The author thanks Hugo Juraver-Geslin, Marion Wassef and Anne H&#233;l&#232;ne Monsoro-Burq for their help and advice, and the Animal Facility of the Institut Curie. The author thanks Paul Johnson for his editing work on the manuscript. This work was supported by the Centre National de la Recherche Scientifique (CNRS UMR8197, INSERM U1024) and by grants from the "Association pour la Recherche sur le Cancer" (ARC 4972 and ARC 5115; FRC DOC20120605233 and LABEX Memolife) and the Fondation Pierre Gilles de Gennes (FPGG0039).

<ol>
	<li>Nieuwkoop, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=IIB,+Pattern+formation+in+the+developing+central+nervous+system+(CNS)+of+the+amphibians+and+birds+(English).">IIB, Pattern formation in the developing central nervous system (CNS) of the amphibians and birds (English).</a> Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen. 94, 121-127 (1991).</li><li>Nieuwkoop, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neural+induction+process;+its+morphogenetic+aspects.">The neural induction process; its morphogenetic aspects.</a> Int J Dev Biol. 43, 615-623 (1999).</li><li>Harland, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+induction.">Neural induction.</a> Curr Opin Genet Dev. 10, 357-362 (2000).</li><li>Sive, H. L., Grainger, R. M., Harland, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Early development of Xenopus laevis : a laboratory manual. , (2000).</li><li>Hoppler, S., Vize, P. D., Hoppler, S., Vize, P. 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> Xenopus protocols : post-genomic approaches. , (2012).</li><li>Franklin Hughes, W., La Velle, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effects+of+early+tectal+lesions+on+development+in+the+retinal+gonglion+cell+layer+of+chick+embryos.">The effects of early tectal lesions on development in the retinal gonglion cell layer of chick embryos.</a> J Comp Neurol. 163, 265-283 (1975).</li><li>Theveneau, E., Mayor, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beads+on+the+run:+beads+as+alternative+tools+for+chemotaxis+assays.">Beads on the run: beads as alternative tools for chemotaxis assays.</a> Methods Mol Biol. 769, 449-460 (2011).</li><li>Juraver-Geslin, H. A., Gomez-Skarmeta, J. L., Durand, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+conserved+barH-like+homeobox-2+gene+barhl2+acts+downstream+of+orthodentricle-2+and+together+with+iroquois-3+in+establishment+of+the+caudal+forebrain+signaling+center+induced+by+Sonic+Hedgehog.">The conserved barH-like homeobox-2 gene barhl2 acts downstream of orthodentricle-2 and together with iroquois-3 in establishment of the caudal forebrain signaling center induced by Sonic Hedgehog.</a> Dev Biol. 396, 107-120 (2014).</li><li>Green, J. B., New, H. V., Smith, 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=Responses+of+embryonic+Xenopus+cells+to+activin+and+FGF+are+separated+by+multiple+dose+thresholds+and+correspond+to+distinct+axes+of+the+mesoderm.">Responses of embryonic Xenopus cells to activin and FGF are separated by multiple dose thresholds and correspond to distinct axes of the mesoderm.</a> Cell. 71, 731-739 (1992).</li><li>Wallingford, J. B., Ewald, A. J., Harland, R. M., Fraser, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calcium+signaling+during+convergent+extension+in+Xenopus.">Calcium signaling during convergent extension in Xenopus.</a> Curr Biol. 11, 652-661 (2001).</li><li>Kiecker, C., Niehrs, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+morphogen+gradient+of+Wnt/beta-catenin+signalling+regulates+anteroposterior+neural+patterning+in+Xenopus.">A morphogen gradient of Wnt/beta-catenin signalling regulates anteroposterior neural patterning in Xenopus.</a> DEVELOPMENT. 128, 4189-4201 (2001).</li><li>Wilson, P. A., Hemmati-Brivanlou, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+epidermis+and+inhibition+of+neural+fate+by+Bmp-4.">Induction of epidermis and inhibition of neural fate by Bmp-4.</a> Nature. 376, 331-333 (1995).</li><li>Afouda, B. A., Hoppler, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xenopus+explants+as+an+experimental+model+system+for+studying+heart+development.">Xenopus explants as an experimental model system for studying heart development.</a> Trends in cardiovascular medicine. 19, 220-226 (2009).</li><li>Afouda, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stem-cell-like+embryonic+explants+to+study+cardiac+development.">Stem-cell-like embryonic explants to study cardiac development.</a> Methods Mol Biol. 917, 515-523 (2012).</li><li>Milet, C., Monsoro-Burq, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissection+of+Xenopus+laevis+neural+crest+for+in+vitro+explant+culture+or+in+vivo+transplantation.">Dissection of Xenopus laevis neural crest for in vitro explant culture or in vivo transplantation.</a> Journal of visualized experiments: JoVE. , (2014).</li><li>Milet, C., Maczkowiak, F., Roche, D. D., Monsoro-Burq, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pax3+and+Zic1+drive+induction+and+differentiation+of+multipotent,+migratory,+and+functional+neural+crest+in+Xenopus+embryos.">Pax3 and Zic1 drive induction and differentiation of multipotent, migratory, and functional neural crest in Xenopus embryos.</a> Proc Natl Acad Sci U S A. 110, 5528-5533 (2013).</li><li>Nieuwkoop, P. D., Faber, J., Nieuwkoop, P. D., Faber, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Normal table of Xenopus laevis (Daudin): a systematical and chronological survey of the development from the fertilized egg till the end of metamorphosis. , (1994).</li><li>Harland, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+situ+hybridization:+an+improved+whole-mount+method+for+Xenopus+embryos.">In situ hybridization: an improved whole-mount method for Xenopus embryos.</a> Methods Cell Biol. 36, 685-695 (1991).</li><li>Turner, D. L., Weintraub, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+achaete-scute+homolog+3+in+Xenopus+embryos+converts+ectodermal+cells+to+a+neural+fate.">Expression of achaete-scute homolog 3 in Xenopus embryos converts ectodermal cells to a neural fate.</a> Genes Dev. 8, 1434-1447 (1994).</li><li>Sive, H. L., Grainger, R. M., Harland, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Removing+the+Vitelline+Membrane+from+Xenopus+laevis+Embryos.">Removing the Vitelline Membrane from Xenopus laevis Embryos.</a> CSH protocols. , (2007).</li><li>Sive, H. L., Grainger, R. M., Harland, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+Cap+Isolation+from+Xenopus+laevis.">Animal Cap Isolation from Xenopus laevis.</a> CSH protocols. , (2007).</li><li>Sive, H. L., Grainger, R. M., Harland, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Embryo+dissection+and+micromanipulation+tools.">Embryo dissection and micromanipulation tools.</a> CSH protocols. , (2007).</li><li>Wilson, S. W., Houart, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review:+Early+Steps+in+the+Development+of+the+Forebrain.">Review: Early Steps in the Development of the Forebrain.</a> Developmental Cell. 6, 167-181 (2004).</li><li>Juraver-Geslin, H. A., Durand, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+development+of+the+neural+plate:+new+roles+for+apoptosis+and+for+one+of+its+main+effectors+caspase-3.">Early development of the neural plate: new roles for apoptosis and for one of its main effectors caspase-3.</a> Genesis. 53, 203-224 (2015).</li><li>Heasman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patterning+the+early+Xenopus+embryo.">Patterning the early Xenopus embryo.</a> Development. 133, 1205-1217 (2006).</li><li>Rubenstein, J. L., Martinez, S., Shimamura, K., Puelles, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+embryonic+vertebrate+forebrain:+the+prosomeric+model.">The embryonic vertebrate forebrain: the prosomeric model.</a> Science. 266, 578-580 (1994).</li><li>Puelles, L., Rubenstein, J. L. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forebrain+gene+expression+domains+and+the+evolving+prosomeric+model.">Forebrain gene expression domains and the evolving prosomeric model.</a> Trends in Neurosciences. 26, 469-476 (2003).</li><li>Martinez-Ferre, A., Martinez, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+regionalization+of+the+diencephalon.">Molecular regionalization of the diencephalon.</a> Frontiers In Neuroscience. 6, 73-73 (2012).</li><li>Scholpp, S., Lumsden, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review:+Building+a+bridal+chamber:+development+of+the+thalamus.">Review: Building a bridal chamber: development of the thalamus.</a> Trends in Neurosciences. 33, 373-380 (2010).</li><li>Coffman, C., Harris, W., Kintner, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xotch,+the+Xenopus+homolog+of+Drosophila+notch.">Xotch, the Xenopus homolog of Drosophila notch.</a> Science. 249, 1438-1441 (1990).</li><li>Pera, E. M., Acosta, H., Gouignard, N., Climent, M., Arregi, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Active+signals,+gradient+formation+and+regional+specificity+in+neural+induction.">Active signals, gradient formation and regional specificity in neural induction.</a> Exp Cell Res. 321, 25-31 (2014).</li><li>Stern, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+induction:+old+problem,+new+findings,+yet+more+questions.">Neural induction: old problem, new findings, yet more questions.</a> Development. 132, 2007-2021 (2005).</li><li>Juraver-Geslin, H. A., Ausseil, J. J., Wassef, M., Durand, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Barhl2+limits+growth+of+the+diencephalic+primordium+through+Caspase3+inhibition+of+beta-catenin+activation.">Barhl2 limits growth of the diencephalic primordium through Caspase3 inhibition of beta-catenin activation.</a> Proc Natl Acad Sci U S A. 108, 2288-2293 (2011).</li><li>Sive, H. L., Grainger, R. M., Harland, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissociation+and+Reaggregation+of+Xenopus+laevis+Animal+Caps.">Dissociation and Reaggregation of Xenopus laevis Animal Caps.</a> CSH protocols. , (2007).</li><li>Harland, R. M., Grainger, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xenopus+research:+metamorphosed+by+genetics+and+genomics.">Xenopus research: metamorphosed by genetics and genomics.</a> Trends Genet. 27, 507-515 (2011).</li><li>Beccari, L., Marco-Ferreres, R., Bovolenta, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+logic+of+gene+regulatory+networks+in+early+vertebrate+forebrain+patterning.">The logic of gene regulatory networks in early vertebrate forebrain patterning.</a> Mech Dev. 130, 95-111 (2013).</li><li>Pani, A. M., 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=Ancient+deuterostome+origins+of+vertebrate+brain+signalling+centres.">Ancient deuterostome origins of vertebrate brain signalling centres.</a> Nature. 483, 289-294 (2012).</li><li>Holland, L. Z., 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=Evolution+of+bilaterian+central+nervous+systems:+a+single+origin?.">Evolution of bilaterian central nervous systems: a single origin?.</a> Evodevo. 4, 27 (2013).</li><li>Pratt, K. G., Khakhalin, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+human+neurodevelopmental+disorders+in+the+Xenopus+tadpole:+from+mechanisms+to+therapeutic+targets.">Modeling human neurodevelopmental disorders in the Xenopus tadpole: from mechanisms to therapeutic targets.</a> Disease models &amp; mechanisms. 6, 1057-1065 (2013).</li><li>Sasai, Y., Ogushi, M., Nagase, T., Ando, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bridging+the+gap+from+frog+research+to+human+therapy:+a+tale+of+neural+differentiation+in+Xenopus+animal+caps+and+human+pluripotent+cells.">Bridging the gap from frog research to human therapy: a tale of neural differentiation in Xenopus animal caps and human pluripotent cells.</a> Development, growth &amp; differentiation. 50, s47-s55 (2008).</li></ol>

The authors have nothing to disclose.

התפתחות עצבית היא בניצוחו של גומלין מורכב בין תוכניות סלולריות התפתחותיים ואותות מהרקמות הסובבות (נבדקו ב3,31,32). כאן אנו מתארים קבוצה של פרוטוקולים שניתן להשתמש בX. laevis עובר לחקור חיצוני וגורמים פנימיים מעורבים בקביעת גורל עצבית והמורפוגנזה עצבית במבח...

מערכת העצבים של בעלי החוליות עולה מהצלחת העצבית כשכבת אחידה של תאי neuroepithelial. הבנה כיצד תוכניות התפתחותיות מושרות, מקודדות, והוקמו במהלך אזורית של הצלחת העצבית היא, כיום, מטרה עיקרית בביולוגיה התפתחותית. בהשוואה למערכות אחרות, עובר Xenopus ניסוי נוח הוא מודל של בחירה לניתוח שלבים מוקדמים של התפתחות עצבית 1,2. זה קל להשיג מספר גדול של עוברים, ופיתוח חיצוני נותן גישה לצעדים הראשונים של neurulation 3. כלים רבים זמינים כדי לתפעל באופן ניסיוני Xenopus laevis (laevis X.) התפתחות עוברית. מיקרו הזרקה של mRNAs או morpholinos (MO), כוללים שיטות פעולה מושרה, יחד עם כלים ביוכימיים ותרופתיים, מאפשר מבוקר רווח של פונקציה (GOF) ואובדן התפקוד (LOF) ושינוי ספציפי של מסלולי איתות 4,5. בלההאאקטודרם גג stocoel, הממוקם סביב קוטב החיה של blastula, או עובר gastrula בשלב מוקדם מאוד, ומכונה &quot;בעלי החיים קאפ &#39;(AC), הוא מקור לתאי pluripotent שניתן לתכנת על ידי מניפולציה של ביטוי גנים לפני explants הכנה. בכתב יד זה הם פרוטוקולים מפורטים לשימוש X. explants laevis AC לבדוק במבחנה ובמנגנונים מולקולריים vivo ותהליכים תאיים התפתחות עצבית בסיסית. טכניקה מוצגת, המאפשרת תצפית יפה של דפוסי ביטוי גנים בצינור עצבי ראשן צפרדעים, צעד ראשוני בזיהוי רמזי נחישות גורל. בעוד התצפית של רקמות רכוב שטוחות נפוצה במחקר של עובר חומוס 6, זה לא תואר כראוי בצפרדעים. מניפולציה של ביטוי גנים על ידי הזרקת mRNA או MO סינטטיים ללסטומרים של 2 או 4 עובר שלב תא מאפשרת תכנות של ACexplants 4. לדוגמא עיכוב של מסלול חלבון העצם המוךפו&quot;גנטי (BMP) על ידי ביטוי של אנטי-BMP גורם הבחור!, נותן זהות עצבית לתאי AC 3. הפרוטוקול מפורט לביצוע חשיפה מבוקר זמן ומקומי של explants AC לרמזים חיצוניים באמצעות מגע ישיר עם חרוז שרף אניוני. לבסוף טכניקה מתוארת לבדיקת תכונות ההתפתחותי של אבות עצביים in vivo על ידי השתלה של explants המעורב הוכן מהתאים נפרדים מתוכנת ניתקו וקשורים-מחדש. עובר הצפרדע הוא מודל רב עוצמה כדי לחקור את ההתפתחות עצבית חוליות מוקדמות. שילוב מניפולציה של ביטוי גנים לexplant תרבויות במבחנה מספק מידע חשוב בחקר האזורי neuroepithelium, התפשטות, והמורפוגנזה 7-12. תכנות של explants AC מותר פיתוח של לב פונקציונלי vivo לשעבר 13,14. השימוששל explant השתלת 15 הובילו לזיהוי של בורר תעתיק המינימלי התרמה תכנית בידול הרכס העצבי 16. Limitans Zona intrathalamica (ZLI) הוא מרכז איתות שמפריש סוניק קיפוד (ששש) כדי לשלוט על הצמיחה ואזורית של המוח הקדמי הזנב. כאשר נחשפו ברציפות שלשש, תאי neuroepithelial coexpressing גני שלושה שעתוק גורם - כמו-barH homeobox-2 (barhl2), orthodenticle-2 (otx2) וIroquois-3 (irx3) - רכישת שני מאפיינים של תא ZLI: הסמכות ל להביע את ששש, ואת היכולת להפריד מתאי צלחת עצביים קדמי. כמערכת מודל, האינדוקציה של גורל ZLI לתאי neuroepithelial יוצג 8. פרוטוקולים אלה מכוונים למתן וכלים פשוטים, זולים, יעילים לביולוגים התפתחותיים וחוקרים אחרים לחקור את MEC הבסיסיhanisms של התנהגויות תא עצביות מרכזיות. פרוטוקולים אלה הם מגוונים מאוד ומאפשרים החקירה של מגוון גדול של רמזי נחישות עצביים חיצוניים ופנימיים. זה מאפשר לטווח ארוך בניתוח vivo של מחויבות עצביות שושלת, אינטראקציות אינדוקטיביים והתנהגויות תא.

<table><tbody><tr><td>Paraformaldehyde</td><td>VWR</td><td>&amp;nbsp;20909.290</td><td>Toxic</td></tr><tr><td>anion exchange resin beads</td><td>Biorad</td><td>140- 1231</td><td></td></tr><tr><td>Bovine Serum Albumin&amp;nbsp;</td><td>SIGMA</td><td>A-7888</td><td>For culture of animal cappH 7.6</td></tr><tr><td>Gentamycine&amp;nbsp;</td><td>GIBCO</td><td>15751-045&amp;nbsp;</td><td>antibiotic</td></tr><tr><td>Bovine Serum Albumin</td><td>SIGMA</td><td>A7906</td><td>&amp;nbsp;for bead preparation</td></tr></tbody></table>

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.

בהתבסס על שיקולים מורפולוגיים במינים שונים, מניפולציות עובריות, ואת דפוס הביטוי של גני רגולציה, מודל רעיוני גורס כי הצלחת העצבית מחולקת למגזרים רוחביים ואורך המגדירים רשת התפתחותית יצירת שדות histogenic מובחנים. בצלחת העצבית, primordia של המוח הקדמי, המוח ה?...

Watch this Scientific Journal Video about Stem cell-like Xenopus Embryonic Explants to Study Early Neural Developmental Features In Vitro and In Vivo at JoVE.com

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.

כמו תא גזע<em&gt; Xenopus</em&gt; Explants העובריים לחקר תכונות המוקדמות עצבי התפתחותית<em&gt; במבחנה</em&gt; ו<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, ...

stem-cell-like-xenopus-embryonic-explants-to-study-early-neural

Universidad de Cartagena UDEC

Research

JoVE Journal

Developmental Biology

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

7.9K Views.  Institut Curie. 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. 

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

Understanding Early Organogenesis Using a Simplified In Situ Hybridization Protocol in Xenopus

Organogenesis is the study of how organs are specified and then acquire their specific shape and functions during development. The Xenopuslaevis embryo is very useful for studying organogenesis because their large size makes them very suitable for identifying organs at the earliest steps in organogenesis. At this time, the primary method used for identifying a specific organ or primordium is whole mount in situ hybridization with labeled antisense RNA probes specific to a gene that is expressed in the organ of interest. In addition, it is relatively easy to manipulate genes or signaling pathways in Xenopus and in situ hybridization allows one to then assay for changes in the presence or morphology of a target organ. Whole mount in situ hybridization is a multi-day protocol with many steps involved. Here we provide a simplified protocol with reduced numbers of steps and reagents used that works well for routine assays. In situ hybridization robots have greatly facilitated the process and we detail how and when we utilize that technology in the process. Once an in situ hybridization is complete, capturing the best image of the result can be frustrating. We provide advice on how to optimize imaging of in situ hybridization results. Although the protocol describes assessing organogenesis in Xenopus laevis, the same basic protocol can almost certainly be adapted to Xenopus tropicalis and other model systems.

Understanding Early Organogenesis Using a Simplified In Situ Hybridization Protocol in Xenopus

The Xenopus laevis embryo continues to be exceptionally useful in the study of early development due to its large size and ease of manipulation. A simplified protocol for whole mount in situ hybridization protocol is provided that can be used in the identification of specific organs in this model system.

הבנת organogenesis המוקדם שימוש פשוטה<em&gt; באתר</em&gt; הכלאת פרוטוקול ב<em&gt; Xenopus</em

Organogenesis is the study of how organs are specified and then acquire their specific shape and functions during development.  The Xenopuslaevis embryo ...

Functional Cloning Using a Xenopus Oocyte Expression System

Identification of genes responsible for embryonic induction poses a number of challenges; to name a few, secreted molecules of interest may be low in abundance, may not be secreted but tethered to the signaling cell(s), or may require the presence of binding partners or upstream regulatory molecules. Thus in a search for gene products capable of eliciting an early lens-inductive response in competent ectoderm, we utilized an expression cloning system that would allow identification of paracrine or juxtacrine factors as well as transcriptional or other regulatory proteins. Pools of mRNA were injected into Xenopus oocytes, and responding tissue placed directly on the oocytes and co-cultured. Following functional cloning of ldb1 from a neural plate stage cDNA library based on its ability to elicit the expression of the early lens placode marker foxe3 in lens-competent animal cap ectoderm, we characterized the mRNA expression pattern, and assayed developmental progression following overexpression or knockdown of ldb1. This system is suitable in a very wide variety of contexts where identification of an inducer or its upstream regulatory molecules is sought using a functional response in competent tissue.

Functional Cloning Using a Xenopus Oocyte Expression System

We describe a Xenopus oocyte and animal cap system for the expression cloning of genes capable of inducing a response in competent ectoderm, and discuss techniques for the subsequent analysis of such genes. This system is useful in the functional identification of a wide range of gene products.

שיבוט פונקציונלי שימוש<em&gt; Xenopus</emמערכת ביטוי ביצית&gt;

Identification of genes responsible for embryonic induction poses a number of challenges; to name a few, secreted molecules of interest may be low in ...

Neural Explant Cultures from Xenopus laevis

The complex process of axon guidance is largely driven by the growth cone, which is the dynamic motile structure at the tip of the growing axon. During axon outgrowth, the growth cone must integrate multiple sources of guidance cue information to modulate its cytoskeleton in order to propel the growth cone forward and accurately navigate to find its specific targets1. How this integration occurs at the cytoskeletal level is still emerging, and examination of cytoskeletal protein and effector dynamics within the growth cone can allow the elucidation of these mechanisms. Xenopus laevis growth cones are large enough (10-30 microns in diameter) to perform high-resolution live imaging of cytoskeletal dynamics (e.g.2-4 ) and are easy to isolate and manipulate in a lab setting compared to other vertebrates. The frog is a classic model system for developmental neurobiology studies, and important early insights into growth cone microtubule dynamics were initially found using this system5-7 . In this method8, eggs are collected and fertilized in vitro, injected with RNA encoding fluorescently tagged cytoskeletal fusion proteins or other constructs to manipulate gene expression, and then allowed to develop to the neural tube stage. Neural tubes are isolated by dissection and then are cultured, and growth cones on outgrowing neurites are imaged. In this article, we describe how to perform this method, the goal of which is to culture Xenopus laevis growth cones for subsequent high-resolution image analysis. While we provide the example of +TIP fusion protein EB1-GFP, this method can be applied to any number of proteins to elucidate their behaviors within the growth cone.

Neural Explant Cultures from Xenopus laevis

Culturing neural explants from dissected Xenopus laevis embryos that express fluorescent fusion proteins allows for imaging of growth cone cytoskeletal dynamics.

תרבויות Explant עצביות מן<em&gt; Xenopus laevis</em

The complex process of axon guidance is largely driven by the growth cone, which is the dynamic motile structure at the tip of the growing axon. During ...

Neuroscience

Ex utero Electroporation and Whole Hemisphere Explants: A Simple Experimental Method for Studies of Early Cortical Development

Cortical development involves complex interactions between neurons and non-neuronal elements including precursor cells, blood vessels, meninges and associated extracellular matrix. Because they provide a suitable organotypic environment, cortical slice explants are often used to investigate those interactions that control neuronal differentiation and development. Although beneficial, the slice explant model can suffer from drawbacks including aberrant cellular lamination and migration. Here we report a whole cerebral hemisphere explant system for studies of early cortical development that is easier to prepare than cortical slices and shows consistent organotypic migration and lamination. In this model system, early lamination and migration patterns proceed normally for a period of two days in vitro, including the period of preplate splitting, during which prospective cortical layer six forms. We then developed an ex utero electroporation (EUEP) approach that achieves ~80% success in targeting GFP expression to neurons developing in the dorsal medial cortex.
The whole hemisphere explant model makes early cortical development accessible for electroporation, pharmacological intervention and live imaging approaches. This method avoids the survival surgery required of in utero electroporation (IUEP) approaches while improving both transfection and areal targeting consistency. This method will facilitate experimental studies of neuronal proliferation, migration and differentiation.

Ex utero Electroporation and Whole Hemisphere Explants: A Simple Experimental Method for Studies of Early Cortical Development

This protocol describes an improved explant procedure that involves ex utero electroporation, dissection and culture of entire cerebral hemispheres from the embryonic mouse. The preparation facilitates pharmacological studies and assays of gene function during early cortical development.

לשעבר הרחם electroporation וexplants חצי כדור שלם: שיטה ניסיונית פשוטה למחקרים בהתפתחות קליפת מוח הקדומה

Cortical development involves complex interactions between neurons and non-neuronal elements including precursor cells, blood vessels, meninges and ...

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.

סידן פלואורסצנטי הדמיה ובעקבות היברידיזציה באתרו לאפיון עצבי בלתי מבשר בקספוס זריזה

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 ...

Live-cell Imaging and Quantitative Analysis of Embryonic Epithelial Cells in Xenopus laevis

Embryonic epithelial cells serve as an ideal model to study morphogenesis where multi-cellular tissues undergo changes in their geometry, such as changes in cell surface area and cell height, and where cells undergo mitosis and migrate. Furthermore, epithelial cells can also regulate morphogenetic movements in adjacent tissues1. A traditional method to study epithelial cells and tissues involve chemical fixation and histological methods to determine cell morphology or localization of particular proteins of interest. These approaches continue to be useful and provide "snapshots" of cell shapes and tissue architecture, however, much remains to be understood about how cells acquire specific shapes, how various proteins move or localize to specific positions, and what paths cells follow toward their final differentiated fate. High resolution live imaging complements traditional methods and also allows more direct investigation into the dynamic cellular processes involved in the formation, maintenance, and morphogenesis of multicellular epithelial sheets. Here we demonstrate experimental methods from the isolation of animal cap tissues from Xenopus laevis embryos to confocal imaging of epithelial cells and simple measurement approaches that together can augment molecular and cellular studies of epithelial morphogenesis.

Live-cell Imaging and Quantitative Analysis of Embryonic Epithelial Cells in Xenopus laevis

Xenopus embryonic epithelia are an ideal model system to study cell behaviors such as polarity development and shape change during epithelial morphogenesis. Traditional histology of fixed samples is increasingly being complemented by live-cell confocal imaging. Here we demonstrate methods to isolate frog tissues and visualize live epithelial cells and their cytoskeleton using live-cell confocal microscopy.

Live-תא הדמיה וניתוח כמותי של תאים אפיתל עובריים ב Xenopus laevis</em

Embryonic epithelial cells serve as an ideal model to study morphogenesis where multi-cellular tissues undergo changes in their geometry, such as changes ...

Biology

Generation of Na&#239;ve Blastoderm Explants from Zebrafish Embryos

Due to their optical clarity and rapid development, zebrafish embryos are an excellent system for examining cell behaviors and developmental processes. However, because of the complexity and redundancy of embryonic signals, it can be challenging to discern the complete role of any single signal during early embryogenesis. By explanting the animal region of the zebrafish blastoderm, relatively na&#239;ve clusters of embryonic cells are generated that can be easily cultured and manipulated ex vivo. By introducing a gene of interest by RNA injection before explantation, one can assess the effect of this molecule on gene expression, cell behaviors, and other developmental processes in relative isolation. Furthermore, cells from embryos of different genotypes or conditions can be combined in a single chimeric explant to examine cell/tissue interactions and tissue-specific gene functions. This article provides instructions for generating zebrafish blastoderm explants and demonstrates that a single signaling molecule - a Nodal ligand - is sufficient to induce germ layer formation and extension morphogenesis in otherwise na&#239;ve embryonic tissues. Due to their ability to recapitulate embryonic cell behaviors, morphogen gradients, and gene expression patterns in a simplified ex vivo system, these explants are anticipated to be of great utility to many zebrafish researchers.

Zebrafish blastoderm explants are generated by isolating embryonic cells from endogenous signaling centers within the early embryo, producing relatively na&#239;ve cell clusters easily manipulated and cultured ex vivo. This article provides instructions for making such explants and demonstrates their utility by interrogating roles for Nodal signaling during gastrulation.

דור של מסלקי בלסטודרם נאיביים מעוברי דגי זברה

Due to their optical clarity and rapid development, zebrafish embryos are an excellent system for examining cell behaviors and developmental processes. ...

Assessing Primary Neurogenesis in Xenopus Embryos Using Immunostaining

Primary neurogenesis is a dynamic and complex process during embryonic development that sets up the initial layout of the central nervous system. During this process, a portion of neural stem cells undergo differentiation and give rise to the first populations of differentiated primary neurons within the nascent central nervous system. Several vertebrate model organisms have been used to explore the mechanisms of neural cell fate specification, patterning, and differentiation. Among these is the African clawed frog, Xenopus, which provides a powerful system for investigating the molecular and cellular mechanisms responsible for primary neurogenesis due to its rapid and accessible development and ease of embryological and molecular manipulations. Here, we present a convenient and rapid method to observe the different populations of neuronal cells within Xenopus central nervous system. Using antibody staining and immunofluorescence on sections of Xenopus embryos, we are able to observe the locations of neural stem cells and differentiated primary neurons during primary neurogenesis.

Assessing Primary Neurogenesis in Xenopus Embryos Using Immunostaining

This article presents a convenient and rapid method for visualizing different neuronal cell populations in the central nervous system of Xenopus embryos using immunofluorescent staining on sections.

הערכת Neurogenesis יסודי<em&gt; Xenopus</em&gt; עוברים באמצעות Immunostaining

Primary neurogenesis is a dynamic and complex process during embryonic development that sets up the initial layout of the central nervous system. During ...

Blastomere Explants to Test for Cell Fate Commitment During Embryonic Development

Fate maps, constructed from lineage tracing all of the cells of an embryo, reveal which tissues descend from each cell of the embryo. Although fate maps are very useful for identifying the precursors of an organ and for elucidating the developmental path by which the descendant cells populate that organ in the normal embryo, they do not illustrate the full developmental potential of a precursor cell or identify the mechanisms by which its fate is determined. To test for cell fate commitment, one compares a cell's normal repertoire of descendants in the intact embryo (the fate map) with those expressed after an experimental manipulation. Is the cell's fate fixed (committed) regardless of the surrounding cellular environment, or is it influenced by external factors provided by its neighbors? Using the comprehensive fate maps of the Xenopus embryo, we describe how to identify, isolate and culture single cleavage stage precursors, called blastomeres. This approach allows one to assess whether these early cells are committed to the fate they acquire in their normal environment in the intact embryo, require interactions with their neighboring cells, or can be influenced to express alternate fates if exposed to other types of signals.

The fate of an individual embryonic cell can be influenced by inherited molecules and/or by signals from neighboring cells. Utilizing fate maps of the cleavage stage Xenopus embryo, single blastomeres can be identified for culture in isolation to assess the contributions of inherited molecules versus cell-cell interactions.

Explants Blastomere לבדיקת מחויבות גורל תא במהלך התפתחות עוברית

Fate maps, constructed from lineage tracing all of the cells of an embryo, reveal  which tissues descend from each cell of the embryo.  Although fate maps ...

Dissection of Xenopus laevis Neural Crest for in vitro Explant Culture or in vivo Transplantation

The neural crest (NC) is a transient dorsal neural tube cell population that undergoes an epithelium-to-mesenchyme transition (EMT) at the end of neurulation, migrates extensively towards various organs, and differentiates into many types of derivatives (neurons, glia, cartilage and bone, pigmented and endocrine cells). In this protocol, we describe how to dissect the premigratory cranial NC from Xenopus laevis embryos, in order to study NC development in vivo and in vitro. The frog model offers many advantages to study early development; abundant batches are available, embryos develop rapidly, in vivo gain and loss of function strategies allow manipulation of gene expression prior to NC dissection in donor and/or host embryos. The NC explants can be plated on fibronectin and used for in vitro studies. They can be cultured for several days in a serum-free defined medium. We also describe how to graft NC explants back into host embryos for studying NC migration and differentiation in vivo.

Dissection of Xenopus laevis Neural Crest for in vitro Explant Culture or in vivo Transplantation

This protocol describes how to dissect premigratory cranial neural crest (NC) from Xenopus laevis neurulas. These explants can be plated on fibronectin and cultured in vitro, or grafted back into host embryos. This technique allows studying the mechanisms of NC epithelium-to-mesenchyme transition, migration, and differentiation.

כמו תא גזע

Summary

Explore More Videos

Chapters in this video

הבנת organogenesis המוקדם שימוש פשוטה

שיבוט פונקציונלי שימוש

תרבויות Explant עצביות מן

לשעבר הרחם electroporation וexplants חצי כדור שלם: שיטה ניסיונית פשוטה למחקרים בהתפתחות קליפת מוח הקדומה

סידן פלואורסצנטי הדמיה ובעקבות היברידיזציה באתרו לאפיון עצבי בלתי מבשר בקספוס זריזה

Live-תא הדמיה וניתוח כמותי של תאים אפיתל עובריים ב Xenopus laevis

דור של מסלקי בלסטודרם נאיביים מעוברי דגי זברה

הערכת Neurogenesis יסודי

Explants Blastomere לבדיקת מחויבות גורל תא במהלך התפתחות עוברית

Dissection של