对于荧光DNA的简易方法<em>原位</em>杂交来压扁染色体
Summary
Here, we present a simple method for performing fluorescence DNA in situ hybridization (DNA ISH) to visualize repetitive heterochromatic sequences on slide-mounted chromosomes. The method requires minimal reagents and it is versatile for use with short or long probes, different tissues, and detection with fluorescence or non-fluorescence-based signals.
Abstract
原位杂交（ISH的DNA）的DNA是一种常用的方法进行映射的序列，以特定的染色体区域。这种方法是在映射高度重复序列，以异染色质区域，其中，计算方法面临令人望而却步的挑战特别有效。在这里，我们描述了一个精简的协议，用于DNA ISH是规避洗甲酰胺是在其他DNA ISH协议的标准步骤。我们的协议被优化用于与携带荧光染料，从而有效地标记在多个不同的昆虫组织类型的异色染色体区域内的重复DNA序列的短单链DNA探针杂交。然而，应用程序可被扩展较大探针和单拷贝（非重复）的DNA序列的可视化中使用。我们证明了该方法通过映射几个不同的重复序列从果蝇染色体挤压神经果蝇细胞和金小蜂vitripennis精母细胞。我们表明杂交模式均小，商业合成的探针和用于比较的较大探针。此过程使用简单的实验室耗材和试剂，是理想的谁与执行DNA ISH一点经验调查。
Introduction
原位杂交（ISH的DNA）的DNA是一种常用的方法进行映射的序列，以特定的染色体区域。可以通过少数的方法，包括缺口转译或长DNA产物1,2-末端标记和deoxygenin（DIG）的掺入-attached核苷酸及其识别通过各种各样的产生内常染色质探针，以单拷贝区基的缀合抗体1-3。在几个或单拷贝数常染色体序列的可视化需要使用任何单一的大型探测器具有高比活或多个较小的探针共同增强信号的鸡尾酒。
与此相反，在异发现高度重复序列，诸如卫星的DNA，是用于DNA ISH更容易的目标，因为它们通常作为几十到重复聚集在被称为块的单染色体区域的数千存在。转座元件也可以是在不同的时染色体位点2个高拷贝数发现。在这些情况下，单个探针具有低比活性可以有效标记异色序列由于在多个位点的杂交。探针的重复序列可被合成市售的短的寡核苷酸（30-50碱基对）和化学缀合与任何多种不同的荧光团。通过基因组测序技术绘制内异染色质重复序列是困难的，因为在高度重复的卫星模块4-6,7建筑脚手架遇到的挑战。目前，ISH站作为在子染色体水平映射这些序列的最有效的方法。这种策略是映射大批正在通过发现正在进行的基因组和转录组测序研究的重复序列的重要。
映射重复序列上滑动安装染色体的效率和易于将选取gre通过对DNA ISH简化协议atly增强。例如，对于DNA的ISH现有的协议涉及杂交的组织中的甲酰胺溶液2,8-多次洗涤，从而增加大致映射序列所需的时间，也产生这种昂贵试剂的大量化学废物。在这里，我们描述了一个修订后的DNA ISH方法规避，需要甲酰胺清洗，并利用基本的实验室设备和试剂。该方法最初是通过使用缀合有荧光染料商业合成的寡核苷酸设计为在果蝇幼虫的神经母细胞异染色质区域高度重复的DNA序列的快速映射。但是，这种方法也适用于通过使用通过其他方式9,10和跨多个不同的组织和染色体类型合成更大的探针映射重复序列。此外，此方法可用于通过使用较长或MULTIP映射常染色质的序列乐，感兴趣的常染色体序列中短探针。
Protocol
Representative Results
Discussion
DNA的原位杂交是经常用于映射特定序列的染色体。我们描述了一个简单的方法DNA ISH高拷贝数，异色序列优化。而不是使用洗涤的甲酰胺溶液中，这是在其他现有的DNA ISH协议的要求，我们直接放置在预加热块组织安装滑动到使DNA变性。这种方法绕过了使用大量的甲酰胺。用于产生脆的杂交信号的一个关键步骤是使用新鲜制备的固定溶液;如果不这样做（或者使用多聚甲醛是已经开放超过一个月新溶…
Disclosures
The authors have nothing to disclose.
Acknowledgements
We thank Zhaohua Irene Tang in the W. M. Keck Science Department for the use of her epifluorescence microscope and the Werren lab for donating Nasonia for dissections. This work was supported in part by an NIH-NRSA fellowship (5F32GM105317-02) to AML.
Materials
| Company | |
| Materials | |
| Poly-L-lysine coated slides (regular slides also can be used) | Sigma Aldrich |
| Ultrafine tweezers (5 gauge) | Dumont |
| 22mmx22mm cover slips, Sigmacote-treated by immersion for 15 seconds, blotting dry, and wiping away all traces of Sigmacote so that cover slip is clear | Fisher |
| Sigmacote | Sigma |
| Filter paper (75-150mm) | |
| Paraffin wax paper | |
| Heat block with thermometer | |
| Dry incubator | |
| Razor blades | |
| Humidity chamber (empty pipette tip box or Tupperware, lined with moistened paper towels or Kimwipes) | |
| Coplin jars (with slide grooves) | |
| Aluminum foil | |
| Pasteur pipettes | |
| 1.5 mL microfuge tubes | |
| Nail polish (clear or colored) | |
| 2-20 μL micropipette and plastic tips | |
| 20-25 standard metal paperclips linked to form a chain | |
| Company/Notes | |
| Reagents | |
| 16% EM grade paraformaldehyde | Electron Microscopy Reagents |
| Acetic acid | Sigma |
| Liquid nitrogen | |
| 100% Ethanol, chemical grade | |
| Commercially synthesized, fluorescently labeled oligos | |
| Long biotinylated probe (e.g. nick translated and biotinylated with BioNick from Invitrogen) | Invitrogen; Alternative steps 2.7.1-2.7.3 |
| Rhodamine-Avidin (for detection of long biotinylated probe) | Roche; Alternative steps 2.7.1-2.7.3 |
| Hybridization buffer | Recipe below |
| 4X SSCT (Saline-sodium citrate + Tween) | Recipe below |
| 0.1X SSC (Saline-sodium citrate) | Recipe below |
| Blocking solution | Recipe below |
| SBT (SSC, Bovine serum albumin, Tween) | Recipe below |
| 1X PBT (Phosphate-buffered saline + Tween) | Recipe below |
| 1X PBS (Phosphate-buffered saline) | |
| Hypotonic solution (0.5% sodium citrate in H2O) | |
| Formamide | Sigma Aldrich |
| Vectashield mounting medium with DAPI | Vector laboratories |
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