提高吞吐量的轰击大麦糊粉层层中基因表达的测定
Summary
提出了一种改进的协议, 用于测量粒子轰击后大麦糊粉层细胞中的瞬时基因表达。采用全自动谷物研磨与96井板酶检测相结合, 为该过程提供了较高的吞吐量。
Abstract
大麦籽粒糊粉层层是植物激素调控基因表达的重要模型体系。在糊粉层细胞中, 萌发或早期幼苗发育所需的基因由赤霉素 (GA) 激活, 而与应激反应相关的基因则由脱落酸 (ABA) 激活。通过粒子轰击引入糊粉层细胞的基因构造, 可以对 GA 和 ABA 信号的机制进行审问, 并利用酶法测定结果的瞬态表达。报告了一种改进的协议, 部分自动化和简化了谷物均匀化步骤和酶的测定, 使吞吐量大大超过现有方法。采用全自动组织均质器进行谷物样品的均匀化, 用96井板系统进行 GUS (β glucuronidase) 测定。使用该协议的代表性结果表明, 磷脂酶 D 活性可以发挥重要作用, 激活HVA1基因表达的 ABA, 通过转录因子 TaABF1。
Introduction
大麦糊粉层层是植物激素调控基因表达研究的一个成熟的模型系统1。特别是, 一些需要发芽或早期幼苗发育的基因由赤霉素 (GA) 激活, 而与应激反应相关的基因则由脱落酸 (ABA) 激活。ga 和 aba 信号通路是交织在一起的, 因为一些 ga 激活基因的表达被 ABA 抑制, 反之亦然1。
了解特定行为者在 GA/ABA 信号中的作用的一个有价值的策略是通过粒子轰击引入效应基因构造, 接着是记者构造的瞬态表达, 从而使结果影响下游基因表达的确定。使用报告基因, 如GUS (β-glucuronidase) 或荧光素酶允许对基因表达式的敏感和定量测量, 特别是在接收到效应器结构的细胞内。例如, 引入了一个对转录因子 TaABF15,6编码的效应器构造, 它建立了 ABA 诱导的基因, 如HVA1是由 TaABF1 诱导的, 而 GA 诱导的基因, 如Amy32b被压抑。粒子轰击作为一种实验策略已被多个实验室用来研究遗传/ABA 信号的不同方面。这项工作已导致识别启动子元素重要的激活两个 GA 诱导的2和 ABA 诱导的基因3, 并发现蛋白激酶4和转录因子5 , 调节这些基因的表达。
现有协议2,3,4,5,6为粒子轰击和随后的瞬态基因表达测量是相当劳动密集型的, 因为每套轰炸在砂浆和杵中, 几乎没有谷物是均匀的, 酶的测定是单独进行的。这篇手稿报告了一个改进的协议, 部分自动化和优化均匀化步骤和 GUS 化验, 以允许大量的吞吐量, 允许更多的治疗在同一实验中测试, 和/或包含更多的复制, 每种治疗获得更有统计学意义的结果。代表的结果显示为HVA1和Amy32b报告器构造的表达式, 由转录因子 TaABF1 以及 GA、ABA 和其他调控分子调控。
Protocol
1. 效应器和报告基因构造的制备 构建使用本构启动子 (如玉米泛素, UBI) 的效应器构造, 以从所需的开放阅读框架中驱动表达式。例如, 构造一个包含UBI::TaABF1的质粒, 以驱动 TaABF15的强本构表达式。 生成包括要测量其活动的启动器的报告器结构, 放置在打开的阅读框架的上游, 如GUS。例如, 构造一个包含HVA1::GUS的质粒, 用于测量从HVA1?…
Representative Results
本文所描述的技术可用于将任何试验基因结构引入大麦籽粒的糊粉层细胞中。然后可以方便地测量测试基因的表达水平 (图 2)。这里描述的高吞吐量协议大大提高了种子研磨和酶测定步骤的效率。该方法已用于评估转录因子 TaABF15、6的能力, 以激活 ABA 诱导的基因HVA17的表达。在这里…
Discussion
通过粒子轰击引入效应基因构造, 其次是记者构造的瞬态表达, 是解剖特定行为者在 GA/ABA 信号中的作用以及由此产生的激素调控基因的宝贵策略。表达.
然而, 在大麦糊粉层单元格中进行此类实验的现有 协议2, 3, 4, 5, 6 是非常劳力密集.每组被轰击的颗粒必须在砂浆和杵中手…
Declarações
The authors have nothing to disclose.
Acknowledgements
作者感谢格雷松巴特勒和玛格丽特-巴雷特帮助进行实验, 朱迪石头的建议谷物均匀化, 和林恩汉努姆征求意见的荧光。这项工作得到了国家科学基金会 (IOB 0443676) 的支持, 由国立卫生研究院国立医学研究院颁发的机构发展奖 (P20GM0103423), 以及赠款来自科尔比学院自然科学分部。
Materials
| GeneElute HP plasmid Maxiprep kit | Sigma | NA0310-1KT | |
| UV-vis spectrophotometer | Nanodrop | ND-1000 | |
| Himalaya barley grains | / | / | A variety of hulless barley (store in the dark at 4° C) |
| sodium succinate | Sigma | S2378 | Reagent for Imbibing Solution |
| calcium chloride (dihydrate) | Fisher | C79-500 | Reagent for Imbibing Solution |
| Imbibing Solution | home made | / | 20 mM sodium succinate, 20 mM calcium chloride, pH 5.0. Sterilize by autoclaving before use. |
| chloramphenicol | Sigma | C0378 | Prepare a 10 mg/mL stock solution in 70% ethanol. |
| vermiculite | Fisher | NC0430369 | Used for vermiculite plates. |
| filter paper circles (90 mm) | Whatman | 1001 090 | Used for vermiculite and for pre-bombardment grain preparation |
| Vermiculite Plates | home made | / | Add 50 mL of vermiculite to a glass petri dish. Place a 90 mm paper circle on top of the vermiculite. Autoclave. |
| forceps (fine pointed) | Fisher | 13-812-42 | Used for removing seed coat from barley grains. |
| forceps (ultra fine point) | Fisher | 12-000-122 | Used for removing seed coat from barley grains. |
| gold microcarriers (1.6 μm) | BioRad | 1652264 | |
| macrocarriers | BioRad | 1652335 | |
| calcium chloride (dihydrate) | Fisher | C79-500 | Prepare a 2.5 M stock solution and store 1 mL aliquots at -20° C. |
| spermidine | Sigma | S0266 | Prepare a 100 mM stock solution and store 500 μL aliquots at -20° C (use within 2 months). |
| rupture discs (1550 psi) | BioRad | 1652331 | |
| stopping screens | BioRad | 1652336 | |
| macrocarrier holders | BioRad | 1652322 | |
| Biolistic particle delivery system | BioRad | PDS-1000/He | |
| sodium phosphate monobasic monohydrate | Sigma | S9638 | Reagent for 1M sodium phosphate pH 7.2 |
| sodium phosphate dibasic | Sigma | S9763 | Reagent for 1M sodium phosphate pH 7.2 |
| 1M sodium phosphate pH 7.2 | home made | / | Combine 6.9 g of sodium phosphate monobasic monohydrate with 7.1 g of sodium phosphate dibasic. Add water to 100 mL. Add NaOH to get pH 7.2. |
| dithiothrietol (DTT) | Sigma | 43819 | Dissolve in water to 1 M. Store at -20° in 1 mL aliquots. |
| leupeptin | Sigma | L2884 | Dissolve in water to 10 mg/mL. Store at -20° C. |
| glycerol | Sigma | G5516 | Prepare a 50% solution in water. |
| Grinding Buffer | home made | / | Combine 10 mL of 1 M sodium phosphate pH 7.2, 500 μL of 1 M DTT, 100 μL of 10 mg/mL leupeptin, and 40 mL of 50% glycerol. Add water to 100 mL. |
| stainlesss steel beads (5 mm) | Qiagen | 69989 | |
| 2.0 mL tubes | Eppendorf | 22363352 | This specific model of tube is recommended for use with the homogenizer. |
| bead homogenizer (TissueLyser) | Qiagen | 85210 | |
| 12mm x 75 mm glass test tubes | Fisher | ||
| luciferin | Goldbio | LUCK-100 | Prepare a 25 mM stock solution and store 1 mL aliquots at -20° C. |
| ATP | Sigma | A7699 | Prepare a 100 mM stock solution and store 250 μL aliquots at -20° C. |
| Tris base | Sigma | T1503 | Reagent for 1M Tris sulfate pH 7.7. |
| sulfuric acid | Sigma | 258105 | Reagent for 1M Tris sulfate pH 7.7. |
| 1M Tris sulfate pH 7.7 | home made | / | Dissolve 12.1 g Tris base in 100 mL of water. Adjust pH to 7.7 with sulfuric acid. |
| magnesium chloride | Sigma | M9397 | Dissolve in water to 2 M. |
| Luciferase Assay Buffer (LAB) | home made | / | Combine 3 mL of 1 M Tris sulfate pH 7.7, 500 μL of 2 M magnesium chloride, 1 mL of 1 M DTT, and 200 μL of 0.5 M EDTA. Add water to 50 mL. |
| Luciferase Assay Mixture | home made | / | Combine 15 mL of LAB, 800 μL of 25 mM luciferin, 200 μL of 100 mM ATP, and 4 mL of water. This makes enough assay mixture (20 mL) for 100 luciferase assays. |
| luminometer (Sirius) | Berthold | / | |
| 4-methylumbelliferyl-β-D-glucuronide (MUG) | Goldbio | MUG1 | Dissolve in DMSO to 100 mM. |
| sodium azide | Sigma | S8032 | Prepare a 2% stock solution in water and store 1 mL aliquots at -20° C. |
| 96 well plates (standard) | Fisher | 12565501 | |
| GUS assay buffer | home made | / | Combine 2.5 mL of MUG, 5 mL of 1 M sodium phosphate pH 7.2, 400 μL of 0.5 M EDTA, 1 mL of 1 M DTT, 100 μL of 10 mg/ml leupeptin, 20 mL of methanol, and 1 mL of 2% sodium azide. Add water to 100 mL. |
| TempPlate sealing film | USA Scientific | 2921-1000 | |
| 96 well plates (black) | Costar | 3916 | |
| sodium carbonate | Sigma | S7795 | Prepare a 200 mM solution in water. |
| 4-methylumbelliferone | Sigma | M1381 | Prepare a 100 μM solution in water. Freeze 1 mL aliquots at -20° C. |
| microplate fluouresence reader | Bio-Tek | FLX-800 |
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Citar este artigo
Uwase, G., Enrico, T. P., Chelimo, D. S., Keyser, B. R., Johnson, R. R. Measuring Gene Expression in Bombarded Barley Aleurone Layers with Increased Throughput. J. Vis. Exp. (133), e56728, doi:10.3791/56728 (2018).