Os autores gostariam de agradecer a Karen Lawrence por sua ajuda com a construção seção que descreve da câmara de eletroporação.

<ol>
	<li>Carroll, S. B., Grenier, J. K., Weatherbee, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> From DNA to diversity : molecular genetics and the evolution of animal design. , (2005).</li><li>Davidson, E. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Genomic regulatory systems : development and evolution. , (2001).</li><li>Ptashne, M., Gann, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Genes &#38; signals. , (2002).</li><li>Blow, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ChIP-Seq+identification+of+weakly+conserved+heart+enhancers.">ChIP-Seq identification of weakly conserved heart enhancers.</a> Nat Genet. 42, 806-810 (2010).</li><li>Visel, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ChIP-seq+accurately+predicts+tissue-specific+activity+of+enhancers.">ChIP-seq accurately predicts tissue-specific activity of enhancers.</a> Nature. 457, 854-858 (2009).</li><li>Matsuda, T., Cepko, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electroporation+and+RNA+interference+in+the+rodent+retina+in+vivo+and+in+vitro.">Electroporation and RNA interference in the rodent retina in vivo and in vitro.</a> Proc Natl Acad Sci U S A. 101, 16-22 (2004).</li><li>Matsuda, T., Cepko, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+expression+of+transgenes+introduced+by+in+vivo+electroporation.">Controlled expression of transgenes introduced by in vivo electroporation.</a> Proc Natl Acad Sci U S A. 104, 1027-1032 (2007).</li><li>LoTurco, J., Manent, J. B., Sidiqi, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+and+improved+tools+for+in+utero+electroporation+studies+of+developing+cerebral+cortex.">New and improved tools for in utero electroporation studies of developing cerebral cortex.</a> Cereb Cortex. 19, 120-125 (2009).</li><li>Matsuda, T., Cepko, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+gene+function+in+the+retina.">Analysis of gene function in the retina.</a> Methods Mol Biol. 423, 259-278 (2008).</li><li>Lee, J., Myers, C. A., Williams, N., Abdelaziz, M., Corbo, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+fine-tuning+of+photoreceptor+cis-regulatory+elements+through+affinity+modulation+of+transcription+factor+binding+sites.">Quantitative fine-tuning of photoreceptor cis-regulatory elements through affinity modulation of transcription factor binding sites.</a> Gene Ther. 17, 1390-1399 (2010).</li><li>Carter-Dawson, L. D., LaVail, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rods+and+cones+in+the+mouse+retina.+II.+Autoradiographic+analysis+of+cell+generation+using+tritiated+thymidine.">Rods and cones in the mouse retina. II. Autoradiographic analysis of cell generation using tritiated thymidine.</a> J Comp Neurol. 188, 263-272 (1979).</li><li>Young, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+differentiation+in+the+retina+of+the+mouse.">Cell differentiation in the retina of the mouse.</a> Anat Rec. 212, 199-205 (1985).</li><li>Corbo, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CRX+ChIP-seq+reveals+the+cis-regulatory+architecture+of+mouse+photoreceptors.">CRX ChIP-seq reveals the cis-regulatory architecture of mouse photoreceptors.</a> Genome Res. 20, 1512-1525 (2010).</li><li>Kim, D. S., Matsuda, T., Cepko, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+core+paired-type+and+POU+homeodomain-containing+transcription+factor+program+drives+retinal+bipolar+cell+gene+expression.">A core paired-type and POU homeodomain-containing transcription factor program drives retinal bipolar cell gene expression.</a> J Neurosci. 28, 7748-7764 (2008).</li><li>Karra, D., Dahm, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfection+techniques+for+neuronal+cells.">Transfection techniques for neuronal cells.</a> J Neurosci. 30, 6171-6177 (2010).</li><li>Onishi, A., Peng, G. H., Chen, S., Blackshaw, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pias3-dependent+SUMOylation+controls+mammalian+cone+photoreceptor+differentiation.">Pias3-dependent SUMOylation controls mammalian cone photoreceptor differentiation.</a> Nat Neurosci. 13, 1059-1065 (2010).</li></ol>

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Eletroporação explante é um meio simples de quantificar cis-regulatórias atividade na retina do rato em desenvolvimento. Comparado com cis-regulatórias análise via transgenia mouse, eletroporação é muito mais barato, exigindo filhotes de rato recém-nascidos só, DNA, instrumentos de dissecação, e eletroporação / equipamentos de cultura de tecidos. É também muito menos tempo consumindo: um experimento requer apenas algumas horas de tempo de preparação, um período de cultura de cerca de oito dias e algumas horas no final do experimento para geração de imagens e análise de dados. Eletroporação explante também é superior à análise de cultura de células baseado em cis-regulatórias desde tecido da retina real é utilizado. A retina desenvolve bastante normalmente em explante cultura faz três distintas camadas celulares (camada nuclear externa, camada nuclear interna e camada de células ganglionares), apesar de fotorreceptores não formulam segmentos externos. Uma outra vantagem é que eletroporação explante é altamente reprodutível. As construções mesmo em retinas electroporated diferentes, mesmo em dias diferentes, geralmente resulta no mesmo nível de expressão relativa. Além disso, como os plasmídeos electroporated são pensados ​​para ser mantida episomally no núcleo e não são incorporados nos cromossomos, que parecem não estar sujeitos aos efeitos da integração mesmo site que atormentam cis-regulatórias análise realizada em camundongos transgênicos. Eletroporação explante tem várias limitações. Primeiro, apenas as células que ainda estão no ciclo celular pode ser eficientemente transduzidas por eletroporação 15. Em P0, varetas e outros mais tarde, nascido tipos de células da retina (células bipolares, células amácrinas, M ller glia) são as populações de células principais visados ​​por este método. Eletroporação de cones fotorreceptores por P0 eletroporação tem sido relatada 16, mas a eficiência parece ser baixa. Uma segunda limitação é que a cultura de explantes além de dois resultados semanas em malformação progressiva da retina e não é recomendada. Se quantificação promotor é necessário em intervalo de tempo final, no entanto, uma eletroporação in vivo 09 de maio será realizada, seguida de dissecção da retina no ponto no tempo desejado, flat-fixação da retina dissecados e quantificação conforme descrito na seção 9. Uma terceira limitação é que este ensaio é apenas moderadamente alto rendimento. Ao contrário dos ensaios de cultura de células-based que pode testar centenas de construções em um único experimento, a técnica descrita neste protocolo requer um mínimo de uma retina do rato por toda construir. Assim, apenas uma dúzia de construções podem ser razoavelmente electroporated em um dia. Uma ressalva adicionais com respeito à quantificação da atividade do promotor com a presente abordagem é que há um potencial para &quot;sangrar-through &#39;de fluorescência DsRed no canal GFP, particularmente quando se examina promotores muito forte. A razão para isto é que o espectro de emissão de DsRed parcialmente idêntica à do GFP. Para contornar esse problema, filtros de emissão otimizada deve ser usado que minimizam a sobreposição espectral entre DsRed e GFP. Quando tal otimizado conjuntos de filtros não estão disponíveis, outra possível solução seria a utilização de uma proteína fluorescente azul-deslocada (por exemplo, BFP ou PCP) em vez de GFP.

<table border="1"><tbody><tr><th> Nome do reagente </th><th> Companhia </th><th> Número de catálogo </th><th> Comentários (opcional) </th></tr><tr><td> Prato eletroporação, MICROSLIDE 453 </td><td> BTX Harvard Apparatus </td><td> 45-0105 </td><td> Ver protocolo seção 1 para modificações </td></tr><tr><td> 100% de borracha de silicone de cimento aquário </td><td> Perfecto Manufacturing </td><td></td><td></td></tr><tr><td> Rack de microtubo de plástico </td><td> Fisher Scientific </td><td> 05-541 </td><td> Apenas a alça de rack será usado </td></tr><tr><td> Ferramenta Dremel </td><td></td><td></td><td> Para cortar a alça fora do rack tubo de plástico </td></tr><tr><td> DMEM </td><td> Gibco / Invitrogen </td><td> 11965 </td><td></td></tr><tr><td> F12 </td><td> Gibco / Invitrogen </td><td> 11765 </td><td></td></tr><tr><td> L-Glu/pen/strep </td><td> Gibco / Invitrogen </td><td> 10378-016 </td><td> Concentração 100X </td></tr><tr><td> Insulina </td><td> Sigma-Aldrich </td><td> I-6634 </td><td> Para o estoque 1000X, ressuspender a 5mg/ml em HCl 5mM e filtro-esterilize </td></tr><tr><td> FBS </td><td> Gibco / Invitrogen </td><td> 26140-079 </td><td></td></tr><tr><td> ECM 830 electroporator de onda quadrada </td><td> BTX Harvard Apparatus </td><td></td><td></td></tr><tr><td> Filtros Nuclepore </td><td> Whatman </td><td> 110606 </td><td> 25mm, 0,2 Hm </td></tr><tr><td> Cultura de tecidos incubadora </td><td></td><td></td><td> 37 ° C, 5% CO 2 </td></tr><tr><td> Lamínulas de vidro # 1.5 </td><td> Fisher Scientific </td><td> 12-544E </td><td> 0,16 milímetros de espessura </td></tr><tr><td> Microscópio composto fluorescente equipado com câmera </td><td></td><td></td><td> Câmera deve ser monocromática (por exemplo, ORCA-ER câmera Hamamatsu) </td></tr><tr><td> EGFP / conjunto de filtros para DsRed microscópio composto </td><td> Chroma Technology Corp </td><td> 86007 </td><td> Este conjunto de filtros bleedthrough minimiza entre o chanenels vermelho e verde </td></tr><tr><td> Software ImageJ </td><td> NIH </td><td></td><td> <a href="http://rsbweb.nih.gov/ij/">http://rsbweb.nih.gov/ij/</a> </td></tr></tbody></table>

quantifying the activity of cis-regulatory elements in the mouse retina by explant electroporation

Fatores de transcrição de genes dentro das redes celulares controlar o padrão espaço-temporal e os níveis de expressão de seus genes-alvo pela ligação a elementos cis-reguladores (CREs), de curta duração (~ 300-600 pb) trechos de DNA genômico, que pode mentir montante, a jusante, ou dentro os íntrons dos genes que controlam. CREs (ie, enhancers / promotores) tipicamente consistem de múltiplos agrupados sítios de ligação para ambos os ativadores e repressores transcripcional 1-3. Eles servem como integradores de lógica de entrada de transcrição dando uma saída unitária na forma de atividade do promotor espaço-temporalmente preciso e quantitativamente exata. A maioria dos estudos de mamíferos cis-regulação, até à data têm contado com transgênese mouse como um meio de doseamento a função realçador de CREs 4-5. Esta técnica é demorado, caro e, por conta dos efeitos local de inserção, em grande parte não-quantitativo. Por outro lado, ensaios quantitativos para a função CRE mamíferos têm sido desenvolvidos em sistemas de cultura de tecidos (por exemplo, dual ensaios luciferase), mas o in vivo relevância destes resultados é muitas vezes incerto. Eletroporação oferece uma excelente alternativa para transgenia mouse tradicional na medida em que permite tanto a avaliação espaço-temporal e quantitativa da cis-regulatórias atividade no tecido vivo em mamíferos. Esta técnica tem sido particularmente útil na análise de cis-regulação no sistema nervoso central, especialmente no córtex cerebral e da retina 6-8. Enquanto eletroporação do mouse na retina, tanto in vivo e ex vivo, foi desenvolvida e amplamente descrito por Matsuda e Cepko 6-7,9, desenvolvemos recentemente uma abordagem simples para quantificar a atividade dos fotorreceptores específicos CREs em electroporated rato retinas 10. Dado que a quantidade de DNA que é introduzido na retina por eletroporação pode variar de experimento para experimento, é necessário incluir um co-electroporated &quot;controle de carga&quot; em todos os experimentos. A este respeito, a técnica é muito semelhante ao ensaio de luciferase dupla utilizada para quantificar atividade do promotor em células em cultura. Quando se examina as fotorreceptoras atividade cis-regulatórias, eletroporação é geralmente realizado em ratos recém-nascidos (dia pós-natal 0, P0) que é o tempo de produção da haste de pico 11-12. Uma vez que os tipos de células da retina tornam-se pós-mitótico, eletroporação é muito menos eficiente. Dada a elevada taxa de nascimento haste em ratos recém-nascidos eo fato de que hastes constituem mais de 70% das células da retina de camundongos adultos, a maioria das células que estão em electroporated P0 são hastes. Por esta razão, os bastonetes são o tipo mais fácil de células da retina para estudar via eletroporação. A técnica aqui descrita é útil principalmente para quantificar a atividade de CREs fotorreceptoras.

Watch this Scientific Journal Video about Quantifying the Activity of cis-Regulatory Elements in the Mouse Retina by Explant Electroporation at JoVE.com

Quantifying the Activity of cis-Regulatory Elements in the Mouse Retina by Explant Electroporation

Este protocolo descreve uma maneira simples e barata para quantificar a atividade de cis-regulatórias elementos (ie, enhancer / promotores) na vida retinas do mouse via eletroporação explante. Preparação de DNA, a dissecção da retina, eletroporação, a cultura de explantes de retina, e pós-fixação análise e quantificação são descritos.

Quantificar a atividade de Cis Elements-Regulação na retina do rato por Eletroporação Remoção

Transcription factors within cellular gene networks control the spatiotemporal pattern and levels of expression of their target genes by binding to ...

quantifying-activity-cis-regulatory-elements-mouse-retina-explant

Research

JoVE Journal

Neuroscience

Quantifying the Activity of cis-Regulatory Elements in the Mouse Retina by Explant Electroporation

14.4K visualizações.  Washington University School of Medicine. Este protocolo descreve uma maneira simples e barata para quantificar a atividade de cis-regulatórias elementos (ie, enhancer / promotores) na vida retinas do mouse via eletroporação explante. Preparação de DNA, a dissecção da retina, eletroporação, a cultura de explantes de retina, e pós-fixação análise e quantificação são descritos.

Vídeo: Quantifying the Activity of cis-Regulatory Elements in the Mouse Retina by Explant Electroporation

Transfection of Mouse Retinal Ganglion Cells by in vivo Electroporation

The targeting and refinement of RGC projections to the midbrain is a popular and powerful model system for studying how precise patterns of neural connectivity form during development. In mice, retinofugal projections are arranged in a topographic manner and form eye-specific layers in the Lateral Geniculate Nucleus (dLGN) of the thalamus and the Superior Colliculus (SC). The development of these precise patterns of retinofugal projections has typically been studied by labeling populations of RGCs with fluorescent dyes and tracers, such as horseradish peroxidase1-4. However, these methods are too coarse to provide insight into developmental changes in individual RGC axonal arbor morphology that are the basis of retinotopic map formation. They also do not allow for the genetic manipulation of RGCs.
Recently, electroporation has become an effective method for providing precise spatial and temporal control for delivery of charged molecules into the retina5-11. Current retinal electroporation protocols do not allow for genetic manipulation and tracing of retinofugal projections of a single or small cluster of RGCs in postnatal mice. It has been argued that postnatal in vivo electroporation is not a viable method for transfecting RGCs since the labeling efficiency is extremely low and hence requires targeting at embryonic ages when RGC progenitors are undergoing differentiation and proliferation6. 
In this video we describe an in vivo electroporation protocol for targeted delivery of genes, shRNA, and fluorescent dextrans to murine RGCs postnatally. This technique provides a cost effective, fast and relatively easy platform for efficient screening of candidate genes involved in several aspects of neural development including axon retraction, branching, lamination, regeneration and synapse formation at various stages of circuit development. In summary we describe here a valuable tool which will provide further insights into the molecular mechanisms underlying sensory map development.

Transfection of Mouse Retinal Ganglion Cells by in vivo Electroporation

We demonstrate an in vivo electroporation protocol for transfecting single or small clusters of retinal ganglion cells (RGCs) and other retinal cell types in postnatal mice over a wide range of ages. The ability to label and genetically manipulate postnatal RGCs in vivo is a powerful tool for developmental studies.

Transfecção de células de camundongo por Ganglionares da Retina In vivo Eletroporação

The targeting and refinement of RGC projections to the midbrain is a popular and powerful model system for studying how precise patterns of neural ...

Neurociência

In vivo Electroporation of Developing Mouse Retina

The functional characterization of genes expressed during mammalian retinal development remains a significant challenge. Gene targeting to generate constitutive or conditional loss of function knockouts remains cost and labor intensive, as well as time consuming. Adding to these challenges, retina expressed genes may have essential roles outside the retina leading to unintended confounds when using a knockout approach. Furthermore, the ability to ectopically express a gene in a gain of function experiment can be extremely valuable when attempting to identify a role in cell fate specification and/or terminal differentiation.
We present a method for the rapid and efficient incorporation of DNA plasmids into the neonatal mouse retina by electroporation. The application of short electrical impulses above a certain field strength results in a transient increase in plasma membrane permeability, facilitating the transfer of material across the membrane 1,2,3,4. Groundbreaking work demonstrated that electroporation could be utilized as a method of gene transfer into mammalian cells by inducing the formation of hydrophilic plasma membrane pores allowing the passage of highly charged DNA through the lipid bilayer 5. Continuous technical development has resulted in the viability of electroporation as a method for in vivo gene transfer in multiple mouse tissues including the retina, the method for which is described herein 6, 7, 8, 9, 10. 
DNA solution is injected into the subretinal space so that DNA is placed between the retinal pigmented epithelium and retina of the neonatal (P0) mouse and electrical pulses are applied using a tweezer electrode. The lateral placement of the eyes in the mouse allows for the easy orientation of the tweezer electrode to the necessary negative pole-DNA-retina-positive pole alignment. Extensive incorporation and expression of transferred genes can be identified by postnatal day 2 (P2). Due to the lack of significant lateral migration of cells in the retina, electroporated and non-electroporated regions are generated. Non-electroporated regions may serve as internal histological controls where appropriate. 
Retinal electroporation can be used to express a gene under a ubiquitous promoter, such as CAG, or to disrupt gene function using shRNA constructs or Cre-recombinase. More targeted expression can be achieved by designing constructs with cell specific gene promoters. Visualization of electroporated cells is achieved using bicistronic constructs expressing GFP or by co-electroporating a GFP expression construct. Furthermore, multiple constructs may be electroporated for the study of combinatorial gene effects or simultaneous gain and loss of function of different genes. Retinal electroporation may also be utilized for the analysis of genomic cis-regulatory elements by generating appropriate expression constructs and deletion mutants. Such experiments can be used to identify cis-regulatory regions sufficient or required for cell specific gene expression 11. Potential experiments are limited only by construct availability.

In vivo Electroporation of Developing Mouse Retina

A method for the incorporation of plasmid DNA into murine retinal cells for the purpose of performing either gain- or loss of function studies in vivo is presented. This method capitalizes on the transient increase in permeability of cell plasma membranes induced by the application of an external electrical field.

Em Eletroporação vivo de Retina do rato em desenvolvimento

The functional characterization of genes expressed during mammalian retinal development remains a significant challenge.  Gene targeting to generate ...

Gene Transfer to the Developing Mouse Inner Ear by In Vivo Electroporation

The mammalian inner ear has 6 distinct sensory epithelia: 3 cristae in the ampullae of the semicircular canals; maculae in the utricle and saccule; and the organ of Corti in the coiled cochlea. The cristae and maculae contain vestibular hair cells that transduce mechanical stimuli to subserve the special sense of balance, while auditory hair cells in the organ of Corti are the primary transducers for hearing 1. Cell fate specification in these sensory epithelia and morphogenesis of the semicircular canals and cochlea take place during the second week of gestation in the mouse and are largely completed before birth 2,3. Developmental studies of the mouse inner ear are routinely conducted by harvesting transgenic embryos at different embryonic or postnatal stages to gain insight into the molecular basis of cellular and/or morphological phenotypes 4,5. We hypothesize that gene transfer to the developing mouse inner ear in utero in the context of gain- and loss-of-function studies represents a complimentary approach to traditional mouse transgenesis for the interrogation of the genetic mechanisms underlying mammalian inner ear development6.
The experimental paradigm to conduct gene misexpression studies in the developing mouse inner ear demonstrated here resolves into three general steps: 1) ventral laparotomy; 2) transuterine microinjection; and 3) in vivo electroporation. Ventral laparotomy is a mouse survival surgical technique that permits externalization of the uterus to gain experimental access to the implanted embryos7. Transuterine microinjection is the use of beveled, glass capillary micropipettes to introduce expression plasmid into the lumen of the otic vesicle or otocyst. In vivo electroporation is the application of square wave, direct current pulses to drive expression plasmid into progenitor cells8-10. 
We previously described this electroporation-based gene transfer technique and included detailed notes on each step of the protocol11. Mouse experimental embryological techniques can be difficult to learn from prose and still images alone. In the present work, we demonstrate the 3 steps in the gene transfer procedure. Most critically, we deploy digital video microscopy to show precisely how to: 1) identify embryo orientation in utero; 2) reorient embryos for targeting injections to the otocyst; 3) microinject DNA mixed with tracer dye solution into the otocyst at embryonic days 11.5 and 12.5; 4) electroporate the injected otocyst; and 5) label electroporated embryos for postnatal selection at birth. We provide representative examples of successfully transfected inner ears; a pictorial guide to the most common causes of otocyst mistargeting; discuss how to avoid common methodological errors; and present guidelines for writing an in utero gene transfer animal care protocol.

Gene Transfer to the Developing Mouse Inner Ear by In Vivo Electroporation

The mouse inner ear is a placode-derived sensory organ whose developmental program is elaborated during gestation. We define an in utero gene transfer technique consisting of three steps: mouse ventral laparotomy, transuterine microinjection, and in vivo electroporation. We use digital video microscopy to demonstrate the critical experimental embryological techniques.

Transferência de genes para a orelha do camundongo Desenvolvimento Inner por<em&gt; In Vivo</em&gt; Eletroporação

The mammalian inner ear has 6 distinct sensory epithelia: 3 cristae in the ampullae of the semicircular canals; maculae in the utricle and saccule; and ...

In vitro Electroporation of the Lower Rhombic Lip of Midgestation Mouse Embryos

The rhombic lip is an embryonic neuroepithelium located in the hindbrain at the junction between the neural tube and the roofplate of the fourth ventricle (reviewed in 1). The rhombic lip can be subdivided into the upper rhombic lip (URL) which encompasses rhombomere 1 (r1) and generates neurons of the cerebellum and the lower rhombic lip (LRL) which gives rise to diverse neuronal brainstem lineages 2-4. LRL derivatives include the auditory neurons of the cochlear nuclei and those of the precerebellar nuclei that are involved in regulating balance and motor control 5-8. Neurogenesis from the LRL occurs over a large temporal window that encompasses embryonic days (E) 9.5-16.55, 9. Different neuronal lineages emerge from the LRL as postmitotic cells (or are born) during distinct developmental days during this neurogenic window. 
Electroporation of gene expression constructs can be used to manipulate gene expression in LRL progenitors and can potentially change the fate of the neurons produced from this region 10-12. Altering gene expression of LRL progenitors in the mouse via in utero electroporation has been highly successful for manipulating lineages born on embryonic day E12.5 or later 10, 12-14. In utero electroporations prior to E12.5 have been unsuccessful primarily due to the lethality associated with puncturing the fourth ventricle roofplate, a necessary step in delivering exogenous DNA that is electroporated into the LRL. However, many LRL derived lineages arise from the LRL earlier than E12.5 9. These earlier born lineages include the neurons that comprise the lateral reticular, external cuneate, and inferior olivary nuclei of the precerebellar system which function to connect inputs from the spinal cord and cortex to the cerebellum 5. In order to manipulate expression in the LRL of embryos younger than E12.5, we developed an in vitro system in which embryos are placed into culture following electroporation.
This study presents an efficient and effective method for manipulating the gene expression of LRL progenitors at E11.5. Embryos electroporated with green fluorescent protein (GFP) driven from the broadly active CAG promoter reproducibly expressed GFP after 24 hours of culture. A critical aspect of this assay is that gene expression is only altered because of the expression of the exogenous gene and not because of secondary effects that result from the electroporation and culturing techniques. It was determined that the endogenous gene expression patterns remain undisturbed in electroporated and cultured embryos. This assay can be utilized to alter the fate of cells emerging from the LRL of embryos younger than E12.5 through the introduction of plasmids for overexpression or knock down (through RNAi) of different pro-neural transcription factors.

In vitro Electroporation of the Lower Rhombic Lip of Midgestation Mouse Embryos

This study describes the development of an in vitro electroporation technique that allows for the manipulation of gene expression in the lower rhombic lip of midgestation embryos.

Em Eletroporação vitro do lábio inferior rômbico de embriões de camundongos Midgestation

The rhombic lip is an embryonic neuroepithelium located in the hindbrain at the junction between the neural tube and the roofplate of the fourth ventricle ...

Genetic Manipulation of the Mouse Developing Hypothalamus through In utero Electroporation

Genetic modification of specific regions of the developing mammalian brain is a very powerful experimental approach. However, generating novel mouse mutants is often frustratingly slow. It has been shown that access to the mouse brain developing in utero with reasonable post-operatory survival is possible. Still, results with this procedure have been reported almost exclusively for the most superficial and easily accessible part of the developing brain, i.e. the cortex. The thalamus, a narrower and more medial region, has proven more difficult to target. Transfection into deeper nuclei, especially those of the hypothalamus, is perhaps the most challenging and therefore very few results have been reported. Here we demonstrate a procedure to target the entire hypothalamic neuroepithelium or part of it (hypothalamic regions) for transfection through electroporation. The keys to our approach are longer narcosis times, injection in the third ventricle, and appropriate kind and positioning of the electrodes. Additionally, we show results of targeting and subsequent histological analysis of the most recessed hypothalamic nucleus, the mammillary body.

Genetic Manipulation of the Mouse Developing Hypothalamus through In utero Electroporation

Despite the functional and medical importance of the hypothalamus, in utero genetic manipulation of its development has rarely been attempted. We show a detailed procedure for in utero electroporation into the mouse hypothalamus and show representative results of total and partial (regional) hypothalamic transfection.

Manipulação genética do rato em desenvolvimento Hipotálamo através<em&gt; In utero</em&gt; Eletroporação

Genetic  modification of specific regions of the developing mammalian brain is a very  powerful experimental approach. However, generating novel mouse ...

Assessment of Vascular Regeneration in the CNS Using the Mouse Retina

The rodent retina is perhaps the most accessible mammalian system in which to investigate neurovascular interplay within the central nervous system (CNS). It is increasingly being recognized that several neurodegenerative diseases such as Alzheimer&#8217;s, multiple sclerosis, and amyotrophic lateral sclerosis present elements of vascular compromise. In addition, the most prominent causes of blindness in pediatric and working age populations (retinopathy of prematurity and diabetic retinopathy, respectively) are characterized by vascular degeneration and failure of physiological vascular regrowth. The aim of this technical paper is to provide a detailed protocol to study CNS vascular regeneration in the retina. The method can be employed to elucidate molecular mechanisms that lead to failure of vascular growth after ischemic injury. In addition, potential therapeutic modalities to accelerate and restore healthy vascular plexuses can be explored. Findings obtained using the described approach may provide therapeutic avenues for ischemic retinopathies such as that of diabetes or prematurity and possibly benefit other vascular disorders of the CNS.

The rodent retina has long been recognized as an accessible window to the brain. In this technical paper we provide a protocol that employs the mouse model of oxygen-induced retinopathy to study the mechanisms that lead to failure of vascular regeneration within the central nervous system after ischemic injury. The described system can also be harnessed to explore strategies to promote regrowth of functional blood vessels within the retina and CNS.

Assessment of Vascular regeneração no SNC Usando o rato Retina

The rodent retina is perhaps the most accessible mammalian system in which to investigate neurovascular interplay within the central nervous system (CNS). ...

Telomerase Activity in the Various Regions of Mouse Brain: Non-Radioactive Telomerase Repeat Amplification Protocol (TRAP) Assay

Telomerase, a ribonucleoprotein, is responsible for maintaining the telomere length and therefore promoting genomic integrity, proliferation, and lifespan. In addition, telomerase protects the mitochondria from oxidative stress and confers resistance to apoptosis, suggesting its possible importance for the surviving of non-mitotic, highly active cells such as neurons. We previously demonstrated the ability of novel telomerase activators to increase telomerase activity and expression in the various mouse brain regions and to protect motor neurons cells from oxidative stress. These results strengthen the notion that telomerase is involved in the protection of neurons from various lesions. To underline the role of telomerase in the brain, we here compare the activity of telomerase in male and female mouse brain and its dependence on age. TRAP assay is a standard method for detecting telomerase activity in various tissues or cell lines. Here we demonstrate the analysis of telomerase activity in three regions of the mouse brain by non-denaturing protein extraction using CHAPS lysis buffer followed by modification of the standard TRAP assay.
In this 2-step assay, endogenous telomerase elongates a specific telomerase substrate (TS primer) by adding TTAGGG 6 bp repeats (telomerase reaction). The telomerase reaction products are amplified by PCR reaction creating a DNA ladder of 6 bp increments. The analysis of the DNA ladder is made by 4.5% high resolution agarose gel electrophoresis followed by staining with highly sensitive nucleic acid stain.
Compared to the traditional TRAP assay that utilize 32P labeled radioactive dCTP&#39;s for DNA detection and polyacrylamide gel electrophoresis for resolving the DNA ladder, this protocol offers a non-toxic time saving TRAP assay for evaluating telomerase activity in the mouse brain, demonstrating the ability to detect differences in telomerase activity in the various female and male mouse brain region.

Telomerase Activity in the Various Regions of Mouse Brain: Non-Radioactive Telomerase Repeat Amplification Protocol TRAP Assay

Telomerase is expressed in the neonatal brain and also in distinct regions of the adult brain. We present a non-toxic time saving TRAP assay for the analysis of telomerase activity in various regions of the mouse brain and detection of differences in telomerase activity between male and female mouse brains.

A atividade da telomerase nas diversas regiões de cérebro de camundongo: A telomerase não-radioativo Repetir Amplification Protocol (TRAP) Assay

Telomerase, a ribonucleoprotein, is responsible for maintaining the telomere length and therefore promoting genomic integrity, proliferation, and ...

Imaging Ca2+ Dynamics in Cone Photoreceptor Axon Terminals of the Mouse Retina

Retinal cone photoreceptors (cones) serve daylight vision and are the basis of color discrimination. They are subject to degeneration, often leading to blindness in many retinal diseases. Calcium (Ca2+), a key second messenger in photoreceptor signaling and metabolism, has been proposed to be indirectly linked with photoreceptor degeneration in various animal models. Systematically studying these aspects of cone physiology and pathophysiology has been hampered by the difficulties of electrically recording from these small cells, in particular in the mouse where the retina is dominated by rod photoreceptors. To circumvent this issue, we established a two-photon Ca2+ imaging protocol using a transgenic mouse line that expresses the genetically encoded Ca2+ biosensor TN-XL exclusively in cones and can be crossbred with mouse models for photoreceptor degeneration. The protocol described here involves preparing vertical sections (&#8220;slices&#8221;) of retinas from mice and optical imaging of light stimulus-evoked changes in cone Ca2+ level. The protocol also allows &#8220;in-slice measurement&#8221; of absolute Ca2+ concentrations; as the recordings can be followed by calibration. This protocol enables studies into functional cone properties and is expected to contribute to the understanding of cone Ca2+ signaling as well as the potential involvement of Ca2+ in photoreceptor death and retinal degeneration.

Imaging Ca2+ Dynamics in Cone Photoreceptor Axon Terminals of the Mouse Retina

We describe a protocol to monitor Ca2+ dynamics in the axon terminals of cone photoreceptors using an ex-vivo&#160;slice preparation of the mouse retina. This protocol allows comprehensive studies of cone Ca2+ signaling in an important mammalian model system, the mouse.

Imagem Ca<sup&gt; 2+</sup&gt; Dynamics nos terminais Cone fotorreceptores Axon do mouse Retina

Retinal cone photoreceptors (cones) serve daylight vision and are the basis of color discrimination. They are subject to degeneration, often leading to ...

In Vivo Gene Transfer to Schwann Cells in the Rodent Sciatic Nerve by Electroporation

The formation of the myelin sheath by Schwann cells (SCs) is essential for rapid conduction of nerve impulses along axons in the peripheral nervous system. SC-selective genetic manipulation in living animals is a powerful technique for studying the molecular and cellular mechanisms of SC myelination and demyelination in vivo. While knockout/knockin and transgenic mice are powerful tools for studying SC biology, these methods are costly and time consuming. Viral vector-mediated transgene introduction into the sciatic nerve is a simpler and less laborious method. However, viral methods have limitations, such as toxicity, transgene size constraints, and infectivity restricted to certain developmental stages. Here, we describe a new method that allows selective transfection of myelinating SCs in the rodent sciatic nerve using electroporation. By applying electric pulses to the sciatic nerve at the site of plasmid DNA injection, genes of interest can be easily silenced or overexpressed in SCs in both neonatal and more mature animals. Furthermore, this in vivo electroporation method allows for highly efficient simultaneous expression of multiple transgenes. Our novel technique should enable researchers to efficiently manipulate SC gene expression, and facilitate studies on SC development and function.

In Vivo Gene Transfer to Schwann Cells in the Rodent Sciatic Nerve by Electroporation

Here, we present an in vivo technique for gene transfer to Schwann cells (SCs) in the rodent sciatic nerve. This simple technique is useful for investigating signaling mechanisms involved in the development and maintenance of myelinating SCs.

Em Gene Vivo Transferência de células de Schwann no nervo ciático de roedores por Eletroporação

The formation of the myelin sheath by Schwann cells (SCs) is essential for rapid conduction of nerve impulses along axons in the peripheral nervous ...

Investigating Mammalian Axon Regeneration: In Vivo Electroporation of Adult Mouse Dorsal Root Ganglion

Electroporation is an essential non-viral gene transfection approach to introduce DNA plasmids or small RNA molecules into cells. A sensory neuron in the dorsal root ganglion (DRGs) extends a single axon with two branches. One branch goes to the peripheral nerve (peripheral branch), and the other branch enters the spinal cord through the dorsal root (central branch). After the neural injury, the peripheral branch regenerates robustly whereas the central branch does not regenerate. Due to the high regenerative capacity, sensory axon regeneration has been widely used as a model system to study mammalian axon regeneration in both the peripheral nervous system (PNS) and the central nervous system (CNS). Here, we describe a previously established approach protocol to manipulate gene expression in mature sensory neurons in vivo via electroporation. Based on transfection with plasmids or small RNA oligos (siRNAs or microRNAs), the approach allows for both loss- and gain-of-function experiments to study the roles of genes-of-interests or microRNAs in regulation of axon regeneration in vivo. In addition, the manipulation of gene expression in vivo can be controlled both spatially and temporally within a relatively short time course. This model system provides a unique tool to investigate the molecular mechanisms by which mammalian axon regeneration is regulated in vivo.

Investigating Mammalian Axon Regeneration: In Vivo Electroporation of Adult Mouse Dorsal Root Ganglion

Electroporation is an effective approach to deliver genes of interests into cells. By applying this approach in vivo on the neurons of adult mouse dorsal root ganglion (DRG), we describe a model to study axon regeneration in vivo.

Investigação regeneração do axônio mamíferos: In Vivo Electroporation do gânglio de raiz Dorsal do rato adulto

Electroporation is an essential non-viral gene transfection approach to introduce DNA plasmids or small RNA molecules into cells. A sensory neuron in the ...