| Generation of Gene Knockout and Gene Replacement with Complete Removal of Full-length Endogenous Transcript Using CRISPR-Trap
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Author:
Date:
2018-10-20
[Abstract] This protocol describes the application of the CRISPR-Trap from designing of the gene targeting strategy to validation of successfully edited clones that was validated on various human cell lines, among them human induced pluripotent stem cells (hiPSCs). The advantage of CRISPR-Trap over conventional approaches is the complete removal of any endogenous full-length transcript from the target gene. CRISPR-Trap is applicable for any target gene with no or little coding sequence in its first exon. Several human cell lines and different genes have so far been edited successfully with CRISPR-Trap.
[摘要] 该协议描述了CRISPR-Trap从设计基因靶向策略到验证成功编辑的克隆的应用，所述克隆在各种人细胞系上得到验证，其中人类诱导的多能干细胞（hiPSC）。 CRISPR-Trap优于常规方法的优点是从靶基因完全去除任何内源全长转录物。 CRISPR-Trap适用于在其第一个外显子中没有编码序列或编码序列很少的任何靶基因。 到目前为止，已经使用CRISPR-Trap成功编辑了几种人细胞系和不同基因。
【背景】CRISPR / Cas9技术的出现促进了基因敲除和基因编辑的基因组靶向。执行敲除的常规方法依赖于引入移码导致过早终止密码子（PTC），截短开放阅读框（ORF）以及随后通过无义介导的mRNA衰变（NMD）降解靶基因的转录物。 。这种方法的一个可能的缺陷是全长转录物，其可以逃避NMD并产生具有残余或甚至显性负功能的C末端截短蛋白。该协议提出了CRISPR-Trap，这是我们最近建立的一种方法（Reber et al。>，2018），成功编辑后将阻止从靶基因位点表达任何全长转录本（图1）。简而言之，这种方法针对CRISPR / ...
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| Bacterial Cell Wall Precursor Phosphatase Assays Using Thin-layer Chromatography (TLC) and High Pressure Liquid Chromatography (HPLC)
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Author:
Date:
2018-03-20
[Abstract] Peptidoglycan encases the bacterial cytoplasmic membrane to protect the cell from lysis due to the turgor. The final steps of peptidoglycan synthesis require a membrane-anchored substrate called lipid II, in which the peptidoglycan subunit is linked to the carrier lipid undecaprenol via a pyrophosphate moiety. Lipid II is the target of glycopeptide antibiotics and several antimicrobial peptides, and is degraded by ‘attacking’ enzymes involved in bacterial competition to induce lysis. Here we describe two protocols using thin-layer chromatography (TLC) and high pressure liquid chromatography (HPLC), respectively, to assay the digestion of lipid II by phosphatases such as Colicin M or the LXG toxin protein TelC from Streptococcus intermedius. The TLC method can also monitor the ...
[摘要] 肽聚糖包裹细菌细胞质膜以保护细胞免于因膨胀而导致的溶解。 肽聚糖合成的最后步骤需要称为脂质II的膜锚定底物，其中肽聚糖亚基通过焦磷酸部分连接至载体脂质十一碳烯醇。 脂质II是糖肽抗生素和几种抗微生物肽的靶标，并且通过参与细菌竞争的“攻击”酶来降解以诱导裂解。 在这里，我们分别描述了两种使用薄层色谱法（TLC）和高压液相色谱法（HPLC）的方案来测定磷脂酶如Colicin M或来自中间链球菌的LXG毒素蛋白TelC对脂质II的消化，的。 TLC方法也可以监测十一异戊二烯基（pyro）磷酸盐的消化，而HPLC方法允许分离脂质II的二 - ，单 - 或非磷酸化二糖五肽产物。
【背景】肽聚糖（PG）球囊是一种必需的细菌大分子，它可以保护细胞免受由于其膨胀引起的破裂并保持细胞的形状（Vollmer和Bertsche，2008; Typas等人，2012）。 PG由通过短肽连接的聚糖链组成。来自不同物种的PG在肽的结构和二级修饰的存在方面有所不同（Vollmer等人，2008）。 ...
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| Assay of Arabinofuranosidase Activity in Maize Roots
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Author:
Date:
2016-03-20
[Abstract] Root is a perfect model for studying the mechanisms of plant cell growth. Along the root length, several zones where cells are at different stages of development can be visualized (Figure 1). The dissection of the root on these zones allows the investigation of biochemical and genetic aspects of different growth steps. Maize primary root is much more massive than the root of other Monocots and thus more convenient for such type of research. Plant cell wall, mainly consisting of polysaccharides, plays an important role in plant life. Therefore, measurement of plant carbohydrate content and glycoside-modifying enzyme activity in plant cells has become an important aspect in plant physiology. One of the well-documented changes of hemicelluloses molecules during elongation growth of monocots ...
[摘要] 根是研究植物细胞生长机制的完美模型。沿着根长度，可以可视化细胞处于不同发育阶段的几个区（图1）。在这些区域上的根的解剖允许调查不同生长步骤的生化和遗传方面。玉米主根比其他单根的根更大，因此这种类型的研究更方便。植物细胞壁，主要由多糖组成，在植物生活中发挥重要作用。因此，植物碳水化合物含量和糖苷修饰酶活性在植物细胞中的测量已经成为植物生理学中的重要方面。在单子叶植物细胞的延长生长期间半纤维素分子的充分证明的变化之一是葡糖醛酸阿拉伯木聚糖的阿拉伯糖取代的减少。这可能是由于该多糖的合成的变化或阿拉伯呋喃糖苷酶的作用引起的。在这里，我们描述的分光光度测量阿拉伯呋喃糖苷酶活性在玉米根中的水解发色底物（4-硝基苯基α-L-阿拉伯呋喃糖苷）的速率的协议。
图1. 四日龄黑暗生长的玉米幼苗面板）。根据Kozlova等人（2012）（右图），初级玉米根的不同区和细胞发育的相应阶段。
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