에서 이미징 칼슘<em> 초파리</em> 계란 활성화에
Summary
이 문서에서는 초파리 계란 활성화 중에 2 + 칼슘을 시각화에 대한 적응력 생체 프로토콜을 설명합니다.
Abstract
Egg activation is a universal process that includes a series of events to allow the fertilized egg to complete meiosis and initiate embryonic development. One aspect of egg activation, conserved across all organisms examined, is a change in the intracellular concentration of calcium (Ca2+) often termed a ‘Ca2+ wave’. While the speed and number of oscillations of the Ca2+ wave varies between species, the change in intracellular Ca2+ is key in bringing about essential events for embryonic development. These changes include resumption of the cell cycle, mRNA regulation, cortical granule exocytosis, and rearrangement of the cytoskeleton.
In the mature Drosophila egg, activation occurs in the female oviduct prior to fertilization, initiating a series of Ca2+-dependent events. Here we present a protocol for imaging the Ca2+ wave in Drosophila. This approach provides a manipulable model system to interrogate the mechanism of the Ca2+ wave and the downstream changes associated with it.
Introduction
계란 (난자) 활성화에서의 세포 내 칼슘의 변화 2+ 농도는 모든 연구 생물 1, 2의 보존 구성 요소입니다. 이 이벤트는 세포주기의 재개 및 저장의 mRNA의 번역을 포함한 칼슘 의존적 공정의 넓은 범위를 개시한다. 때문에 세포 내 칼슘 농도의 일시적인 변화를 시각화 칼슘이 요구 사항에 주요 관심이었다.
역사적으로, 모델 생물은 알의 크기와 가용성에 따라 계란 활성화에 대한 연구에 선정되었다. 다양한 시각화 방법을 포함 이러한 시스템에서 2 + 농도에 따라 세포 내 칼슘의 변화를 정량화하기 위해 사용되었습니다 송사리 3의 광 단백질의 쿼린을; 등의 Fura-2 성게와 햄스터 4,5에서와 같이 칼슘 민감한 형광 염료; 칼슘 – 녹색 1 덱스 트란 Xenopus의 6인치
생성 및 유전자 인코딩 칼슘 지표 (GECIs)의 개선은 생체 내 7에 칼슘을 2 + 역학을 시각화 할 수있는 능력을 변형시켰다. 이러한 유전자 구조물은 특정 조직에서 발현 및 조직 침윤성 제제 8에 대한 필요성을 제한한다.
GCaMPs 인해 높은 칼슘 친화력 매우 효과적이었다 GECIs의 녹색 형광 단백질 (GFP) 기반 클래스이며, 신호 – 대 – 잡음 비율 및 용량 9-11을 정의한다. 칼슘의 존재에서, GCaMP 착체, 칼 모듈 린에 칼슘의 결합으로 시작하고, 형태 적 변화를 겪는다 시리즈 그 GFP 성분 (9)의 형광 강도 향상을 초래한다.
GCaMPs 광범위 세포 내 칼슘 (12)의 변화를 시각화하기 위해 초파리 신경 세포에 대한 연구에 사용되어왔다. 최근 applicati에성숙한 초파리 계란 2 + 칼슘을 시각화하는 GCaMP 기술에 계란 활성화 (13, 14)에서 단일 과도 칼슘 파를 밝혔다. 칼슘 2 + 웨이브는 생체 활성 분석 (13, 14)를 사용하여 생체 (13)에 배란 동안이나 높은 배율에서 낮은 배율로 시각화 할 수 있습니다. 생체 외 분석에서, 각각의 성숙 난자가 난소로부터 단리 및 저장성 용액을 사용하여 활성화되는, 생체 활성 15-17 사건 요점을 되풀이하는 것으로 나타났다 활성화 완충액이라.
이 생체 분석은 약물 중단, 물리적 조작과 유전자 돌연변이 등 다양한 실험 조건에서 칼슘 2 + 파의 쉬운 고해상도 시각화 할 수 있습니다. 이 문서에서는 생체 활성화 및 일에 대한 성숙한 초파리 계란의 준비를 보여줍니다GCaMP를 사용하여 칼슘 파를 시각화하는 데 사용되는 전자 후속 현미경. 이 방법은 칼슘 파의 개시 및 제어를 테스트하기 위해 하류 결과를 조사하는데 사용될 수있다.
Protocol
Representative Results
Discussion
The first critical step in this protocol is isolating the mature eggs without damage. This can be achieved by gentile maneuvering of the eggs with the dissecting probe. Practice will enable this manipulation to be executed without damage to the eggs. A second crucial step is avoiding the loss of the sample when activation buffer is applied to the mature egg in oil. Application of the activation buffer should be done slowly and without contact with the coverslip. This step can be challenging if the microscope set-up does not allow for an easy access to the sample. Moving axillary parts of the microscope, such as a temperature incubator, is advisable.
Modifications to this protocol can be made in order to visualize other fluorescently tagged factors, instead of Ca2+ at egg activation. More generally, different stages of Drosophila development or the results of adding a different buffer could be analyzed using this protocol.
Troubleshooting may be required if the settings on the microscope are not optimal for visualizing the signal from the sample. This can be achieved by increasing or decreasing the laser power, altering capture range and adjusting the Z-stack parameters. Another issue might be eggs consistently moving out of the field of view upon the addition of activation buffer. If this happens regularly, allow the mature eggs to settle on the coverslips for a longer period of time, 15 to 20 minutes. Beware that using a higher viscosity oil will alter the displacement of the oil by activation buffer.
This technique presented here is limited by the working distance of the objective, dehydration of the mature eggs and the ability to dissect the mature eggs without damage. However, when compared to in vivo imaging methods where the mature oocyte passes through the adult female and is deposited 13, our method enables more spatial resolution, the option to physically manipulate the mature egg before activation and the ability to test the role of egg activation without fertilization.
There are many potential future applications of this technique, including testing reporter constructs for cellular components at egg activation and visualizing the Ca2+ wave in mutant backgrounds 14,24. Together with experimental and genetic tools, the ex vivo egg activation assay presented here enables the study of the trigger, propagation and downstream effects of the universally conserved Ca2+ wave.
Declarações
The authors have nothing to disclose.
Acknowledgements
우리는이 원고의 준비 기간 동안 지원 로라 Bampton, 알렉스 데이비슨, 리차드 파튼, 아리타 아차에 감사하고 있습니다; 계란 활성화에 대한 토론 마리아나 Wolfner; 영상 지원을위한 매트 WAYLAND; 그리고 할머니 후 실험실에서 일반적으로 지원.
이 작품은 TTW 캠브리지, ISSF 대학 [허가 번호 097814]에 의해 지원되었다.
Materials
| Dry active yeast | Fleischman’s | #2192 | |
| Dissecting microscope | Leica | MZ6 | Various will work |
| Lamp | Mircotec Fibre optic | MF0-90 | Various will work |
| Medical wipes | Kimberly-Clark Corporation | KLEW3020 | |
| Marker pen | Stabilo | 841/46 | OHPen universal, black – available in most stationary shops. Superfine Width 0.4mm |
| CO2 pad | Genesee Scientific | 59-114 (789060 Dutscher) | |
| Cover slip No. 1.5, 22 x 50mm | International- No1-VWR Cat=631-0137-22-50mm | Menzel-Glaser-22-50mm-MNJ 400-070T | |
| Halocarbon oil, series 95 | Halocarbon Products Corp. | Distributor in Europe: | |
| Solvadis (GMBH) | |||
| Oil 10 S | VWR Chemicals | 24627.188 | Can be used instead of Halocarbon oil, series 95 |
| Forceps | Fine Science Tools | 11252-00 | Whilst these tool should be clean, use of an autoclave is not necessary, ethanol would be sufficient. |
| Probe | Fine Science Tools | 10140-01 | |
| Glass pipette | Fisherbrand, | FB50251 | Pasteur Pipettes, glass, unplugged, 150mm length |
| Vial | Regina Industries | P1014 | GPPS 80mm x 25mm |
Referências
- Stricker, S. A. Comparative biology of calcium signaling during fertilization and egg activation in animals. Dev Biol. 211 (2), 157-176 (1999).
- Horner, V. L., Wolfner, M. F. Transitioning from egg to embryo: triggers and mechanisms of egg activation. Dev Dyn. 237 (3), 527-544 (2008).
- Gilkey, J. C., Jaffe, L. F., Ridgway, E. B., Reynolds, G. T. A free calcium wave traverses the activating egg of the medaka, Oryzias latipes. J Chem Biol. 76 (2), 448-466 (1978).
- Fujiwara, T., Nakada, K., Shirakawa, H., Miyazaki, S. Development of inositol trisphosphate-induced calcium release mechanism during maturation of hamster oocytes. Dev Biol. 156 (1), 69-79 (1993).
- Hafner, M., Petzelt, C., Nobiling, R., Pawley, J. B., Kramp, D., Schatten, G. Wave of free calcium at fertilization in the sea urchin egg visualized with fura-2. Cell Motil Cytoskeleton. 9 (3), 271-277 (1988).
- Fontanilla, R. A., Nuccitelli, R. Characterization of the sperm-induced calcium wave in Xenopus eggs using confocal microscopy. Biophys J. 75 (4), 2079-2087 (1998).
- Kotlikoff, M. I. Genetically encoded Ca2+ indicators: using genetics and molecular design to understand complex physiology. J Physiol. 578, 55-67 (2007).
- Douglass, A. . New Techniques in Systems Neuroscience. , (2015).
- Nakai, J., Ohkura, M., Imoto, K. A high signal-to-noise Ca(2+) probe composed of a single green fluorescent protein. Nat Biotechnol. 19 (2), 137-141 (2001).
- Akerboom, J., et al. Optimization of a GCaMP calcium indicator for neural activity imaging. J Neurosci. 32 (40), 13819-13840 (2012).
- Chen, T. -. W., et al. Ultrasensitive fluorescent proteins for imaging neuronal activity. Nature. 499 (7458), 295-300 (2013).
- Wang, J., Wong, A., Flores, J., Vosshall, L., Axel, R. Two-photon calcium imaging reveals an odor-evoked map of activity in the fly brain. Cell. 112 (2), 271-282 (2003).
- Kaneuchi, T., et al. Calcium waves occur as Drosophila oocytes activate. Proc Natl Acad Sci U S A. 112 (3), 791-796 (2015).
- York-Andersen, A. H., Parton, R. M., Bi, C. J., Bromley, C. L., Davis, I., Weil, T. T. A single and rapid calcium wave at egg activation in Drosophila. Biol Open. 4 (4), 553-560 (2015).
- Mahowald, A. P., Goralski, T. J., Caulton, J. H. In vitro activation of Drosophila eggs. Dev Biol. 98 (2), 437-445 (1983).
- Page, A. W., Orr-Weaver, T. L. Activation of the meiotic divisions in Drosophila oocytes. Dev Biol. 183 (2), 195-207 (1997).
- Horner, V. L., Wolfner, M. F. Mechanical stimulation by osmotic and hydrostatic pressure activates Drosophila oocytes in vitro in a calcium-dependent manner. Dev Biol. 316 (1), 100-109 (2008).
- Weil, T. T., Parton, R. M., Davis, I. Preparing individual Drosophila egg chambers for live imaging. J Vis Exp. (60), (2012).
- . Essentials of Biology 1: yeast, Drosophila and C. elegans. Drosophila Maintenance. JoVE Science Education Database. , (2016).
- Melom, J. E., Littleton, J. T. Mutation of a NCKX Eliminates Glial Microdomain Calcium Oscillations and Enhances Seizure Susceptibility. J Neurosci. 33 (3), 1169-1178 (2013).
- Munro, E., Nance, J., Priess, J. R. Cortical flows powered by asymmetrical contraction transport PAR proteins to establish and maintain anterior-posterior polarity in the early C. elegans embryo. Dev Cell. 7 (3), 413-424 (2004).
- Maruyama, R., et al. EGG-3 regulates cell-surface and cortex rearrangements during egg activation in Caenorhabditis elegans. Curr Biol. 17 (18), 1555-1560 (2007).
- Wong, G. K., Woods, M. A., Szymczak, R. K., Gavlik, A. Disruption of normal actin cytoskeletal reorganization affects cell cycle time in fertilized sea urchin eggs. Mol Biol Cell. 15, 23 (2004).
- Horner, V. L., et al. The Drosophila calcipressin sarah is required for several aspects of egg activation. Curr Biol. 16 (14), 1441-1446 (2006).
