| Quantification of Protein Kinase A (PKA) Activity by An in vitro Radioactive Assay Using the Mouse Sperm Derived Enzyme
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Author:
Date:
2020-06-20
[Abstract] In order to acquire fertilizing potential, mammalian sperm must undergo a process known as capacitation, which relies on the early activation of Protein Kinase A (PKA). Frequently, PKA activity is assessed in whole-cell experiments by analyzing the phosphorylation status of its substrates in a western-blot. This technique faces two main disadvantages: it is not a direct measure of the kinase activity and it is a time-consuming approach. However, since PKA can be readily obtained from sperm extracts, in vitro assays such as the “radioactive assay” can be performed using the native enzyme. Unlike western-blot, the radioactive assay is a straightforward technique to evaluate PKA activity by quantification of incorporated 32P into a peptidic ...
[摘要] [Abstract]为了获得受精潜能，哺乳动物的精子必须经历一个被称为电容的过程，这个过程依赖于蛋白激酶A（PKA）的早期激活。通常，在全细胞实验中，通过分析其底物在western-blot中的磷酸化状态来评估PKA的活性。这种技术面临着两个主要的缺点：它不是对激酶活性的直接测量，而且是一种耗时的方法。然而，由于PKA可以很容易地从精子提取物中获得，体外检测如"放射性检测"可以使用原生酶进行。与western-blot不同的是，放射性测定法是一种直接的技术，通过将整合的32P定量到肽类底物中来评价PKA的活性。这种方法很容易允许分析PKA的不同激动剂或拮抗剂。由于小鼠精子是可溶性PKA的丰富来源，这种测定法可以进行简单的分馏，使PKA既可用于体外测试药物对PKA活性的影响，也可用于跟踪PKA活性在增容开始时的变化。
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| Host-regulated Hepatitis B Virus Capsid Assembly in a Mammalian Cell-free System
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Author:
Date:
2018-04-20
[Abstract] The hepatitis B virus (HBV) is an important global human pathogen and represents a major cause of hepatitis, liver cirrhosis and liver cancer. The HBV capsid is composed of multiple copies of a single viral protein, the capsid or core protein (HBc), plays multiple roles in the viral life cycle, and has emerged recently as a major target for developing antiviral therapies against HBV infection. Although several systems have been developed to study HBV capsid assembly, including heterologous overexpression systems like bacteria and insect cells, in vitro assembly using purified protein, and mammalian cell culture systems, the requirement for non-physiological concentrations of HBc and salts and the difficulty in manipulating host regulators of assembly presents major limitations ...
[摘要] 乙型肝炎病毒（HBV）是一种重要的全球人类病原体，并且是肝炎，肝硬化和肝癌的主要原因。 HBV衣壳由单个病毒蛋白的多个拷贝组成，衣壳或核心蛋白（HBc）在病毒生命周期中起着多重作用，并且最近已经成为开发抗HBV病毒疗法的主要靶标。尽管已经开发了几种用于研究HBV衣壳组装的系统，包括异源过表达系统如细菌和昆虫细胞，使用纯化蛋白质和哺乳动物细胞培养系统进行体外组装，但对非生理浓度HBc和盐以及难以操纵装配的宿主调节物在生理相关条件下的衣壳装配的详细研究方面存在主要限制。我们最近开发了基于兔网织红细胞裂解物（RRL）的哺乳动物无细胞系统，其中HBc以生理浓度表达并在近生理条件下组装成衣壳。该系统已经揭示了HBc装配要求，这是以前装配系统所不能预料的。此外，该系统中的衣壳组装受可容易操作的内源宿主因子调控。在这里，我们提供了这种无细胞衣壳装配系统的详细协议，包括如何操纵调节装配的宿主因子的说明。
【背景】乙型肝炎病毒（HBV）是一种重要的全球人类病原体，其长期感染全世界数以亿计的人并且代表病毒性肝炎，肝硬化和肝癌的主要原因（Seeger等人， 2013; Trepo et。，2014）。 HBV通过逆转录RNA中间体（所谓的前基因组RNA（pgRNA））在核衣壳内（NC）复制其基因组DNA（一种宽松的环状部分双链DNA（RC ...
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