我们要感谢穆罕默德·萨利姆，精武和克里希南Raghunathan有益的讨论。在拍摄中我们也感谢普里亚Begani寻求帮助。这项工作是由美国国立卫生研究院授予R01 AI071727（以AO）和R01 GM110052（SLV到）的支持。

第1天:使用基于裂解物，小麦胚芽体外转录翻译系统的Gag蛋白表达 1，HIV-1加格的制备<ol><li>从冰柜中取出商业麦胚CECF试剂盒所有试剂（小麦胚芽裂解物储存在-80ºC;在-20ºC其他试剂）。解冻他们在冰上并如表1所示混合组分。 </li></ol><table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> 混合-1（进料混合） </td><td></td></tr><tr><td>进料液</td><td> 900微升</td></tr><tr><td>氨基酸</td><td> 80微升</td></tr><tr><td>蛋氨酸</td><td> 20微升</td></tr><tr><td> 总 </td><td> 1000微升 </td></tr><tr><td></td><td></td></tr><tr><td> 混合-2（裂解液混合） </str翁&gt; </td><td></td></tr><tr><td>小麦胚芽裂解液</td><td> 15微升</td></tr><tr><td>核糖核酸酶自由水</td><td> 7微升</td></tr><tr><td>氨基酸</td><td> 4微升</td></tr><tr><td>蛋氨酸</td><td> 1微升</td></tr><tr><td>质粒DNA的TE缓冲液（1微克/微升）** </td><td> 4微升</td></tr><tr><td>反应缓冲液</td><td> 15微升</td></tr><tr><td> RNA酶抑制剂* </td><td> 4微升</td></tr><tr><td> 总 </td><td> 50微升 </td></tr></tbody></table> 表1:小麦胚芽反应所需要的混合物组成。 注意:如果该实验的目的是检验的RNA去除被RNA酶上的Gag膜结合的效果，替换无RNase水核糖核酸酶抑制剂。质粒DNA应根据制造商的指令免于杂质。然而，对lasmids使用常规制备，但不无内毒素，质粒分离试剂盒已被成功使用。制造商的指令还建议使用溶解于无核酸酶的水的DNA。如果使用悬浮于TE [10mM的Tris-盐酸含有1mM EDTA（pH7.4）中的DNA，应避免使用低浓度的DNA，因为EDTA于TE可能影响产量。溶于TE缓冲液以0.8-1微克/微升的浓度范围的质粒已经成功地被使用。 <ol start="2"><li>首先添加料混合物（混合-1）插入反应盒（透明室）。然后将溶胞产物混合物（混合-2）添加到另一个室（红色）。不引入任何气泡，同时加入混合物到各自室中，因为这可能会导致溶液组分低效交换，从而降低反应效率。 </li><li>覆盖随试剂盒提供的粘合膜的腔室。 </li><li>插入反应盒插入盒座和incubaTE的Eppendorf恒温R.装配24小时24ºC以900rpm的恒定速度晃动</li></ol>第2天:准备GUVs由Electroformation和收获小麦胚芽裂解液 2. GUVs的制备<ol><li>等分试样的脂质溶解于无机溶剂，例如在与有聚四氟乙烯衬里衬和用Parafilm包裹螺旋盖玻璃小瓶氯仿或氯仿的混合物和甲醇。处理脂类汉密尔顿式玻璃注射器，如果可用，耐氯仿的塑料提示。取出含有脂质用于从-20 C冷柜GUV制备玻璃小瓶中。 <ol><li>一旦小瓶平衡至室温，确认通过视觉检查该脂质悬浮液是清楚的。血脂，特别是酸性脂类，如棕榈酰油酰磷脂酰丝氨酸（POPS）和PI（4,5）P2的质量，是成功的重要实验。不要使用油脂是在等分试样的时间超过2个月。 </li></ol></li><li>预暖的热块到所需的温度。该温度必须高于脂质（多个）具有最高的Tm的熔化温度（T M）高至少5ºC。 </li><li>计算根据所需摩尔脂质比所需要的脂质的卷。用于研究的HIV-1的Gag这里结合，使用以下摩尔比示于表2。 </li></ol><table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> 脂质组合 </td><td> 摩尔比 </td><td> 体积（微升） </td><td> 股权集中度 </td></tr><tr><td> POPC + POPS +澈</td><td> 46.​​6 + 23.3 + 30 </td><td> 19.74 + 10.18 + 6.57 </td><td> POPC，POPS，澈:10毫克/毫升</td></tr><tr><td rowspan="2"> POPC + POPS +澈+脑-PI（4,5）P2 </td><td行跨度="2"&gt; 40 + 20 + 30 + 10 </td><td rowspan="2"> 16.11 + 8.3 + 6.25 + 58.19 </td><td> POPC，POPS，澈:10毫克/毫升</td></tr><tr><td>脑-PI（4,5）P 2:1毫克/毫升</td></tr></tbody></table> 表2:不同血脂卷用来获取GUVs。 <ol start="4"><li>添加脂质的所需卷到一个干净的螺旋盖玻璃小瓶。 </li><li>使用ITO涂布的尺寸为25×50×1.1 立方毫米和电阻70-100Ω（如在产品目录中所述）的幻灯片。将两个ITO镀膜载玻片干净的长椅上。每个electroformation室需要两个铟锡氧化物（ITO）涂覆的玻璃载片。验证该玻璃载片的导电面朝上，通过使用万用表检查的电阻。它应该显示的约200Ω的值。确保幻灯片的表面是干净的通过使用不起毛的抹布70％酒精轻轻擦拭。 </li><li>清洗由里注射器的针的外表面用氯仿nsing它和将散热块上的注射器。 </li><li>将带有导电朝上加热块上的新的ITO膜的玻璃载玻片，并允许它平衡至所需的温度通常为约2-3分钟。不重复使用在ITO涂覆的玻璃载片的潜在风险，即在载玻片在ITO涂层可能清洁程序期间被损坏。 </li><li>使用40-50微升脂质混合物的体积为均匀，但快于载玻片上的脂质的扩频每个幻灯片。调整用合适的有机溶剂的总体积，例如氯仿。 <ol><li>放置在载玻片脂质混合物的总体积的一半，并立即使用清洁注射器（步骤2.6），留下一个均匀的脂质膜（整个滑动2-3次移动所述针）传播脂质。轻轻（但很快）传播所述脂质膜以避免对薄涂敷ITO任何损坏。非均匀扩散或蔓延粗糙可能导致次优产量或GUVs的计算的异质性。 </li><li>因此，通过检查在继续下一步骤之前传播之后脂质膜确保均匀扩散。如果薄膜的不透明度出现过度不均匀，采用了新的幻灯片重做的过程。 </li></ol></li><li>放置一个培养皿与涂布面朝上内侧被覆滑动。 </li><li>重复步骤2.6-2.9使用另一ITO涂布滑动的混合物的其余部分。 </li><li>放置在常规的真空干燥室含有幻灯片60-90分钟以除去有机溶剂任何微量培养皿。 </li><li>在此过程中，培养箱设定为相同的温度，该加热块（65ºC在大多数情况下），并预温300毫在孵化蔗糖溶液。 </li><li>干燥后，将培养皿在板凳上，并放置在载玻片上清洁的表面。 </li><li>轻轻擦拭用70％的乙醇和干燥它完井将PDMS垫片（ 图1）tely。 </li><li>将其放置在脂质包被的载玻片， 如图1和轻轻用力按下，使该垫圈形成水密封。确认不存在与PDMS垫片和滑动之间的间隙。这导致了浅腔用于保存蔗糖溶液的形成。 </li></ol><img alt="图1" src="/files/ftp_upload/54293/54293fig1.jpg" /> 图1:用于electroformation在ITO镀膜玻璃幻灯片的版式 <a href="https://www.jove.com/files/ftp_upload/54293/54293fig1large.jpg" target="_blank">，请点击此处查看该图的放大版本。</a> <ol start="16"><li>填充预热蔗糖溶液的腔室，没有任何气泡。 </li><li>在上面放置另一涂覆滑板，使一个紧密的密封。确保有没有气泡。 如图2的最终组装应出现。紧固室全光照摹长尾夹。 </li></ol><img alt="图2" src="/files/ftp_upload/54293/54293fig2.jpg" /> 图2:在electroformation室（侧视）的示意图 <a href="https://www.jove.com/files/ftp_upload/54293/54293fig2large.jpg" target="_blank">，请点击此处查看该图的放大版本。</a> <ol start="18"><li>吸去除多余的蔗糖和清洁使用不起毛的抹布的幻灯片。紧滑动到铜条使得导电两侧都与酒吧均匀接触。确保载玻片只有一个导电侧是与一个铜条接触。 </li><li>连接铜排使用鳄鱼夹的函数发生器的输出。放置组件培养箱内，以允许组件平衡至所需温度。 </li><li>应用10Hz的正弦波频率和1伏90分钟的电位差。 EnsurË，电压为1V通过万用表， 如图3，继续进行90分钟的处理。 </li></ol><img alt="图3" src="/files/ftp_upload/54293/54293fig3.jpg" /> 图3:在从万用表的电极放置用于测量频率和电流的位置 <a href="https://www.jove.com/files/ftp_upload/54293/54293fig3large.jpg" target="_blank">，请点击此处查看该图的放大版本。</a> <ol start="21"><li> 90分钟后，将频率缓慢降低至2赫兹，并继续electroformation另外10分钟。在这段时间，收获的体外翻译反应（步骤3.1-3.2）。 </li><li>关闭功能发生器并允许组件（通过关闭培养箱和离开培养箱门稍微打开）冷却到室温缓慢。 </li><li>冷却后，断开电缆连接到发电机从滑动组件。 GUVs可能是非常脆弱的，因此，需要进行很温和处理。仔细把装配了替补席上。 </li><li>轻轻取出使用镊子顶部滑动拆卸室。收获用裁员1000微升尖，并转移到一个干净的试管蔗糖含停牌GUVs。轻拿轻放管以防止GUVs中断。 </li><li>立即使用GUVs。当在室温下保存GUVs是稳定的收获后至少90分钟。 </li></ol> 3.收获体外翻译反应<ol><li>收获使用微量成管含有从红色室所需的蛋白质， 在体外翻译反应。 </li><li>要删除聚集的蛋白质，在16,200 XG自旋裂解液15分钟，在台式离心机，并小心地将上清转移到另一管。 </li></ol> 4. GUV结合分析<ol><li>使用切尖，混合51;含有翻译的蛋白质和5μlGUVs的在管体外翻译反应的升和在室温下孵育2-3分钟。 </li><li>用一个干净的盖玻片一个小孔（3-4毫米直径）附加PDMS表，并确保密封轻轻并牢牢压在盖玻片。 </li><li>从步骤4.1 10微升的混合物放入小孔。 </li><li>图像在室温下倒置外延或共聚焦荧光显微镜下的混合物。 注意:为了防止蒸发，在成像腔室可以由盖玻片覆盖。 </li></ol>

<ol>
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C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unilamellar+vesicle+formation+and+encapsulation+by+microfluidic+jetting.">Unilamellar vesicle formation and encapsulation by microfluidic jetting.</a> Proc Natl Acad Sci U S A. 105 (12), 4697-4702 (2008).</li><li>Yamauchi, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+consensus+motif+for+N-myristoylation+of+plant+proteins+in+a+wheat+germ+cell-free+translation+system.">The consensus motif for N-myristoylation of plant proteins in a wheat germ cell-free translation system.</a> FEBS J. 277 (17), 3596-3607 (2010).</li><li>Olety, B., Veatch, S. L., Ono, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphatidylinositol-(4,5)-Bisphosphate+Acyl+Chains+Differentiate+Membrane+Binding+of+HIV-1+Gag+from+That+of+the+Phospholipase+Cdelta1+Pleckstrin+Homology+Domain.">Phosphatidylinositol-(4,5)-Bisphosphate Acyl Chains Differentiate Membrane Binding of HIV-1 Gag from That of the Phospholipase Cdelta1 Pleckstrin Homology Domain.</a> J Virol. 89 (15), 7861-7873 (2015).</li><li>Morales-Penningston, N. F., 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=GUV+preparation+and+imaging:+minimizing+artifacts.">GUV preparation and imaging: minimizing artifacts.</a> Biochim Biophys Acta. 1798 (7), 1324-1332 (2010).</li><li>Veatch, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electro-formation+and+fluorescence+microscopy+of+giant+vesicles+with+coexisting+liquid+phases.">Electro-formation and fluorescence microscopy of giant vesicles with coexisting liquid phases.</a> Methods Mol Biol. 398, 59-72 (2007).</li><li>Ayuyan, A. G., Cohen, F. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+peroxides+promote+large+rafts:+effects+of+excitation+of+probes+in+fluorescence+microscopy+and+electrochemical+reactions+during+vesicle+formation.">Lipid peroxides promote large rafts: effects of excitation of probes in fluorescence microscopy and electrochemical reactions during vesicle formation.</a> Biophys J. 91 (6), 2172-2183 (2006).</li><li>Montes, L. 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We declare that we have no conflicting interests.

如上所述GUV结合测定法提供了在场景中其他蛋白质 - 类脂相互作用测定法有其局限性一个很好的选择。该测定允许我们检查与脂质双层上下文天然长酰基链肉豆蔻酰化全长Gag和酸性脂质之间的相互作用，并通过加格脂质的高密度蔗糖梯度或其它结合后处理没有冗长浮选离心这样做复合物。另一个优点是，加格的行为可以在复杂的混合物中进行检验（ 例如 ，在细胞溶质组分的存在），这是不容易在其他实时技术来实现，例如表面等离子体基于共振的测定法。因此，可以认为，这里所描述的测定法允许的Gag酸性脂质相互作用的实时评估中比在该领域使用的其它测定法的更天然上下文。 但是，也有与方法相关联的局限性好。以确保在给定的制剂GUVs具有相似的组成相互之间以及与原始混合物，electroformation必须远高于具有存在于混合物25,26转变温度最高的脂质的转变温度下进行。然而，可能的是脂质为更长的时间更高的温度的暴露可能导致脂质击穿25,27。因此，要控制GUVs的质量中，除了通过包含荧光脂质染料（ 例如 ，DID），理想的是测试感兴趣的脂[ 例如 ，PI（4,5）P2的功能的使能目视检查]使用特定脂质探针。此外，与产生在一定温度下，以相分离GUV组合物，必须小心观察蛋白质 - GUV相互作用时以精确地保持期望的温度。另一个限制是高离子强度溶液与电不相容形成这里描述的协议，因此GUVs生长并保持在300毫蔗糖溶液26。值得注意的是，然而，一些研究已经成功地使用在生理离子强度缓冲在他们修改electroformation协议28。 一个关键方面是加格的量。兔网织红细胞裂解物基于的系统通常用于在脂质体浮选试验制备全长HIV-1的Gag的。然而，在此系统中得到的YFP标记的全长Gag的量为不足的Gag的可视化结合GUVs。为了解决这个问题，在小麦胚芽基于裂解物无细胞转录 - 翻​​译系统，这将产生约8-10倍的Gag的更高量的，在当前的试验中使用。然而，如果GUV结合实验需要在不存在的真核细胞裂解物的组件来执行，可以使用标记有荧光团的纯化蛋白作为最近已经完成（在下面描述）。 它已经表明，特定和有效的Gag到膜的结合是由各种因素，如肉豆蔻酸调节的协同处理，RNA，脂类头基和酰基链，和Gag-Gag的相互作用（在参考29中综述）。 在体外系统描述此处可以延伸到解决因素的作用单独或组合了解加格膜结合的协同过程的事件的顺序。到目前为止，所描述的测定系统中的Gag的结合，但不是一个规范哺乳动物细胞起源的PI阐明不饱和的PI（4,5）P2酰基链的意想不到的作用（4,5）P 2 -结合结构域（磷脂酶C三角洲1）24，即尚未透露脂质体浮选试验的发现的PH结构域。基于GUV的测定系统也被用于了解加格生物学的其它方面。使用含有人工诱导的彩信插科打诨衍生erization主题和GUVs与筏式和非筏样结构域，凯勒等人研究加格分区之间的关系，"筏状"域和多聚化30。卡尔森等人的研究，采用了GUV系统和纯化及荧光标记加格通过膜结合的Gag 31，了解运输所需的各种排序的胞内复合物（ESCRT）蛋白招募的顺序。近日，又有研究报告使用加格用荧光团共轭32的GUV加格诱导囊泡出芽过程的重建。的HIV-1的Gag多聚导致形成submembrane加格晶格的是在装配过程中认为是曲线的膜。因此，与加格-GUV测定系统进一步的改进，膜的曲率变化和Gag膜之间的关系的结合，这可以说是HIV组件的至少很好理解方面，可以分析为正在FO完成r其他细胞曲率敏感蛋白质33。 总之，使用这个协议中，可以得到足够量的肉豆蔻酰化全长的Gag的和可视的Gag结合GUV膜。这个协议可以进一步开发研究HIV-1的组装和出芽过程中的各个阶段。

人类免疫缺陷病毒1型（HIV-1）是一种有包膜的病毒，在大多数细胞类型组装在和从质膜（PM）的芽。 HIV-1病毒粒子的装配是由称为PR55 的Gag（GAG）的55 kDa的病毒核心蛋白驱动。加格被合成为四个主要的结构域，即，矩阵，衣壳，核衣壳和P6，以及两个间隔肽SP1和SP2组成的前体多蛋白。在装配过程中，矩阵（MA）域负责加格靶向组装现场，衣壳（CA）域介导的Gag Gag的相互作用，核衣壳（NC）域募集病毒基因组RNA和P6新兵宿主因素，援助从质膜病毒颗粒断裂。加格也通过加入在其N-末端14个碳的脂肪酸或肉豆蔻部分的经历共翻译修饰。 膜的Gag的结合是用于病毒装配的一项基本要求，因为mutants是在膜结合缺陷不能产生病毒颗粒。我们和其他人已经表明，膜是由马域内偶信号介导的Gag的结合:一种介导与脂质双层和称为高碱性区域MA域内的碱性残基簇（疏水相互作用的N-末端肉豆蔻基HBR）与上下午1-4酸性脂相互作用。使用polyphosphoinositide 5-磷酸酶IV（5ptaseIV），其催化PM-特定酸性磷脂phosphatidylinositol-的水解酶的异位表达Gag的膜相互作用的研究（4,5）-bisphosphate [PI（4,5）P 2]到磷脂酰肌醇-4-磷酸，在细胞中建议的Gag-PM定位由PI（4,5）P2 3,5-介导的。但是， 在体外研究旨在理解的Gag-PI（4,5）P2的更多的机械细节2相互作用已被证明是具有挑战性的原因很多。对于例如，全长的纯化肉豆蔻酰化的HIV-1 Gag的生化实验已经至少部分技术上难以由于加格的倾向纯化期间聚集。因此，HIV-1 Gag的截短形式，如秘耳-MA或秘耳-MA-CA，或者非肉豆蔻酰化形式已被频繁地研究，必要的Gag纯化而使用（ 如 ，核磁共振，蛋白足迹，和表面等离子体共振6-9）。备选地，耦合体外转录-翻译反应已被用于产生其它生化研究1,2-全长肉豆蔻酰化的HIV-1 Gag的。典型地，在这个系统中，一个编码的Gag质粒被转录并用真核细胞裂解物（ 例如 ，兔网织红细胞裂解物），缺少任何细胞膜和信使RNA的但含有用于转录和翻译机器翻译。反应后，将含有Gag的细胞裂解物与我混合mbranes与脂类加格相互作用的分析。除了 ​​易于制备全长肉豆蔻酰化的Gag的，使用体外转录翻译系统的方法具有的Gag合成和随后的膜结合反应发生在一个"真核细胞溶胶状"环境，可能更好地代表生理条件的优点。此属性促成了研究，结果表明绑定MA域RNA分子调节加格在竞争方式1,2,10-12结合酸性血脂。然而，由于在这些细胞裂解物获得的Gag蛋白质的总量不高，与放射性标记的氨基酸的蛋白质的代谢标记是必要的它们的检测。 根据不同的方法来测量的Gag - 脂质相互作用，已经使用了各种膜制剂。每一种方法都有其优势和局限性。大多数基于核磁共振的检验都要求短酰基利用脂质链是水溶性（ 例如 ，C 4和C8-PI（4,5）P 2）6,8。而核磁共振方法来测试的Gag的结合具有在细胞中发现的长酰基链正在开发中的脂质，它们迄今已8,13只有在用肉豆蔻酰化或nonmyristoylated MA。可替代地，从脂质制备具有天然长度的酰基链的脂质体已在生化方法如脂质体浮选或荧光脂质体珠粒结合测定2,3,10,14-16使用。然而，在这些测定中使用脂质体具有的直径小，因而它们的膜有陡峭的和积极的曲率。与此相反，在颗粒组装的在HIV-1感染的细胞中的早期阶段，加格结合到PM，这是上的Gag的规模几乎平坦，并随后出芽期间诱导负曲率。因此，陡峭，正曲率脂质体膜可能不是理想的脂质双层研究加格脂相互作用。至于脂质体海军报通货膨胀测定，另一个潜在需要注意的是加格脂质复合高渗性蔗糖梯度离心过程中暴露可能影响实验结果。为缓解这些限制，并提供一个互补的实验系统中，为GAG结合到巨单层囊泡（GUVs）测定法已被开发，近年来。 GUVs是单脂双层囊泡，其直径延伸至几十微米。因此，这些膜的曲率类似于上的Gag的规模的PM。此外，由于它的大尺寸，这使得在光学显微镜目视检查，膜在混合时可以在不加格 - 脂质复合物的后续处理可以很容易地确定的荧光标记或标记的Gag蛋白结合这些囊泡。 在这里，我们描述了一个协议，以研究HIV-1 Gag的膜使用从electroformation方法获得GUVs约束力。各种方法，如温和水合，凝胶辅助水合，麦克风rofluidic喷射和electroformation 17-22已被用来获取GUVs。对于这里所描述的协议中，electroformation方法在形成具有酸性脂质和其相对的易用性，而不需要昂贵的设置的GUVs使用主要是因为它的效率。自的Gag的可视化就必须荧光报道，黄色荧光蛋白（YFP）的基因加入到的Gag（加格-YFP）的C末端。的gag-YFP蛋白通过在小麦胚芽裂解物的体外转录和翻译反应的基础上连续交换连续流（CECF）技术获得的。在该技术中，既除去反应和反应底物和能量分量的供给抑制副产物的在基于透析的机制得以实现。这些反应中，使用T7启动子的控制下编码的Gag-YFP的质粒。值得注意的是，如上文所示，小麦胚芽裂解支持豆蔻无需额外的元件23,24。使用这种方法，就已经可以得到足够数量的全长上GUV膜24肉豆蔻酰化的Gag-YFP为加格的可视化。在这里，我们描述了与HIV-1 GAG结合到PI协议（4,5）P2含GUV膜可以无需冗长后续处理以下结合反应，并提出，这种方法已经存在补充加格膜结合试验，并可以进行检查扩展进一步了解HIV-1的Gag膜结合。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Digital Multimeter</td>
			<td>Meterman</td>
			<td>30XR</td>
			<td>A generic multimeter that can measure resistance and volts will serve the purpose.</td>
		</tr>
		<tr>
			<td>Function Generator</td>
			<td>Instek</td>
			<td>GFG-8216A</td>
			<td>A generic function generator that is capable of generating a sine wave at 10hz and 1V is sufficient.</td>
		</tr>
		<tr>
			<td>ITO coated glass slides</td>
			<td>Delta Technologies, Loveland, CO</td>
			<td>CG-90IN</td>
			<td></td>
		</tr>
		<tr>
			<td>Incubator</td>
			<td>Hoefer</td>
			<td></td>
			<td>Any incubator that can accurately maintain temperature will be sufficient</td>
		</tr>
		<tr>
			<td>Vacuum chamber</td>
			<td>Nalgene</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Thermomixer R</td>
			<td>Eppendorf</td>
			<td>21516-166</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe</td>
			<td>Hamilton</td>
			<td>80400</td>
			<td>Gauge 22S, Syringe number 702</td>
		</tr>
		<tr>
			<td>PDMS</td>
			<td>Sylgard elastomer base kit, Dow-Corning</td>
			<td>Sylgard, 184</td>
			<td></td>
		</tr>
		<tr>
			<td>RTS 100 Wheat Germ CECF Kit</td>
			<td>BiotechRabbit, 
			Berlin, Germany</td>
			<td>BR1401001</td>
			<td></td>
		</tr>
		<tr>
			<td>DiD</td>
			<td>Life Technologies, Carlsbad, CA&#160;</td>
			<td>D7757</td>
			<td></td>
		</tr>
		<tr>
			<td>POPC</td>
			<td>Avanti Polar Lipids, Alabaster, AL&#160;</td>
			<td>850457C</td>
			<td></td>
		</tr>
		<tr>
			<td>POPS</td>
			<td>Avanti Polar Lipids</td>
			<td>840034C</td>
			<td></td>
		</tr>
		<tr>
			<td>Cholesterol</td>
			<td>Avanti Polar Lipids</td>
			<td>700041P</td>
			<td></td>
		</tr>
		<tr>
			<td>Brain-PI(4,5)P2&#160;</td>
			<td>Avanti Polar Lipids</td>
			<td>840046X</td>
			<td></td>
		</tr>
	</tbody>
</table>

visualization of hiv-1 gag binding to giant unilamellar vesicle (guv) membranes

HIV-1的结构蛋白，PR55 的Gag（或加格），在病毒组装过程中结合到在细胞质膜。加格膜结合是病毒颗粒形成的一个重要步骤，因为在加格膜结合导致病毒颗粒生产严重受损的缺陷。获得的Gag-脂质膜相互作用的机理的细节，基于核磁共振，蛋白足迹，表面等离子体共振，脂质体浮选离心或荧光脂质珠体外方法结合迄今已开发的。然而，每一个的这些体外方法有其局限性。为了克服这些局限性，并提供一个互补的方式来先前建立的方法，我们开发了一种体外测定，其中HIV-1 Gag和脂质膜之间的相互作用发生在一个"细胞样"的环境。在该测定中，GAG结合到脂质膜在视觉上分析使用YFP - taggeð加格在小麦胚芽合成基于体外翻译系统，并通过electroformation技术制备GUVs。在这里，我们描述了背景和协议，以获得必要的测定肉豆蔻酰化全长的Gag蛋白和GUV膜和检测的Gag-GUV通过显微镜约束力。

<html>使用上述协议中，我们制备POPC + POPS +澈组成GUVs（摩尔比:4.66:2.33:3）。该组合物被选为大约反映PM的PS和胆固醇的浓度。稳健高效加格结合仅观察到时，大脑PI（4,5）P 2被纳入POPC + POPS +澈混合物（POPC + POPS +澈+脑-PI（4,5）P2 [摩尔比:4:2:3:1]在本实施例中）（ 图4，比较面板B和D与A和C）。的Gag-YFP结合POPC +组成GUVs POPS +澈+脑-PI（4,5）P 2由膜表面上的增加的荧光强度是显而易见的。这种增加也可以看出在沿线穿越GUV边界（XX&#39;在图4C和D）的荧光强度分布（ 图4，下图）。 负载/ 54293 / 54293fig4.jpg"/&gt; 图4: 加格与脑-PI（4,5）P2 -contianing GUVs POPC + POPS +澈（A和C）和POPC + POPS +澈+ PI的共聚焦截面（4,5）P2。 GUVs（B和D）。加格-YFP的分布显示为绿色。所选GUVs（黄色框）的放大图像示于面板C和D荧光强度绘制交叉GUVs（X到X&#39;）的相对侧随机选择的线被示出的图像下方型材沿。酒吧= 5微米。 <a href="https://www.jove.com/files/ftp_upload/54293/54293fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about Visualization of HIV-1 Gag Binding to Giant Unilamellar Vesicle GUV Membranes at JoVE.com

Visualization of HIV-1 Gag Binding to Giant Unilamellar Vesicle GUV Membranes

We illustrate here an in vitro membrane binding assay in which interactions between HIV-1 Gag and lipid membranes are visually analyzed using YFP-tagged Gag synthesized in a wheat germ-based in vitro translation system and GUVs prepared by an electroformation technique.

HIV-1 Gag的可视化绑定到巨人的单片囊泡（GUV）膜

The structural protein of HIV-1, Pr55Gag (or Gag), binds to the plasma membrane in cells during the virus assembly process. Membrane binding of Gag is an ...

visualization-hiv-1-gag-binding-to-giant-unilamellar-vesicle-guv

Nanyang Technological University

Research

JoVE Journal

Immunology and Infection

Visualization of HIV-1 Gag Binding to Giant Unilamellar Vesicle (GUV) Membranes

8.8K 次观看.  University of Michigan Medical School. We illustrate here an in vitro membrane binding assay in which interactions between HIV-1 Gag and lipid membranes are visually analyzed using YFP-tagged Gag synthesized in a wheat germ-based in vitro translation system and GUVs prepared by an electroformation technique. 

视频: Visualization of HIV-1 Gag Binding to Giant Unilamellar Vesicle GUV Membranes

Genotypic Inference of HIV-1 Tropism Using Population-based Sequencing of V3

Background: Prior to receiving a drug from CCR5-antagonist class in HIV therapy, a patient must undergo an HIV tropism test to confirm that his or her viral population uses the CCR5 coreceptor for cellular entry, and not an alternative coreceptor. One approach to tropism testing is to examine the sequence of the V3 region of the HIV envelope, which interacts with the coreceptor.
Methods: Viral RNA is extracted from blood plasma. The V3 region is amplified in triplicate with nested reverse transcriptase-PCR. The amplifications are then sequenced and analyzed using the software, RE_Call. Sequences are then submitted to a bioinformatic algorithm such as geno2pheno to infer viral tropism from the V3 region. Sequences are inferred to be non-R5 if their geno2pheno false positive rate falls below 5.75%. If any one of the three sequences from a sample is inferred to be non-R5, the patient is unlikely to respond to a CCR5-antagonist.

HIV tropism can be inferred from the V3 region of the viral envelope. V3 is PCR amplified in triplicate using nested RT-PCR, sequenced, and interpreted using bioinformatic software. Samples with with 1 or more sequence(s) with low g2P scores are classified as non-R5 virus.

V3的HIV - 1取向的基因型推理使用人口为基础的测序

Background: Prior to receiving a drug from CCR5-antagonist class in HIV therapy, a patient must undergo an HIV tropism test to confirm that his or her ...

科研

免疫与感染

Prediction of HIV-1 Coreceptor Usage (Tropism) by Sequence Analysis using a Genotypic Approach

Maraviroc (MVC) is the first licensed antiretroviral drug from the class of coreceptor antagonists. It binds to the host coreceptor CCR5, which is used by the majority of HIV strains in order to infect the human immune cells (Fig. 1). Other HIV isolates use a different coreceptor, the CXCR4. Which receptor is used, is determined in the virus by the Env protein (Fig. 2). Depending on the coreceptor used, the viruses are classified as R5 or X4, respectively. MVC binds to the CCR5 receptor inhibiting the entry of R5 viruses into the target cell. During the course of disease, X4 viruses may emerge and outgrow the R5 viruses. Determination of coreceptor usage (also called tropism) is therefore mandatory prior to administration of MVC, as demanded by EMA and FDA. 
The studies for MVC efficiency MOTIVATE, MERIT and 1029 have been performed with the Trofile assay from Monogram, San Francisco, U.S.A. This is a high quality assay based on sophisticated recombinant tests. The acceptance for this test for daily routine is rather low outside of the U.S.A., since the European physicians rather tend to work with decentralized expert laboratories, which also provide concomitant resistance testing. These laboratories have undergone several quality assurance evaluations, the last one being presented in 20111.
For several years now, we have performed tropism determinations based on sequence analysis from the HIV env-V3 gene region (V3)2. This region carries enough information to perform a reliable prediction. 
The genotypic determination of coreceptor usage presents advantages such as: shorter turnover time (equivalent to resistance testing), lower costs, possibility to adapt the results to the patients' needs and possibility of analysing clinical samples with very low or even undetectable viral load (VL), particularly since the number of samples analysed with VL&lt;1000 copies/&mu;l roughly increased in the last years (Fig. 3).
The main steps for tropism testing (Fig. 4) demonstrated in this video: 
1. Collection of a blood sample 
 2. Isolation of the HIV RNA from the plasma and/or HIV proviral DNA from blood mononuclear cells 
 3. Amplification of the env region 
 4. Amplification of the V3 region 
 5. Sequence reaction of the V3 amplicon 
 6. Purification of the sequencing samples 
 7. Sequencing the purified samples 
 8. Sequence editing 
 9. Sequencing data interpretation and tropism prediction

Prediction of HIV-1 Coreceptor Usage Tropism by Sequence Analysis using a Genotypic Approach

The prediction of the coreceptor usage of HIV-1 is required for the administration of a new class of antiretroviral drugs, i.e. coreceptor antagonists. It can be performed by sequence analysis of the env gene and subsequent interpretation through an internet based interpretation system (geno2pheno[coreceptor]).

使用基因型的方法预测HIV-1辅助用途（归经）的序列分析

Maraviroc (MVC) is the first licensed antiretroviral drug from the class of coreceptor antagonists. It binds to the host coreceptor CCR5, which is used by ...

In vitro Uncoating of HIV-1 Cores

The genome of the retroviruses is encased in a capsid surrounded by a lipid envelope. For lentiviruses, such as HIV-1, the conical capsid shell is composed of CA protein arranged as a lattice of hexagon. The capsid is closed by 7 pentamers at the broad end and 5 at the narrow end of the cone1, 2. Encased in this capsid shell is the viral ribonucleoprotein complex, and together they comprise the core.
Following fusion of the viral membrane with the target cell membrane, the HIV-1 is released into the cytoplasm. The capsid then disassembles releasing free CA in the soluble form3 in a process referred to as uncoating. The intracellular location and timing of HIV-1 uncoating are poorly understood. Single amino-acid substitutions in CA that alter the stability of the capsid also impair the ability of HIV-1 to infect cells4. This indicates that the stability of the capsid is critical for HIV-1 infection.
HIV-1 uncoating has been difficult to study due to lack of availability of sensitive and reliable assays for this process. Here we describe a quantitative method for studying uncoating in vitro using cores isolated from infectious HIV-1 particles. The approach involves isolation of cores by sedimentation of concentrated virions through a layer of detergent and into a linear sucrose gradient, in the cold. To quantify uncoating, the isolated cores are incubated at 37&deg;C for various timed intervals and subsequently pelleted by ultracentrifugation. The extent of uncoating is analyzed by quantifying the fraction of CA in the supernatant. This approach has been employed to analyze effects of viral mutations on HIV-1 capsid stability4, 5, 6. It should also be useful for studying the role of cellular factors in HIV-1 uncoating.

In vitro Uncoating of HIV-1 Cores

Uncoating is an essential step in the early phase of the HIV-1 life cycle and is defined as the disassembly of the capsid shell and the release of the viral ribonucleoprotein complex (vRNP). Here, we demonstrate techniques for isolating intact cores from HIV-1 virions and for quantifying their uncoating in vitro.

在体外对HIV - 1核心脱壳

The genome of the retroviruses is encased in a capsid surrounded by a lipid envelope. For lentiviruses, such as HIV-1, the conical capsid shell is ...

Imaging of HIV-1 Envelope-induced Virological Synapse and Signaling on Synthetic Lipid Bilayers

Human immunodeficiency virus type 1 (HIV-1) infection occurs most efficiently via cell to cell transmission2,10,11. This cell to cell transfer between CD4+ T cells involves the formation of a virological synapse (VS), which is an F-actin-dependent cell-cell junction formed upon the engagement of HIV-1 envelope gp120 on the infected cell with CD4 and the chemokine receptor (CKR) CCR5 or CXCR4 on the target cell 8. In addition to gp120 and its receptors, other membrane proteins, particularly the adhesion molecule LFA-1 and its ligands, the ICAM family, play a major role in VS formation and virus transmission as they are present on the surface of virus-infected donor cells and target cells, as well as on the envelope of HIV-1 virions1,4,5,6,7,13. VS formation is also accompanied by intracellular signaling events that are transduced as a result of gp120-engagement of its receptors. Indeed, we have recently showed that CD4+ T cell interaction with gp120 induces recruitment and phosphorylation of signaling molecules associated with the TCR signalosome including Lck, CD3&zeta;, ZAP70, LAT, SLP-76, Itk, and PLC&gamma;15.
In this article, we present a method to visualize supramolecular arrangement and membrane-proximal signaling events taking place during VS formation. We take advantage of the glass-supported planar bi-layer system as a reductionist model to represent the surface of HIV-infected cells bearing the viral envelope gp120 and the cellular adhesion molecule ICAM-1. The protocol describes general procedures for monitoring HIV-1 gp120-induced VS assembly and signal activation events that include i) bi-layer preparation and assembly in a flow cell, ii) injection of cells and immunofluorescence staining to detect intracellular signaling molecules on cells interacting with HIV-1 gp120 and ICAM-1 on bi-layers, iii) image acquisition by TIRF microscopy, and iv) data analysis. This system generates high-resolution images of VS interface beyond that achieved with the conventional cell-cell system as it allows detection of distinct clusters of individual molecular components of VS along with specific signaling molecules recruited to these sub-domains.

This article describes a method to visualize formation of an HIV-1 envelope-induced virological synapse on glass supported planar bilayers by total internal reflection fluorescence (TIRF) microscopy. The method can also be combined with immunofluorescence staining to detect activation and redistribution of signaling molecules that occur during HIV-1 envelope-induced virological synapse formation.

艾滋病毒的成像1信封引起的病毒学突触信号合成脂双层

Human immunodeficiency virus type 1 (HIV-1) infection occurs most efficiently via cell to cell transmission2,10,11. This cell to cell transfer between ...

New Tools to Expand Regulatory T Cells from HIV-1-infected Individuals

CD4+ Regulatory T cells (Tregs) are potent immune modulators and serve an important function in human immune homeostasis. Depletion of Tregs has led to measurable increases in antigen-specific T cell responses in vaccine settings for cancer and infectious pathogens. However, their role in HIV-1 immuno-pathogenesis remains controversial, as they could either serve to suppress deleterious HIV-1-associated immune activation and thus slow HIV-1 disease progression or alternatively suppress HIV-1-specific immunity and thereby promote virus spread. Understanding and modulating Treg function in the context of HIV-1 could lead to potential new strategies for immunotherapy or HIV vaccines. However, important open questions remain on their role in the context of HIV-1 infection, which needs to be carefully studied.
Representing roughly 5% of human CD4+ T cells in the peripheral blood, studying the Treg population has proven to be difficult, especially in HIV-1 infected individuals where HIV-1-associated CD4 T cell and with that Treg depletion occurs. The characterization of regulatory T cells in individuals with advanced HIV-1 disease or tissue samples, for which only very small biological samples can be obtained, is therefore extremely challenging. We propose a technical solution to overcome these limitations using isolation and expansion of Tregs from HIV-1-positive individuals.
Here we describe an easy and robust method to successfully expand Tregs isolated from HIV-1-infected individuals in vitro. Flow-sorted CD3+CD4+CD25+CD127low Tregs were stimulated with anti-CD3/anti-CD28 coated beads and cultured in the presence of IL-2. The expanded Tregs expressed high levels of FOXP3, CTLA4 and HELIOS compared to conventional T cells and were shown to be highly suppressive. Easier access to large numbers of Tregs will allow researchers to address important questions concerning their role in HIV-1 immunopathogenesis. We believe answering these questions may provide useful insight for the development of an effective HIV-1 vaccine.

CD4+ Regulatory T cells are potent immune-modulators and serve important functions in immune homeostasis. The paucity of these cells in peripheral blood makes functional studies challenging, specifically in the context of HIV-1-infection. We here describe a method to isolate and expand functional CD4+ Tregs from peripheral blood from HIV-1-infected individuals.

新工具展开调节性T细胞的HIV-1感染的个体

CD4+ Regulatory T cells (Tregs) are potent immune modulators and serve an important function in human immune homeostasis. Depletion of Tregs has led to ...

A Restriction Enzyme Based Cloning Method to Assess the In vitro Replication Capacity of HIV-1 Subtype C Gag-MJ4 Chimeric Viruses

The protective effect of many HLA class I alleles on HIV-1 pathogenesis and disease progression is, in part, attributed to their ability to target conserved portions of the HIV-1 genome that escape with difficulty. Sequence changes attributed to cellular immune pressure arise across the genome during infection, and if found within conserved regions of the genome such as Gag, can affect the ability of the virus to replicate in vitro. Transmission of HLA-linked polymorphisms in Gag to HLA-mismatched recipients has been associated with reduced set point viral loads. We hypothesized this may be due to a reduced replication capacity of the virus. Here we present a novel method for assessing the in vitro replication of HIV-1 as influenced by the gag gene isolated from acute time points from subtype C infected Zambians. This method uses restriction enzyme based cloning to insert the gag gene into a common subtype C HIV-1 proviral backbone, MJ4. This makes it more appropriate to the study of subtype C sequences than previous recombination based methods that have assessed the in vitro replication of chronically derived gag-pro sequences. Nevertheless, the protocol could be readily modified for studies of viruses from other subtypes. Moreover, this protocol details a robust and reproducible method for assessing the replication capacity of the Gag-MJ4 chimeric viruses on a CEM-based T cell line. This method was utilized for the study of Gag-MJ4 chimeric viruses derived from 149 subtype C acutely infected Zambians, and has allowed for the identification of residues in Gag that affect replication. More importantly, the implementation of this technique has facilitated a deeper understanding of how viral replication defines parameters of early HIV-1 pathogenesis such as set point viral load and longitudinal CD4+ T cell decline.

A Restriction Enzyme Based Cloning Method to Assess the In vitro Replication Capacity of HIV-1 Subtype C Gag-MJ4 Chimeric Viruses

HIV-1 pathogenesis is defined by both viral characteristics and host genetic factors. Here we describe a robust method that allows for reproducible measurements to assess the impact of the gag gene sequence variation on the in vitro replication capacity of the virus.

限制性内切酶克隆方法，以评估<em&gt;在体外</em&gt; HIV-1 C亚型的Gag-MJ4嵌合病毒的复制能力

The protective effect of many HLA class I alleles on HIV-1 pathogenesis and disease progression is, in part, attributed to their ability to target ...

Conformational Evaluation of HIV-1 Trimeric Envelope Glycoproteins Using a Cell-based ELISA Assay

HIV-1 envelope glycoproteins (Env) mediate viral entry into target cells and are essential to the infectious cycle. Understanding how those glycoproteins are able to fuel the fusion process through their conformational changes could lead to the design of better, more effective immunogens for vaccine strategies. Here we describe a cell-based ELISA assay that allows studying the recognition of trimeric HIV-1 Env by monoclonal antibodies. Following expression of HIV-1 trimeric Env at the surface of transfected cells, conformation specific anti-Env antibodies are incubated with the cells. A horseradish peroxidase-conjugated secondary antibody and a simple chemiluminescence reaction are then used to detect bound antibodies. This system is highly flexible and can detect Env conformational changes induced by soluble CD4 or cellular proteins. It requires minimal amount of material and no highly-specialized equipment or know-how. Thus, this technique can be established for medium to high throughput screening of antigens and antibodies, such as newly-isolated antibodies.

Understanding viral surface antigens conformations is required to evaluate antibody neutralization and guide the design of effective vaccine immunogens. Here we describe a cell-based ELISA assay that allows the study of the recognition of trimeric HIV-1 Env expressed at the surface of transfected cells by specific anti-Env antibodies.

HIV-1的三聚体包膜糖蛋白的构象评估使用基于细胞的ELISA检测

HIV-1 envelope glycoproteins (Env) mediate viral entry into target cells and are essential to the infectious cycle. Understanding how those glycoproteins ...

Isolation of Exosomes from the Plasma of HIV-1 Positive Individuals

Exosomes are small vesicles ranging in size from 30 nm to 100 nm that are released both constitutively and upon stimulation from a variety of cell types. They are found in a number of biological fluids and are known to carry a variety of proteins, lipids, and nucleic acid molecules. Originally thought to be little more than reservoirs for cellular debris, the roles of exosomes regulating biological processes and in diseases are increasingly appreciated.
Several methods have been described for isolating exosomes from cellular culture media and biological fluids. Due to their small size and low density, differential ultracentrifugation and/or ultrafiltration are the most commonly used techniques for exosome isolation. However, plasma of HIV-1 infected individuals contains both exosomes and HIV viral particles, which are similar in size and density. Thus, efficient separation of exosomes from HIV viral particles in human plasma has been a challenge.
To address this limitation, we developed a procedure modified from Cantin et. al., 2008 for purification of exosomes from HIV particles in human plasma. Iodixanol velocity gradients were used to separate exosomes from HIV-1 particles in the plasma of HIV-1 positive individuals. Virus particles were identified by p24 ELISA. Exosomes were identified on the basis of exosome markers acetylcholinesterase (AChE), and the CD9, CD63, and CD45 antigens. Our gradient procedure yielded exosome preparations free of virus particles. The efficient purification of exosomes from human plasma enabled us to examine the content of plasma-derived exosomes and to investigate their immune modulatory potential and other biological functions.

Techniques describing a gradient procedure to separate exosomes from human immunodeficiency virus (HIV) particles are described. This procedure was used to isolate exosomes away from HIV particles in human plasma from HIV-infected individuals. The isolated exosomes were analyzed for cytokine/chemokine content.

从HIV-1阳性者的血浆分离外来体的

Exosomes are small vesicles ranging in size from 30 nm to 100 nm that are released both constitutively and upon stimulation from a variety of cell types. ...

Measurement of In Vitro Integration Activity of HIV-1 Preintegration Complexes

HIV-1 envelope proteins engage cognate receptors on the target cell surface, which leads to viral-cell membrane fusion followed by the release of the viral capsid (CA) core into the cytoplasm. Subsequently, the viral Reverse Transcriptase (RT), as part of a namesake nucleoprotein complex termed the Reverse Transcription Complex (RTC), converts the viral single-stranded RNA genome into a double-stranded DNA copy (vDNA). This leads to the biogenesis of another nucleoprotein complex, termed the pre-integration complex (PIC), composed of the vDNA and associated virus proteins and host factors. The PIC-associated viral integrase (IN) orchestrates the integration of the vDNA into the host chromosomal DNA in a temporally and spatially regulated two-step process. First, the IN processes the 3&#39; ends of the vDNA in the cytoplasm and, second, after the PIC traffics to the nucleus, it mediates integration of the processed vDNA into the chromosomal DNA. The PICs isolated from target cells acutely infected with HIV-1 are functional in vitro, as they are competent to integrate the associated vDNA into an exogenously added heterologous target DNA. Such PIC-based in vitro integration assays have significantly contributed to delineating the mechanistic details of retroviral integration and to discovering IN inhibitors. In this report, we elaborate upon an updated HIV-1 PIC assay that employs a nested real-time quantitative Polymerase Chain Reaction (qPCR)-based strategy for measuring the in vitro integration activity of isolated native PICs.

Measurement of In Vitro Integration Activity of HIV-1 Preintegration Complexes

This report describes an in vitro assay for measuring the human immunodeficiency virus type 1 (HIV-1) preintegration complex (PIC)-associated integration activity in the cytoplasmic extracts of acutely infected cells. The integration of PIC-associated HIV-1 DNA into heterologous target DNA is quantified by using a nested real-time polymerase chain reaction strategy.

测量<em&gt;体外</em&gt; HIV-1 Preintegration配合物的整合活动

HIV-1 envelope proteins engage cognate receptors on the target cell surface, which leads to viral-cell membrane fusion followed by the release of the ...

SILAC Based Proteomic Characterization of Exosomes from HIV-1 Infected Cells

Proteomics is the large-scale analysis of proteins. Proteomic techniques, such as liquid chromatography tandem mass spectroscopy (LC-MS/MS), can characterize thousands of proteins at a time. These powerful techniques allow us to have a systemic understanding of cellular changes, especially when cells are subjected to various stimuli, such as infections, stresses, and specific test conditions. Even with recent developments, analyzing the exosomal proteome is time-consuming and often involves complex methodologies. In addition, the resultant large dataset often needs robust and streamlined analysis in order for researchers to perform further downstream studies. Here, we describe a SILAC-based protocol for characterizing the exosomal proteome when cells are infected with HIV-1. The method is based on simple isotope labeling, isolation of exosomes from differentially labeled cells, and mass spectrometry analysis. This is followed by detailed data mining and bioinformatics analysis of the proteomic hits. The resultant datasets and candidates are easy to understand and often offer a wealth of information that is useful for downstream analysis. This protocol is applicable to other subcellular compartments and a wide range of test conditions.

Here, we describe a quantitative proteomics method using the technique of stable isotope labeling by amino acids in cell culture (SILAC) to analyze the effects of HIV-1 infection on host exosomal proteomes. This protocol can be easily adapted to cells under different stress or infection conditions.