这项工作得到了美国国立卫生研究院（NIH）资助:RO1 EY012085（给JXJ）和F32DK134051（给FMA）以及韦尔奇基金会资助:AQ-1507（给JXJ）。内容完全由作者负责，并不一定代表美国国立卫生研究院的官方观点。这些数字部分是用 Biorender.com 创建的。

本研究是按照《动物福利法》和《动物福利实施条例》的原则，根据《实验动物护理和使用指南》的原则进行的。所有动物程序均由德克萨斯大学圣安东尼奥健康科学中心机构动物护理和使用委员会批准。有关协议的概述，请参阅 图 1;有关本协议中使用的所有材料、试剂和仪器的详细信息，请参阅 材料表 。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/65727/65727fig01.jpg"> 图1:实验大纲。1. 方案的第一步是确定特定的靶蛋白，鉴定相关基因序列，并生成 DNA 片段。 2 . 通过初始克隆到接头载体中，将基因序列克隆到逆转录病毒载体中， 3. 然后是病毒载体。 4. 使用包装细胞制备高滴度病毒颗粒，以收获和浓缩。 5. 最后一步，也是该协议的重点，是将RCAS（A）病毒颗粒的鸡晶状体显微注射到晶状体腔中。 <a href="https://www.jove.com/files/ftp_upload/65727/65727fig01large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
1. 高滴度重组逆转录病毒的制备
<ol><li>聚合酶链反应 （PCR） 制备靶蛋白 DNA 片段 注:本节旨在扩增与靶晶状体蛋白相对应的DNA序列。有关详细信息，请参见 7,8。<ol><li>设计与目标蛋白相对应的PCR引物，以制备具有羧基末端的DNA片段，具有或不具有FLAG表位序列（5'-GACTACAAGGACGACGATGACAAG-3'），终止密码子和限制性内切酶位点（即EcoRI）存在于CLa12NCO的多接头区域内）根据先前发表的方案中注明的规格，具有足够的限制性内切酶的序列1，7、8、10、11。</li>
		<li>进行PCR反应10。将设计引物的 100 pmol 正义和反义与 0.5 μg 连接蛋白 cDNA（例如 Cx50、Cx43 或嵌合 Cx50*43L 组合）混合到所选的 PCR 反应缓冲液中。执行30个循环，每个循环包括94°C1分钟，58°C1分钟和72°C1分钟，然后在72°C下最终延伸10分钟。</li>
		<li>使用凝胶纯化试剂盒分离和纯化PCR产物。</li>
		<li>根据制造商的说明，使用选择的限制性内切酶消化纯化的PCR产物。</li>
	</ol></li>
	<li>将DNA插入片段克隆到接头质粒中 注:将 DNA 片段插入接头载体中无需辅助细胞/病毒即可提高 RCAS（A） 载体稳定性14.有关详细信息，请参见 7,8。<ol><li>使用粘性末端连接反应将 DNA 片段亚克隆到衔接质粒 Cla12NCO 中。将PCR片段与限制性内切酶和Cla12NCO以2-5:1的比例混合。使用感受态细胞进行连接和DNA转化。</li>
		<li>使用 DNA 分离试剂盒分离 DNA。</li>
		<li>对 DNA 进行测序以确保准确性。</li>
	</ol></li>
	<li>克隆到RCAS（A）病毒载体中 注:将DNA片段插入载体（RCAS（A）逆转录病毒）中，以便将基因稳定转导到发育中的鸡胚14,15的细胞中。有关详细信息，请参见7、8、15。<ol><li>用 ClaI（每 1 μg DNA 1 个单位）消化目的载体的 Cla12NCO-DNA 片段并凝胶分离片段。</li>
		<li>将 DNA 片段亚克隆到 ClaI 线性化的 RCAS（A） 质粒中。使用限制性内切酶SalI区分RCAS（A）质粒上的ClaI位点。</li>
		<li>通过用 ClaI 和 SalI 限制性内切酶消化来确认插入片段在构建体上的正确方向。</li>
		<li>使用 DNA 分离试剂盒分离 DNA。</li>
		<li>测定DNA浓度。</li>
	</ol></li>
	<li>雏鸡胚胎成纤维细胞 （CEF） 细胞的转染和 RCAS（A） 收获 注:病毒包装细胞 CEF 用于获取/收获含有病毒颗粒的细胞培养基15,16。有关详细信息，请参见7、8、15。<ol><li>根据制造商的说明，使用转染试剂用重组逆转录病毒 DNA 构建体转染 CEF 细胞。</li>
		<li>对转染细胞进行蛋白质印迹，以检查其目标蛋白的表达。</li>
		<li>当转染的细胞达到汇合时，开始收集上清液培养基，对其进行适当的处理/过滤（使用0.22μm过滤器去除任何细胞碎片），并储存在-80°C直至准备浓缩。</li>
	</ol></li>
	<li>病毒储备液的浓度和滴度 注意:必须过滤来自含有病毒颗粒的细胞的沉淀和大量培养基。此外，必须进行病毒滴度测定以确定病毒对宿主细胞的强度。有关详细信息，请参见6、7、8、15。<ol><li>解冻含有病毒粒子的培养基。</li>
		<li>将培养基在4°C下以72,000× g 旋转2小时。</li>
		<li>倒出上清液，用残留的（~50μL）培养基重悬病毒沉淀，并在-80°C下储存在~10μL病毒储备液中直至使用。</li>
		<li>对于滴度测定，使用 QT-6 或 CEF 细胞，用病毒储备液的连续稀释液转染细胞。</li>
		<li>汇合后，使用4%甲醛固定细胞。</li>
		<li>病毒 gag 蛋白的免疫染色或碱性磷酸酶的组织化学过程以获得滴度，定义为（集落形成单位）CFU/毫升 （CFU/mL）。</li>
	</ol></li>
</ol><img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/65727/65727fig02.jpg"> 图 2:雏鸡晶状体显微注射的仪器和设置 。 （A） P-30手动立式微电极微量移液器拉拔器。（1） 插图显示正在拉动的玻璃微量移液器。（B） （2） 种蛋孵化器。将鸡蛋在37°C培养箱中孵育~65-68小时，以达到注射逆转录病毒的第18阶段（具有密封的空中央腔）。（C） 显微注射设置。（3）照明设备，（4）微型注射器，（5）解剖显微镜，（6）德拉蒙德显微操纵器，（7）用于可视化的计算机/相机。 <a href="https://www.jove.com/files/ftp_upload/65727/65727fig02large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
2. 小鸡晶状体显微注射
<ol><li>准备用品<ol><li>显微注射用玻璃微量移液器的制备17 注:玻璃毛细管用于制造尖端点和外径 （OD） 为 ~11 μm 的玻璃微量移液器，用于显微注射。设置如图 2A所示。<ol><li>将硼硅酸盐玻璃毛细管连接到手动立式微量移液器拉拔器中的橡胶缓冲夹上。</li>
			<li>将加热温度 （HEAT 1） 设置为 950 °C 并进行预拉以获得更薄、更柔软的玻璃毛细管。</li>
			<li>将加热温度（HEAT 2）设置为790°C，并进行二次拉动以产生最终的微量移液器。</li>
			<li>使用微量移液器研磨机，将吸头开口锐化至外径~11μm。</li>
			<li>对于未来的实验，将玻璃微量移液器放在玻璃罐内的海绵夹紧垫中。</li>
		</ol></li>
		<li>受精卵孵化至发育阶段 18 注:在晶状体发育过程中，在胚胎发育的~65-68小时，晶状体与外胚层分离并形成具有中央腔的密封囊泡;注射到这个空晶状体腔中，限制表达到增殖的晶状体细胞7,8,18。<ol><li>将受精鸡蛋在37°C加湿摇摆培养箱中孵育~65-68小时（图2B）。</li>
		</ol></li>
	</ol></li>
	<li>鸡蛋的打开 注意:此步骤描述了用于显微注射的胚胎的识别和暴露。有关详细信息，请参见 7,8。<ol><li>用 70% 乙醇彻底擦拭工作区域。</li>
		<li>从孵化器中取出鸡蛋，用 70% 乙醇大量喷洒，然后让它们风干。</li>
		<li>将鸡蛋的较大一端朝上放在蛋架上。</li>
		<li>使用一对锋利的齿镊子，小心地敲击蛋壳并去除蛋壳的碎片，在鸡蛋的较大端产生一个直径为~2厘米的孔（图3A）。</li>
		<li>使用解剖显微镜，定位胚胎。</li>
		<li>一旦找到胚胎和雏鸡晶状体，使用解剖显微镜和精细解剖镊子和剪刀切断立即覆盖胚胎顶部的羊膜（图3B）。 注意:不要切得太宽（仅足以暴露胚胎~0.5 cm x 0.5 cm），否则胚胎可能会沉入卵黄块中;如果可能的话，也要避免接触血管。</li>
		<li>用60毫米的培养皿盖住鸡蛋的开口，为下一步做准备。</li>
	</ol></li>
	<li>显微注射浓缩病毒储备液 注:将含有用于转导的靶蛋白DNA片段的病毒颗粒插入晶状体腔内的细胞中。设置如图 2C 所示。有关详细信息，请参见6、7、8。<ol><li>在冰上解冻病毒库存。</li>
		<li>为了在注射过程中可视化病毒原液，将 1 μL 的 10x Fast Green 稀释到一小瓶含有 10 μL 的病毒原液中。</li>
		<li>为确保没有大块未溶解的物质可能堵塞玻璃微量移液器，在4°C下以10,000× g 离心溶液10秒，以沉淀"大块"并将上清液转移到新管中，同时将溶液保持在冰上。</li>
		<li>在 35 mm x 10 mm 培养皿上，放置拉伸的实验室封口膜，并在薄膜顶部加入 1 μL 无菌盐水 （PBS）（未灭菌，覆盖面被认为是"干净的"）。</li>
		<li>将准备好的玻璃微量移液器连接到自动微微注射器。</li>
		<li>按下 填充模式 ，将无菌盐水 （PBS） 填充到玻璃微量移液器中，然后使用 注射模式 测试分配的 1 μL 液体。</li>
		<li>将第二个拉伸的实验室封口膜放在新的 35 mm x 10 mm 细胞培养皿的表面上，并在薄膜顶部加入 1 μL 快速绿色染色的病毒储备液。</li>
		<li>将微量移液器的尖端降低到病毒储液中，然后按 压填充模型 ，用~1μL病毒储液器填充玻璃微量移液器。 注意:为避免变干，每当程序暂停时，将装满的微量移液器的尖端放入无菌盐水 （PBS） 中。</li>
		<li>在解剖显微镜的帮助下，将连接到自动注射器的填充玻璃微量移液器降低到胚胎晶状体腔的目标区域。</li>
		<li>调整光源以确保晶状体囊泡轮廓清晰可见。 注意:右晶状体的内腔（朝上）通常用于注射，左晶状体（朝下）保持完整作为对侧对照。</li>
		<li>一旦确定微量移液器的位置在晶状体腔内的正确位置，注射5-40nL的病毒储备液（图3C）。 注意:练习对于最佳注射位置非常必要。</li>
		<li>等待~45秒，然后轻轻取出玻璃微量移液器。</li>
		<li>使用解剖显微镜检查是否成功显微注射到晶状体腔中，方法是检查应保持在晶状体空腔中且没有任何泄漏的固绿染料。</li>
		<li>注射程序后，用透明胶带密封蛋壳开口。</li>
		<li>将胚胎放回37°C加湿的培养箱中，没有任何旋转运动，直到达到所需的胚胎年龄进行晶状体解剖。</li>
	</ol></li>
</ol><img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/65727/65727fig03.jpg"> 图 3:显微注射雏鸡制备和示意图 。 （A） 打开鸡蛋。（B）切割羊膜。（C）鸡晶状体腔显微注射示意图。 <a href="https://www.jove.com/files/ftp_upload/65727/65727fig03large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>

研究鸡晶状体发育过程中的蛋白质表达

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L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+series+of+normal+stages+in+the+development+of+the+chick+embryo.">A series of normal stages in the development of the chick embryo.</a> Developmental Dynamics. 195 (4), 231-272 (1992).</li><li>Hallagan, J. B., Allen, D. C., Borzelleca, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+safety+and+regulatory+status+of+food,+drug+and+cosmetics+colour+additives+exempt+from+certification.">The safety and regulatory status of food, drug and cosmetics colour additives exempt from certification.</a> Food and Chemical Toxicology. 33 (6), 515-528 (1995).</li><li>Okada, T. S., Eguchi, G., Takeichi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+expression+of+differentiation+by+chicken+lens+epithelium+in+in+vitro+cell+culture.">The expression of differentiation by chicken lens epithelium in in vitro cell culture.</a> Development, Growth &amp; Differentiation. 13 (4), 323-336 (1971).</li><li>Menko, A. S., Klukas, K. A., Johnson, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chicken+embryo+lens+cultures+mimic+differentiation+in+the+lens.">Chicken embryo lens cultures mimic differentiation in the lens.</a> Developmental Biology. 103 (1), 129-141 (1984).</li><li>Parreno, J., 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=Methodologies+to+unlock+the+molecular+expression+and+cellular+structure+of+ocular+lens+epithelial+cells.">Methodologies to unlock the molecular expression and cellular structure of ocular lens epithelial cells.</a> Frontiers in Cell and Developmental Biology. 10, 983178 (2022).</li><li>Edwards, A., Gupta, J. D., Harley, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photomicrographic+evaluation+of+drug-induced+cataracts+in+cultured+embryonic+chick+lens.">Photomicrographic evaluation of drug-induced cataracts in cultured embryonic chick lens.</a> Experimental Eye Research. 15 (4), 495-498 (1973).</li><li>Musil, L. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+cultures+of+embryonic+chick+lens+cells+as+a+model+system+to+study+lens+gap+junctions+and+fiber+cell+differentiation.">Primary cultures of embryonic chick lens cells as a model system to study lens gap junctions and fiber cell differentiation.</a> Journal of Membrane Biology. 245 (7), 357-368 (2012).</li><li>West-Mays, J. A., Pino, G., Lovicu, F. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+use+of+the+lens+epithelial+explant+system+to+study+lens+differentiation+and+cataractogenesis.">Development and use of the lens epithelial explant system to study lens differentiation and cataractogenesis.</a> Progress in Retinal and Eye Research. 29 (2), 135-143 (2010).</li><li>Upreti, A., 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=Lens+epithelial+explants+treated+with+vitreous+humor+undergo+alterations+in+chromatin+landscape+with+concurrent+activation+of+genes+associated+with+fiber+cell+differentiation+and+innate+immune+response.">Lens epithelial explants treated with vitreous humor undergo alterations in chromatin landscape with concurrent activation of genes associated with fiber cell differentiation and innate immune response.</a> Cells. 12 (3), 501 (2023).</li><li>Walker, J. L., Wolff, I. M., Zhang, L., Menko, 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=Activation+of+SRC+kinases+signals+induction+of+posterior+capsule+opacification.">Activation of SRC kinases signals induction of posterior capsule opacification.</a> Investigative Ophthalmology &amp; Visual Science. 48 (5), 2214-2223 (2007).</li><li>Briskin, M. J., 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=Heritable+retroviral+transgenes+are+highly+expressed+in+chickens.">Heritable retroviral transgenes are highly expressed in chickens.</a> Proceedings of the National Academy of Sciences of the United States of America. 88 (5), 1736-1740 (1991).</li><li>Hughes, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+RCAS+vector+system.">The RCAS vector system.</a> Folia Biologica. 50 (3-4), 107-119 (2004).</li></ol>

作者声明，该研究是在没有任何可被解释为潜在利益冲突的商业或财务关系的情况下进行的。

该实验模型提供了在完整晶状体中表达目标蛋白质的机会，从而研究了这些蛋白质在晶状体结构和功能中的功能相关性。胚胎雏鸡显微注射模型部分基于Fekete等人的工作。al.6，并由Jiang等人进一步发展。al.8 并已被用作将病毒质粒和试剂（如激动剂、小干扰 RNA （siRNA） 和肽）插入雏鸡晶状体的手段 1,9,10,11,12,13。<...

该协议的目的是描述RCAS（A）（具有复制能力的禽肉瘤/白血病逆转录病毒A）的胚胎鸡晶状体显微注射的方法。在胚胎鸡晶状体中有效的逆转录病毒递送已被证明是 体内研究晶 状体蛋白在正常晶状体生理学、病理状况和发育中的分子机制和结构功能的有前途的工具。此外，该实验模型还可用于人类先天性白内障等疾病的治疗靶点识别和药物筛选。总而言之，该协议旨在为开发用于研究晶状体蛋白的可定制平台制定必要的步骤。
胚胎雏鸡（Gallus domesticus）由于其晶状体结构和功能与人类晶状体相似，是研究晶状体发育和生理学的成熟动物模型1,2,3,4。使用具有复制能力的 RCAS（A） 禽逆转录病毒被认为是在雏鸡胚胎中表达外源蛋白的高效、快速和可定制的系统。值得注意的是，它具有独特的能力，可以将靶基因转移限制在增殖的晶状体纤维细胞中，而不需要组织特异性启动子，使用独特的胚胎发育时间框架，其中空晶状体腔的存在允许原位 RCAS（A） 显微注射到受限位点，以便在增殖晶状体纤维细胞内表达外源性蛋白质5，6,7,8.
这里深入描述的鸡胚显微注射程序最初部分基于 Fekete 等人的工作。al.6 并由 Jiang 等人进一步发展。Al.8，并已被用作将病毒和非病毒质粒引入胚胎雏鸡晶状体的手段1,9,10,11,12,13。总体而言，先前的工作证明了利用这种方法研究晶状体发育、分化、细胞通讯和疾病进展的潜力，以及发现和测试晶状体病理状况（如白内障）的治疗靶点。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.22 &#181;m Filter</td>
			<td>Corning</td>
			<td>431118</td>
			<td>For removing cellular debris from media</td>
		</tr>
		<tr>
			<td>35 mm x 10 mm Culture Dish</td>
			<td>FisherScientific</td>
			<td>50-202-030</td>
			<td>For using during microinjection</td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Fisherbrand</td>
			<td>13-100-676</td>
			<td>Spinning down solution</td>
		</tr>
		<tr>
			<td>Constructs</td>
			<td>GENEWIZ</td>
			<td>-</td>
			<td>For generation of constructs</td>
		</tr>
		<tr>
			<td>Dissecting microscope</td>
			<td>AmScope</td>
			<td>SM-4TZ-144A</td>
			<td>Visualization of lens for microinjection</td>
		</tr>
		<tr>
			<td>DNA PCR primers</td>
			<td>Integrated DNA Technologies</td>
			<td>-</td>
			<td>Generation of primers: 
			 
			Intracellular loop (IL)-deleted Cx50 (residues 1&#8211;97 and 149&#8211;400) as well as the Cla12NCO vector were obtained with the following pair of primers: sense, CTCCTGAGAACCTACATCCT; antisense, CACCGCATGCCCAAAGTACAC 
			 
			ILs of Cx43 (residues 98&#8211;150) and Cx46 (residues 98&#8211;166) were&#160; obtained with the following pairs of primers: sense, TACGTGATGAGGAAAGAAGAG; antisense, TCCTCCACGCATCTTTACCTTG; sense, CACATTGTACGCATGGAAGAG; antisense, AGCACCTCCC AT ACGGATTC, respectively 
			 
			Cla12NCO-Cx43 construct template was obtained with the following pair of primers: sense, CTGCTTCGTACTTACATCATC; antisense, GAACAC GTGCGCCAGGTAC 
			 
			ILs of Cx50 (residues 98&#8211;148) or Cx46 (residues 98&#8211;166) were cloned by using Cla12NCO-Cx50 and Cla12NCO-Cx46 constructs as the templates with the following pair of primers: sense, CACCATGTCCGCATGGAGGAGA; antisense, GGTCCCC TC CAGGCGAAAC; sense, CACATTGTACGCATGGAAGAG; antisense, AGCACCTCCCATACGGATTC, respectively</td>
		</tr>
		<tr>
			<td>Drummond Nanoject II Automatic Nanoliter Injector</td>
			<td>Drummond Scientific</td>
			<td>3-000-204</td>
			<td>Microinjection Pipet</td>
		</tr>
		<tr>
			<td>Dual Gooseneck Lights Microscope Illuminator</td>
			<td>AmScope</td>
			<td>LED-50WY</td>
			<td>Lighting for visualization</td>
		</tr>
		<tr>
			<td>Dulbecco&#8217;s Modified Eagle Medium (DMEM)</td>
			<td>Invitrogen</td>
			<td></td>
			<td>For cell culture</td>
		</tr>
		<tr>
			<td>Egg Holder</td>
			<td>-</td>
			<td>-</td>
			<td>Homemade styrofoam rings with 2-inch diameter and one-half inch height</td>
		</tr>
		<tr>
			<td>Egg Incubator</td>
			<td>GQF Manufacturing Company Inc.</td>
			<td>1502</td>
			<td>For incubation of fertilized eggs</td>
		</tr>
		<tr>
			<td>Fast Green</td>
			<td>Fisher scientific</td>
			<td>F99-10</td>
			<td>For visualization of viral stock injection</td>
		</tr>
		<tr>
			<td>Fertilized white leghorn chicken eggs</td>
			<td>Texas A&#38;M University</td>
			<td>N/A</td>
			<td>Animal model of choice for microinjection (https://posc.tamu.edu/fertile-egg-orders/)</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>Hyclone Laboratories</td>
			<td></td>
			<td>For cell culture</td>
		</tr>
		<tr>
			<td>Fluorescein-conjugated anti-mouse IgG</td>
			<td>Jackson ImmunoResearch</td>
			<td>115-095-003</td>
			<td>For anti-FLAG&#160; 1:500</td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>FisherScientific</td>
			<td>22-327379</td>
			<td>For moving things around and isolation</td>
		</tr>
		<tr>
			<td>Glass capillaries</td>
			<td>Sutter Instruments</td>
			<td>B100-75-10</td>
			<td>Glass micropipette for microinjection (O.D. 1.0 mm, I.D. 0.75 mm, 10 cm length)</td>
		</tr>
		<tr>
			<td>Lipofectamine</td>
			<td>Invitrogen</td>
			<td>L3000001</td>
			<td>For transfection</td>
		</tr>
		<tr>
			<td>Manual vertical micropipette puller</td>
			<td>Sutter Instruments</td>
			<td>P-30</td>
			<td>To obtain glass micropipette of the correct size</td>
		</tr>
		<tr>
			<td>Microcentrifuge Tubes</td>
			<td>FisherScientific</td>
			<td>02-682-004</td>
			<td>Dissolving solution</td>
		</tr>
		<tr>
			<td>Microscope</td>
			<td>Keyence</td>
			<td>BZ-X710</td>
			<td>For imaging staining</td>
		</tr>
		<tr>
			<td>Parafilm</td>
			<td>FisherScientific</td>
			<td>03-448-254</td>
			<td>Placing solution</td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>Invitrogen</td>
			<td></td>
			<td>For cell culture</td>
		</tr>
		<tr>
			<td>Pico-Injector</td>
			<td>Harvard Apparatus</td>
			<td>PLI-100</td>
			<td>For delivering small liquid volumes precisely through micropipettes by applying a regulated pressure for a digitally set period of time</td>
		</tr>
		<tr>
			<td>rabbit anti-chick AQP0</td>
			<td>Self generated</td>
			<td>-</td>
			<td>Jiang JX, White TW, Goodenough DA, Paul DL. Molecular cloning and functional characterization of chick lens fiber connexin 45.6. Mol Biol Cell. 1994 Mar;5(3):363-73. doi: 10.1091/mbc.5.3.363.</td>
		</tr>
		<tr>
			<td>rabbit anti-FLAG antibody</td>
			<td>Rockland Immunichemicals</td>
			<td>600-401-383</td>
			<td>For staining FLAG</td>
		</tr>
		<tr>
			<td>Rhodamine-conjugated anti-rabbit IgG&#160;</td>
			<td>Jackson ImmunoResearch</td>
			<td>111-295-003</td>
			<td>For anti-AQP0&#160; 1:500</td>
		</tr>
		<tr>
			<td>Sponge clamping pad</td>
			<td>Sutter Instruments</td>
			<td>BX10</td>
			<td>For storage of glass micropipette</td>
		</tr>
	</tbody>
</table>

microinjection of recombinant rcas(a) retrovirus into embryonic chicken lens

胚胎鸡（Gallus domesticus）是一种成熟的动物模型，用于研究晶状体发育和生理学，因为它与人类晶状体高度相似。RCAS（A）是一种具有复制能力的鸡逆转录病毒，可感染分裂细胞，是研究晶状体发育过程中野生型和突变蛋白原 位 表达和功能的有力工具，在早期发育阶段通过显微注射到晶状体囊泡的空腔中，将其作用限制在周围增殖的晶状体细胞中。与转基因模型和 离体 培养等其他方法相比，使用具有复制能力的禽逆转录病毒提供了一种高效、快速和可定制的系统来表达雏鸡胚胎中的外源蛋白。具体来说，靶向基因转移可以局限于增殖的晶状体纤维细胞，而不需要组织特异性启动子。在本文中，我们将简要概述重组逆转录病毒RCAS（A）制备所需的步骤，提供显微注射程序的详细、全面的概述，并提供该技术的样本结果。

在确定特定靶蛋白和鉴定相关基因序列后，总体实验方法包括将基因序列克隆到逆转录病毒 RCAS（A） 载体中，方法是初始克隆到接头载体中，然后是病毒载体。其次，使用包装细胞制备高滴度病毒颗粒，以收获和浓缩病毒粒子。前两个主要步骤已基本描述，代表性结果在其他地方呈现6、7、8、14、<sup...

Watch this Scientific Journal Video about Investigating Lens Development and Function Through Microinjection of RCASA Retrovirus in Embryonic Chicken Lens at JoVE.com

作者聚焦:通过在胚胎鸡晶状体中显微注射 RCAS（A） 逆转录病毒来研究晶状体的发育和功能 

该协议论文描述了RCAS（A）逆转录病毒的胚胎鸡晶状体显微注射的方法，作为研究晶状体发育过程中蛋白质原 位 功能和表达的工具。

重组RCAS（A）逆转录病毒显微注射到胚胎鸡晶状体中

Embryonic chicken (Gallus domesticus) is a well-established animal model for the study of lens development and physiology, given its high degree of ...

所提出的RCAS逆转录病毒胚胎鸡晶状体显微注射方法旨在作为研究晶状体发育过程中蛋白质原位功能和表达的工具。与转基因模型和离体培养等其他方法相比，具有复制能力的禽逆转录病毒为在雏鸡胚胎中表达外源蛋白提供了一种高效、快速和可定制的系统。靶向基因转移可以局限于增殖的晶状体纤维细胞，而不需要启动子。利用这种方法研究晶状体发育、分化、细胞通讯和疾病进展，以及发现和测试晶状体病理状况（如白内障）的治疗靶点具有突出的潜力。

microinjection-recombinant-rcas-retrovirus-into-embryonic-chicken

Research

JoVE Journal

Biology

Microinjection of Recombinant RCAS(A) Retrovirus into Embryonic Chicken Lens

873 次观看.  University of Texas Health Science Center, San Antonio. 所提出的RCAS逆转录病毒胚胎鸡晶状体显微注射方法旨在作为研究晶状体发育过程中蛋白质原位功能和表达的工具。与转基因模型和离体培养等其他方法相比，具有复制能力的禽逆转录病毒为在雏鸡胚胎中表达外源蛋白提供了一种高效、快速和可定制的系统。靶向基因转移可以局限于增殖的晶状体纤维细胞，而不需要启动子。利用这种方法研究晶状体发育、分化、细胞通...

视频: 作者聚焦:通过在胚胎鸡晶状体中显微注射 RCAS（A） 逆转录病毒来研究晶状体的发育和功能 

Windowing Chicken Eggs for Developmental Studies

The study of development has been greatly aided by the use of the chick embryo as an experimental model.  The ease of accessibility of the embryo has allowed for experiments to map cell fates using several approaches, including chick quail chimeras and focal dye labeling.  In addition, it allows for molecular perturbations of several types, including placement of protein-coated beads and introduction of plasmid DNA using in ovo electroporation.  These experiments have yielded important data on the development of the central and peripheral nervous systems.  For many of these studies, it is necessary to open the eggshell and reclose it without perturbing the embryo's growth.  The embryo can be examined at successive developmental stages by re-opening the eggshell.  While there are several excellent methods for opening chicken eggs, in this article we demonstrate one method that has been optimized for long survival times.  In this method, the egg rests on its side and a small window is cut in the shell.  After the experimental procedure, the shell is used to cover the egg for the duration of its development.  Clear plastic tape overlying the eggshell protects the embryo and helps retain hydration during the remainder of the incubation period.  This method has been used beginning at two days of incubation and has allowed survival through mature embryonic ages.

The ease of accessibility of the embryo has allowed for experiments to map cell fates using several approaches, including chick quail chimeras and focal dye labeling. In this article we demonstrate one egg preparation method that has been optimized for long survival times.

发育研究的窗口鸡蛋

The study of development has been greatly aided by the use of the chick embryo as an experimental model.  The ease of accessibility of the embryo has ...

科研

生物学

Production of Replication-Defective Retrovirus by Transient Transfection of 293T cells

Our lab studies human myeloproliferative diseases induced by such oncogenes as Bcr-Abl or growth factor receptor-derived oncogenes (ZNF198-FGFR1, Bcr-PDGFR&#945;, etc.). We are able to model and study a human-like disease in our mouse model, by transplanting bone marrow cells previously infected with a retrovirus expressing the oncogene of interest. Replication-defective retrovirus encoding a human oncogene and a marker (GFP, RFP, antibiotic resistance gene, etc.) is produced by a transient transfection protocol using 293T cells, a human renal epithelial cell line transformed by the adenovirus E1A gene product. 293 cells have the unusual property of being highly transfectable by calcium phosphate (CaPO4), with up to 50-80% transfection efficiency readily attainable. Here, we co-transfect 293 cells with a retroviral vector expressing the oncogene of interest and a plasmid that expresses the gag-pol-env packaging functions, such as the single-genome packaging constructs kat or pCL, in this case the EcoPak plasmid. The initial transfection is further improved by use of chloroquine. Stocks of ecotropic virus, collected as culture supernatant 48 hrs. post-transfection, can be stored at -80&deg;C and used for infection of cell-lines in view of transformation and in vitro studies, or primary cells such as mouse bone marrow cells, that can then be used for transplant in our mouse model.

This technique demonstrates an efficient way to prepare replication-defective retroviral stocks encoding a human oncogene, and subsequently used for induction of myeloproliferative disease in the mouse model.

瞬时转染293T细胞复制缺陷型逆转录病毒生产

Our lab studies human myeloproliferative diseases induced by such oncogenes as Bcr-Abl or growth factor receptor-derived oncogenes (ZNF198-FGFR1, ...

Intranuclear Microinjection of DNA into Dissociated Adult Mammalian Neurons

Primary neuronal cell cultures are valuable tools to study protein function since they represent a more biologically relevant system compared to immortalized cell lines. However, the post-mitotic nature of primary neurons prevents effective heterologous protein expression using common procedures such as electroporation or chemically-mediated transfection. Thus, other techniques must be employed in order to effectively express proteins in these non-dividing cells.
In this article, we describe the steps required to perform intranuclear injections of cDNA constructs into dissociated adult sympathetic neurons. This technique, which has been applied to different types of neurons, can successfully induce heterologous protein expression. The equipment essential for the microinjection procedure includes an inverted microscope to visualize cells, a glass injection pipet filled with cDNA solution that is connected to a N2(g) pressure delivery system, and a micromanipulator. The micromanipulator coordinates the injection motion of microinjection pipet with a brief pulse of pressurized N2 to eject cDNA solution from the pipet tip. 
This technique does not have the toxicity associated with many other transfection methods and enables multiple DNA constructs to be expressed at a consistent ratio. The low number of injected cells makes the microinjection procedure well suited for single cell studies such as electrophysiological recordings and optical imaging, but may not be ideal for biochemical assays that require a larger number of cells and higher transfection efficiencies. Although intranuclear microinjections require an investment of equipment and time, the ability to achieve high levels of heterologous protein expression in a physiologically relevant environment makes this technique a very useful tool to investigate protein function.

Direct intranuclear injection of cDNA is an effective transfection technique for post-mitotic cells. This method provides high levels of heterologous protein expression from single or multiple cDNA constructs and enables protein function to be studied in a physiologically relevant environment with a variety of single cell assays.

游离成年哺乳动物元DNA的细胞核内内微量注射

Primary neuronal cell cultures are valuable tools to study protein function since they represent a more biologically relevant system compared to ...

Differentiation of Embryonic Stem Cells into Oligodendrocyte Precursors

Oligodendrocytes are the myelinating cells of the central nervous system. For regenerative cell therapy in demyelinating diseases, there is significant interest in deriving a pure population of lineage-committed oligodendrocyte precursor cells (OPCs) for transplantation. OPCs are characterized by the activity of the transcription factor Olig2 and surface expression of a proteoglycan NG2. Using the GFP-Olig2 (G-Olig2) mouse embryonic stem cell (mESC) reporter line, we optimized conditions for the differentiation of mESCs into GFP+Olig2+NG2+ OPCs. In our protocol, we first describe the generation of embryoid bodies (EBs) from mESCs. Second, we describe treatment of mESC-derived EBs with small molecules: (1) retinoic acid (RA) and (2) a sonic hedgehog (Shh) agonist purmorphamine (Pur) under defined culture conditions to direct EB differentiation into the oligodendroglial lineage. By this approach, OPCs can be obtained with high efficiency (&gt;80%) in a time period of 30 days. Cells derived from mESCs in this protocol are phenotypically similar to OPCs derived from primary tissue culture. The mESC-derived OPCs do not show the spiking property described for a subpopulation of brain OPCs in situ. To study this electrophysiological property, we describe the generation of spiking mESC-derived OPCs by ectopically expressing NaV1.2 subunit. The spiking and nonspiking cells obtained from this protocol will help advance functional studies on the two subpopulations of OPCs.

We describe a small molecule-based protocol for differentiation of mouse embryonic stem cells into oligodendrocyte precursor cells (OPCs). This protocol generates Olig2+NG2+ OPCs with high efficiency by 30 days of differentiation. We also describe a method to generate "spiking" OPCs that can fire action potentials.

胚胎干细胞分化成少突胶质前体

Oligodendrocytes are the myelinating cells of the central nervous system. For regenerative cell therapy in demyelinating diseases, there is significant ...

Xenotransplantation of Human Stem Cells into the Chicken Embryo

The chicken embryo is a classical animal model for studying normal embryonic and fetal development and for xenotransplantation experiments to study the behavior of cells in a standardized in vivo environment. The main advantages of the chicken embryo include low cost, high accessibility, ease of surgical manipulation and lack of a fully developed immune system. Xenotransplantation into chicken embryos can provide valuable information about cell proliferation, differentiation and behavior, the responses of cells to signals in defined embryonic tissue niches, and tumorigenic potential. Transplanting cells into chicken embryos can also be a step towards transplantation experiments in other animal models. Recently the chicken embryo has been used to evaluate the neurogenic potential of human stem and progenitor cells following implantation into neural anlage1-6. In this video we document the entire procedure for transplanting human stem cells into the developing central nervous system of the chicken embryo. The procedure starts with incubation of fertilized eggs until embryos of the desired age have developed. The eggshell is then opened, and the embryo contrasted by injecting dye between the embryo and the yolk. Small lesions are made in the neural tube using microsurgery, creating a regenerative site for cell deposition that promotes subsequent integration into the host tissue. We demonstrate injections of human stem cells into such lesions made in the part of the neural tube that forms the hindbrain and the spinal cord, and into the lumen of the part of the neural tube that forms the brain. Systemic injections into extraembryonic veins and arteries are also demonstrated as an alternative way to deliver cells to vascularized tissues including the central nervous system. Finally we show how to remove the embryo from the egg after several days of further development and how to dissect the spinal cord free for subsequent physiological, histological or biochemical analyses.

In this paper we present a method for transplanting human stem cells into various regions of the central nervous system of the chicken embryo. This provides an in vivo model for assessing the proliferation and differentiation of various types of human stem cells in embryonic tissue environments.

人类干细胞异种移植到鸡胚

The chicken embryo is a classical animal model for studying normal embryonic and fetal development and for xenotransplantation experiments to study the ...

Analyzing the Function of Small GTPases by Microinjection of Plasmids into Polarized Epithelial Cells

Epithelial cells polarize their plasma membrane into biochemically and functionally distinct apical and basolateral domains where the apical domain faces the 'free' surfaces and the basolateral membrane is in contact with the substrate and neighboring cells. Both membrane domains are separated by tight junctions, which form a diffusion barrier. Apical-basolateral polarization can be recapitulated successfully in culture when epithelial cells such as Madin-Darby Canine Kidney (MDCK) cells are seeded at high density on polycarbonate filters and cultured for several days 1 2. Establishment and maintenance of cell polarity is regulated by an array of small GTPases of the Ras superfamily such as RalA, Cdc42, Rab8, Rab10 and Rab13 3 4 5 6 7. Like all GTPases these proteins cycle between an inactive GDP-bound state and an active GTP-bound state. Specific mutations in the nucleotide binding regions interfere with this cycling 8. For example, Rab13T22N is permanently locked in the GDP-form and thus dubbed 'dominant negative', whereas Rab13Q67L can no longer hydrolyze GTP and is thus locked in a 'dominant active' state 7. To analyze their function in cells both dominant negative and dominant active alleles of GTPases are typically expressed at high levels to interfere with the function of the endogenous proteins 9. An elegant way to achieve high levels of overexpression in a short amount of time is to introduce the plasmids encoding the relevant proteins directly into the nuclei of polarized cells grown on filter supports using microinjection technique. This is often combined with the co-injection of reporter plasmids that encode plasma membrane receptors that are specifically sorted to the apical or basolateral domain. A cargo frequently used to analyze cargo sorting to the basolateral domain is a temperature sensitive allele of the vesicular stomatitis virus glycoprotein (VSVGts045) 10. This protein cannot fold properly at 39&deg;C and will thus be retained in the endoplasmic reticulum (ER) while the regulatory protein of interest is assembled in the cytosol. A shift to 31&deg;C will then allow VSVGts045 to fold properly, leave the ER and travel to the plasma membrane 11. This chase is typically performed in the presence of cycloheximide to prevent further protein synthesis leading to cleaner results. Here we describe in detail the procedure of microinjecting plasmids into polarized cells and subsequent incubations including temperature shifts that allow a comprehensive analysis of regulatory proteins involved in basolateral sorting.

This article details the procedures involved in overexpression and analysis of small GTPases in polarized epithelial cells using microinjection technique.

为极化上皮细胞注射质粒的小GTP酶的功能分析

Epithelial cells polarize their plasma membrane into biochemically and functionally distinct apical and basolateral domains where the apical domain faces ...

Efficient Differentiation of Mouse Embryonic Stem Cells into Motor Neurons

Direct differentiation of embryonic stem (ES) cells into functional motor neurons represents a promising resource to study disease mechanisms, to screen new drug compounds, and to develop new therapies for motor neuron diseases such as spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS). Many current protocols use a combination of retinoic acid (RA) and sonic hedgehog (Shh) to differentiate mouse embryonic stem (mES) cells into motor neurons1-4. However, the differentiation efficiency of mES cells into motor neurons has only met with moderate success. We have developed a two-step differentiation protocol5 that significantly improves the differentiation efficiency compared with currently established protocols. The first step is to enhance the neuralization process by adding Noggin and fibroblast growth factors (FGFs). Noggin is a bone morphogenetic protein (BMP) antagonist and is implicated in neural induction according to the default model of neurogenesis and results in the formation of anterior neural patterning6. FGF signaling acts synergistically with Noggin in inducing neural tissue formation by promoting a posterior neural identity7-9. In this step, mES cells were primed with Noggin, bFGF, and FGF-8 for two days to promote differentiation towards neural lineages. The second step is to induce motor neuron specification. Noggin/FGFs exposed mES cells were incubated with RA and a Shh agonist, Smoothened agonist (SAG), for another 5 days to facilitate motor neuron generation. To monitor the differentiation of mESs into motor neurons, we used an ES cell line derived from a transgenic mouse expressing eGFP under the control of the motor neuron specific promoter Hb91. Using this robust protocol, we achieved 51&plusmn;0.8% of differentiation efficiency (n = 3; p &lt; 0.01, Student's t-test)5. Results from immunofluorescent staining showed that GFP+ cells express the motor neuron specific markers, Islet-1 and choline acetyltransferase (ChAT). Our two-step differentiation protocol provides an efficient way to differentiate mES cells into spinal motor neurons.

We developed a new protocol to improve efficiency of in vitro differentiation of mouse embryonic stem cells into motor neurons. The differentiated ES cells acquired motor neurons features as evidenced by expression of neuronal and motor neuron markers using immunohistochemical techniques.

高效的小鼠胚胎干细胞分化成运动神经元

Direct differentiation of embryonic stem (ES) cells into functional  motor neurons represents a promising resource to study disease mechanisms, to  screen ...

A System for ex vivo Culturing of Embryonic Pancreas

The pancreas controls vital functions of our body, including the production of digestive enzymes and regulation of blood sugar levels1. Although in the past decade many studies have contributed to a solid foundation for understanding pancreatic organogenesis, important gaps persist in our knowledge of early pancreas formation2. A complete understanding of these early events will provide insight into the development of this organ, but also into incurable diseases that target the pancreas, such as diabetes or pancreatic cancer. Finally, this information will generate a blueprint for developing cell-replacement therapies in the context of diabetes.
 During embryogenesis, the pancreas originates from distinct embryonic outgrowths of the dorsal and ventral foregut endoderm at embryonic day (E) 9.5 in the mouse embryo3,4. Both outgrowths evaginate into the surrounding mesenchyme as solid epithelial buds, which undergo proliferation, branching and differentiation to generate a fully mature organ2,5,6. Recent evidences have suggested that growth and differentiation of pancreatic cell lineages, including the insulin-producing &beta;-cells, depends on proper tissue-architecture, epithelial remodeling and cell positioning within the branching pancreatic epithelium7,8. However, how branching morphogenesis occurs and is coordinated with proliferation and differentiation in the pancreas is largely unknown. This is in part due to the fact that current knowledge about these developmental processes has relied almost exclusively on analysis of fixed specimens, while morphogenetic events are highly dynamic.
 Here, we report a method for dissecting and culturing mouse embryonic pancreatic buds ex vivo on glass bottom dishes, which allow direct visualization of the developing pancreas (Figure 1). This culture system is ideally devised for confocal laser scanning microscopy and, in particular, live-cell imaging. Pancreatic explants can be prepared not only from wild-type mouse embryos, but also from genetically engineered mouse strains (e.g. transgenic or knockout), allowing real-time studies of mutant phenotypes. Moreover, this ex vivo culture system is valuable to study the effects of chemical compounds on pancreatic development, enabling to obtain quantitative data about proliferation and growth, elongation, branching, tubulogenesis and differentiation. In conclusion, the development of an ex vivo pancreatic explant culture method combined with high-resolution imaging provides a strong platform for observing morphogenetic and differentiation events as they occur within the developing mouse embryo.

A System for ex vivo Culturing of Embryonic Pancreas

Here, we describe a method for isolation, culture and manipulation of mouse embryonic pancreas. This represents an excellent ex vivo system for studying various aspects of pancreatic development, including morphogenesis, differentiation and growth. Pancreatic bud explants can be cultured for several days and used in a range of different applications, including whole-mount immunofluorescence and live imaging.

一个系统<em&gt;体外</em培养的胚胎胰腺

The pancreas controls vital functions of our body,  including the production of digestive enzymes and regulation of blood sugar  levels1. Although in the ...

Gene Transfer into Older Chicken Embryos by ex ovo Electroporation

The chicken embryo provides an excellent model system for studying gene function and regulation during embryonic development. In ovo electroporation is a powerful method to over-express exogenous genes or down-regulate endogenous genes in vivo in chicken embryos1. Different structures such as DNA plasmids encoding genes2-4, small interfering RNA (siRNA) plasmids5, small synthetic RNA oligos6, and morpholino antisense oligonucleotides7 can be easily transfected into chicken embryos by electroporation. However, the application of in ovo electroporation is limited to embryos at early incubation stages (younger than stage HH20 - according to Hamburg and Hamilton)8 and there are some disadvantages for its application in embryos at later stages (older than stage HH22 - approximately 3.5 days of development). For example, the vitelline membrane at later stages is usually stuck to the shall membrane and opening a window in the shell causes rupture of the vessels, resulting in death of the embryos; older embryos are covered by vitelline and allantoic vessels, where it is difficult to access and manipulate the embryos; older embryos move vigorously and is difficult to control the orientation through a relatively small window in the shell.
In this protocol we demonstrate an ex ovo electroporation method for gene transfer into chicken embryos at late stages (older than stage HH22). For ex ovo electroporation, embryos are cultured in Petri dishes9 and the vitelline and allantoic vessels are widely spread. Under these conditions, the older chicken embryos are easily accessed and manipulated. Therefore, this method overcomes the disadvantages of in ovo electroporation applied to the older chicken embryos. Using this method, plasmids can be easily transfected into different parts of the older chicken embryos10-12.

Gene Transfer into Older Chicken Embryos by ex ovo Electroporation

A method of gene transfer into chicken embryos at later incubation stages (older than Hamburger and Hamilton stage (HH) 22) is described. This method overcomes disadvantages of in ovo electroporation applied to older chicken embryos and is a useful technique to study gene function and regulation at older developmental stages.

基因转移到老年人的鸡胚<em&gt;前OVO</em&gt;电穿孔

The chicken embryo provides an  excellent model system for studying gene function and regulation during  embryonic development. In ovo electroporation is ...

Dissecting Mechanoenzymatic Properties of Processive Myosins with Ultrafast Force-Clamp Spectroscopy

Ultrafast force-clamp spectroscopy (UFFCS) is a single molecule technique based on laser tweezers that allows the investigation of the chemomechanics of both conventional and unconventional myosins under load with unprecedented time resolution. In particular, the possibility to probe myosin motors under constant force right after the actin-myosin bond formation, together with the high rate of the force feedback (200 kHz), has shown UFFCS to be a valuable tool to study the load dependence of fast dynamics such as the myosin working stroke. Moreover, UFFCS enables the study of how processive and non-processive myosin-actin interactions are influenced by the intensity and direction of the applied force.
By following this protocol, it will be possible to perform ultrafast force-clamp experiments on processive myosin-5 motors and on a variety of unconventional myosins. By some adjustments, the protocol could also be easily extended to the study of other classes of processive motors such as kinesins and dyneins. The protocol includes all the necessary steps, from the setup of the experimental apparatus to sample preparation, calibration procedures, data acquisition and analysis.

Presented here is a comprehensive protocol to perform ultrafast force-clamp experiments on processive myosin-5 motors, which could be easily extended to the study of other classes of processive motors. The protocol details all the necessary steps, from the setup of the experimental apparatus to sample preparation, data acquisition and analysis.

超快力钳谱分析合成性肌球蛋白的机械酶学特性

Ultrafast force-clamp spectroscopy (UFFCS) is a single molecule technique based on laser tweezers that allows the investigation of the chemomechanics of ...