| Preparation of Drosophila Polytene Chromosomes, Followed by Immunofluorescence Analysis of Chromatin Structure by Multi-fluorescence Correlations
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Author:
Date:
2020-07-05
[Abstract] Drosophila larval salivary gland polytene chromosome squashes have been used for decades to analyze genome-wide protein-binding patterns, transcriptional activation processes, and changes in chromatin structure at specific genetic loci. There have been many evolutions of the squashing protocol over the years, with sub-optimal reproducibility and low sample success rate as accepted caveats. However, low sample success rates are an obvious disadvantage when polytene chromosomes are used for more high-throughput approaches, such as genetic or antibody screens, or for experiments requiring high-quality chromosome structure preservation. Here we present an exceptionally reproducible squashing and fluorescence staining protocol, which generates high-quality fluorescence images on ...
[摘要] [摘要] 果蝇几十年来，幼虫唾液腺多线染色体压片被用来分析全基因组蛋白质结合模式、转录激活过程以及特定基因位点染色质结构的变化。在过去的几年中，压榨方案已经有了许多改进，次优的重复性和较低的样本成功率是公认的警告。然而，当多线染色体用于更高通量的方法，如遗传或抗体筛查，或用于需要高质量染色体结构保存的实验时，低样本成功率是一个明显的缺点。在这里，我们提出了一个特别可重复的挤压和荧光染色协议，它可以在扩散良好的染色体上生成高质量的荧光图像。接下来是我们的新的、半自动的MATLAB分析程序，用于以逐像素的方式确定多线染色体上单个位点上感兴趣的荧光信号之间的相关性。在我们的案例中，我们已经用这种方法来评估染色体在基因组位点的变化，这些位点被核孔蛋白的异位靶向。我们的分析程序的使用提高了对染色质结构的变化或染色质的蛋白质补充的无偏结论的能力，而不考虑免疫荧光染色的样本变化。由于它只是基于特定位置的荧光强度的差异，因此所提供的分析程序不局限于对多线染色体的分析，并且可以应用于许多不同的上下文中，其中任何特定位置的荧光信号之间的相关性是感兴趣的。
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| Preparation of Precisely Oriented Cryosections of Undistorted Drosophila Wing Imaginal Discs for High Resolution Confocal Imaging
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Author:
Date:
2018-02-05
[Abstract] The combination of immunofluorescence and laser scanning confocal microscopy (LSM) is essential to high-resolution detection of molecular distribution in biological specimens. A frequent limitation is the need to image deep inside a tissue or in a specific plane, which may be inaccessible due to tissue size or shape. Recreating high-resolution 3D images is not possible because the point-spread function of light reduces the resolution in the Z-axis about 3-fold, compared to XY, and light scattering obscures signal deep in the tissue. However, the XY plane of interest can be chosen if embedded samples are precisely oriented and sectioned prior to imaging (Figure 1). Here we describe the preparation of frozen tissue sections of the Drosophila wing imaginal disc, which allows us to ...
[摘要] 免疫荧光和激光扫描共聚焦显微镜（LSM）的组合是高分辨率检测生物样品中分子分布的关键。频繁的限制是需要在组织内或在特定的平面深处进行成像，这可能由于组织大小或形状而不可接近。因为与XY相比，光的点扩散函数将Z轴的分辨率降低了约3倍，并且光散射使组织中的深层信号模糊，所以不可能重新创建高分辨率3D图像。然而，如果嵌入的样品在成像之前被精确地定向和切片，则可以选择感兴趣的XY平面（图1）。在这里，我们描述的果蝇翅成像光盘的冰冻组织切片的准备，这使得我们能够获得高分辨率的图像，在整个这个折叠上皮的深度。
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图1.上皮结构和未畸变的折叠模式在发育果蝇翅膀的这个冰冻部分的整个深度中都被揭示出来。通过机翼囊横向背腹节。 A.冷冻切片显示贯穿上皮深度的信号的α-连环蛋白（A'，A“，洋红色）的细胞核（A，绿色）和亚细胞分布。基底表面清晰可辨（箭头）。 A是“A的数字增强图像”。 B.在显示为XZ正交视图的自顶向下视图中收集的图像的Z-堆叠揭示了α-连环蛋白（B'，B“）甚至数字增强图像（B”）的细胞核（B）但很少可辨别的细节。未能揭示基底上皮表面（箭头）。 ...
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