Name: dissection and live-imaging of the late embryonic drosophila gonad
Uploaded: 2020-10-17T14:00:00
Description: Watch this Scientific Journal Video about Dissection and Live-Imaging of the Late Embryonic Drosophila Gonad at JoVE.com

Gostaríamos de agradecer a Lindsey W. Plasschaert e Justin Sui por suas contribuições substanciais para o desenvolvimento precoce deste protocolo. Os autores são gratos à comunidade de moscas por sua generosidade com reagentes, e particularmente a Ruth Lehmann e Benjamin Lin por seu dom da linha no5'-Lifeact-tdtomato p2a tdkatushka2 Caax nos3' antes de sua publicação. Foram utilizados no estudo os estoques obtidos no Bloomington Drosophila Stock Center (NIH P40OD018537). Este trabalho foi apoiado pelo NIH RO1 GM060804, R33AG04791503 e R35GM136270 (S.D), bem como bolsas de treinamento T32GM007229 (B.W.) e F32GM125123 (L.A.).

1. Preparação do dia-anterior à dissecação
<ol><li>Afie eletróticamente uma agulha de tungstênio24 para que o diâmetro resultante seja de aproximadamente 0,03 mm. Ajuste a tensão fornecida a aproximadamente 14 V e use 3,3 M NaOH. A nitidez não deve levar mais do que 1 ou 2 min. ATENÇÃO: O NaOH é altamente corrosivo e causará queimaduras após o contato com a pele. Use luvas e óculos durante o manuseio, e trabalhe dentro de um capô de fumaça. NOTA: Após o uso, armazene NaO...

<ol>
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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Time-lapse+live+imaging+of+stem+cells+in+drosophila+testis.">Time-lapse live imaging of stem cells in drosophila testis.</a> Current Protocols in Stem Cell Biology. 0331, 1-9 (2009).</li><li>Anllo, L., Plasschaert, L. W., Sui, J., DiNardo, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Live+imaging+reveals+hub+cell+assembly+and+compaction+dynamics+during+morphogenesis+of+the+Drosophila+testis+niche.">Live imaging reveals hub cell assembly and compaction dynamics during morphogenesis of the Drosophila testis niche.</a> Developmental Biology. 446, 102-118 (2019).</li><li>Rebecca Sheng, X., Matunis, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Live+imaging+of+the+Drosophila+spermatogonial+stem+cell+niche+reveals+novel+mechanisms+regulating+germline+stem+cell+output.">Live imaging of the Drosophila spermatogonial stem cell niche reveals novel mechanisms regulating germline stem cell output.</a> Development. 138, 3367-3376 (2011).</li><li>Aboim, A. 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Durante a gonadogênese, a gônada embrionária, e particularmente o nicho de células-tronco dentro da gônada masculina15, sofre rápidas alterações morfológicas. Mecanismos de desenvolvimento que fundamentam essas mudanças dinâmicas são melhor compreendidos através de técnicas de imagem ao vivo. No entanto, no estágio 17 embrionário, a imagem in vivo da gônada torna-se impossível pelo início das contrações musculares em larga escala17. Com este pr...

O teste de melanogaster Drosophila tem servido de paradigma para nossa compreensão de muitos processos celulares dinâmicos. Estudos desse modelo lançaram luz sobre a regulação da divisão de células-tronco 1,2,3, desenvolvimento de células germinativas 4,5, biologia piRNA 6,7,8 e eventos de sinalização de células-tronco de nicho 9,10,11,12,13. Este modelo é vantajoso porque é geneticamente tratável14,15 e é um dos poucos onde podemos viver células-tronco em seu ambiente natural 3,16,17,18. No entanto, a imagem viva deste modelo tem sido limitada ao tecido adulto e aos estágios embrionários iniciais, deixando uma lacuna em nosso conhecimento da dinâmica gonadal no embrião tardio, o estágio preciso quando o nicho está se formando e começando a funcionar.
A gônada embrionária em estágio tardio é uma esfera, consistindo de células de nicho somáticas no anterior, e células germinativas enciontadas por células gândalos somáticas em todas as regiões mais posteriores19. Este órgão pode ser retratado ao vivo até o início do estágio 17 17,20,21. Novas imagens são evitadas devido ao início de contrações musculares em larga escala. Essas contrações são tão severas que empurram a gônada para fora do quadro de imagem, e tal movimento não pode ser corrigido com software de imagem. Nosso laboratório está interessado em desvendar os mecanismos de formação de nicho, que ocorre durante esse período indescritível para imagens ao vivo. Por isso, geramos uma abordagem ex vivo para imagem viva da gônada a partir do Estágio 16 embrionário, facilitando o estudo da dinâmica celular durante esse período crucial de desenvolvimento da gônada. Trabalhos anteriores do nosso laboratório mostram que essa imagem ex vivo recapitula fielmente o desenvolvimento da gônsia vivo 17. Esta técnica é a primeira e única do seu tipo para a gônus embrionária Drosophila.
Aqui, apresentamos o protocolo de dissecção necessário para ex vivo live-imaging da gônada durante estágios embrionários tardios. Este protocolo pode ser combinado com tratamentos farmacológicos, ou manipulação transgênica de linhagens celulares específicas dentro da gônada. Usando essa técnica, temos imagens com sucesso dos passos da formação do nicho de células-tronco17. Essa abordagem de imagem é, portanto, fundamental para o campo da biologia das células-tronco, pois permitirá a visualização dos estágios iniciais de formação de nicho em tempo real dentro de seu ambiente natural15,17. Embora este método seja benéfico para o campo da biologia das células-tronco, é adicionalmente aplicável para visualizar quaisquer processos dinâmicos que ocorram na gônada durante este ponto de tempo de desenvolvimento, incluindo rearranjos celulares22, adesão celular 2,12,23 e migração celular23. Esse protocolo de dissecção aumentará assim nossa compreensão de muitos processos biológicos celulares fundamentais.

<table>
	<tbody>
		<tr>
			<td>Alfa Aesar&#160;Tungsten wire</td>
			<td>Fisher Scientific</td>
			<td>AA10408G6</td>
			<td>0.25mm (0.01 in.) dia., 99.95% (metals basis)</td>
		</tr>
		<tr>
			<td>D. melanogaster: His2Av::mRFP1</td>
			<td>Bloomington Drosophila Stock Center (BDSC)</td>
			<td>FBtp0056035</td>
			<td>Schuh, Lehner, &#38; Heidmann, Current Biology, 2007</td>
		</tr>
		<tr>
			<td>D. melanogaster: nos-lifeact::tdtomato</td>
			<td>Gift from Ruth Lehmann Lab</td>
			<td></td>
			<td>Lin, Luo, &#38; Lehmann, Nature Communications, 2020: nos5&#39;- Lifeact-tdtomato p2a tdkatushka2 Caax nos3&#39;</td>
		</tr>
		<tr>
			<td>D. melanogaster: P-Dsix4-eGFP::Moesin</td>
			<td></td>
			<td>FBtp0083398</td>
			<td>Sano et al., PLoS One, 2012</td>
		</tr>
		<tr>
			<td>Diamond-tipped knife</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Double-sided tape</td>
			<td>Scotch</td>
			<td>665</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>GIBCO</td>
			<td>10082</td>
			<td></td>
		</tr>
		<tr>
			<td>Imaging dish</td>
			<td>MatTek</td>
			<td>P35GC-1.5-14-C</td>
			<td></td>
		</tr>
		<tr>
			<td>Imaging software</td>
			<td>Molecular Devices</td>
			<td></td>
			<td>MetaMorph Microscopy Automation and Image Analysis Software v7.8.4.0</td>
		</tr>
		<tr>
			<td>Insulin, bovine</td>
			<td>Sigma</td>
			<td>l0516</td>
			<td>Store aliquots at 4 &#176;C</td>
		</tr>
		<tr>
			<td>Needle holder</td>
			<td>Fisher Scientific</td>
			<td>08-955</td>
			<td></td>
		</tr>
		<tr>
			<td>Nytex basket</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/streptomycin</td>
			<td>Corning</td>
			<td>30-002-Cl</td>
			<td></td>
		</tr>
		<tr>
			<td>Ringer&#39;s solution</td>
			<td></td>
			<td></td>
			<td>2 mM MgCl2, 2 mM CaCl2, 130 mM NaCl, 5mM KCl, 36 mM Sucrose, 5mM Hepe&#8217;s Buffer; adjusted with NaOH until pH of 7.3 is achieved</td>
		</tr>
		<tr>
			<td>Schneider&#39;s Insect Media</td>
			<td>GIBCO</td>
			<td>21720-024</td>
			<td></td>
		</tr>
	</tbody>
</table>

dissection and live-imaging of the late embryonic drosophila gonad

A gônada embrionária masculina Drosophila melanogaster é um modelo vantajoso para estudar vários aspectos da biologia do desenvolvimento, incluindo, mas não se limitando ao desenvolvimento de células germinativas, biologia piRNA e formação de nicho. Aqui, apresentamos uma técnica de dissecção ao vivo da gônada ex vivo durante um período em que a imagem ao vivo in vivo é altamente ineficaz. Este protocolo descreve como transferir embriões para um prato de imagem, escolher embriões masculinos adequadamente encenados e dissecar a gônada de seu tecido circundante, mantendo sua integridade estrutural. Após a dissecção, as gôngas podem ser imagens usando um microscópio confocal para visualizar processos celulares dinâmicos. O procedimento de dissecção requer tempo e destreza precisos, mas fornecemos informações sobre como prevenir erros comuns e como superar esses desafios. Pelo que sabemos, este é o primeiro protocolo de dissecção para a gônada embrionária Drosophila , e permitirá imagens vivas durante uma janela de tempo inacessível. Esta técnica pode ser combinada com manipulações transgênicas específicas do tipo farmacológico ou celular para estudar quaisquer processos dinâmicos que ocorram dentro ou entre as células em seu ambiente gonadal natural.

Ilustramos a preparação do prato de imagem na Figura 1, como descrito na "preparação do dia da dissecação". Esses métodos devem, em última análise, resultar em embriões bem hidratados aderidos a uma tira de deslizamento de cobertura, que é temporariamente fixada na parte inferior do prato e submersa na solução de Ringer (Figura 1F). Uma faca de ponta de diamante permite que se corte limpamente uma tampa de 22 x 22 mm em três a quatro tiras menores ...

Watch this Scientific Journal Video about Dissection and Live-Imaging of the Late Embryonic Drosophila Gonad at JoVE.com

Dissection and Live-Imaging of the Late Embryonic Drosophila Gonad

Aqui, fornecemos um protocolo de dissecção necessário para a imagem viva da gônada masculina Drosophila . Este protocolo permitirá a observação de processos celulares dinâmicos em condições normais ou após manipulação transgênica ou farmacológica.

Dissecção e Live-Imaging do Drosophila Gonad embrionário tardio

The Drosophila melanogaster male embryonic gonad is an advantageous model to study various aspects of developmental biology including, but not limited to, ...

Cell dynamics are most easily understood with live imaging. This protocol enables live imaging of the developmental stage of gonadogenesis that was previously inaccessible to visualization. The fine dissections necessary to isolate the gonad require delicate and precise manipulations under high magnification.Only a visual demonstration can convey how to execute each step. Someone new to this technique might struggle with rapid timing and delicate tissue manipulations required at certain steps. We recommend practicing sections of this protocol separately while learning.Begin by cutting a 22-by-22-millimeter cover slip into four equally sized strips using a diamond-tipped knife. Pick up one strip using forceps, and spread 30 microliters of heptane glue solution on both sides of the strip. Tilt the strip at various angles to achieve an even layer of glue residue as the heptane evaporates.Store the strip in an empty cover slip box. Set a slanted but upright position to minimize contact with the box and to maintain its stickiness. Then close the box.Transfer aged dechorionated embryos to a small watch glass filled with 500 to 750 microliters of heptane. Draw the embryos into the narrow portion of the micro pipette and slowly aggregate them near the inner tip of the pipette before gently pipetting them onto the slide. Twist the corner of a tissue wipe into a fine tip and wick away heptane from the embryos on the slide, making it easier to capture them on a glue-covered strip.Pick up a glue-covered strip using forceps and gently touch it to the embryos. Place the strip in the imaging dish, just outside the Poly-D-Lysine-coated center with embryo side up. Press the strip bound to the dish to ensure that it is fixed in place.Immediately flood the dish with two to 3.5 milliliters of Ringer's solution to submerge the embryos and prevent them from drying. During the dissection, tissue debris may stick to the dissecting needle. To get rid of this debris, periodically raise the needle just above the surface of the Ringer's solution.Select stage 16 embryos with three gut constrictions that create four stacked gut segments. To begin devitellinization, pierce the selected embryo at the anterior end with a tungsten needle and peel the vitelline membrane off the embryo. Hook the needle through the embryo in a region far from the gonads and transfer the embryo to the polylysine-coated region of the cover slip.Drag it against the bottom until it adheres. Similarly, arrange all the devitellinized embryos in a row along the top of the cover slip, leaving plenty of space below. Filet the embryo to expose its interior and slice through the embryo from its center by moving the needle posteriorly between the gonads.Tease out some internal tissue to reveal the gonad and allow it to adhere to the cover slip. Using a needle, slice a piece of tissue, including the gonad, and separate it from the remaining carcass. Then, draw this tissue to a fresh region of the coated cover slip to adhere it to the dish.Remove as much of the surrounding tissue from the gonad as possible by carefully guiding away the extraneous tissue and adhering the gonad to a fresh sticky region of the dish. Make sure not to touch the goad directly to avoid damaging it. Following dissection, add registration marks to the outside of the dissecting dish to help with locating gonads at the confocal microscope later.Remove the glue-coated strip from the dish by gently inserting the bottom prong of a pair of forceps under the strip, clasping the forceps, and then tilting the strip upwards to free it from the dish minimizing disturbance of the adhered gonads. Place the imaging dish in the stage holder using the registration marks to place the dish in the same approximate orientation as during dissection. Use Brightfield microscopy and a lower power objective to identify and focus on any piece of tissue adhered to the cover slip.Switch the IP settings to reveal fluorescence, and use the binocular eye pieces to systemically scan the dish, marking the position of each gonad within the imaging software. Gently remove the entire stage holder assembly with the imaging dish still in its holder and place the assembly on the work bench. Remove some of the Ringer's solution with a P1000 micropipette from the inside upper ledge of the imaging dish.Then remove approximately 50 to 100 microliters of the solution from under the surface using a P200 micropipette, making sure not to remove all solution. Add approximately 200 microliters of imaging media containing insulin under the surface of the remaining Ringer's solution. Add the remaining imaging media to the dish, starting at the outermost rim of the upper ledge.While pipetting, move toward the central dome of the fluid and eventually merge the tube by brushing the pipette tip across both. Switch the microscope to a higher power objective and apply proper immersion fluid. Then replace the stage holder assembly.Adjust the focus to the marked gonad position and begin imaging. Bright field visualization of an isolated gonad on a confocal microscope reveals a dark shadow surrounding the gonad periphery, which is the extracellular matrix that maintains the integrity of gonads during imaging. An example of a healthy well-cultured gonad expressing labeled and somatic gonadal cells and histone markers is shown here.If the gonads are not sufficiently hydrated during imaging, the tissue shrivels. A gonad whose extracellular matrix is damaged during dissection has a compromised boundary, which is evident by the presence of gonad-specific cells outside of the confines of the gonad. Prior to compaction, the forming stem cell niche in the X-VIVO cultured gonad initially appears as a loose aggregate of somatic cells at the gonad anterior.The niche cells are surrounded by germline stem cells. The niche aggregate initially exhibits an irregular boundary. Throughout the course of imaging, the individual niche cells rearrange their positions such that the niche aggregate acquires smoother borders, resulting in a decrease of the niche area.When attempting this protocol it is important to work quickly when transferring embryos to a coated dish and to be delicate when dissecting the gonad away from the surrounding tissue. X-VIVO culture can be combined with both genetic and pharmacological manipulations, allowing for multifaceted approaches to investigate events occurring during male or female gonadogenesis. This technique made it possible for us to visualize how the stem cell niche acquires its final architecture.Consequently, we can now form and test hypotheses about underlying cell dynamics that drive its morphogenesis.

Research

JoVE Journal

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