We are grateful to Gurdon laboratory members for useful discussion. K.M. is a Research Fellow at Wolfson College and is supported by the Herchel Smith Postdoctoral Fellowship and the Great Britain Sasakawa Foundation. Gurdon laboratory is supported by grants from the Wellcome Trust (RG69899) and MRC to J.B.G.

<ol>
	<li>Miyamoto, K., Gurdon, J. B., Trounson, A., Gosden, R., Eichenlaub-Ritter, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insights+into+the+amphibian+egg+to+understand+the+mammalian+oocyte.">Insights into the amphibian egg to understand the mammalian oocyte.</a> Biology and Pathology of the Oocyte: Role in Fertility, Medicine, and Nuclear Reprogramming. , 1-11 (2013).</li><li>Heasman, J., Kofron, M., Wylie, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beta-catenin+signaling+activity+dissected+in+the+early+Xenopus+embryo:+a+novel+antisense+approach.">Beta-catenin signaling activity dissected in the early Xenopus embryo: a novel antisense approach.</a> Developmental biology. 222 (1), 124-134 (2000).</li><li>Oelgeschlager, M., Kuroda, H., Reversade, B., De Robertis, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chordin+is+required+for+the+Spemann+organizer+transplantation+phenomenon+in+Xenopus+embryos.">Chordin is required for the Spemann organizer transplantation phenomenon in Xenopus embryos.</a> Developmental cell. 4 (2), 219-230 (2003).</li><li>Szenker, E., Lacoste, N., Almouzni, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+developmental+requirement+for+HIRA-dependent+H3.3+deposition+revealed+at+gastrulation+in+Xenopus.">A developmental requirement for HIRA-dependent H3.3 deposition revealed at gastrulation in Xenopus.</a> Cell reports. 1 (6), 730-740 (2012).</li><li>Heasman, J., Holwill, S., Wylie, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fertilization+of+cultured+Xenopus+oocytes+and+use+in+studies+of+maternally+inherited+molecules.">Fertilization of cultured Xenopus oocytes and use in studies of maternally inherited molecules.</a> Methods in cell biology. 36, 213-230 (1991).</li><li>Heasman, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overexpression+of+cadherins+and+underexpression+of+beta-catenin+inhibit+dorsal+mesoderm+induction+in+early+Xenopus+embryos.">Overexpression of cadherins and underexpression of beta-catenin inhibit dorsal mesoderm induction in early Xenopus embryos.</a> Cell. 79 (5), 791-803 (1994).</li><li>Hulstrand, A. M., Schneider, P. N., Houston, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+antisense+oligonucleotides+in+Xenopus+oocytes.">The use of antisense oligonucleotides in Xenopus oocytes.</a> Methods. 51 (1), 75-81 (2010).</li><li>Miyamoto, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+Wave1+is+required+for+reprogramming+transcription+in+oocytes+and+for+normal+development.">Nuclear Wave1 is required for reprogramming transcription in oocytes and for normal development.</a> Science. 341 (6149), 1002-1005 (2013).</li><li>Halley-Stott, R. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mammalian+nuclear+transplantation+to+Germinal+Vesicle+stage+Xenopus+oocytes+-+a+method+for+quantitative+transcriptional+reprogramming.">Mammalian nuclear transplantation to Germinal Vesicle stage Xenopus oocytes - a method for quantitative transcriptional reprogramming.</a> Methods. 51 (1), 56-65 (2010).</li><li>Astrand, C., Belikov, S., Wrange, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histone+acetylation+characterizes+chromatin+presetting+by+NF1+and+Oct1+and+enhances+glucocorticoid+receptor+binding+to+the+MMTV+promoter.">Histone acetylation characterizes chromatin presetting by NF1 and Oct1 and enhances glucocorticoid receptor binding to the MMTV promoter.</a> Experimental cell research. 315 (15), 2604-2615 (2009).</li><li>Amaya, E., Kroll, K. 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+method+for+generating+transgenic+frog+embryos.">A method for generating transgenic frog embryos.</a> Methods in molecular biology. 97, 393-414 (1999).</li><li>Kroll, K. L., Amaya, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transgenic+Xenopus+embryos+from+sperm+nuclear+transplantations+reveal+FGF+signaling+requirements+during+gastrulation.">Transgenic Xenopus embryos from sperm nuclear transplantations reveal FGF signaling requirements during gastrulation.</a> Development. 122 (10), 3173-3183 (1996).</li><li>Smith, S. J., Fairclough, L., Latinkic, B. V., Sparrow, D. B., Mohun, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xenopus+laevis+transgenesis+by+sperm+nuclear+injection.">Xenopus laevis transgenesis by sperm nuclear injection.</a> Nature protocols. 1 (5), 2195-2203 (2006).</li><li>Drury, K. C., Schorderet-Slatkine, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+cycloheximide+on+the+'autocatalytic'+nature+of+the+maturation+promoting+factor+(MPF)+in+oocytes+of+Xenopus+laevis.">Effects of cycloheximide on the 'autocatalytic' nature of the maturation promoting factor (MPF) in oocytes of Xenopus laevis.</a> Cell. 4 (3), 269-274 (1975).</li><li>Smith, L. D., Ecker, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+the+oocyte+nucleus+in+physiological+maturation+in+Rana+pipiens.">Role of the oocyte nucleus in physiological maturation in Rana pipiens.</a> Developmental biology. 19 (3), 281-309 (1969).</li><li>Miyamoto, K., Pasque, V., Jullien, J., Gurdon, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+actin+polymerization+is+required+for+transcriptional+reprogramming+of+Oct4+by+oocytes.">Nuclear actin polymerization is required for transcriptional reprogramming of Oct4 by oocytes.</a> Genes &amp; development. 25 (9), 946-958 (2011).</li><li>Schneider, P. N., Hulstrand, A. M., Houston, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fertilization+of+Xenopus+oocytes+using+the+host+transfer+method.">Fertilization of Xenopus oocytes using the host transfer method.</a> J. Vis. Exp. (45), (2010).</li><li>Ishibashi, S., Cliffe, R., Amaya, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+efficient+bi-allelic+mutation+rates+using+TALENs+in+Xenopus+tropicalis).">Highly efficient bi-allelic mutation rates using TALENs in Xenopus tropicalis).</a> Biology open. 1 (12), 1273-1276 (2012).</li><li>Sakane, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeted+mutagenesis+of+multiple+and+paralogous+genes+in+Xenopus+laevis+using+two+pairs+of+transcription+activator-like+effector+nucleases.">Targeted mutagenesis of multiple and paralogous genes in Xenopus laevis using two pairs of transcription activator-like effector nucleases.</a> Development, growth &amp; differentiation. 56 (1), 108-114 (2014).</li><li>Nakayama, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simple+and+efficient+CRISPR/Cas9-mediated+targeted+mutagenesis+in+Xenopus+tropicalis.">Simple and efficient CRISPR/Cas9-mediated targeted mutagenesis in Xenopus tropicalis.</a> Genesis. 51 (12), 835-843 (2013).</li><li>Guo, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+RNA/Cas9-mediated+genome+editing+in+Xenopus+tropicalis.">Efficient RNA/Cas9-mediated genome editing in Xenopus tropicalis.</a> Development. 141 (3), 707-714 (2014).</li></ol>

The authors have nothing to disclose.

Abbiamo qui i dettagli di un nuovo metodo per esaurire i fattori materni o iperespressione fattori esogeni prima della fecondazione. Questo sistema richiede due microiniezioni, ma salta la chirurgia di rane, utilizzato nel metodo di trasferimento ospitante 7,17. E &#39;ottimale per rimuovere il passo chirurgia rana in termini di cura degli animali. Inoltre, non dobbiamo prendere in considerazione per la qualità delle rane femminili accoglienza per gli esperimenti di trasferimento, il che significa che possiamo sbarazzarci di un fattore biologico che influenza il successo degli esperimenti. Pertanto in questo sistema la qualità degli ovociti ottenuti da rane PMSG-innescato è un importante fattore biologico che è fondamentale per gli esperimenti di successo. La qualità degli ovociti può essere giudicato dopo la raccolta di ovaio o dopo defolliculation. Se qualsiasi anomalia si osserva in queste fasi, è ottimale per raccogliere un&#39;altra ovaio da una nuova rana. Un altro punto in cui è possibile controllare la qualità degli ovociti è dopo la maturazione degli ovociti. Se meno di 80% di progesteronee-trattati ovociti mostrano segni di maturazione, non si può essere in grado di ottenere il numero sufficiente di embrioni per ulteriori analisi. L&#39;uso di defolliculation enzimatica anziché defolliculation manuale è anche un altro vantaggio di questo sistema per ridurre il lavoro necessario per defolliculation. Tuttavia, è ancora possibile che defolliculation manuale può dare uno sviluppo migliore del trattamento enzimatico. Come mostrato in Figura 3, quasi il 10% del maturato in vitro ovociti può raggiungere la fase di nuoto girino. Questi dati sono raccolti da 13 esperimenti indipendenti, compresi quelli riportati in 8 e nuovi esperimenti di iniezione. Metodo di trasferimento Host bisogno 75-150 ovociti in ogni trattamento per ottenere dati significativi dal 30-60% degli ovociti trasferiti può raggiungere la fase neurula 17. Il nostro metodo di solito inizia con 200-300 ovociti in ciascun gruppo sperimentale dal momento che circa il 40-60% degli embrioni spaccati può raggiungere ilfase risposta muscolare. Questi dati suggeriscono che entrambi i metodi supportano una velocità di sviluppo ragionevole. Finora abbiamo ottenuto 10 rane vive di controllo mRNA-iniezione e controllo antisenso ovociti oligo-iniettato con questa tecnica, che indica che questo approccio supporta lo sviluppo attraverso la metamorfosi. Il nostro metodo di manipolazione ovocita-ICSI offre l&#39;opportunità di verificare il ruolo dei fattori materni durante molto precoce dello sviluppo embrionale, subito dopo la fecondazione. Inoltre, la sovraespressione di fattori che modificano la cromatina prima della fecondazione può rendere possibile rimodellare la cromatina materna prima della fecondazione per comprendere gli stati cromatina materni necessari per lo sviluppo. Questa strategia può anche lavorare bene con gli attuali sistemi di editing gene come la trascrizione attivatore-like effettrici nucleasi (TALEN) 18,19 e CRISPR / CAS9 20,21 dal momento che questi può essere espresso anche prima della fecondazione. Pertanto, il nostro nuovo approccio ha un Potential da utilizzare per molte applicazioni in futuro.

Xenopus laevis è un diffuso, potente organismo modello per studiare lo sviluppo 1. Questo perché le uova di Xenopus sono insolitamente grande (circa 1,2-1,4 mm, in confronto alle controparti di mammifero essendo circa 0,1 mm) e abbondante. Le uova contengono componenti maternamente sintetizzati e conservati, che sono sufficienti per guidare lo sviluppo embrionale fino transizione a metà blastula (MBT, che si verificano nella fase 8-8.5 con 4.000-8.000 cellule). MBT è accompagnata da attivazione del genoma zygotic, che quindi produce prodotti genici embrionali che indirizzano un ulteriore sviluppo. Numerosi studi volti a identificare i fattori materni importanti per lo sviluppo. Molti studi si basano sulla iniezione di oligonucleotidi antisenso (oligonucleotidi) compresi oligonucleotidi morfolino in embrioni fecondati, nel qual caso la degradazione di proteine ​​materni può essere osservato nella fase gastrula 2-4. In alternativa, mRNA sono iniettati a em fecondatobryos a disturbare le funzioni del gene o di tracciare sorti di proteine ​​sovraespresse. Tuttavia, l&#39;iniezione in embrioni stadio unicellulare normalmente non influenza i livelli di espressione delle proteine ​​materne alle primissime fasi embrionali prima MBT. Heasman e Wylie stabilito il metodo di trasferimento dell&#39;host per superare questo problema 5. In loro metodo, gli ovociti defolliculated manualmente vengono iniettati con oligonucleotidi antisenso e trasferiti in femmine di accoglienza 6. Le proteine ​​sono inibiti prima della fecondazione in modo che i ruoli delle proteine ​​ha diminuito in sviluppo embrionale precoce possono essere esaminate. Questo metodo esaurimento materno ha portato all&#39;identificazione di numerosi ruoli di sviluppo uniche di proteine ​​materne, come rivisto in 7. In questo rapporto, abbiamo dettaglio il nostro metodo recentemente sviluppato, in cui è raggiunto l&#39;esaurimento materno o sovraespressione di mRNA prima della fecondazione, senza defolliculation manuale e trasferimento di accoglienza8. Defolliculation manuale richiede un sacco di tempo e di trasferimento di accoglienza spesso ha bisogno di tecniche abili e la licenza specifica per la chirurgia degli animali, ostacolando così l&#39;uso frequente del metodo di esaurimento materno. Defolliculation e trasferimento di accoglienza sono sostituite da defolliculation enzimatica 9,10 e iniezione intracitoplasmatica di spermatozoi (ICSI) 11-13, rispettivamente. ICSI alle uova è stato originariamente utilizzato per la produzione di rane transgeniche 12. Sperma ed embrionali nuclei sono stati trapiantati in in vitro ovociti maturati anfibi 11,14,15. Qui, dimostriamo il nostro metodo step-by-step per iniettare sperma al vitro ovociti maturati che sono stati pre-iniettato con oligonucleotidi antisenso o mRNA.

<table border="0" cellpadding="0" cellspacing="0" width="589">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Name of Reagent/ Equipment</td>
			<td style="width:87px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Pregnant Mare Serum Gonadotropin (PMSG)&#160;</td>
			<td style="width:87px;">MSD Animal Health</td>
			<td style="width:119px;">Vm 01708/4309</td>
			<td>PMSG-Intervet 5000iu powder and solvent for solution for injection</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Ethyl 3-aminobenzoate methanesulfonate salt (MS222)</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">A5040</td>
			<td>For anesthesia</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:216px;">Liberase TM Research Grade</td>
			<td style="width:87px;">Roche</td>
			<td style="width:119px;">05 401 127 001</td>
			<td>For oocyte defolliculation. Store at -20oC</td>
		</tr>
		<tr height="72">
			<td height="72" style="height:72px;width:216px;">Drummond Nanoject</td>
			<td style="width:87px;">Drummond Scientific Company</td>
			<td style="width:119px;">3-000-205/206</td>
			<td>For microinjection</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">glass capillary&#160;</td>
			<td style="width:87px;">Alpha laboratories</td>
			<td style="width:119px;">7&#8221; Drummond #3-000-203-G/XL</td>
			<td>For microinjection</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Micropipette Puller&#160;</td>
			<td style="width:87px;">SUTTER Instrument</td>
			<td style="width:119px;">Model D-97</td>
			<td>For microinjection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">UltraPure Agarose</td>
			<td style="width:87px;">Invitrogen</td>
			<td style="width:119px;">16500-500</td>
			<td>For invitro maturation and ICSI</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">14 ml ultra-clear centrifuge tube&#160;</td>
			<td style="width:87px;">Beckman Coulter United Kingdom Ltd</td>
			<td style="width:119px;">344060</td>
			<td>For sperm purification</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">OptiPrep Density Gradient Medium (Iodixanol)</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">D1556</td>
			<td>For sperm purification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Digitonin</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">D141</td>
			<td>Cell permeabilization reagent</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Shaker</td>
			<td style="width:87px;">Hybaid&#160;</td>
			<td style="width:119px;">HB-SHK-1</td>
			<td>For oocyte defolliculation.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Dissecting microscope (Stereo zoom microscope)</td>
			<td style="width:87px;">ZEISS</td>
			<td style="width:119px;">Semi SV6</td>
			<td>For oocyte collection and microinjection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">50 &#956;m pore filter</td>
			<td style="width:87px;">CellTrics</td>
			<td style="width:119px;">04-0042-2317</td>
			<td>For sperm purification</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Ultracentrifuge</td>
			<td style="width:87px;">Beckman Coulter</td>
			<td style="width:119px;">Optima L-100XP</td>
			<td>For sperm purification</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">50 ml centrifuge tube</td>
			<td style="width:87px;">Cellstar Greiner Bio-One</td>
			<td style="width:119px;">227261 or 210261</td>
			<td>Oocyte collection and defolliculation reaction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">15 ml centrifuge tube</td>
			<td style="width:87px;">FALCON</td>
			<td style="width:119px;">352097</td>
			<td>For sperm purification</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">90 mm Petri dish&#160;</td>
			<td style="width:87px;">Thermo Scientific</td>
			<td style="width:119px;">101VR20/C</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Easy-Grip Cell Culture Dish, 60x15 mm</td>
			<td style="width:87px;">FALCON</td>
			<td style="width:119px;">353004</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Easy-Grip Cell Culture Dish, 35x15 mm</td>
			<td style="width:87px;">FALCON</td>
			<td style="width:119px;">351008</td>
			<td></td>
		</tr>
	</tbody>
</table>

manipulation and in vitro maturation of xenopus laevis oocytes, followed by intracytoplasmic sperm injection, to study embryonic development

Amphibian eggs have been widely used to study embryonic development. Early embryonic development is driven by maternally stored factors accumulated during oogenesis. In order to study roles of such maternal factors in early embryonic development, it is desirable to manipulate their functions from the very beginning of embryonic development. Conventional ways of gene interference are achieved by injection of antisense oligonucleotides (oligos) or mRNA into fertilized eggs, enabling under- or over-expression of specific proteins, respectively. However, these methods normally require more than several hours until protein expression is affected, and, hence, the interference of gene functions is not effective during early embryonic stages. Here, we introduce an experimental system in which expression levels of maternal proteins can be altered before fertilization. Xenopus laevis oocytes obtained from ovaries are defolliculated by incubating with enzymes. Antisense oligos or mRNAs are injected into defolliculated oocytes at the germinal vesicle (GV) stage. These oocytes are in vitro matured to eggs at the metaphase II (MII) stage, followed by intracytoplasmic sperm injection (ICSI). By this way, up to 10% of ICSI embryos can reach the swimming tadpole stage, thus allowing functional tests of specific gene knockdown or overexpression. This approach can be a useful way to study roles of maternally stored factors in early embryonic development.

Lo sviluppo embrionale di embrioni ICSI con ovociti in vitro maturazione è stata esaminata (Figura 3A). Tassi maturazione degli ovociti GV alla fase MII sono variabili e dipende in gran parte la qualità degli ovociti. In buone esperimenti, quasi il 100% degli ovociti GV rispondere alle progesterone e mostrano segni di maturazione degli ovociti, diventando infine le uova in fase MII. Tutti ovociti maturati sono stati sottoposti a ICSI e circa il 25% di uova iniettate spaccati (Figura 3A, n = 13 per il controllo scrambled ovociti oligo-iniettato e n = 7 per non ovociti oligo-iniezione). Circa il 60% o 80% degli embrioni spaccati, prodotti a partire da ovociti oligo-iniettato controllo o ovocita non per iniezione, rispettivamente, hanno raggiunto la fase blastula / gastrula. Tra gli embrioni blastula / gastrula, circa la metà degli embrioni in campioni oligo-iniettato erano di buona qualità (quasi segni di scissione anormale e apoptosi), mentre l&#39;82% degli embrioni blastula / gastrula erano di buona qualità in ncampioni on-iniettati (Figura 3A). Infine, il 41% e l&#39;11% degli embrioni spaccati in campioni oligo-iniettato raggiunsero la risposta muscolare e le fasi di nuoto girino, rispettivamente, mentre il 60% e il 29% degli embrioni spaccati in campioni non iniettato fatto (Figura 3A). Questi embrioni ICSI sono la miscela di embrioni normali e patologici (Figura 3B). Alcuni di loro subiscono metamorfosi e si sviluppano a maturare rane 8. Questi risultati suggeriscono che l&#39;iniezione di oligonucleotidi antisenso in ovociti GV, seguiti da IVM e ICSI, permette efficiente sviluppo embrionale precoce. Anche se l&#39;iniezione di oligonucleotidi antisenso si diminuisce lo sviluppo embrionale, siamo ancora in grado di ottenere un numero sufficiente di embrioni per molti scopi sperimentali come il controllo i tassi di sviluppo, RT-PCR, Western Blot e così via. <img alt="Figura 1" src="/files/ftp_upload/52496/52496fig1highres.jpg" /> Fico<html> ure 1: Esempi tipici di Xenopus laevis ovociti di buona qualità o di cattiva qualità per esperimenti di maturazione in vitro. (A) Un esempio di ovociti di qualità cattiva. Ad esempio, gli ovociti mostrano pigmentazione frammentarie non vengono utilizzate per gli esperimenti successivi. Ogni Xenopus laevis ovocita è di circa 1,2-1,4 mm di diametro. (B) Un ovocita parzialmente defolliculated. La metà destra del ovocita è coperta da cellule follicolari, che possono essere distinti dalla presenza di vasi sanguigni. Una freccia indica una zona priva di cellule del follicolo e in cui l&#39;ago di iniezione viene iniettato. (C) Un esempio di ovociti di buona qualità, che sono altrettanto dimensioni e mostrano emisferi animali uniformemente pigmentate con netto contrasto tra l&#39;emisfero animale e l&#39;emisfero vegetale. 2496 / 52496fig2highres.jpg &quot;/&gt; Figura 2:. Xenopus laevis ovociti prima e dopo la maturazione degli ovociti dopo la maturazione, macchie bianche chiare appaiono nella parte superiore degli emisferi animali e cellule follicolari sono staccata. Ogni Xenopus laevis ovocita è di circa 1 mm di diametro. <img alt="Figura 3" src="/files/ftp_upload/52496/52496fig3highres.jpg" /> Figura 3: Sviluppo di embrioni ICSI, prodotti da ovociti in vitro maturato. (A) Sviluppo di ICSI embrioni per ogni fase è riassunta. Gli oociti sono stati iniettati con controllo strapazzate oligonucleotidi antisenso (iniezione oligo di controllo) o senza iniezione (non iniezione), seguiti da IVM e ICSI. Il corrispondente numero di embrioni in ciascuna fase è indicata sopra le barre. Media ± SEM è mostrato. N = 4-13 esperimenti indipendenti / diverso females. (B) Esempi di sopravvivere embrioni ICSI. Questi embrioni tailbud fase sono stati prodotti in un esperimento, in cui circa 200 ovociti sono stati usati come materiale di partenza.

Watch this Scientific Journal Video about Manipulation and In Vitro Maturation of Xenopus laevis Oocytes, Followed by Intracytoplasmic Sperm Injection, to Study Embryonic Development at JoVE.com

Manipulation and In Vitro Maturation of Xenopus laevis Oocytes, Followed by Intracytoplasmic Sperm Injection, to Study Embryonic Development

We describe methods of manipulating Xenopus laevis immature oocytes, in vitro maturation of oocytes to eggs, and intracytoplasmic sperm injection. This protocol allows degradation of some maternal proteins and overexpression of genes of interest at fertilization, and hence is valuable to study roles of specific factors in early embryonic development.

Manipolazione e<em&gt; In Vitro</em&gt; Maturazione di<em&gt; Xenopus laevis</em&gt; ovociti, seguito da Iniezione intracitoplasmatica di spermatozoi, per studiare lo sviluppo embrionale

Amphibian eggs have been widely used to study embryonic development. Early embryonic development is driven by maternally stored factors accumulated during ...

manipulation-vitro-maturation-xenopus-laevis-oocytes-followed

Research

JoVE Journal

Developmental Biology

Manipulation and In Vitro Maturation of Xenopus laevis Oocytes, Followed by Intracytoplasmic Sperm Injection, to Study Embryonic Development

22.1K Views.  University of Cambridge. We describe methods of manipulating Xenopus laevis immature oocytes, in vitro maturation of oocytes to eggs, and intracytoplasmic sperm injection. This protocol allows degradation of some maternal proteins and overexpression of genes of interest at fertilization, and hence is valuable to study roles of specific factors in early embryonic development.

Video: Manipulation and In Vitro Maturation of Xenopus laevis Oocytes, Followed by Intracytoplasmic Sperm Injection, to Study Embryonic Development

Expression of Fluorescent Proteins in Branchiostoma lanceolatum by mRNA Injection into Unfertilized Oocytes

We report here a robust and efficient protocol for the expression of fluorescent proteins after mRNA injection into unfertilized oocytes of the cephalochordate amphioxus, Branchiostoma lanceolatum. We use constructs for membrane and nuclear targeted mCherry and eGFP that have been modified to accommodate amphioxus codon usage and Kozak consensus sequences. We describe the type of injection needles to be used, the immobilization protocol for the unfertilized oocytes, and the overall injection set-up. This technique generates fluorescently labeled embryos, in which the dynamics of cell behaviors during early development can be analyzed using the latest in vivo imaging strategies. The development of a microinjection technique in this amphioxus species will allow live imaging analyses of cell behaviors in the embryo as well as gene-specific manipulations, including gene overexpression and knockdown. Altogether, this protocol will further consolidate the basal chordate amphioxus as an animal model for addressing questions related to the mechanisms of embryonic development and, more importantly, to their evolution.

Expression of Fluorescent Proteins in Branchiostoma lanceolatum by mRNA Injection into Unfertilized Oocytes

We report here the robust and efficient expression of fluorescent proteins after mRNA injection into unfertilized oocytes of Branchiostoma lanceolatum. The development of the microinjection technique in this basal chordate will pave the way for far-reaching technical innovations in this emerging model system, including in vivo imaging and gene-specific manipulations.

L&#39;espressione di proteine ​​fluorescenti in<em&gt; Branchiostoma lanceolatum</em&gt; By mRNA iniezione in ovociti non fecondate

We report here a robust and efficient protocol for the expression of fluorescent proteins after mRNA injection into unfertilized oocytes of the ...

Ricerca

Biologia dello sviluppo

Culture of Embryonic Mouse Cochlear Explants and Gene Transfer by Electroporation

Auditory hair cells located within the mouse organ of Corti detect and transmit sound information to the central nervous system. The mechanosensory hair cells are aligned in one row of inner hair cells and three rows of outer hair cells that extend along the basal to apical axis of the cochlea. The explant culture technique described here provides an efficient method to isolate and maintain cochlear explants from the embryonic mouse inner ear. Also, the morphology and molecular characteristics of sensory hair cells and nonsensory supporting cells within the cochlear explant cultures resemble those observed in vivo and can be studied within its intrinsic cellular environment. The cochlear explants can serve as important experimental tools for the identification and characterization of molecular and genetic pathways that are involved in cellular specification and patterning. Although transgenic mouse models provide an effective approach for gene expression studies, a considerable number of mouse mutants die during embryonic development thereby hindering the analysis and interpretation of developmental phenotypes. The organ of Corti from mutant mice that die before birth can be cultured so that their in vitro development and responses to different factors can be analyzed. Additionally, we describe a technique for electroporating embryonic cochlear explants ex vivo which can be used to downregulate or overexpress specific gene(s) and analyze their potential endogenous function and test whether specific gene product is necessary or sufficient in a given context to influence mammalian cochlear development1-8.

We present a method that describes isolation and culture of cochlear explants from embryonic mouse inner ear. We also demonstrate a method for gene transfer into cochlear explants via square-wave electroporation. The in vitro explant culture coupled with gene transfer technique enables researchers to study the effects of altering gene expression during development.

Cultura della embrionali di topo cocleari espianti e Gene Transfer con elettroporazione

Auditory hair cells located within the mouse organ of Corti detect and transmit sound information to the central nervous system. The mechanosensory hair ...

Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients

This protocol describes a method to visualise ligands distributed across a field of cells. The ease of expressing exogenous proteins, together with the large size of their cells in early embryos, make Xenopus laevis a useful model for visualising GFP-tagged ligands. Synthetic mRNAs are efficiently translated after injection into early stage Xenopus embryos, and injections can be targeted to a single cell. When combined with a lineage tracer such as membrane tethered RFP, the injected cell (and its descendants) that are producing the overexpressed protein can easily be followed. This protocol describes a method for the production of fluorescently tagged Wnt and Shh ligands from injected mRNA. The methods involve the micro dissection of ectodermal explants (animal caps) and the analysis of ligand diffusion in multiple samples. By using confocal imaging, information about ligand secretion and diffusion over a field of cells can be obtained. Statistical analyses of confocal images provide quantitative data on the shape of ligand gradients. These methods may be useful to researchers who want to test the effects of factors that may regulate the shape of morphogen gradients.

Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients

The manuscript here provides a simple set of methods for analysing the secretion and diffusion of fluorescently tagged ligands in Xenopus. This provides a context for testing the ability of other proteins to modify ligand distribution and allowing experiments that may give insight into mechanisms regulating morphogen gradients.

Utilizzando Analisi confocale di<em&gt; Xenopus laevis</em&gt; Per Indagare modulatori di Wnt e Shh morphogen gradienti

This protocol describes a method to visualise ligands distributed across a field of cells. The ease of expressing exogenous proteins, together with the ...

Stem cell-like Xenopus Embryonic Explants to Study Early Neural Developmental Features In Vitro and In Vivo

Understanding the genetic programs underlying neural development is an important goal of developmental and stem cell biology. In the amphibian blastula, cells from the roof of the blastocoel are pluripotent. These cells can be isolated, and programmed to generate various tissues through manipulation of genes expression or induction by morphogens. In this manuscript protocols are described for the use of Xenopus laevis blastocoel roof explants as an assay system to investigate key in vivo and in vitro features of early neural development. These protocols allow the investigation of fate acquisition, cell migration behaviors, and cell autonomous and non-autonomous properties. The blastocoel roof explants can be cultured in a serum-free defined medium and grafted into host embryos. This transplantation into an embryo allows the investigation of the long-term lineage commitment, the inductive properties, and the behavior of transplanted cells in vivo. These assays can be exploited to investigate molecular mechanisms, cellular processes and gene regulatory networks underlying neural development. In the context of regenerative medicine, these assays provide a means to generate neural-derived cell types in vitro that could be used in drug screening.

Stem cell-like Xenopus Embryonic Explants to Study Early Neural Developmental Features In Vitro and In Vivo

In Xenopus embryos, cells from the roof of the blastocoel are pluripotent and can be programmed to generate various tissues. Here, we describe protocols to use amphibian blastocoel roof explants as an assay system to investigate key in vivo and in vitro features of early neural development.

Cellule staminali simil-<em&gt; Xenopus</em&gt; Embrionali espianti di studiare Caratteristiche precoce dello sviluppo neurale<em&gt; In Vitro</em&gt; E<em&gt; In Vivo</em

Understanding the genetic programs underlying neural development is an important goal of developmental and stem cell biology. In the amphibian blastula, ...

Technique to Target Microinjection to the Developing Xenopus Kidney

The embryonic kidney of Xenopus&#160;laevis (frog), the pronephros, consists of a single nephron, and can be used as a model for kidney disease. Xenopus embryos are large, develop externally, and can be easily manipulated by microinjection or surgical procedures. In addition, fate maps have been established for early Xenopus embryos. Targeted microinjection into the individual blastomere that will eventually give rise to an organ or tissue of interest can be used to selectively overexpress or knock down gene expression within this restricted region, decreasing secondary effects in the rest of the developing embryo. In this protocol, we describe how to utilize established Xenopus fate maps to target the developing Xenopus kidney (the pronephros), through microinjection into specific blastomere of 4- and 8-cell embryos. Injection of lineage tracers allows verification of the specific targeting of the injection. After embryos have developed to stage 38 - 40, whole-mount immunostaining is used to visualize pronephric development, and the contribution by targeted cells to the pronephros can be assessed. The same technique can be adapted to target other tissue types in addition to the pronephros.

Technique to Target Microinjection to the Developing Xenopus Kidney

Here, we present a protocol to use fate maps and lineage tracers to target injections into individual blastomeres that give rise to the kidney of Xenopus laevis embryos.

Tecnica a Target microiniezione per lo sviluppo<em&gt; Xenopus</em&gt; Kidney

The embryonic kidney of Xenopus&#160;laevis (frog), the pronephros, consists of a single nephron, and can be used as a model for kidney disease. Xenopus ...

Functional Manipulation of Maternal Gene Products Using In Vitro Oocyte Maturation in Zebrafish

Cellular events that take place during the earliest stages of animal embryonic development are driven by maternally derived gene products deposited into the developing oocyte. Because these events rely on maternal products which typically act very soon after fertilization-that preexist inside the egg, standard approaches for expression and functional reduction involving the injection of reagents into the fertilized egg are typically ineffective. Instead, such manipulations must be performed during oogenesis, prior to or during the accumulation of maternal products. This article describes in detail a protocol for the in vitro maturation of immature zebrafish oocytes and their subsequent in vitro fertilization, yielding viable embryos that survive to adulthood. This method allows the functional manipulation of maternal products during oogenesis, such as the expression of products for phenotypic rescue and tagged construct visualization, as well as the reduction of gene function through reverse-genetics agents.

Functional Manipulation of Maternal Gene Products Using In Vitro Oocyte Maturation in Zebrafish

An optimized protocol for the in vitro maturation of zebrafish oocytes used for the manipulation of maternal gene products is presented here.

Manipolazione funzionale delle materne genica Utilizzando<em&gt; In Vitro</em&gt; La maturazione degli ovociti in Zebrafish

Cellular events that take place during the earliest stages of animal embryonic development are driven by maternally derived gene products deposited into ...

Visualization and Quantitative Analysis of Embryonic Angiogenesis in Xenopus tropicalis

Blood vessels supply oxygen and nutrients throughout the body, and the formation of the vascular network is under tight developmental control. The efficient in vivo visualization of blood vessels and the reliable quantification of their complexity are key to understanding the biology and disease of the vascular network. Here, we provide a detailed method to visualize blood vessels with a commercially available fluorescent dye, human plasma acetylated low density lipoprotein DiI complex (DiI-AcLDL), and to quantify their complexity in Xenopus tropicalis. Blood vessels can be labeled by a simple injection of DiI-AcLDL into the beating heart of an embryo, and blood vessels in the entire embryo can be imaged in live or fixed embryos. Combined with gene perturbation by the targeted microinjection of nucleic acids and/or the bath application of pharmacological reagents, the roles of a gene or of a signaling pathway on vascular development can be investigated within one week without resorting to sophisticated genetically engineered animals. Because of the well-defined venous system of Xenopus and its stereotypic angiogenesis, the sprouting of pre-existing vessels, vessel complexity can be quantified efficiently after perturbation experiments. This relatively simple protocol should serve as an easily accessible tool in diverse fields of cardiovascular research.

Visualization and Quantitative Analysis of Embryonic Angiogenesis in Xenopus tropicalis

This protocol demonstrates a fluorescence-based method to visualize the vasculature and to quantify its complexity in Xenopus tropicalis. Blood vessels can be imaged minutes after the injection of a fluorescent dye into the beating heart of an embryo after genetic and/or pharmacological manipulations to study cardiovascular development in vivo.

Visualizzazione e analisi quantitativa di angiogenesi embrionale in<em&gt; Xenopus tropicalis</em

Blood vessels supply oxygen and nutrients throughout the body, and the formation of the vascular network is under tight developmental control. The ...

Organotypic Culture Method to Study the Development Of Embryonic Chicken Tissues

The embryonic chicken is commonly used as a reliable model organism for vertebrate development. Its accessibility and short incubation period makes it ideal for experimentation. Currently, the study of these developmental pathways in the chicken embryo is conducted by applying inhibitors and drugs at localized sites and at low concentrations using a variety of methods. In vitro tissue&#160;culturing is a technique that enables the study of tissues separated from the host organism, while simultaneously bypassing many of the physical limitations present when working with whole embryos, such as the susceptibility of embryos to high doses of potentially lethal chemicals. Here, we present an organotypic culturing protocol for culturing the embryonic chicken half head in vitro, which presents new opportunities for the examination of developmental processes beyond the currently established methods.

Here, we present an organotypic culturing protocol to grow embryonic chicken organs in vitro. Using this method, the development of embryonic chicken tissue can be studied, while maintaining a high degree of control over the culture environment.

Metodo di coltura organotypic per studiare lo sviluppo dei tessuti embrionali di pollo

The embryonic chicken is commonly used as a reliable model organism for vertebrate development. Its accessibility and short incubation period makes it ...

Microinjection of DNA into Eyebuds in Xenopus laevis Embryos and Imaging of GFP Expressing Optic Axonal Arbors in Intact, Living Xenopus Tadpoles

The primary visual projection of tadpoles of the aquatic frog Xenopus laevis serves as an excellent model system for studying mechanisms that regulate the development of neuronal connectivity. During establishment of the retino-tectal projection, optic axons extend from the eye and navigate through distinct regions of the brain to reach their target tissue, the optic tectum. Once optic axons enter the tectum, they elaborate terminal arbors that function to increase the number of synaptic connections they can make with target interneurons in the tectum. Here, we describe a method to express DNA encoding green fluorescent protein (GFP), and gain- and loss-of-function gene constructs, in optic neurons (retinal ganglion cells) in Xenopus embryos. We explain how to microinject a combined DNA/lipofection reagent into eyebuds of one day old embryos such that exogenous genes are expressed in single or small numbers of optic neurons. By tagging genes with GFP or co-injecting with a GFP plasmid, terminal axonal arbors of individual optic neurons with altered molecular signaling can be imaged directly in brains of intact, living Xenopus tadpoles several days later, and their morphology can be quantified. This protocol allows for determination of cell-autonomous molecular mechanisms that underlie the development of optic axon arborization in vivo.

Microinjection of DNA into Eyebuds in Xenopus laevis Embryos and Imaging of GFP Expressing Optic Axonal Arbors in Intact, Living Xenopus Tadpoles

This protocol aims to demonstrate how to microinject a DNA/DOTAP mixture into eyebuds of one day old Xenopus laevis embryos, and how to image and reconstruct individual green fluorescent protein (GFP) expressing optic axonal arbors in tectal midbrains of intact, living Xenopus tadpoles.

Microiniezione di DNA in boccioli di occhiali in embrioni di Xenopus lavis e imaging di GFP Expressing Optic Aboral Arbors in Intact, Living Xenopus Tadpoles

The primary visual projection of tadpoles of the aquatic frog Xenopus laevis serves as an excellent model system for studying mechanisms that regulate the ...

Fluorescent Calcium Imaging and Subsequent In Situ Hybridization for Neuronal Precursor Characterization in Xenopus laevis

Spontaneous intracellular calcium activity can be observed in a variety of cell types and is proposed to play critical roles in a variety of physiological processes. In particular, appropriate regulation of calcium activity patterns during embryogenesis is necessary for many aspects of vertebrate neural development, including proper neural tube closure, synaptogenesis, and neurotransmitter phenotype specification. While the observation that calcium activity patterns can differ in both frequency and amplitude suggests a compelling mechanism by which these fluxes might transmit encoded signals to downstream effectors and regulate gene expression, existing population-level approaches have lacked the precision necessary to further explore this possibility. Furthermore, these approaches limit studies of the role of cell-cell interactions by precluding the ability to assay the state of neuronal determination in the absence of cell-cell contact. Therefore, we have established an experimental workflow that pairs time-lapse calcium imaging of dissociated neuronal explants with a fluorescence in situ hybridization assay, allowing the unambiguous correlation of calcium activity pattern with molecular phenotype on a single-cell level. We were successfully able to use this approach to distinguish and characterize specific calcium activity patterns associated with differentiating neural cells and neural progenitor cells, respectively; beyond this, however, the experimental framework described in this article could be readily adapted to investigate correlations between any time-series activity profile and expression of a gene or genes of interest.

Fluorescent Calcium Imaging and Subsequent In Situ Hybridization for Neuronal Precursor Characterization in Xenopus laevis

We present a two-part protocol that combines fluorescent calcium imaging with in situ hybridization, allowing the experimenter to correlate patterns of calcium activity with gene expression profiles on a single-cell level.

Imaging fluorescente del calcio e successiva ibridazione in situ per la caratterizzazione neuronale del precursore in Xenopus laevis

Spontaneous intracellular calcium activity can be observed in a variety of cell types and is proposed to play critical roles in a variety of physiological ...