荧光蛋白的表达<em>披文昌鱼</em>通过基因注射到未受精的卵母细胞
Summary
我们在这里报告的强大和高效表达荧光蛋白的mRNA注射后进入披文昌鱼的未受精的卵母细胞。显微注射技术在此基础脊索动物的发展铺平道路，在这个新兴的模型系统深远的技术创新，包括在体内成像和基因特异的操作。
Abstract
We report here a robust and efficient protocol for the expression of fluorescent proteins after mRNA injection into unfertilized oocytes of the cephalochordate amphioxus, Branchiostoma lanceolatum. We use constructs for membrane and nuclear targeted mCherry and eGFP that have been modified to accommodate amphioxus codon usage and Kozak consensus sequences. We describe the type of injection needles to be used, the immobilization protocol for the unfertilized oocytes, and the overall injection set-up. This technique generates fluorescently labeled embryos, in which the dynamics of cell behaviors during early development can be analyzed using the latest in vivo imaging strategies. The development of a microinjection technique in this amphioxus species will allow live imaging analyses of cell behaviors in the embryo as well as gene-specific manipulations, including gene overexpression and knockdown. Altogether, this protocol will further consolidate the basal chordate amphioxus as an animal model for addressing questions related to the mechanisms of embryonic development and, more importantly, to their evolution.
Introduction
在开发过程中，单个细胞产生了一个完整的有机体中高度复杂的过程，涉及到两个细胞分裂和运动。为了更好地了解的细胞行为的动力学所依据的生物学原理，发育生物学家已经开始使用基于荧光的体内成像技术。细胞的特定区室，如细 胞膜，可以通过处理来用荧光染料标记，通过组织穿透1的缺乏特异性和阻碍的方法，或由具体引入的编码荧光蛋白2外源性的mRNA胚胎。不同的技术可用于有效递送外源性化合物，如的mRNA。这些包括，但不限于，微注射，电穿孔，轰击与微粒，脂质转染和转导3,4。虽然所有这些方法可以用于引入外源性化合物成发育中的胚胎，只有微量注射允许预定义的和精确的批量应用到每个单元3。显微注射技术已被描述为所有主要发育模型系统4（ 例如 ，果蝇，线虫，斑马鱼，蛙，小鼠），以及对于某些替代模式4中 ，其中包括那些用于旨在了解发育机制的演化比较研究（ 例如 ，海葵，蠕虫环节动物，海胆，海鞘囊中，文昌鱼文昌鱼）。
Cephalochordates，连同被囊动物和脊椎动物建立脊索动物门，是特别适合的模型来研究脊索动物的演变和脊椎动物从脊椎动物的祖先5-8的多样化。在文昌鱼谱系很早脊索动物进化过程中分道扬镳;和现存cephalochordates，其被细分为三个属（ 麸chiostoma，Asymmetron和Epigonichthys），类似于脊椎动物无论是在整体解剖和基因组架构5-8的条款。已经描述到目前为止的约30种cephalochordates的五个可供胚胎和发育研究6,9：Asymmetron lucayanum（巴哈马文昌鱼）， 文昌鱼floridae（佛罗里达文昌鱼）， 文昌鱼披 （欧洲文昌鱼）， 文昌鱼 （中国的文昌鱼） 文昌鱼与日本血吸虫 （日本文昌鱼）。这三个品种的成熟的成年人（B.披针叶，B.文昌鱼和B.血吸虫 ）可诱导产卵按需在繁殖季节10,11。此外，至少对于B.披 ，高效产卵也可诱发在人造海水12，从而使这个特定文昌鱼物种laborator访问IES没有获得天然海水。的结合，在二披针叶 ，一个方便，可靠地获得胚胎具有高效的交付方法，如显微注射，至今在文昌鱼开发（在B. floridae和B.文昌鱼 ）13-15，只交付技术将使的发展新套件的操控技术，包括血统tracing-和动态细胞行为为基础的方法。
一种协议，它的mRNA的显微注射高效表达的B.荧光蛋白披针叶胚胎，因此开发。此外，提供一个基本的工具包B的实时成像披胚胎，载体系统被开发，使膜相关和荧光蛋白的细胞核表达。用于膜靶向，增强型绿色荧光蛋白（EGFP）融合到mCherry和EGFP的人的HRAS CAAX盒和核定位是由融合到斑马鱼组蛋白2B（H2B）外显子（ 图1中 ，补充文件1）中获得。此外，其目标是优化蛋白质的翻译，所述构建体含有Kozak序列和密码子已被修改，并适于使用在二披针叶 。两者合计，这里介绍的注射方法和表达载体将作为新的实验方法为cephalochordates产生的基础，特别是分析采用最新的基于荧光的体内成像技术。
Protocol
Representative Results
Discussion
在这篇文章中，我们提出，第一次，详细的和可重复的协议，用于注射的B.卵披针叶 ，其中，经过B. floridae 13,14和B.文昌鱼 15，因此第三文昌鱼物种，其中这样的技术已被描述。重要的是，这里描述的协议也包括载体系统适合于荧光蛋白的B中生产的描述从体外产生的mRNA注入的披 （以下描述）。总之，这些新的工具允许在文昌?…
Divulgations
The authors have nothing to disclose.
Acknowledgements
笔者想承认的“Animalerie中央去伊维特河畔吉夫”的支持畜牧业。这项工作是由ANR（ANR-09-BLAN-0262-02和ANR-11-JSV2-002-01）迈克尔·舒伯特支持基金，由欧盟FP6授予“Embryomics”，并通过了ANR授予“ANR- 10 BLAN-121801开发进程“让 – 弗朗索瓦·尼古拉和纳丁Peyriéras。若昂·伊曼纽尔卡瓦略通过FCT博士奖学金资助（SFRH / BD /二千零一十二分之八万六千八百七十八）。
请求对这里所描述的载体，可以直接给作者。
Materials
| Name of Material/ Equipment | Company | Catalog Number | Comments/Description |
| Consumables | |||
| 35 mm Petri dishes | Falcon | 353001 | culture-treated |
| Filtration unit (Stericup 1L) | Fisher | W21719 | 0.22 micron filtration |
| Spin-X tubes | Costar | 8160 | 0.22 micron filtration tube |
| Needle storage jar for 1.2 mm diameter capillaries | WPI | E212 | |
| Pasteur Pipettes | 230 mm long | ||
| Aspiration tube | Dutscher | 75056 | |
| Capillaries for injection needles | Sutter | BF 120-94-10 | Borosilicate glass with filament, OD 1.20 mm, ID 0.94 mm, length 10 mm |
| Reagents | |||
| Low-melting agarose | SIGMA | A9414 | |
| Phenol Red | SIGMA | 114537 | |
| Glycerol | SIGMA | G2025 | |
| Poly-L-Lysine hydrobromide | SIGMA | P9155 | |
| H2O Dnase, Rnase-free | Gibco | 10977-035 | |
| mMessage mMachine SP6 Transcription kit | Ambion | AM1340 | mRNA synthesis kit |
| Phenol pH8 | SIGMA | P4557 | |
| 24:1 chloroform:isoamylic alcohol | SIGMA | C0549 | |
| 5:1 phenol pH4.7:chloroform | SIGMA | P1944 | |
| Reef Crystal salts (200 kg) | Europrix | Commercial salts | |
| Equipment | |||
| Fluorescent dissecting scope with 200x magnification | Leica | MZ16F | 25x oculars, DSR and GFP2 filters |
| Micromanipulator | Marzhauzer | M-33 | |
| Injector | Picospritzer | model II or III | |
| Needle puller | Sutter | P97 | heating-filament needle puller |
| Fine forceps | FINE SCIENCE TOOLS GMBH | 11252-30 | Dumont #5 |
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