Summary

利用荧光蛋白监视非洲锥虫Glycosome动态

Published: August 19, 2014
doi:

Summary

Glycosome dynamics in African trypanosomes are difficult to study by traditional cell biology techniques such as electron and fluorescence microscopy. As a means of observing dynamic organelle behavior, a fluorescent-organelle reporter system has been used in conjunction with flow cytometry to monitor real-time glycosome dynamics in live parasites.

Abstract

布氏锥虫是一种kinetoplastid寄生虫引起非洲人类锥虫病(HAT),或昏睡病和消耗性疾病,那加那病,牛1。哺乳动物宿主的血流和采采蝇矢量之间的寄生虫交替。许多细胞器的组合物,以响应这些不同的胞外条件2-5改变。

Glycosomes是高度专业化的过氧化物酶体中,许多参与糖酵解的酶是条块。在发展和环保监管的方式4-11 Glycosome成分的变化。目前,用于研究glycosome动力学中最常见的技术是电子和荧光显微镜;技术是昂贵,费时费力,而且不容易适用于高通量分析。

为了克服这些限制,荧光-glycosome报道系统中该增强型黄色荧光蛋白(EYFP)融合于过氧化物酶体靶向序列(PTS2),其引导融合蛋白glycosomes 12,已经建立。经PTS2eYFP融合蛋白的进口,glycosomes成为荧光。细胞器的降解和回收导致的​​荧光,可以通过流式细胞术测量的损失。大量的细胞(5000个细胞/秒)可在实时无需大量的样品制备待分析诸如固定和装配。这种方法提供了检测响应波动的环境条件变化的细胞器组成的快速路。

Introduction

布氏锥虫引起非洲昏睡病在人类和一种消耗性疾病,那加那病,牛。在这些疾病的治疗中使用的药物是陈旧的和非常有毒的,疫苗无法提供,并且对于耐药性的发展潜力就必须寻找新的药物靶标1。

在它的生命周期,T布氏,昆虫载体和哺乳动物宿主之间交替;两台主机,在目前非常不同的环境中的寄生虫必须生存。发生的许多代谢和形态的变化,因为寄生虫暴露于不同的环境条件。其中最显着的变化是单膜界的寄生虫特异性微体观察,称为glycosomes 13。

血糖水平相对较高(约5毫米)的血液和血液寄生虫(BSF)通过糖酵解WH产生ATP的专ILE线粒体代谢被抑制14。不像其它真核生物中,糖酵解发生在细胞质中,T.布氏最间隔化的glycosomes 14,15糖酵解酶。 à吸血过程中的寄生虫就由采采蝇和体验葡萄糖下降,其中下降到检测不到的水平之内被摄入的飞行15分钟。昆虫的新陈代谢,procyclic形式(PCF),寄生虫是更灵活和葡萄糖,以及氨基酸,如脯氨酸,可以在ATP 16-18的合成中使用。比较蛋白质组学研究揭示生命周期中glycosomal和依赖性变化线粒体蛋白与糖蛋白在血液中的寄生虫增加,参与TCA循环和呼吸链13,19线粒体蛋白。虽然许多研究都集中在BSF和PCF glycosomes之间的差异,知之甚少发生响应于被膜中的PCF glycosomes的变化ironmental变化。

在苍蝇的肠,血糖水平低,瞬间增加在喂食20。在大多数在体外研究中,PCF寄生虫生长在含葡萄糖的介质。然而,最近的研究已经表明,在反应显著PCF代谢变化成葡萄糖的可用性17。在没有葡萄糖,脯氨酸摄取和脯氨酸脱氢酶活性增加了18。这种变化在线粒体代谢很可能伴随着glycosome组成和形态的变化,但是,这并没有被直接评估。

电子和荧光显微镜是用来共同技术研究glycosome动力学T。布氏 2,21-24。这些协议是时间和劳动力密集型的,昂贵的,并且难以适应实时研究和高通量的协议。为了克服这个限制,荧光细胞器报告系统Used来研究哺乳动物和酵母细胞器系统已被修改用于T。布氏 12。

荧光的细胞器报告系统已被广泛用于在高等真核生物如酵母,植物和哺乳动物细胞25-27。在这样的系统中,荧光蛋白融合到靶向蛋白质到特定细胞器的氨基酸序列。靶蛋白的降解或合成是通过荧光测定和改变的细胞器组合物是通过改变细胞的荧光反射。

当增强型黄色荧光蛋白(EYFP)的开放读框融合至II型过氧化物酶体靶向序列(PTS2) 如图12所示 ,PTS2eYFP蛋白质导入到成熟,导入感受态glycosomes和荧光可以通过流式细胞仪进行监测。在glycosome组成变化是通过改变细胞的荧光反射。这个系统可以在甲阶辅助咏调控环境引起的变化glycosome组成的机制。

此手稿描述了一种glycosome报告系统在PCF中的寄生虫的产生结合流式细胞术监测活寄生虫实时glycosome动力学,并提供如何被用于跟踪响应于不同的环境变化glycosome组合物的例子。总之,glycosome组合物是由胞外葡萄糖浓度和对数相培养的通路影响到新鲜培养基触发变化glycosome组合物。此系统可以被修改以研究在锥虫及其它寄生虫其它细胞器的动态行为。

Protocol

1,一般锥虫畜牧称重固体为SDM79媒体制剂( 表1)。 保存在4℃的50毫升锥形或保鲜袋包。注:本产品保质期至少为6个月。 解冻的胎牛血清(FBS)在37℃水浴,并通过逆周期混合。注:FBS是从供应商的无菌溶液好评。过滤消毒FBS降低其支持寄生虫的生长能力。 一旦整个瓶解冻,热灭活血清30分钟,在56℃水浴,定期搅拌,尽量减少血清成分的沉淀。 ?…

Representative Results

在这个系统中,观察到在glycosome组合物中的葡萄糖依赖性变化。当细胞生长在含葡萄糖的介质,两个总体观察;一个亮点,一个朦胧( 图2A)。昏暗的细胞怀有不成熟glycosomes,并未进口PTS2eYFP而明亮的细胞怀有成熟和未成熟glycosomes 12的混合物。当葡萄糖是存在于所述介质,glycosome蛋白的错误定位是致死15,28和glycosome蛋白表达可能紧密进口耦合。这种紧密调控负责暗淡的…

Discussion

Glycosomes是必不可少的,动态的,寄生虫特异性的细胞器。调节这些细胞器的生物合成,维持,增殖和重塑的过程可能包括可能被利用于治疗目的的药物靶标。尽管潜在的高丰度这样的药物靶点,glycosome生物合成领域已经落后于其它生物体类似过程的研究落后,主要是由于缺乏一个易于处理的,高吞吐量的系统,通过该监测快速,动态的细胞器中的反应在活细胞中。

荧光的细…

Divulgaciones

The authors have nothing to disclose.

Acknowledgements

This work was funded by the Creative Inquiry Program for Undergraduate Research and the Calhoun Honors College at Clemson University.

Materials

Adenosine Avocado Research Chemicals Ltd A10781 SDM79 Ingredient
L-Alanine Avocado Research Chemicals Ltd A15804 SDM79 Ingredient
L-arginine CalBiochem 1820 SDM79 Ingredient
p-aminobenzoic acid ICN Biomedicals 102569 SDM79 Ingredient
Basal Medium Eagle Vitamin Solution (100X) Sigma B6891 SDM79 Ingredient
Biotin Fisher BP232-1 SDM79 Ingredient
Calcium Chloride VWR BDH0224 Cytomix
EDTA Fisher S311-100 Cytomix ingredient
EZNA Gel Extraction kit Omega Biotek D2500-01 DNA purifiation
Research grade Serum Fisher 03-600-511 SDM79 Ingredient
Folic acid ICN Biomedicals 101725 SDM79 Ingredient
Glucosamine HCl ICN Biomedicals 194671 SDM79 Ingredient
Glucose GIBCO 15023-021 SDM79 Ingredient
L-glutamine CalBiochem 3520 SDM79 Ingredient
Glycerol Acros Organics Ac15892-0010 Freezing media
Graces insect cell media powder GIBCO 11300-043 SDM79 Ingredient
Hemin MP Biomedicals 194025 SDM79 Ingredient
Guanosine Avocado Research Chemicals Ltd A11328 SDM79 Ingredient
HEPES MP Biomedicals 194025 SDM79 Ingredient
Magnesium Chloride Fisher BP214-500 Cytomix ingredient
L-methionine Fisher BP388-100 SDM79 Ingredient
MEM Amino Acids (50X) Cellgro 25-030-CI SDM79 Ingredient
NEAA Mixture (100X) Lonza 13-114E SDM79 Ingredient
Minimal Essential Medium (1X) with L-glutamine Cellgro 10-010-CM SDM79 Ingredient
MOPS Fisher BP308-500 SDM79 Ingredient
Sodium Biocarbonate Fisher S233-500 SDM79 Ingredient
Penicillin-Streptomycin Solution Cellgro 30-002-CI SDM79 Ingredient
L-phenylalanine ICN Biomedicals 102623 SDM79 Ingredient
Potassium Chloride Fisher P217-500 Cytomix ingredient
Potassium Phosphate Dibasic Anhydrous Fisheer P290-212 Cytomix ingredient
L-proline Fisher BP392-100 SDM79 Ingredient
L-serine Acros Organics 56-45-1 SDM79 Ingredient
Pyruvic acid, sodium salt Acros Organics 113-24-6 SDM79 Ingredient
L-taurine TCI America A0295 SDM79 Ingredient
L-threonine Acros Organics 72-19-5 SDM79 Ingredient
L-tyrosine ICN Biomedicals 103183 SDM79 Ingredient
E.Z.N.A.Cycle Pure kit Omega Biotek D6492-02 DNA purification
Binding buffer Omega Biotek PDR041 DNA purification
SPW wash buffer  Omega Biotek PDR045 DNA purification
Gene Pulser Xcell  Biorad 165-2660 Trypanosome transformation
4 mm electroporation cuvettes VWR Trypanosome transformation

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Bauer, S., Conlon, M., Morris, M. Using Fluorescent Proteins to Monitor Glycosome Dynamics in the African Trypanosome. J. Vis. Exp. (90), e51647, doi:10.3791/51647 (2014).

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