我们感谢奥布赖恩在UIC实验室关键的实验评价和讨论。这项工作是由美国心脏协会授予11SDG5230003威乐和国家推进转化科学中心 - UIC批准UL1TR000050临床和转化科学中心。

1。细胞转染<ol><li>板细胞转染前一天，电镀免疫细胞较少。 <ol><li>的免疫：在6孔的板，涂层的玻璃盖玻片（1）用0.02％的明胶在37℃下至少4小时，洗一次的介质，并为每个反应孔，板1×10 5 HEK 293T细胞在2毫升的完整的​​生长培养基[Dulbecco改良的Eagle培养基（DMEM）中加10％FBS]。 </li><li>对于流式细胞术和Western blot分析：板1.2×10 5 HEK 293T细胞/孔，在2毫升完全培养基的6孔板（0.3×10 5的HEK 293T细胞在0.5ml完全培养基的24孔板中，每孔）。 </li></ol></li><li>准备用于转染的DNA，根据制造商的协议：Effectene（Qiagen公司）用于免疫荧光。中转-LT1（Mirus公司）用于流式细胞仪和Western blot分析。下面列出了所使用的DNA量。 <table border="1"><tbody><tr><tD&gt; </td><td> 24孔培养板（纳克） </td><td> 6孔板（纳克） </td></tr><tr><td> CFP矢量</td><td> 10 </td><td> 50 </td></tr><tr><td> VN N-AKAP - LBC </td><td> 200 </td><td> 1000 </td></tr><tr><td> VC的N-PDE4D3-FL（PDE4D3全长） </td><td> 2.5，5，10，20，40，80 </td><td> 100 </td></tr><tr><td> VC N-PDE4D3 UCR1（PDE4D3含有UCR1域的N-末端片段） </td><td></td><td> 100 </td></tr><tr><td> VC N-PDE4D3 UCR2 + CAT（PDE4D3 UCR2和催化结构域的C-末端片段） </td><td></td><td> 100 </td></tr></tbody></table>转用（6）Effectene： <ol><li>添加指示的质粒DNA量+ 4微升增强到100微升缓冲EC，混合，在室温下孵育5分钟。 </li><li>添加5微升Effectene，混合，和孵育10分钟室温。添加逐滴细胞。 </li></ol>转公交LT1（6-well/24-well）： <ol><li>指定量的质粒DNA加入到250μl/50微升的Opti-MEM I的无血清培养基的无菌管中。 </li><li>添加过境-LT1试剂的稀释的DNA混合物和吸管轻轻混合。 （过境LT1试剂：DNA比例是3微升过境LT1试剂的每1微克DNA）。 </li><li>在室温下孵育30分钟，并逐滴加入细胞。 </li></ol></li></ol> 2。流式细胞仪，免疫印迹，免疫细胞制备方法<ol><li>染后24小时，检查前收获细胞荧光落射荧光显微镜下。 </li><li>流式细胞仪分析细胞的准备： <ol><li>用0.5毫升/ 2毫升为24-well/6-well板冰冷的PBS洗涤细胞。 </li><li>使用50μl/250微升0.05％胰蛋白酶分离细胞。 </li><li>用200μl/ 1毫升的DMEM培养基中和胰蛋白酶。 </li><li>合作250微升细胞llect（24孔和6孔板），在500×g离心5分钟，通过离心分离，用Western印迹分析的其它细胞（1毫升）。 </li><li>细胞重悬于250微升FACS缓冲[PBS + 0.5％（W / V）BSA + 2毫米EDTA]，储存在冰流式细胞仪分析。细胞也可以固定在1％多聚甲醛（在PBS中），不会立即生效，如果流式细胞分析。 </li></ol></li><li>平行进行的Western印迹分析的细胞制备方法：用流式细胞仪分析细胞制备方法。 <ol><li>用2ml冰冷的PBS 1X洗涤细胞，裂解细胞，加入100μl的细胞裂解缓冲液[10mM磷酸钠缓冲液，pH值为6.95，150 mM氯化钠，5mM的EDTA，5mM的EGTA，1％的Triton X-100] 。 </li><li>通过离心收集细胞裂解液在4℃下以21,000×g的10分钟</li><li>量化Bradford蛋白检测蛋白浓度，装入等量的每通道蛋白SDS-PAGE，并转​​移到硝酸纤维素免疫。 </li></醇&gt; </li><li>免疫细胞制备。 <ol><li>用2ml PBS冲洗细胞3次，在1毫升的3.7％多聚甲醛（在PBS中）在室温下10分钟固定细胞，然后用2毫升的PBS洗涤3次，持续5分钟。 </li><li>挂载，盖玻片载玻片上，用安装介质。如果需要使用指甲油密封盖玻片边缘。 </li><li>将在4℃检查前的幻灯片。 </li></ol></li></ol> 3。流式细胞仪和免疫荧光显微镜<ol><li>使用的Beckman Coulter公司青色ADP，装有488纳米，405纳米，642纳米的固态激光器的流式细胞术进行。峰会软件用于采集和分析。 <ol><li>校准流式细胞仪使用标准的珠子。 </li><li>剧情前向散射（FSC）/侧向散射（SSC）的线性浇注活细胞人口规模。 </li><li>剧情FSC /电压脉冲宽度选通非聚合活细胞群体。 </li><li>剧情count/FL6（CFP fluorescencE，405 nm）的非聚集现场浇注CFP阳性细胞对数刻度。 </li><li>的的剧情count/FL1（YFP的荧光，488 nm）的对数刻度附设强度。 </li><li>运行YFP-CFP-双阴性样品，调整FSC，SSC，FL1和FL6光电倍增管（PMT）电压来设置每个信号的阈值。 </li><li>跑单阳性（两个YFP +和CFP +）样品未来离线补偿</li><li>获得至少10,000门事件（非聚合现场CFP +细胞）进行分析。 </li></ol></li><li>免疫荧光显微镜使用蔡司​​LSM 510共聚焦显微镜注：重要的是要保持所有的设置（如变焦，针孔探测器的增益，放大器的失调，帧大小，扫描速度快，扫描平均，和激光功率）之间的一致样品进行适当比较的所有数据。 </li></ol> 4。数据分析（使用首脑软件执行） <ol><li>设置分析本收类似协议正确的门控离子： 1号门FSC / SSC点图活细胞。 2号门在FSC /脉冲宽度1号门非聚合活细胞中。 3号门，3号门计数/ CFP非聚合CFP +活细胞。 </li><li>补偿YFP和CFP信号的使用YFP +和CFP +单阳性细胞。 </li><li>重新确定切断线CFP / YFP的阳性细胞。 </li><li>进出口YFP的平均荧光强度（MFI）CFP +细胞到Excel的数据绘制。 </li><li>标准化YFP MFI AKAP - LBC，PDE4D3表达水平，并装载控制α-微管蛋白，Western blot检测。 </li></ol>

<ol>
	<li>Collura, V., Boissy, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=From+protein-protein+complexes+to+interactomics.">From protein-protein complexes to interactomics.</a> Subcell Biochem. 43, 135-183 (2007).</li><li>Stumpf, M. 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=Estimating+the+size+of+the+human+interactome.">Estimating the size of the human interactome.</a> Proc. Natl. Acad. Sci. U.S.A. 105, 6959-6964 (2008).</li><li>Shekhawat, S. S., Ghosh, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Split-protein+systems:+beyond+binary+protein-protein+interactions.">Split-protein systems: beyond binary protein-protein interactions.</a> Curr. Opin. Chem. Biol. 15, 789-797 (2011).</li><li>Dwane, S., Kiely, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tools+used+to+study+how+protein+complexes+are+assembled+in+signaling+cascades.">Tools used to study how protein complexes are assembled in signaling cascades.</a> Bioeng. Bugs. 2, 247-259 (2011).</li><li>Piehler, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+methodologies+for+measuring+protein+interactions+in+vivo+and+in+vitro.">New methodologies for measuring protein interactions in vivo and in vitro.</a> Curr. Opin. Struct. Biol. 15, 4-14 (2005).</li><li>Kerppola, T. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+implementation+of+bimolecular+fluorescence+complementation+(BiFC)+assays+for+the+visualization+of+protein+interactions+in+living+cells.">Design and implementation of bimolecular fluorescence complementation (BiFC) assays for the visualization of protein interactions in living cells.</a> Nat. Protoc. 1, 1278-1286 (2006).</li><li>Shyu, Y. J., Suarez, C. D., Hu, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualization+of+ternary+complexes+in+living+cells+by+using+a+BiFC-based+FRET+assay.">Visualization of ternary complexes in living cells by using a BiFC-based FRET assay.</a> Nat. Protoc. 3, 1693-1702 (2008).</li><li>Wong, K. A., O'Bryan, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bimolecular+fluorescence+complementation.">Bimolecular fluorescence complementation.</a> J. Vis. Exp. (50), e2643 (2011).</li><li>Sugarbaker, E. V., Thornthwaite, J. T., Temple, W. T., Ketcham, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+cytometry:+general+principles+and+applications+to+selected+studies+in+tumor+biology.">Flow cytometry: general principles and applications to selected studies in tumor biology.</a> Int. Adv. Surg. Oncol. 2, 125-153 (1979).</li><li>Koshy, S., Alizadeh, P., Timchenko, L. T., Beeton, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+measurement+of+GLUT4+translocation+to+the+plasma+membrane+by+flow+cytometry.">Quantitative measurement of GLUT4 translocation to the plasma membrane by flow cytometry.</a> J. Vis. Exp. (45), e2429 (2010).</li><li>Smith, 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=Basic+confocal+microscopy.">Basic confocal microscopy.</a> Curr. Protoc. Mol. Biol. Chapter 14 (Unit 14), 11 (2008).</li><li>Westwick, J. K., Lamerdin, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+drug+discovery+with+contextual+assays+and+cellular+systems+analysis.">Improving drug discovery with contextual assays and cellular systems analysis.</a> Methods Mol. Biol. 756, 61-73 (2011).</li><li>Kilpatrick, L. E., Holliday, N. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissecting+the+pharmacology+of+G+protein-coupled+receptor+signaling+complexes+using+bimolecular+fluorescence+complementation.">Dissecting the pharmacology of G protein-coupled receptor signaling complexes using bimolecular fluorescence complementation.</a> Methods Mol. Biol. 897, 109-138 (2012).</li></ol>

作者宣称，他们有没有竞争经济利益。

附设一个简单而敏感的方法来研究蛋白质相互作用。然而，此方法可以不被使用，以确定新的蛋白质 - 蛋白质相互作用，它是特别方便的，以确认细胞内的蛋白 - 蛋白相互作用和学习功能性质，如细胞内的本地化的蛋白质复合物，蛋白质 - 蛋白质相互作用的网站的映射，并筛查，可以调节蛋白质相互作用的小分子/肽。 ，因为VN和VC片段的非荧光，荧光背景低，从而帮助检测灵敏度。需要时间来成?...

650000蛋白质-蛋白质相互作用，估计存在于人类的相互作用组，发挥着重要的角色，在维持正常的细胞功能1,2。除了 ​​免疫共沉淀（CO-IP）的黄金标准蛋白质相互作用研究从细胞裂解物，一些蛋白质片段互补分析（PCA）已发展到提高灵敏度检测细胞内的蛋白质相互作用3。这些技术包括福斯特共振能量转移（FRET），生物发光共振能量转移（BRET），和双分子荧光互补（附设）4,5。附设是基于荧光蛋白的两个片段（在这里我们使用金星，YFP变种），分别融合到一个潜在的相互作用的蛋白伙伴（在本示例中，我们使用AKAP - LBC和PDE4D3）促进协会。相互作用的两种蛋白质在细胞内的查询结果以功能性荧光的兴趣，它可以是由f可视化luorescence显微镜可以使用活的或固定的细胞6,7,8。相较于其他的PCA，附设敏感的和技术上的挑战，有潜力在活细胞中的细胞定位研究。然而，这种技术的主要缺点是，一旦形成，荧光蛋白复合物不能被逆转。因此，它是不是一个很好的方法来研究动态蛋白质相互作用。在本文中，我们使用附设映射AKAP - LBC PDE4D3的相互作用位点监测的荧光强度金星。相比传统的分析，使用荧光显微镜，这是费时和劳动密集的（如果不进行使用自动化高通过机械），流式细胞术十万个单元格在一个异构的人口提供了一个简单的定量分析，在很短的时间9， 10。在这里，我们开展了流式细胞附设分析和传统的合作IP并排侧比较，表明2米然而，ethods提供可比数据的流式细胞仪附设分析耗时少，并使用更少的材料是有限的感兴趣的细胞时，这可能是更有用的。

<table border="1">
	<tbody>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>REAGENTS</td>
		</tr>
		<tr>
			<td>Dulbecco's modified Eagle's media (DMEM)</td>
			<td>Invitrogen</td>
			<td>11965-092</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Penicilin-Streptomycin (pen/strep), 100x</td>
			<td>Invitrogen</td>
			<td>15070-063</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>Invitrogen</td>
			<td>16000-044</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Anti-Flag antibody</td>
			<td>Sigma</td>
			<td>M2, F1804</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Anti-HA antibody</td>
			<td>Covance</td>
			<td>16B12, MMS-101R</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&alpha;-tubulin</td>
			<td>Sigma</td>
			<td>DM1A, T9026</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Anti-GFP antibody</td>
			<td>Clontech</td>
			<td>632569</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Cell culture plates, 6-well tissue culture treated</td>
			<td>Thermo Fisher Scientific</td>
			<td>130184</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>HEK 293T cells</td>
			<td>ATCC</td>
			<td>CRL-11268</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Maxiprep plasmid purification kit, high speed</td>
			<td>Qiagen</td>
			<td>12663</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Dulbecco's Phosphate-buffered saline (DPBS), sterile 1x</td>
			<td>Invitrogen</td>
			<td>14190-144</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Trypsin-EDTA, 0.05% (w/v)</td>
			<td>Gibco</td>
			<td>25300</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Polystyrene round-bottom tubes for FACS staining</td>
			<td>BD Biosciences</td>
			<td>352052</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Fisher Scientific</td>
			<td>S74337MF</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Prolong gold antifade reagent with DAPI</td>
			<td>Invitrogen</td>
			<td>P-36931</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Superfrost plus Microscope slides</td>
			<td>Fisher Scientific</td>
			<td>12-550-15</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Fisherfinest premium cover glass</td>
			<td>Fisher Scientific</td>
			<td>12-548-5P</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>EQUIPMENT</td>
		</tr>
		<tr>
			<td>CO2 air-jacketed Incubator</td>
			<td>NuAIR DH autoflow</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Confocal microscope LSM510 META</td>
			<td>Carl Zeiss, Inc</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Electrophoresis and transfer unit</td>
			<td>Biorad</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Cyan ADP Flow Cytometer</td>
			<td>Beckman Coulter</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
	</tbody>
</table>

flow cytometric analysis of bimolecular fluorescence complementation: a high throughput quantitative method to study protein-protein interaction

其中的方法来研究细胞内蛋白质相互作用，双分子荧光互补（附设）是相对简单和敏感。附设是根据生产的荧光使用两个非荧光的荧光蛋白的片段（金星，黄色荧光蛋白的变型中，这里使用的是）。非荧光金星片段的（VN和VC）的两个相互作用的蛋白质（在这种情况下，AKAP-LBC和PDE4D3）稠合，得到的荧光由于VN-AKAP-LBC-VC-的PDE4D3相互作用和形成荧光蛋白的功能细胞内。 附设提供的蛋白质复合物的亚细胞定位和蛋白质相互作用的强度，根据荧光强度的信息。但是，附设分析用显微镜量化蛋白 - 蛋白相互作用的强度是耗时且有些主观的，因为蛋白表达的异质性和相互作用。通过耦合流式细胞仪分析与附设的方法，荧光附设的蛋白 - 蛋白相互作用的信号可以精确地测量在短时间内大量的细胞。在这里，我们展示了这种方法的应用程序AKAP-LBC的互动所需要的地区PDE4D3映射。这种高的通过方法可以应用于筛选因子，调节蛋白 - 蛋白相互作用。

AKAP-LBC和PDE4D3的结构（ 图1B）的融合VN和VC片段，分别AKAP - LBC和PDE4D3结果功能YFP的荧光（ 图1A）的相互作用。在这里，我们使用地图AKAP - LBC结合位点PDE4D3附设的方法。 PDE4家族蛋白中上游保守区域1（UCR1），，上游保守区域2（UCR2）和催化区（CAT）是保守的，因此，全长度（FL），UCR1和UCR2加CAT被用于筛选结合部位的PDE4D3 AKAP-LBC。 VN-AKAP-LBC和VC-PDE4D3片段在HEK 293T细胞荧光结?...

Watch this Scientific Journal Video about Flow Cytometric Analysis of Bimolecular Fluorescence Complementation: A High Throughput Quantitative Method to Study Protein-protein Interaction at JoVE.com

Flow Cytometric Analysis of Bimolecular Fluorescence Complementation: A High Throughput Quantitative Method to Study Protein-protein Interaction

流式细胞仪分析双分子荧光互补提供了一种高通量定量研究蛋白质相互作用的方法。此方法可用于测绘的蛋白结合位点，并用于筛选调节蛋白 - 蛋白相互作用的因素。

双分子荧光互补流式细胞仪分析：高通量的定量方法研究蛋白质 - 蛋白质相互作用

Among methods to study protein-protein interaction inside cells, Bimolecular Fluorescence Complementation (BiFC) is relatively simple and sensitive. BiFC ...

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Research

JoVE Journal

Biology

18.3K 次观看.  University of Illinois at Chicago. 流式细胞仪分析双分子荧光互补提供了一种高通量定量研究蛋白质相互作用的方法。此方法可用于测绘的蛋白结合位点，并用于筛选调节蛋白 - 蛋白相互作用的因素。

视频: Flow Cytometric Analysis of Bimolecular Fluorescence Complementation: A High Throughput Quantitative Method to Study Protein-protein Interaction

A Neuronal and Astrocyte Co-Culture Assay for High Content Analysis of Neurotoxicity

High Content Analysis (HCA) assays combine cells and detection reagents with automated imaging and powerful image analysis algorithms, allowing measurement of multiple cellular phenotypes within a single assay. In this study, we utilized HCA to develop a novel assay for neurotoxicity. Neurotoxicity assessment represents an important part of drug safety evaluation, as well as being a significant focus of environmental protection efforts. Additionally, neurotoxicity is also a well-accepted in vitro marker of the development of neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Recently, the application of HCA to neuronal screening has been reported. By labeling neuronal cells with &beta;III-tubulin, HCA assays can provide high-throughput, non-subjective, quantitative measurements of parameters such as neuronal number, neurite count and neurite length, all of which can indicate neurotoxic effects. However, the role of astrocytes remains unexplored in these models. Astrocytes have an integral role in the maintenance of central nervous system (CNS) homeostasis, and are associated with both neuroprotection and neurodegradation when they are activated in response to toxic substances or disease states. GFAP is an intermediate filament protein expressed predominantly in the astrocytes of the CNS. Astrocytic activation (gliosis) leads to the upregulation of GFAP, commonly accompanied by astrocyte proliferation and hypertrophy. This process of reactive gliosis has been proposed as an early marker of damage to the nervous system. The traditional method for GFAP quantitation is by immunoassay. This approach is limited by an inability to provide information on cellular localization, morphology and cell number. We determined that HCA could be used to overcome these limitations and to simultaneously measure multiple features associated with gliosis - changes in GFAP expression, astrocyte hypertrophy, and astrocyte proliferation - within a single assay. In co-culture studies, astrocytes have been shown to protect neurons against several types of toxic insult and to critically influence neuronal survival. Recent studies have suggested that the use of astrocytes in an in vitro neurotoxicity test system may prove more relevant to human CNS structure and function than neuronal cells alone. Accordingly, we have developed an HCA assay for co-culture of neurons and astrocytes, comprised of protocols and validated, target-specific detection reagents for profiling &beta;III-tubulin and glial fibrillary acidic protein (GFAP). This assay enables simultaneous analysis of neurotoxicity, neurite outgrowth, gliosis, neuronal and astrocytic morphology and neuronal and astrocytic development in a wide variety of cellular models, representing a novel, non-subjective, high-throughput assay for neurotoxicity assessment. The assay holds great potential for enhanced detection of neurotoxicity and improved productivity in neuroscience research and drug discovery.

This article describes a novel protocol and reagent set designed for sensitive measurement of neurotoxic effects of compounds and treatments on co-cultures of neurons and astrocytes using high content analysis. Results demonstrate that high content analysis represents an exciting novel technology for neurotoxicity assessment.

一个神经元和星形胶质细胞共培养检测神经毒性的高含量分析

High Content Analysis (HCA) assays combine cells and detection reagents with automated imaging and powerful image analysis algorithms, allowing ...

科研

生物学

A high-throughput method to globally study the organelle morphology in S. cerevisiae

High-throughput methods to examine protein localization or organelle morphology is an effective tool for studying protein interactions and can help achieve an comprehensive understanding of molecular pathways. In Saccharomyces cerevisiae, with the development of the non-essential gene deletion array, we can globally study the morphology of different organelles like the endoplasmic reticulum (ER) and the mitochondria using GFP (or variant)-markers in different gene backgrounds. However, incorporating GFP markers in each single mutant individually is a labor-intensive process. Here, we describe a procedure that is routinely used in our laboratory. By using a robotic system to handle high-density yeast arrays and drug selection techniques, we can significantly shorten the time required and improve reproducibility. In brief, we cross a GFP-tagged mitochondrial marker (Apc1-GFP) to a high-density array of 4,672 nonessential gene deletion mutants by robotic replica pinning.  Through diploid selection, sporulation, germination and dual marker selection, we recover both alleles. As a result, each haploid single mutant contains Apc1-GFP incorporated at its genomic locus. Now, we can study the morphology of mitochondria in all non-essential mutant background. Using this high-throughput approach, we can conveniently study and delineate the pathways and genes involved in the inheritance and the formation of organelles in a genome-wide setting.

GFP-fusion proteins are widely used to visualize organelles by confocal microscopy. However, screening for mutations that affect the morphology of organelles generally requires individual mutagenesis and is time consuming. Here, we demonstrate a method to simultaneously incorporate organelle-GFP markers in almost 5,000 non-essential genes in yeast.

一种高通量的方法，在全球范围内研究在酿酒酵母中的细胞器形态

High-throughput methods to examine protein localization or organelle morphology is an effective tool for studying protein interactions and can help ...

Bimolecular Fluorescence Complementation (BiFC) Assay for Protein-Protein Interaction in Onion Cells Using the Helios Gene Gun

Investigation of gene function in diverse organisms relies on knowledge of how the gene products interact with each other in their normal cellular environment. The Bimolecular Fluorescence Complementation (BiFC) Assay1 allows researchers to visualize protein-protein interactions in living cells and has become an essential research tool. This assay is based on the facilitated association of two fragments of a fluorescent protein (GFP) that are each fused to a potential interacting protein partner. The interaction of the two protein partners would facilitate the association of the N-terminal and C-terminal fragment of GFP, leading to fluorescence. For plant researchers, onion epidermal cells are an ideal experimental system for conducting the BiFC assay because of the ease in obtaining and preparing onion tissues and the direct visualization of fluorescence with minimal background fluorescence. The Helios Gene Gun (BioRad) is commonly used for bombarding plasmid DNA into onion cells. We demonstrate the use of Helios Gene Gun to introduce plasmid constructs for two interacting Arabidopsis thaliana transcription factors, SEUSS (SEU) and LEUNIG HOMOLOG (LUH)2 and the visualization of their interactions mediated by BiFC in onion epidermal cells.

Bimolecular Fluorescence Complementation BiFC Assay for Protein-Protein Interaction in Onion Cells Using the Helios Gene Gun

This article illustrates how to properly use the BioRad Helios Gene Gun to introduce plasmid DNA into onion epidermal cells and how to test for protein-protein interactions in onion cells based on the principle of Bimolecular Fluorescence Complementation (BiFC)

双分子荧光互补（附设）检测蛋白质相互作用的洋葱细胞使用的Helios基因枪

Investigation of gene function in diverse organisms relies on knowledge of how the gene products interact with each other in their normal cellular ...

Bimolecular Fluorescence Complementation

Defining the subcellular distribution of signaling complexes is imperative to understanding the output from that complex. Conventional methods such as immunoprecipitation do not provide information on the spatial localization of complexes. In contrast, BiFC monitors the interaction and subcellular compartmentalization of protein complexes. In this method, a fluororescent protein is split into amino- and carboxy-terminal non-fluorescent fragments which are then fused to two proteins of interest. Interaction of the proteins results in reconstitution of the fluorophore (Figure 1)1,2. A limitation of BiFC is that once the fragmented fluorophore is reconstituted the complex is irreversible3. This limitation is advantageous in detecting transient or weak interactions, but precludes a kinetic analysis of complex dynamics. An additional caveat is that the reconstituted flourophore requires 30min to mature and fluoresce, again precluding the observation of real time interactions4. BiFC is a specific example of the protein fragment complementation assay (PCA) which employs reporter proteins such as green fluorescent protein variants (BiFC), dihydrofolate reductase, b-lactamase, and luciferase to measure protein:protein interactions5,6. Alternative methods to study protein:protein interactions in cells include fluorescence co-localization and F&ouml;rster resonance energy transfer (FRET)7. For co-localization, two proteins are individually tagged either directly with a fluorophore or by indirect immunofluorescence. However, this approach leads to high background of non-interacting proteins making it difficult to interpret co-localization data. In addition, due to the limits of resolution of confocal microscopy, two proteins may appear co-localized without necessarily interacting. With BiFC, fluorescence is only observed when the two proteins of interest interact. FRET is another excellent method for studying protein:protein interactions, but can be technically challenging. FRET experiments require the donor and acceptor to be of similar brightness and stoichiometry in the cell. In addition, one must account for bleed through of the donor into the acceptor channel and vice versa. Unlike FRET, BiFC has little background fluorescence, little post processing of image data, does not require high overexpression, and can detect weak or transient interactions. Bioluminescence resonance energy transfer (BRET) is a method similar to FRET except the donor is an enzyme (e.g. luciferase) that catalyzes a substrate to become bioluminescent thereby exciting an acceptor. BRET lacks the technical problems of bleed through and high background fluorescence but lacks the ability to provide spatial information due to the lack of substrate localization to specific compartments8. Overall, BiFC is an excellent method for visualizing subcellular localization of protein complexes to gain insight into compartmentalized signaling.

The subcellular localization of proteins is important in determining the spatio-temporal regulation of cell signaling. Here, we describe bimolecular fluorescence complementation (BiFC) as a straightforward method for monitoring the spatial interactions of proteins in the cell.

双分子荧光互补

Defining the subcellular distribution of signaling complexes is imperative to understanding the output from that complex. Conventional methods such as ...

Detection of Protein Interactions in Plant using a Gateway Compatible Bimolecular Fluorescence Complementation (BiFC) System

We have developed a BiFC technique to test the interaction between two proteins in vivo. This is accomplished by splitting a yellow fluorescent protein (YFP) into two non-overlapping fragments. Each fragment is cloned in-frame to a gene of interest. These constructs can then be co-transformed into Nicotiana benthamiana via Agrobacterium mediated transformation, allowing the transit expression of fusion proteins. The reconstitution of YFP signal only occurs when the inquest proteins interact 1-7. To test and validate the protein-protein interactions, BiFC can be used together with yeast two hybrid (Y2H) assay. This may detect indirect interactions which can be overlooked in the Y2H. Gateway technology is a universal platform that enables researchers to shuttle the gene of interest (GOI) into as many expression and functional analysis systems as possible8,9. Both the orientation and reading frame can be maintained without using restriction enzymes or ligation to make expression-ready clones. As a result, one can eliminate all the re-sequencing steps to ensure consistent results throughout the experiments. We have created a series of Gateway compatible BiFC and Y2H vectors which provide researchers with easy-to-use tools to perform both BiFC and Y2H assays10. Here, we demonstrate the ease of using our BiFC system to test protein-protein interactions in N. benthamiana plants.

Detection of Protein Interactions in Plant using a Gateway Compatible Bimolecular Fluorescence Complementation BiFC System

We have developed a technique to test protein-protein interactions in plant. A yellow fluorescent protein (YFP) is split into two non-overlapping fragments. Each fragment is cloned in-frame to a gene of interest via Gateway system, enabling expression of fusion proteins. Reconstitution of YFP signal only occurs when the inquest proteins interact.

使用网关兼容双分子荧光互补（附设）系统在植物蛋白相互作用检测

We have developed a BiFC technique to test the interaction between two proteins in vivo. This is accomplished by splitting a yellow fluorescent protein ...

A Liquid Phase Affinity Capture Assay Using Magnetic Beads to Study Protein-Protein Interaction: The Poliovirus-Nanobody Example

In this article, a simple, quantitative, liquid phase affinity capture assay is presented. Provided that one protein can be tagged and another protein labeled, this method can be implemented for the investigation of protein-protein interactions. It is based on one hand on the recognition of the tagged protein by cobalt coated magnetic beads and on the other hand on the interaction between the tagged protein and a second specific protein that is labeled. First, the labeled and tagged proteins are mixed and incubated at room temperature. The magnetic beads, that recognize the tag, are added and the bound fraction of labeled protein is separated from the unbound fraction using magnets. The amount of labeled protein that is captured can be determined in an indirect way by measuring the signal of the labeled protein remained in the unbound fraction. The described liquid phase affinity assay is extremely useful when conformational conversion sensitive proteins are assayed. The development and application of the assay is demonstrated for the interaction between poliovirus and poliovirus recognizing nanobodies1. Since poliovirus is sensitive to conformational conversion2 when attached to a solid surface (unpublished results), the use of ELISA is limited and a liquid phase based system should therefore be preferred. An example of a liquid phase based system often used in polioresearch3,4 is the micro protein A-immunoprecipitation test5. Even though this test has proven its applicability, it requires an Fc-structure, which is absent in the nanobodies6,7. However, as another opportunity, these interesting and stable single-domain antibodies8 can be easily engineered with different tags. The widely used (His)6-tag shows affinity for bivalent ions such as nickel or cobalt, which can on their turn be easily coated on magnetic beads. We therefore developed this simple quantitative affinity capture assay based on cobalt coated magnetic beads. Poliovirus was labeled with 35S to enable unhindered interaction with the nanobodies and to make a quantitative detection feasible. The method is easy to perform and can be established with a low cost, which is further supported by the possibility of effectively regenerating the magnetic beads.

In this article, a simple, quantitative, liquid phase affinity capture assay is presented. It is a reliable technique based on the interaction between magnetic beads and tagged proteins (e.g. nanobodies) on one hand and the affinity between the tagged protein and a second, labeled protein (e.g. poliovirus) on the other.

液相亲和捕获试验用磁珠研究蛋白质相互作用：脊髓灰质炎病毒的Nanobody范例

In this article, a simple, quantitative, liquid phase affinity capture assay is presented. Provided that one protein can be tagged and another protein ...

Quantitative Analysis of Autophagy using Advanced 3D Fluorescence Microscopy

Prostate cancer is the leading form of malignancies among men in the U.S. While surgery carries a significant risk of impotence and incontinence, traditional chemotherapeutic approaches have been largely unsuccessful. Hormone therapy is effective at early stage, but often fails with the eventual development of hormone-refractory tumors. We have been interested in developing therapeutics targeting specific metabolic deficiency of tumor cells. We recently showed that prostate tumor cells specifically lack an enzyme (argininosuccinate synthase, or ASS) involved in the synthesis of the amino acid arginine1. This condition causes the tumor cells to become dependent on exogenous arginine, and they undergo metabolic stress when free arginine is depleted by arginine deiminase (ADI)1,10. Indeed, we have shown that human prostate cancer cells CWR22Rv1 are effectively killed by ADI with caspase-independent apoptosis and aggressive autophagy (or macroautophagy)1,2,3. Autophagy is an evolutionarily-conserved process that allows cells to metabolize unwanted proteins by lysosomal breakdown during nutritional starvation4,5. Although the essential components of this pathway are well-characterized6,7,8,9, many aspects of the molecular mechanism are still unclear - in particular, what is the role of autophagy in the death-response of prostate cancer cells after ADI treatment? In order to address this question, we required an experimental method to measure the level and extent of autophagic response in cells - and since there are no known molecular markers that can accurately track this process, we chose to develop an imaging-based approach, using quantitative 3D fluorescence microscopy11,12.
Using CWR22Rv1 cells specifically-labeled with fluorescent probes for autophagosomes and lysosomes, we show that 3D image stacks acquired with either widefield deconvolution microscopy (and later, with super-resolution, structured-illumination microscopy) can clearly capture the early stages of autophagy induction. With commercially available digital image analysis applications, we can readily obtain statistical information about autophagosome and lysosome number, size, distribution, and degree of colocalization from any imaged cell. This information allows us to precisely track the progress of autophagy in living cells and enables our continued investigation into the role of autophagy in cancer chemotherapy.

Autophagy is a ubiquitous process that enables cells to degrade and recycle proteins and organelles. We apply advanced fluorescence microscopy to visualize and quantify the small, but essential, physical changes associated with the induction of autophagy, including the formation and distribution of autophagosomes and lysosomes, and their fusion into autolysosomes.

采用先进的3D荧光显微镜定量分析自噬

Prostate cancer is the leading form of malignancies among men in the U.S. While surgery carries a significant risk of impotence and incontinence, ...

A High Throughput MHC II Binding Assay for Quantitative Analysis of Peptide Epitopes

Biochemical assays with recombinant human MHC II molecules can provide rapid, quantitative insights into immunogenic epitope identification, deletion, or design1,2. Here, a peptide-MHC II binding assay is scaled to 384-well format. The scaled down protocol reduces reagent costs by 75% and is higher throughput than previously described 96-well protocols1,3-5. Specifically, the experimental design permits robust and reproducible analysis of up to 15 peptides against one MHC II allele per 384-well ELISA plate. Using a single liquid handling robot, this method allows one researcher to analyze approximately ninety test peptides in triplicate over a range of eight concentrations and four MHC II allele types in less than 48 hr. Others working in the fields of protein deimmunization or vaccine design and development may find the protocol to be useful in facilitating their own work. In particular, the step-by-step instructions and the visual format of JoVE should allow other users to quickly and easily establish this methodology in their own labs.

Biochemical assays with recombinant human MHC II molecules can provide rapid, quantitative insights into immunogenic epitope identification, deletion, or design. &#160;Here, a peptide-MHC II binding assay scaled to 384-well plates is described. This cost effective format should prove useful in the fields of protein deimmunization and vaccine design and development.

高通量MHC II类分子结合分析抗原表位肽的定量分析

Biochemical assays with recombinant human MHC II molecules can provide rapid, quantitative insights into immunogenic epitope identification, deletion, or ...

Protein-protein Interactions Visualized by Bimolecular Fluorescence Complementation in Tobacco Protoplasts and Leaves

Many proteins interact transiently with other proteins or are integrated into multi-protein complexes to perform their biological function. Bimolecular fluorescence complementation (BiFC) is an in vivo method to monitor such interactions in plant cells. In the presented protocol the investigated candidate proteins are fused to complementary halves of fluorescent proteins and the respective constructs are introduced into plant cells via agrobacterium-mediated transformation. Subsequently, the proteins are transiently expressed in tobacco leaves and the restored fluorescent signals can be detected with a confocal laser scanning microscope in the intact cells. This allows not only visualization of the interaction itself, but also the subcellular localization of the protein complexes can be determined. For this purpose, marker genes containing a fluorescent tag can be coexpressed along with the BiFC constructs, thus visualizing cellular structures such as the endoplasmic reticulum, mitochondria, the Golgi apparatus or the plasma membrane. The fluorescent signal can be monitored either directly in epidermal leaf cells or in single protoplasts, which can be easily isolated from the transformed tobacco leaves. BiFC is ideally suited to study protein-protein interactions in their natural surroundings within the living cell. However, it has to be considered that the expression has to be driven by strong promoters and that the interaction partners are modified due to fusion of the relatively large fluorescence tags, which might interfere with the interaction mechanism. Nevertheless, BiFC is an excellent complementary approach to other commonly applied methods investigating protein-protein interactions, such as coimmunoprecipitation, in vitro pull-down assays or yeast-two-hybrid experiments.

Formation of protein complexes in vivo can be visualized by bimolecular fluorescence complementation. Interaction partners are fused to complementary parts of fluorescent tags and transiently expressed in tobacco leaves, resulting in a reconstituted fluorescent signal upon close proximity of the two proteins.

蛋白质 - 蛋白质相互作用的双分子荧光互补的烟草原生质体和叶片可视化

Many proteins interact transiently with other proteins or are integrated into multi-protein complexes to perform their biological function. Bimolecular ...

High-throughput Image Analysis of Tumor Spheroids: A User-friendly Software Application to Measure the Size of Spheroids Automatically and Accurately

The increasing number of applications of three-dimensional (3D) tumor spheroids as an in vitro model for drug discovery requires their adaptation to large-scale screening formats in every step of a drug screen, including large-scale image analysis. Currently there is no ready-to-use and free image analysis software to meet this large-scale format. Most existing methods involve manually drawing the length and width of the imaged 3D spheroids, which is a tedious and time-consuming process. This study presents a high-throughput image analysis software application &#8211; SpheroidSizer, which measures the major and minor axial length of the imaged 3D tumor spheroids automatically and accurately; calculates the volume of each individual 3D tumor spheroid; then outputs the results in two different forms in spreadsheets for easy manipulations in the subsequent data analysis. The main advantage of this software is its powerful image analysis application that is adapted for large numbers of images. It provides high-throughput computation and quality-control workflow. The estimated time to process 1,000 images is about 15 min&#160;on a minimally configured laptop, or around 1 min&#160;on a multi-core performance workstation. The graphical user interface (GUI) is also designed for easy quality control, and users can manually override the computer results. The key method used in this software is adapted from the active contour algorithm, also known as Snakes, which is especially suitable for images with uneven illumination and noisy background that often plagues automated imaging processing in high-throughput screens. The complimentary &#8220;Manual Initialize&#8221; and &#8220;Hand Draw&#8221; tools provide the flexibility to SpheroidSizer in dealing with various types of spheroids and diverse quality images. This high-throughput image analysis software remarkably reduces labor and speeds up the analysis process. Implementing this software is beneficial for 3D tumor spheroids to become a routine in vitro model for drug screens in industry and academia.

We present a high-throughput image analysis software application to measure the size of three-dimensional tumor spheroids imaged with bright-field microscopy. This application provides a fast and effective way to examine the effects of therapeutic drugs on spheroids, which is beneficial for researchers who wish to use spheroids in drug screens.

肿瘤细胞球体的高通量图像分析：一个用户友好的软件应用来测量球体的大小自动准确

The increasing number of applications of three-dimensional (3D) tumor spheroids as an in vitro model for drug discovery requires their adaptation to ...