Immunocoloration phospho-épitopes dans ciliées organes de Mont entiers embryons de poissons zèbres
Summary
Techniques sont décrites à immunocoloration phospho-épitopes dans embryons de poisson zèbre entiers et ensuite procéder à deux couleurs confocal fluorescent localisation dans des structures cellulaires aussi petites que les cils primaires. Les techniques de fixation et d'imagerie peuvent définir l'emplacement et de la cinétique de l'apparition ou de l'activation de protéines spécifiques.
Abstract
La prolifération rapide des cellules, l'expression tissu-spécifique des gènes et de l'émergence de réseaux de signalisation caractérisent le développement embryonnaire précoce de tous les vertébrés. La cinétique et l'emplacement des signaux – même à l'intérieur des cellules individuelles – dans l'embryon en développement complète l'identification des gènes du développement importants. immunocoloration techniques sont décrites qui ont été montré pour définir les cinétiques de signaux intracellulaires et des animaux entiers dans des structures aussi petites que les cils primaires. Les techniques de fixation, d'imagerie et de traitement des images en utilisant un laser à balayage composé microscope confocal peut être complété en aussi peu que 36 heures.
Le poisson zèbre (Danio rerio) est un organisme souhaitable pour les enquêteurs qui cherchent à mener des études dans une espèce de vertébré qui est abordable et pertinente à la maladie humaine. KO ou passes rabattues génétiques doivent être confirmées par la perte du produit protéique réelle. Cette confirmation de la perte de protéinespeut être réalisée en utilisant les techniques décrites ici. Des indices dans les voies de signalisation peuvent également être déchiffrés en utilisant des anticorps qui sont réactifs avec des protéines qui ont été modifiées après la traduction par phosphorylation. La préservation et l'optimisation de l'état phosphorylée d'un épitope est donc essentiel de cette détermination et est accompli par ce protocole.
Cette étude décrit les techniques pour fixer des embryons au cours des premières 72 heures de développement et de co-localiser une variété d'épitopes pertinents avec cils dans des vésicules (KV) de l'Kupffer, le rein et l'oreille interne. Ces techniques sont simples, ne nécessitent pas de dissection et peut être complété en une période relativement courte de temps. Projection des piles d'images confocale en une seule image est un moyen utile de présenter ces données.
Introduction
The techniques described here are the outcome of studies that have sought to define downstream targets of Ca2+ signals during events that occur during early development, including fertilization, gastrulation, somitogenesis and trunk, eye, brain and organ formation.1-3 The original discoveries of embryonic Ca2+ signaling were dependent on the use of natural and engineered Ca2+ indicators, such as aequorin4 and fura-2.5 Even with current technology, the detection of transient elevations of Ca2+ requires cumbersome analytical tools and does not reveal the targets of such Ca2+ signals.
This laboratory investigates Ca2+ signals that act through the Ca2+/calmodulin-dependent (multifunctional) protein kinase known as CaMK-II, an enzyme that is enriched in the central nervous system and originally identified as a regulator of long-term potentiation.6 CaMK-II is not brain-specific, is widely expressed and highly conserved throughout the entire lifespan and bodies of species throughout the animal kingdom, including invertebrates.7,8 CaMK-II has the unique capability of sustaining its own activity even after Ca2+ levels have diminished due to its ability to autophosphorylate at Thr287. In this autophosphorylated state, CaMK-II remains active in a Ca2+/CaM-independent manner, until dephosphorylated.6 Thus, the localization of phosphorylated CaMK-II (Thr287) can identify cells in which natural, relevant Ca2+ elevations have occurred.
An antibody against autophosphorylated (P-Thr287) mammalian CaMK-II has been well-characterized and was initially used to localize activated CaMK-II in brain tissue.9 Zebrafish (Danio rerio) have seven CaMK-II genes10,11 whose protein products contain a sequence of MHRQE[pT287]VECLK in this region.10,11 This sequence is very similar to the phosphopeptide antigen used to create this rabbit polyclonal antibody (MHRQE[pT]VDCLK; Upstate/Millipore) and therefore it was not a complete surprise that this antibody cross-reacted with zebrafish CaMK-II. This laboratory showed that this antibody reacts with zebrafish CaMK-II in proportion to autophosphorylation and Ca2+/CaM-independent activity.12 Additional pan-specific CaMK-II antibodies have also been shown to cross-react with zebrafish CaMK-II.13
This antibody has been used to demonstrate that zebrafish CaMK-II is preferentially activated in cells on one side of the zebrafish Kupffer’s Vesicle (KV), the ciliated organ necessary for establishment of left/right asymmetry.12 This antibody was used to demonstrate that CaMK-II is transiently activated in four adjacent cells on the left side of the KV during the exact same developmental phase that organ positioning is determined.12 In addition to the Kupffer’s Vesicle (KV), autophosphorylated (P-T287) was also located in specific intracellular sites in other ciliated tissues including the kidney, neuromasts, and inner ear.12,13 In the zebrafish kidney, P-T287-CaMK-II is enriched along the apical border of ciliated ductal cells and within cloacal cilia where it influences their assembly.13 Finally, in the developing inner ear, P-T287-CaMK-II is intensely concentrated at the base of cilia and influences cell differentiation through the Delta-Notch signal pathway.14 In summary, the detection of activated CaMK-II has pinpointed sites of intracellular Ca2+ release and illuminated potential new signaling pathways.
These discoveries were completely dependent on developing a sensitive and accurate method to localize activated (P-T287-autophosphorylated) CaMK-II. The methods to fix and immunostain the zebrafish KV, kidney and inner ear are described. The limitations of this technique are also described. These techniques should be useful to any investigator who seeks to obtain high-resolution images in two fluorescent channels of not just phospho-epitopes, but any epitope, during early vertebrate development.
Protocol
Representative Results
Discussion
La méthode / méthanol PFA a été développé dans ce laboratoire avec l'objectif principal d'optimiser la immunolocalisation du -CaMK-II épitope phospho-T 287 au cours du développement du poisson zèbre. Cette méthode localisée succès P-CaMK-II lors de la formation de plusieurs organes ciliées dont le KV de poisson zèbre, 12 oreille interne 14 et les reins. 13 en particulier au stade de KV, cette technique était nécessaire. Le succès de cette méthode est …
Disclosures
The authors have nothing to disclose.
Acknowledgements
Ce travail a été soutenu par la National Science Foundation subvention IOS-0817658.
Materials
| 1-phenyl-2-thiourea (PTU) | Sigma | P-7629 | 0.12% Stock solution. Dilute 1:40 in system water |
| Alexa488 anti-mouse IgG | Life Technologies | A11001 | Goat polyclonal, use at 1:500 |
| Alexa488 anti-rabbit IgG | Life Technologies | A11008 | Goat polyclonal, use at 1:500 |
| Alexa488 phalloidin | Life Technologies | A12379 | Preferentially binds to F-actin |
| Alexa568 anti-mouse IgG | Life Technologies | A11004 | Goat polyclonal, use at 1:500 |
| Alexa568 anti-rabbit IgG | Life Technologies | A11011 | Goat polyclonal, use at 1:500 |
| anti-acetylated a-tubulin | Sigma | T7451 | Mouse monoclonal, use at 1:500 |
| anti-phospho-T287 CaMK-II | EMD Millipore | 06-881 | Rabbit polyclonal, use at 1:20 |
| anti-total CaMK-II | BD Biosciences | 611292 | Mouse monoclonal, use at 1:20 |
| Ethanol | Fisher | S96857 | Lab grade, 95% denatured |
| Forceps | Fine Science Tools | 11252-20 | Dumont #5 |
| Glass coverslips | VWR | 16004-330 | #1 thickness |
| Glass microscope slides | Fisher | 12-550-15 | Standard glass slides |
| Methanol | Fisher | A411 | Store in freezer |
| Microcentrifuge tubes | VWR | 20170-038 | capped tubes, not sterile |
| Normal goat serum | Life Technologies | 16210-064 | Aliquot 1ml tubes, store in freezer |
| Paraformaldehyde | Sigma | P-6148 | Reagent grade, crystalline |
| Phosphate buffered saline (PBS) | Quality Biological | 119-069-131 | 10X stock solution or made in lab |
| Triton X-100 | Sigma | BP-151 | 10% solution in water, store at room temp |
| Tween-20 | Life Technologies | 85113 | 10% solution in water, store at room temp |
| Compound microscope | Nikon | E-600 | Mount on vibration-free table |
| C1 Plus two-laser scanning confocal | Nikon | C1 Plus | Run by EZ-C1 program, but upgrades use "Elements" |
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