<td style="width:141px;">BD Falcon</td>
			<td style="width:119px;">352098</td>
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			<td height="21" style="height:21px;width:216px;">Ultra-clear Centrifuge Tubes</td>
			<td style="width:141px;">Beckman Coulter</td>
			<td style="width:119px;">344059</td>
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			<td height="21" style="height:21px;width:216px;">JOKLIK Modified MEM</td>
			<td style="width:141px;">Lonza</td>
			<td style="width:119px;">04-719Q</td>
			<td></td>
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			<td height="21" style="height:21px;width:216px;">Fetal Bovine Serum</td>
			<td style="width:141px;">Atlas&#160;</td>
			<td style="width:119px;">F-0500-A</td>
			<td>Heat inactivated</td>
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			<td style="width:141px;">Gemini Bio-Products</td>
			<td style="width:119px;">400-110</td>
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			<td height="21" style="height:21px;width:216px;">1M Tris-HCl pH 8.0</td>
			<td style="width:141px;">Mediatech</td>
			<td style="width:119px;">46-031-CM</td>
			<td></td>
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			<td height="21" style="height:21px;width:216px;">Magnesium Chloride</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP214-500</td>
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			<td style="width:119px;">194844</td>
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			<td height="21" style="height:21px;width:216px;">HEPES</td>
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			<td style="width:119px;">BP310-500</td>
			<td></td>
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			<td height="21" style="height:21px;width:216px;">DTT</td>
			<td style="width:141px;">Alexis Biomedicals</td>
			<td style="width:119px;">280-001-G-010</td>
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			<td height="21" style="height:21px;width:216px;">Glycerol</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP229-4</td>
			<td></td>
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			<td height="21" style="height:21px;width:216px;">5M Sodium Chloride Solution</td>
			<td style="width:141px;">Mediatech</td>
			<td style="width:119px;">46-032-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">EDTA 0.5M Solution</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">E7889-100ml</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">EDTA</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP120-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">PMSF</td>
			<td style="width:141px;">Thermo Scientific</td>
			<td style="width:119px;">36978</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ammonium Sulfate</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">A702-500</td>
			<td></td>
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		<tr height="42">
			<td height="42" style="height:42px;width:216px;">cOmplete EDTA-Free Protease inhibitor cocktail tablets</td>
			<td style="width:141px;">Roche</td>
			<td style="width:119px;">04 693 132 001</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Slide-A-Lyzer Dialysis Cassettes Kit</td>
			<td style="width:141px;">Thermo Scientific</td>
			<td style="width:119px;">66372</td>
			<td>MWCO 7000 0.5ml-3ml</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">15ml Dounce Tissue grinder set</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">D9938-1SET</td>
			<td>Different sizes available</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Expand High Fidelity PCR Kit</td>
			<td style="width:141px;">Roche</td>
			<td style="width:119px;">11 732 650 001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">10mM dNTP Mix</td>
			<td style="width:141px;">Invitrogen</td>
			<td style="width:119px;">Y02256</td>
			<td>10mM each nucleotide</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">MaxiScript SP6/T7 Kit</td>
			<td style="width:141px;">Ambion</td>
			<td style="width:119px;">AM1322</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">m7G(5&#39;)ppp(5&#39;) G RNA Cap</td>
			<td style="width:141px;">New England Biolabs</td>
			<td style="width:119px;">S1404S</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Century Marker Template Plus</td>
			<td style="width:141px;">Ambion</td>
			<td style="width:119px;">AM7782</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Easytides UTP [alpha-32p]-250uCi</td>
			<td style="width:141px;">Perkin Elmer</td>
			<td style="width:119px;">BLU507H250UC</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gel loading buffer II</td>
			<td style="width:141px;">Ambion</td>
			<td style="width:119px;">8546G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">DEPC treated water</td>
			<td style="width:141px;">Ambion</td>
			<td style="width:119px;">AM9906</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">10x TAE</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP13354</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">10x TBE</td>
			<td style="width:141px;">Ameresco Life Sciences</td>
			<td style="width:119px;">0658-4L</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">10x PBS</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP399-20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Urea</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP169-212</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ammonium Persulfate</td>
			<td style="width:141px;">Bio-Rad</td>
			<td style="width:119px;">161-0700</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">TEMED</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP150-20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ammonium Acetate</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">A637-500</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">40% 19:1 Acrylamide:Bis-acrylamide</td>
			<td style="width:141px;">Bio-Rad</td>
			<td style="width:119px;">161-0144</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Glycogen</td>
			<td style="width:141px;">Roche</td>
			<td style="width:119px;">10 901 393 001</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">100% Absolute Ethanol 200 Proof</td>
			<td style="width:141px;">Acros</td>
			<td style="width:119px;">61509-0040</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Acid Phenol-Chloroform</td>
			<td style="width:141px;">Ambion</td>
			<td style="width:119px;">9720</td>
			<td>For RNA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Scintilation Fluid</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">SX18-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Rnase Inhibitor</td>
			<td style="width:141px;">Promega</td>
			<td style="width:119px;">N261B</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Poly (Vinyl alcohol) PVA</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">P8136-250G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Creatine Phosphate</td>
			<td style="width:141px;">Calbiochem</td>
			<td style="width:119px;">2380</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">100mM dATP</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP2560-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">SDS</td>
			<td style="width:141px;">Acros</td>
			<td style="width:119px;">23042-5000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Proteinase K</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP1700-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Adjustable Sequencing Unit</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z351881-1EA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Binder Clips</td>
			<td style="width:141px;">Office Depot</td>
			<td style="width:119px;">838-056</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">20cmx42cm glass plates</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z352543</td>
			<td>1SET</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">20cmx22cm glass plates</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z35252-7</td>
			<td>1SET</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">20cmx42cm Aluminum Cooling Plates</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z352667</td>
			<td>1EA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">0.4mmx22cm Spacers</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z35230-6</td>
			<td>1SET</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">0.4mmx42cm Spacers</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z352314-1</td>
			<td>1SET</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">8-well Comb</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z35195-4</td>
			<td>1EA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">16-well Comb</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z351962</td>
			<td>1EA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">32-well Comb</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z351970</td>
			<td>1EA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gel Repel Coating</td>
			<td style="width:141px;">C.B.S. Scientific</td>
			<td style="width:119px;">SGR-0401</td>
			<td>or SGR-0101 for individual bottle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gel Loading Tips</td>
			<td style="width:141px;">Rainin</td>
			<td style="width:119px;">GT-10-4</td>
			<td>0.1-10uL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sequencing PowerPac HV</td>
			<td style="width:141px;">Bio-Rad</td>
			<td style="width:119px;">PowerPac HV</td>
			<td>5000V/500mA/400W</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gel Dryer Model 583</td>
			<td style="width:141px;">Bio-Rad</td>
			<td style="width:119px;">Model 583</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Hydrotech Vacuum Pump for gel dryer</td>
			<td style="width:141px;">Bio-Rad</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Glogos II Glow-in-the-dark Markers</td>
			<td style="width:141px;">Agilent</td>
			<td style="width:119px;">420201</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Film 8x10</td>
			<td style="width:141px;">Midsci</td>
			<td style="width:119px;">BX810</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Film 14x17</td>
			<td style="width:141px;">Phenix</td>
			<td style="width:119px;">F-BX1417</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Autoradiography Cassette</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">FBCA 1417</td>
			<td>8x10 size available</td>
		</tr>
	</tbody>
</table>

analysis of rna processing reactions using cell free systems: 3' end cleavage of pre-mrna substrates in vitro

哺乳动物mRNA的3&#39;末端不被由RNA聚合酶II（RNPII）突然终止转录的形成。相反，RNPII合成前体的mRNA之外的成熟RNA的末端，内切酶活性的主动过程，需要在特定的位点。前体RNA切割的CA二核苷酸后通常会发生10-30个核苷酸下游的共识polyA位点（AAUAAA）。从裂解复合物，约800 kDa的多因子蛋白复合物，蛋白质完成这个特定的核酸酶活性。特定的RNA序列的上游和多聚A位点的下游控制裂解复合物的募集。紧接在切割后，mRNA前由聚腺苷酸聚合酶（PAP）多聚腺苷酸化，以产生成熟的稳定的RNA消息。 一种RNA转录物的3&#39;端的处理可以使用移动的核提取物与特定的放射性标记的RNA底物进行研究。总之，长32 &lt;/ SUP&gt; P-标记的未裂解的前体RNA被孵育体外核提取物和裂解是通过凝胶电泳和放射自显影评估。当适当的切割发生在较短的5&#39;裂解产物进行检测和定量。在这里，我们描述了裂解分析法详细使用，作为一个例子，对HIV-1的mRNA的3&#39;末端加工。

将RNA的poly（A）的HIV-1的部位（ 图2）的裂解试验的代表性结果。我们可以观察到的未裂解的RNA底物，它是最慢迁移带在凝胶的顶部。具体的裂解产物是运行在上面的预期大小的凝胶更快最激烈的较短片段的带，并且是从mutpoly（A）的控制，其中包含多聚腺苷酸序列（mutPolyA）+ RNA的点突变的裂解测定法特别缺席基材。输入基板的降解产物有时可观察到。裂解活性的定量可以通过未切割?...

Watch this Scientific Journal Video about Analysis of RNA Processing Reactions Using Cell Free Systems: 3' End Cleavage of Pre-mRNA Substrates in vitro at JoVE.com

Analysis of RNA Processing Reactions Using Cell Free Systems: 3&#039; End Cleavage of Pre-mRNA Substrates in vitro

RNA聚合酶II合成延伸超过所述成熟mRNA的3&#39;末端的前体RNA。的成熟RNA的末端cotranscriptionally生成的，在由RNA序列决定的一个部位，通过裂解复合物的内切核酸酶的活性。在这里，我们详细研究裂解反应在体外的方法。

前体mRNA底物的3&#39;末端切割：用无细胞体系中的RNA加工反应分析<em&gt;在体外</em

The 3&#8217; end of mammalian mRNAs is not formed by abrupt termination of transcription by RNA polymerase II (RNPII). Instead, RNPII synthesizes ...

analysis-rna-processing-reactions-using-cell-free-systems-3-end

Research

JoVE Journal

Biology

Analysis of RNA Processing Reactions Using Cell Free Systems: 3' End Cleavage of Pre-mRNA Substrates in vitro

12.7K 次观看.  The Scripps Research Institute.  RNA聚合酶II合成延伸超过所述成熟mRNA的3'末端的前体RNA。的成熟RNA的末端cotranscriptionally生成的，在由RNA序列决定的一个部位，通过裂解复合物的内切核酸酶的活性。在这里，我们详细研究裂解反应在体外的方法。 

视频: Analysis of RNA Processing Reactions Using Cell Free Systems: 3' End Cleavage of Pre-mRNA Substrates in vitro

Video Bioinformatics Analysis of Human Embryonic Stem Cell Colony Growth

Because video data are complex and are comprised of many images, mining information from video material is difficult to do without the aid of computer software.  Video bioinformatics is a powerful quantitative approach for extracting spatio-temporal data from video images using computer software to perform dating mining and analysis. In this article, we introduce a video bioinformatics method for quantifying the growth of human embryonic stem cells (hESC) by analyzing time-lapse videos collected in a Nikon BioStation CT incubator equipped with a camera for video imaging. In our experiments, hESC colonies that were attached to Matrigel were filmed for 48 hours in the BioStation CT.  To determine the rate of growth of these colonies, recipes were developed using CL-Quant software which enables users to extract various types of data from video images.  To accurately evaluate colony growth, three recipes were created. The first segmented the image into the colony and background, the second enhanced the image to define colonies throughout the video sequence accurately, and the third measured the number of pixels in the colony over time.  The three recipes were run in sequence on video data collected in a BioStation CT to analyze the rate of growth of individual hESC colonies over 48 hours. To verify the truthfulness of the CL-Quant recipes, the same data were analyzed manually using Adobe Photoshop software. When the data obtained using the CL-Quant recipes and Photoshop were compared, results were virtually identical, indicating the CL-Quant recipes were truthful. The method described here could be applied to any video data to measure growth rates of hESC or other cells that grow in colonies. In addition, other video bioinformatics recipes can be developed in the future for other cell processes such as migration, apoptosis, and cell adhesion.  

Video bioinformatics is the automated processing, analysis, understanding, and data mining of biological spatio-temporal data extracted from microscopic videos. The purpose of this article is to demonstrate a method for measuring human embryonic stem cell colony growth using a video bioinformatics method.

视频人类胚胎干细胞克隆生长的生物信息学分析

Because video data are complex and are comprised of many images, mining information from video material is difficult to do without the aid of computer ...

科研

生物学

Visualization of MG53-mediated Cell Membrane Repair Using in vivo and in vitro Systems

Repair of acute injury to the cell membrane is an elemental process of normal cellular physiology, and defective membrane repair has been linked to many degenerative human diseases. The recent discovery of MG53 as a key component of the membrane resealing machinery allows for a better molecular understanding of the basic biology of tissue repair, as well as for potential translational applications in regenerative medicine. Here we detail the experimental protocols for exploring the in vivo function of MG53 in repair of muscle injury using treadmill exercise protocols on mouse models, for testing the ex vivo membrane repair capacity by measuring dye entry into isolated muscle fibers, and for monitoring the dynamic process of MG53-mediated vesicle trafficking and cell membrane repair in cultured cells using live cell confocal microscopy.

Visualization of MG53-mediated Cell Membrane Repair Using in vivo and in vitro Systems

Described here are protocols used to visualize the dynamic process of MG53-mediated cell membrane repair in whole animals and at the cellular level. These methods can be applied to investigate the cell biology of plasma membrane resealing and regenerative medicine.

MG53介导的细胞膜使用维修的可视化在体内在体外系统

Repair of acute injury to the cell membrane is an elemental process of normal cellular physiology, and defective membrane repair has been linked to many ...

Single Read and Paired End mRNA-Seq Illumina Libraries from 10 Nanograms Total RNA

Whole transcriptome sequencing by mRNA-Seq is now used extensively to perform global gene expression, mutation, allele-specific expression and other genome-wide analyses. mRNA-Seq even opens the gate for gene expression analysis of non-sequenced genomes. mRNA-Seq offers high sensitivity, a large dynamic range and allows measurement of transcript copy numbers in a sample. Illumina&#x2019;s genome analyzer performs sequencing of a large number (&gt; 107) of relatively short sequence reads (&lt; 150 bp).The &quot;paired end&quot; approach, wherein a single long read is sequenced at both its ends, allows for tracking alternate splice junctions, insertions and deletions, and is useful for de novo transcriptome assembly.
One of the major challenges faced by researchers is a limited amount of starting material. For example, in experiments where cells are harvested by laser micro-dissection, available starting total RNA may measure in nanograms. Preparation of mRNA-Seq libraries from such samples have been described1, 2 but involves significant PCR amplification that may introduce bias. Other RNA-Seq library construction procedures with minimal PCR amplification have been published3, 4 but require microgram amounts of starting total RNA.
Here we describe a protocol for the Illumina Genome Analyzer II platform for mRNA-Seq sequencing for library preparation that avoids significant PCR amplification and requires only 10 nanograms of total RNA. While this protocol has been described previously and validated for single-end sequencing5, where it was shown to produce directional libraries without introducing significant amplification bias, here we validate it further for use as a paired end protocol. We selectively amplify polyadenylated messenger RNAs from starting total RNA using the T7 based Eberwine linear amplification method, coined &quot;T7LA&quot; (T7 linear amplification). The amplified poly-A mRNAs are fragmented, reverse transcribed and adapter ligated to produce the final sequencing library. For both single read and paired end runs, sequences are mapped to the human transcriptome6 and normalized so that data from multiple runs can be compared. We report the gene expression measurement in units of transcripts per million (TPM), which is a superior measure to RPKM when comparing samples7.

Here we describe a method for preparation of both single read and paired end Illumina mRNA-Seq sequencing libraries for gene expression analysis based on T7 linear RNA amplification. This protocol requires only 10 nanograms of starting total RNA and generates highly consistent libraries representing whole transcripts.

单次读取和配对的最终从10微克总RNA的mRNA - Seq的Illumina的图书馆

Whole transcriptome sequencing by mRNA-Seq is now used extensively to perform global gene expression, mutation, allele-specific expression and other ...

In vitro Transcription and Capping of Gaussia Luciferase mRNA Followed by HeLa Cell Transfection

In vitro transcription is the synthesis of RNA transcripts by RNA polymerase from a linear DNA template containing the corresponding promoter sequence (T7, T3, SP6) and the gene to be transcribed (Figure 1A). A typical transcription reaction consists of the template DNA, RNA polymerase, ribonucleotide triphosphates, RNase inhibitor and buffer containing Mg2+ ions.
Large amounts of high quality RNA are often required for a variety of applications. Use of in vitro transcription has been reported for RNA structure and function studies such as splicing1, RNAi experiments in mammalian cells2, antisense RNA amplification by the "Eberwine method"3, microarray analysis4 and for RNA vaccine studies5. The technique can also be used for producing radiolabeled and dye labeled probes6. Warren, et al. recently reported reprogramming of human cells by transfection with in vitro transcribed capped RNA7. The T7 High Yield RNA Synthesis Kit from New England Biolabs has been designed to synthesize up to 180 &mu;g RNA per 20 &mu;l reaction. RNA of length up to 10kb has been successfully transcribed using this kit. Linearized plasmid DNA, PCR products and synthetic DNA oligonucleotides can be used as templates for transcription as long as they have the T7 promoter sequence upstream of the gene to be transcribed.
Addition of a 5' end cap structure to the RNA is an important process in eukaryotes. It is essential for RNA stability8, efficient translation9, nuclear transport10 and splicing11. The process involves addition of a 7-methylguanosine cap at the 5' triphosphate end of the RNA. RNA capping can be carried out post-transcriptionally using capping enzymes or co-transcriptionally using cap analogs. In the enzymatic method, the mRNA is capped using the Vaccinia virus capping enzyme12,13. The enzyme adds on a 7-methylguanosine cap at the 5' end of the RNA using GTP and S-adenosyl methionine as donors (cap 0 structure). Both methods yield functionally active capped RNA suitable for transfection or other applications14 such as generating viral genomic RNA for reverse-genetic systems15 and crystallographic studies of cap binding proteins such as eIF4E16.
In the method described below, the T7 High Yield RNA Synthesis Kit from NEB is used to synthesize capped and uncapped RNA transcripts of Gaussia luciferase (GLuc) and Cypridina luciferase (CLuc). A portion of the uncapped GLuc RNA is capped using the Vaccinia Capping System (NEB). A linearized plasmid containing the GLuc or CLuc gene and T7 promoter is used as the template DNA. The transcribed RNA is transfected into HeLa cells and cell culture supernatants are assayed for luciferase activity. Capped CLuc RNA is used as the internal control to normalize GLuc expression.

In vitro Transcription and Capping of Gaussia Luciferase mRNA Followed by HeLa Cell Transfection

This method describes high yield in vitro synthesis of both capped and uncapped mRNA from a linearized plasmid containing the Gaussia luciferase (GLuc) gene. The RNA is purified and a fraction of the uncapped RNA is enzymatically capped using the Vaccinia virus capping enzyme. In the final step, the mRNA is transfected into HeLa cells and cell culture supernatants are assayed for luciferase activity.

在体外转录和Gaussia荧光素酶基因的上限由HeLa细胞转染

In vitro transcription is the synthesis of RNA transcripts by RNA polymerase from a linear DNA template containing the corresponding promoter sequence ...

Cell Specific Analysis of Arabidopsis Leaves Using Fluorescence Activated Cell Sorting

After initiation of the leaf primordium, biomass accumulation is controlled mainly by cell proliferation and expansion in the leaves1. However, the Arabidopsis leaf is a complex organ made up of many different cell types and several structures. At the same time, the growing leaf contains cells at different stages of development, with the cells furthest from the petiole being the first to stop expanding and undergo senescence1. Different cells within the leaf are therefore dividing, elongating or differentiating; active, stressed or dead; and/or responding to stimuli in sub-sets of their cellular type at any one time. This makes genomic study of the leaf challenging: for example when analyzing expression data from whole leaves, signals from genetic networks operating in distinct cellular response zones or cell types will be confounded, resulting in an inaccurate profile being generated.
To address this, several methods have been described which enable studies of cell specific gene expression. These include laser-capture microdissection (LCM)2 or GFP expressing plants used for protoplast generation and subsequent fluorescence activated cell sorting (FACS)3,4, the recently described INTACT system for nuclear precipitation5 and immunoprecipitation of polysomes6.
FACS has been successfully used for a number of studies, including showing that the cell identity and distance from the root tip had a significant effect on the expression profiles of a large number of genes3,7. FACS of GFP lines have also been used to demonstrate cell-specific transcriptional regulation during root nitrogen responses and lateral root development8, salt stress9 auxin distribution in the root10 and to create a gene expression map of the Arabidopsis shoot apical meristem11. Although FACS has previously been used to sort Arabidopsis leaf derived protoplasts based on autofluorescence12,13, so far the use of FACS on Arabidopsis lines expressing GFP in the leaves has been very limited4. In the following protocol we describe a method for obtaining Arabidopsis leaf protoplasts that are compatible with FACS while minimizing the impact of the protoplast generation regime. We demonstrate the method using the KC464 Arabidopsis line, which express GFP in the adaxial epidermis14, the KC274 line, which express GFP in the vascular tissue14 and the TP382 Arabidopsis line, which express a double GFP construct linked to a nuclear localization signal in the guard cells (data not shown; Figure 2). We are currently using this method to study both cell-type specific expression during development and stress, as well as heterogeneous cell populations at various stages of senescence.

Cell Specific Analysis of Arabidopsis Leaves Using Fluorescence Activated Cell Sorting

A method for producing Arabidopsis leaf protoplasts that are compatible with fluorescence activated cell sorting (FACS), allowing for studies of specific cell populations. This method is compatible with any Arabidopsis line that expresses GFP in a subset of cells.

细胞特异性分析<em&gt;拟南芥</em&gt;叶用荧光激活细胞分选

After initiation of the leaf primordium, biomass accumulation is controlled mainly by cell proliferation and expansion in the leaves1. However, the ...

Substrate Generation for Endonucleases of CRISPR/Cas Systems

The interaction of viruses and their prokaryotic hosts shaped the evolution of bacterial and archaeal life. Prokaryotes developed several strategies to evade viral attacks that include restriction modification, abortive infection and CRISPR/Cas systems. These adaptive immune systems found in many Bacteria and most Archaea consist of clustered regularly interspaced short palindromic repeat (CRISPR) sequences and a number of CRISPR associated (Cas) genes (Fig. 1) 1-3. Different sets of Cas proteins and repeats define at least three major divergent types of CRISPR/Cas systems 4. The universal proteins Cas1 and Cas2 are proposed to be involved in the uptake of viral DNA that will generate a new spacer element between two repeats at the 5' terminus of an extending CRISPR cluster 5. The entire cluster is transcribed into a precursor-crRNA containing all spacer and repeat sequences and is subsequently processed by an enzyme of the diverse Cas6 family into smaller crRNAs 6-8. These crRNAs consist of the spacer sequence flanked by a 5' terminal (8 nucleotides) and a 3' terminal tag derived from the repeat sequence 9. A repeated infection of the virus can now be blocked as the new crRNA will be directed by a Cas protein complex (Cascade) to the viral DNA and identify it as such via base complementarity10. Finally, for CRISPR/Cas type 1 systems, the nuclease Cas3 will destroy the detected invader DNA 11,12 .
These processes define CRISPR/Cas as an adaptive immune system of prokaryotes and opened a fascinating research field for the study of the involved Cas proteins. The function of many Cas proteins is still elusive and the causes for the apparent diversity of the CRISPR/Cas systems remain to be illuminated. Potential activities of most Cas proteins were predicted via detailed computational analyses. A major fraction of Cas proteins are either shown or proposed to function as endonucleases 4.
Here, we present methods to generate crRNAs and precursor-cRNAs for the study of Cas endoribonucleases. Different endonuclease assays require either short repeat sequences that can directly be synthesized as RNA oligonucleotides or longer crRNA and pre-crRNA sequences that are generated via in vitro T7 RNA polymerase run-off transcription. This methodology allows the incorporation of radioactive nucleotides for the generation of internally labeled endonuclease substrates and the creation of synthetic or mutant crRNAs. Cas6 endonuclease activity is utilized to mature pre-crRNAs into crRNAs with 5'-hydroxyl and a 2',3'-cyclic phosphate termini.

CRISPR/Cas systems mediate adaptive immunity in Bacteria and Archaea. Many Cas proteins are proposed to act as endoribonucleases acting on crRNA precursors of varying length. Here we illustrate three different approaches to generate pre-crRNA substrates for the biochemical analysis of Cas endonuclease activity.

CRISPR / CAS系统内切酶的底物生成

The  interaction of viruses and their prokaryotic hosts shaped the evolution of  bacterial and archaeal life. Prokaryotes developed several strategies to ...

HeLa Based Cell Free Expression Systems for Expression of Plasmodium Rhoptry Proteins

Malaria causes significant global morbidity and mortality. No routine vaccine is currently available. One of the major reasons for lack of a vaccine is the challenge of identifying suitable vaccine candidates. Malarial proteins expressed using prokaryotic and eukaryotic cell based expression systems are poorly glycosylated, generally insoluble and undergo improper folding leading to reduced immunogenicity. The wheat germ, rabbit reticulocyte lysate and Escherichia coli lysate cell free expression systems are currently used for expression of malarial proteins. However, the length of expression time and improper glycosylation of proteins still remains a challenge. We demonstrate expression of Plasmodium proteins in vitro using HeLa based cell free expression systems, termed &#8220;in vitro human cell free expression systems&#8221;. The 2 HeLa based cell free expression systems transcribe mRNA in 75 min and 3 &#181;l of transcribed mRNA is sufficient to translate proteins in 90 min. The 1-step expression system is a transcription and translation coupled expression system; the transcription and co-translation occurs in 3 hr. The process can also be extended for 6 hr by providing additional energy. In the 2-step expression system, mRNA is first transcribed and then added to the translation mix for protein expression. We describe how to express malaria proteins; a hydrophobic PF3D7_0114100 Maurer&#8217;s Cleft &#8211; 2 transmembrane (PfMC-2TM) protein, a hydrophilic PF3D7_0925900 protein and an armadillo repeats containing protein PF3D7_1361800, using the HeLa based cell free expression system. The proteins are expressed in micro volumes employing 2-step and 1-step expression strategies. An affinity purification method to purify 25 &#181;l of proteins expressed using the in vitro human cell free expression system is also described. Protein yield is determined by Bradford&#8217;s assay and the expressed and purified proteins can be confirmed by western blotting analysis. Expressed recombinant proteins can be used for immunizations, immunoassays and protein sequencing.

HeLa Based Cell Free Expression Systems for Expression of Plasmodium Rhoptry Proteins

Expression of malarial proteins in cell based systems remains challenging. We demonstrate two step and one step IVT (in vitro translation) cell free expression systems for expressing malarial recombinant rhoptry proteins from HeLa cells. We use a Ni-resin affinity based purification system to purify the rhoptry proteins.

基于海拉细胞自由表达系统中的表达<em&gt;疟原虫</em&gt;棒状体蛋白

Malaria causes significant global morbidity and mortality. No routine vaccine is currently available. One of the major reasons for lack of a vaccine is ...

A Cell Free Assay to Study Chromatin Decondensation at the End of Mitosis

During the vertebrate cell cycle chromatin undergoes extensive structural and functional changes. Upon mitotic entry, it massively condenses into rod shaped chromosomes which are moved individually by the mitotic spindle apparatus. Mitotic chromatin condensation yields chromosomes compacted fifty-fold denser as in interphase. During exit from mitosis, chromosomes have to re-establish their functional interphase state, which is enclosed by a nuclear envelope and is competent for replication and transcription. The decondensation process is morphologically well described, but in molecular terms poorly understood: We lack knowledge about the underlying molecular events and to a large extent the factors involved as well as their regulation. We describe here a cell-free system that faithfully recapitulates chromatin decondensation in vitro, based on mitotic chromatin clusters purified from synchronized HeLa cells and X. laevis egg extract. Our cell-free system provides an important tool for further molecular characterization of chromatin decondensation and its co-ordination with processes simultaneously occurring during mitotic exit such as nuclear envelope and pore complex re-assembly.

The molecular mechanisms of the decondensation of highly compacted mitotic chromatin are ill-defined. We present a cell-free assay based on mitotic chromatin clusters isolated from HeLa cells and Xenopus laevis egg extract that faithfully reconstitutes the decondensation process in vitro.

无细胞化验，研究染色质解聚在有丝分裂的结束

During the vertebrate cell cycle chromatin undergoes extensive structural and functional changes. Upon mitotic entry, it massively condenses into rod ...

Detection of RNA-binding Proteins by In Vitro RNA Pull-down in Adipocyte Culture

RNA-binding proteins (RBPs) are emerging as a regulatory layer in the development and function of adipose. RBPs play a key role in the gene expression regulation at posttranscriptional levels by affecting the stability and translational efficiency of target mRNAs. RNA pull-down technique has been widely used to study RNA-protein interaction, which is necessary to elucidate the mechanism underlying RBPs&#39; as well as long non-coding RNAs&#39; (lncRNAs) function. However, the high lipid abundance in adipocytes poses a technical challenge in conducting this experiment. Here a detailed RNA pull-down protocol is optimized for primary adipocyte culture. An RNA fragment from androgen receptor&#39;s (AR) 3&#39; untranslated region (3&#39;UTR) containing an adenylate-uridylate-rich elementwas used as an example to demonstrate how to retrieve its RBP partner, HuR protein, from adipocyte lystate. The method described here can be applied to detect the interactions between RBPs and noncoding RNAs, as well as between RBPs and coding RNAs.

Detection of RNA-binding Proteins by In Vitro RNA Pull-down in Adipocyte Culture

An RNA pull-down protocol is optimized here for detection of interactions between RNA-binding proteins (RBPs) and noncoding as well as coding RNAs. An RNA fragment from androgen receptor (AR) was used as an example to demonstrate how to retrieve its RBP from lystate of primary brown adipocytes.

RNA结合蛋白的检测通过<em&gt;体外</em在脂肪细胞培养&gt; RNA下拉

RNA-binding proteins (RBPs) are emerging as a regulatory layer in the development and function of adipose. RBPs play a key role in the gene expression ...

3' End Sequencing Library Preparation with A-seq2

Studies in the last decade have revealed a complex and dynamic variety of pre-mRNA cleavage and polyadenylation reactions. mRNAs with long 3&#39; untranslated regions (UTRs) are generated in differentiated cells whereas proliferating cells preferentially express transcripts with short 3&#39;UTRs. We describe the A-seq protocol, now at its second version, which was developed to map polyadenylation sites genome-wide and study the regulation of pre-mRNA 3&#39; end processing. Also this current protocol takes advantage of the polyadenylate (poly(A)) tails that are added during the biogenesis of most mammalian mRNAs to enrich for fully processed mRNAs. A DNA adaptor with deoxyuracil at its fourth position allows the precise processing of mRNA 3&#39; end fragments for sequencing. Not including the cell culture and the overnight ligations, the protocol requires about 8 h hands-on time. Along with it, an easy-to-use software package for the analysis of the derived sequencing data is provided. A-seq2 and the associated analysis software provide an efficient and reliable solution to the mapping of pre-mRNA 3&#39; ends in a wide range of conditions, from 106 or fewer cells.

3&#039; End Sequencing Library Preparation with A-seq2

This protocol describes a method for mapping pre-mRNA 3&#39; end processing sites.