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.

אנחנו כאן פירוט שיטה חדשה לרוקן גורמים אימהיים או לביטוי יתר גורמים אקסוגניים לפני ההפריה. מערכת זו דורשת שני microinjections, אבל במקום זה מדלג הניתוח של צפרדעים, המשמש ב7,17 שיטת העברת מארח. זה הוא אופטימלי כדי להסיר את שלב ניתוח הצפרדע במונחים של טיפול בבעלי חיים. יתר על כן, אין לנו לקחת בחשבון לאיכות של צפרדעי נקבת מארח לניסויי ההעברה, מה שאומר שאנחנו יכולים להיפטר מגורם ביולוגי אחד שמשפיע על ההצלחה של ניסויים. לכן במערכת זו האיכות של ביציות שהתקבלו מצפרדעים דרוכים-PMSG היא גורם ביולוגי מרכזי שהוא מפתח לניסויים מוצלחים. האיכות של ביציות יכולה להישפט לאחר איסוף defolliculation השחלה או אחרי. אם כל חריגות שנצפו בשלבים האלה, זה אופטימלי כדי לאסוף השחלה אחרת מצפרדע חדשה. נקודה נוספת, כאשר אתה יכול לבדוק את איכות הביצית היא לאחר הבשלת ביצית. אם פחות מ -80% מprogesteronביציות שטופלו דואר להראות סימנים של התבגרות, ייתכן שלא תוכל לקבל מספיק מספר העוברים לניתוח נוסף. השימוש בdefolliculation האנזימטית במקום defolliculation הידני הוא גם יתרון נוסף של שימוש במערכת זו כדי להפחית את העבודה הדרושה לdefolliculation. עם זאת, זה עדיין אפשרי שdefolliculation הידני עשוי לתת פיתוח טוב יותר מאשר הטיפול האנזימטית. כפי שניתן לראות באיור 3, כמעט 10% במבחנה התבגרו ביציות יכולים להגיע לשלב ראשן שחייה. נתונים אלה נאספו מ -13 ניסויים עצמאיים כוללים אלה שדווחו ב- 8 וחדשים ניסויי הזרקה. שיטת העברת מארח צריך 75-150 ביציות בכל טיפול לקבלת נתונים משמעותיים מאז 30-60% מהביציות הועברו יכולים להגיע לשלב neurula 17. השיטה שלנו בדרך כלל מתחילה עם 200-300 ביציות בכל קבוצת ניסוי מאז כ 40-60% מעוברים ביקעו יכולים להגיעשלב תגובת שרירים. נתונים אלה מראים כי שני השיטות לתמוך בשיעור התפתחותי סביר. עד כה יש לנו להשיג 10 צפרדעים בחיים מביציות מוזרקות אוליגו antisense-הזריק mRNA ובקרת שליטה באמצעות טכניקה זו, מצביעה על כך שגישה זו תומכת בפיתוח באמצעות מטמורפוזה. שיטת המניפולציה-ICSI הביצית שלנו מספקת הזדמנות לבחון את תפקידם של גורמים אימהיים במהלך התפתחות עוברית בשלב מוקדם מאוד, זמן קצר לאחר ההפריה. בנוסף, ביטוי יתר של גורמי שינוי הכרומטין לפני ההפריה יכול לעשות את זה אפשרי לשפץ הכרומטין האימהי לפני ההפריה להבנת מצבי הכרומטין אימהיים הכרחיות לפיתוח. אסטרטגיה זו יכולה גם לעבוד היטב עם מערכות עריכת הגן הנוכחיות כגון nuclease תמלול כמו activator-מפעיל (Talen) 18,19 וCRISPR / CAS9 20,21 מאז אלה יכולים לבוא לידי ביטוי עוד לפני ההפריה. לכן, לגישה החדשה שלנו potentiאל לשמש ליישומים רבים בעתיד.

laevis Xenopus הוא בשימוש נרחב אורגניזם מודל רב עוצמה, ללמוד פיתוח 1. סיבה לכך הוא ביצי Xenopus הן גדול במיוחד (כ 1.2-1.4 מ&quot;מ, בהשוואה לעמיתיהם יונקים להיות על 0.1 מ&quot;מ) ושפע. ביצים מכילות רכיבים אימהיים מסונתזים ומאוחסנים, שהם מספיק כדי לנהוג התפתחות עוברית עד מעבר אמצע blastula (MBT, המתרחשות בשלב 8-8.5 עם 4,000-8,000 תאים). MBT מלווה בהפעלת הגנום zygotic, אשר לאחר מכן מייצרת מוצרי גן עובריים המכוונים את התפתחות נוספת. מחקרים רבים שמטרה לזהות גורמים אימהיים חשובים להתפתחות. מחקרים רבים מסתמכים על הזריקה של oligonucleotides antisense (oligos) כולל oligonucleotides morpholino לעוברי מופרים, ובמקרה זה פירוק של חלבונים אימהיים ניתן לצפות בשלב gastrula 2-4. לחלופין, mRNAs מוזרק להם מופריםbryos להפריע פונקציות גן או לאתר את גורלם של חלבוני ביטוי יתר. עם זאת, ההזרקה לעוברי שלב אחד תא בדרך כלל אינה משפיעה על רמות ביטוי של חלבונים אימהיים בשלבים עובריים בשלב מוקדם מאוד לפני MBT. Heasman ויילי הקימו את שיטת העברת מארח ללהתגבר על בעיה זו 5. בשיטה שלהם, ביציות defolliculated ידנית מוזרקות עם oligos antisense והועברו לנקבות מארח 6. חלבונים downregulated לפני הפריה כך שניתן לבחון תפקידים של חלבוני downregulated בהתפתחות עוברית מוקדמת. שיטת האזילה אימהית זה הובילה לזיהוי של מספר תפקידים התפתחותיים ייחודיים של חלבונים אימהיים, כפי שנסקרה ב- 7. בדוח זה, הפרט השיטה שפותחה לאחרונה, שבה דלדול אימהי או ביטוי יתר של mRNA לפני ההפריה מושגת ללא defolliculation ידני והעברת מארח8. Defolliculation הידני דורש הרבה זמן והעברת מארח לעתים קרובות צריכה טכניקות מיומנים והרישיון הספציפי לניתוח בעלי חיים, ובכך פוגעים שימוש תכוף בשיטת האזילה האימהית. Defolliculation והעברת מארח יוחלפו על ידי defolliculation האנזימטית 9,10 והזרקת זרע intracytoplasmic (ICSI) 11-13, בהתאמה. ICSI לביצים שימש במקור כדי לייצר צפרדעים מהונדסים 12. גרעיני זרע ועובריים גם הושתלו במבחנה ביציות דו-חיים התבגרו 11,14,15. כאן, אנו מציגים שיטת צעד-אחר-צעד שלנו להזריק זרע לביציות במבחנה התבגרו שהיו לפני שהוזרק עם oligos antisense או 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.

התפתחות עוברית של עוברי ICSI באמצעות ביציות מבחנה התבגרה נבדקה (איור 3 א). שיעורי הבשלה של ביציות GV לבמה MII משתנים ובמידה רבה תלויים באיכות הביצית. בניסויים טובים, כמעט 100% מביציות GV להגיב לסימני פרוגסטרון ותכנית של הבשלת ביצית, סוף סוף הופכים לביצים בשלב MII. כל הביציות התבגרו היו נתונים לICSI וכ -25% מביצים שהוחדרו ביקעו (איור 3 א, n = 13 לשליטה מקושקשות ביציות מוזרקות אוליגו וn = 7 ללא ביציות מוזרקות אוליגו). כ -60% או 80% מעוברים ביקעו, המופקים מביציות מוזרקות אוליגו שליטה או ביצית-הזריק עישון, בהתאמה, הגיעו לשלב blastula / gastrula. בין עוברי blastula / gastrula, כמחצית מעוברים בדגימות מוזרקת אוליגו היתה באיכות טובה (כמעט ללא סימני מחשוף נורמלי ואפופטוזיס) ואילו 82% מעוברי blastula / gastrula היו באיכות טובה בnדגימות מוזרקות על-(איור 3 א). לבסוף, 41% ו -11% מעוברים ביקעו בדגימות מוזרקות אוליגו הגיעו תגובת השרירים ושלבי ראשן שחייה, בהתאמה, ואילו 60% ו -29% מעוברים ביקעו בדגימות מוזרקות אינם עשו (איור 3 א). עוברי ICSI אלה הם התערובת של עוברים נורמלים ולא נורמלים (איור 3). חלקם עוברים מטמורפוזה ולפתח להתבגר צפרדעי 8. תוצאות אלו מצביעות על כך שהזרקה של oligonucleotides antisense לתוך ביציות GV, ואחריו IVM וICSI, מאפשרת התפתחות עוברית מוקדמת יעילה. למרות שההזרקה של oligos antisense עצמו מקטינה התפתחות עוברית, אנחנו עדיין הצלחנו להשיג מספיק עוברים למטרות ניסויים רבים כגון בדיקת שיעורים התפתחותית, RT-PCR, כתם מערבי וכן הלאה. <img alt="איור 1" src="/files/ftp_upload/52496/52496fig1highres.jpg" /> איור<html> יור 1: דוגמאות אופייניות של Xenopus laevis ביציות באיכות טובה או באיכות גרועה לניסויי התבגרות במבחנה. (א) דוגמא של ביציות באיכות גרועות. לדוגמא, ביציות מראים פיגמנטציה בלתי סדיר אינן משמשות לניסויים הבאים. כל Xenopus laevis ביצית היא כ 1.2-1.4 מ&quot;מ קוטר. (ב) ביצית defolliculated באופן חלקי. המחצית הימנית של הביצית היא מכוסה על ידי תאי זקיק, שניתן להבחין בנוכחותם של כלי דם. חץ מראה על שטח חופשי של תאי זקיק ושלתוכו מחט הזריקה מוזרקת. (ג) דוגמא של ביציות באיכות טובות, שהם שווים בהגודל ולהראות ההמיספרות בבעלי חיים באופן שווה עם פיגמנט ניגוד ברור בין האונה בעלי החיים וחצי הכדור הצמחי. 2,496 / 52496fig2highres.jpg &quot;/&gt; איור 2:. Xenopus laevis ביציות לפני ואחרי ההתבגרות לאחר הבשלת ביצית, כתמים ברורים לבנים מופיעים בחלק העליון של ההמיספרות בעלי חיים ותאי זקיקם התקלף. כל ביצית laevis Xenopus היא כ 1 מ&quot;מ בקוטר. <img alt="איור 3" src="/files/ftp_upload/52496/52496fig3highres.jpg" /> איור 3: פיתוח של עוברי ICSI, המופקים מביציות מבחנה התבגרה. (א) לפיתוח של עוברי ICSI לכל שלב הוא סיכם. ביציות הוזרקו שליטה מקושקשת oligonucleotides antisense (הזרקת אוליגו שליטה) או בלי הזרקה (הזרמה שאינה), ואחריו IVM וICSI. המספר המתאים של עוברים בכל שלב מוצג לעיל הסורג והבריח. ממוצע ± SEM מוצג. N = 4-13 ניסויים עצמאיים / f שונהemales. (ב) דוגמאות לשרוד עוברי ICSI. עובר שלב tailbud אלה יוצרו בניסוי אחד, שבו כ -200 ביציות שמשו כחומר מוצא.

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.

ומניפולציה<em&gt; במבחנה</em&gt; ההבשלה של<em&gt; Laevis Xenopus</em&gt; ביציות, ואחריו הזרקת Intracytoplasmic זרע, לחקר התפתחות העוברית

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.

ביטוי של חלבונים ניאון ב<em&gt; Lanceolatum מיתרני הראש</em&gt; על ידי הזרקת mRNA לביציות מופרה

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

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.

תרבות של עוברי Explants שבלול העכבר וג&#39;ין העברה על ידי Electroporation

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.

באמצעות ניתוח של Confocal<em&gt; Laevis Xenopus</em&gt; לחקירת מאפננים של עירובים מורפוגן Wnt וששש

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.

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, ...

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.

טכניקה לכוון Microinjection אל פיתוח<em&gt; Xenopus</em&gt; כליה

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.

מניפולציה פונקציונלית של מוצרים אימהיים הגן באמצעות<em&gt; במבחנה</em&gt; הבשלת ביצית דג הזברה

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.

ויזואליזציה וניתוח כמותי של אנגיוגנזה עובריים ב<em&gt; Xenopus טרופי</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.

שיטת Organotypic תרבות ללמוד על התפתחות עובריים עוף רקמות

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.

הזרקת דנ א לתוך eyebuds ב xenopus זריזה העוברים והדמיה של gfp המבטא האופטי axonal הביע בשלמותו, חי 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.

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 ...