עבודה זו נתמכה על ידי theNIH grantNS042626. אנו מודים קוץ קורט קליפורניה בסן פרנסיסקו ניקון הדמיה מרכז סיוע הדמיה.

1. הכנה של עוברים דג הזברה <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> יומיים לפני electroporation, להקים כלובי דגים ההזדווגות של סוג בר באמצעות מחיצות כדי להפריד בין זכרים לנקבות. </li><li style=";text-align:right;direction:rtl"> יום אחד לפני electroporation, למשוך את חוצצים ב ההזדווגות כלובים מן היום הקודם. </li><li style=";text-align:right;direction:rtl"> איסוף עוברים דגירה 50 עוברי מופרית בתווך העוברי המכיל 30 מ&quot;ל phenylthiourea 0.003% (PTU) על 28.5 ° C. </li><li style=";text-align:right;direction:rtl"> ביום electroporation, dechorionate את העוברים באופן ידני עם מלקחיים קנס (Inox 5, דומון אלקטרונית, שוויץ), כאשר העוברים מגיעים לשלב ההתפתחותי של 22hpf. ואז להעביר את העוברים עד 3 10ml electroporation של הצלצול (180 mM NaCl, KCl 5 מ&quot;מ, 1.8 מ&quot;מ CaCl2, 5 pH Hepes mM 7.2) המכיל 0.003% PTU. </li><li style=";text-align:right;direction:rtl"> הוסף 420 μl tricaine מניות (4mg/ml) כדי electroporation 10ml הצלצול של להרדים את העוברים. </li></ol> 2. הכנה electroporation <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> מחטים זכוכית זריקה נשלפו מן הנימים (1.2 מ&quot;מ OD, 0.9 מזהה מ&quot;מ, עם נימה) על Flaming-P897 חולץ בראון (סאטר מכשירים, Novato, קליפורניה, ארה&quot;ב). קצה המחט נותק עם מלקחיים כדי לקבל סוף חדה כפי שמוצג 1D דמות. קוטר קצה צריך להיות סביב 10 מיקרומטר וזווית להתחדד צריך להיות סביב 30 מעלות. </li><li style=";text-align:right;direction:rtl"> הכן 0.8% ו -1% נקודת התכה נמוכה agarose (Shelton מדעיים, Inc קטלוג # IB70050) בתמיסה electroporation של הצלצול. Aliquot agarose פתרון 2 צינורות microcentrifuge מ&quot;ל. שמור את aliquots בתוך גוש חום ~ 37 ° C. </li><li style=";text-align:right;direction:rtl"> המערכת Gal4/UAS משמש כונן ביטוי גנים ובתאים עצביים העוברים electroporated. שני פלסמידים משמשים: פלסמיד EF1α-GFF-PT2KXIG, שבו Gal4FF הוא מונע על ידי EF1α מקדם בכל מקום, ואת הפלסמיד כטב&quot;מ-E1B-EGFP-PT2KXIG. </li><li style=";text-align:right;direction:rtl"> הכן EF1α-GFF ו-PT2KXIG כטב&quot;מ-E1B-EGFP PT2KXIG-DNA פלסמיד באמצעות GenEluteTM HP פלסמיד Midiprep Kit (Sigma). </li><li style=";text-align:right;direction:rtl"> פלסמידים מרוכזים מכן על ידי משקעים נתרן אצטט / אתנול בריכוז הסופי של 1-2 מיקרוגרם / μl ב 10 mM טריס · Cl (PH 8.5). </li><li style=";text-align:right;direction:rtl"> מערבבים את שני פלסמידים לדלל עם nuclease ללא H2O לריכוז סופי של 500 ng / μl עבור כל פלסמיד. תוספת של פנול אדום (בדילול מלא 1 / 10 הנפח הכולל) לפתרון היא המועדפת עבור להדמיה של הלידה. שמור את פתרון ה-DNA על הקרח. </li><li style=";text-align:right;direction:rtl"> ממש לפני, electroporation backload מחט הזריקה עם פתרון ה-DNA 2 μl לכוונן את עוצמת הזריקה עד 2 nl. </li></ol> 3. Electroporation <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> מיקרוסקופ לנתיחה stero (STEMI Zeiss 2000 עם הגדלה מקסימלית של 50x), מזרק בלחץ אוויר (Narishige IM microinjector 300), שני micromanipulators (WPI M3301R, מכשירים Precision העולם, סרסוטה, פלורידה, ארה&quot;ב), וכן גירוי חשמלי (SD9 רבוע ממריץ הדופק, דשא Tlefactor, מערב וורוויק, רוד איילנד, ארה&quot;ב) מוגדרים כפי שמוצג באיור 1 א. </li><li style=";text-align:right;direction:rtl"> להר עוברים, לטבול 2 עוברים 1% נקודת התכה נמוכה agarose. מיד לאחר מכן להסיר את העוברים מן agarose עם פיפטה זכוכית. </li><li style=";text-align:right;direction:rtl"> מניחים את העוברים על מכסה פלסטיק צלחת פטרי הפוכה בטיפות בודדות של agarose. להתמצא עוברים בעדינות עם בדיקה סיבים למצב הגבי-up לפני agarose מבצרת כך forebrain נגיש הן אלקטרודות מחט microinjection (איור 1B). עוברים חייב להיות מותקן בתוך agarose טיפות בודדות. </li><li style=";text-align:right;direction:rtl"> לתפעל את האלקטרודות עם micromanipulator שמאל. הכנס את האלקטרודות לתוך agarose כפי שמוצג באיור 1 ב. אישית אירידיום ופלטינה מקביל אלקטרודות דו קוטבית 125 מיקרומטר בקוטר 500 מיקרומטר ברווח מזה משמשים electroporation (fhc, קטלוג # PBSA0575). </li><li style=";text-align:right;direction:rtl"> הכנס את המחט microinjection לתוך החדר forebrain ו להזריק תערובת DNA 4nl, כמו זורם נוזל אדום את הנפיחות של החדר ניתן להבחין. </li><li style=";text-align:right;direction:rtl"> מיד, אחת 28.5 V הדופק לאורך 1 אלפית השנייה יושמה באופן ידני. ואז להפוך את הקוטביות וליישם עוד 28.5 V הדופק לאורך 1 אלפית השנייה. זה יגרום תיוג פסיפס הבילטרליים של תאים עצביים forebrain אבי. </li><li style=";text-align:right;direction:rtl"> לאחר electroporation של 10 עוברים, מוסיפים 5 מ&quot;ל בינוני עובריים כדי לכסות את העוברים ואת הקליפה agarose עם סכין microsurgical לשחרר את העוברים. </li><li style=";text-align:right;direction:rtl"> העברת עוברים electroporated לצלחת טרי בינוני 30 מ&quot;ל עובריים המכיל 0.003% PTU ו לדגור על 28.5 ° C. </li></ol> 4. הרכבה ו - זמן לשגות הדמיה חיה <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> בסביבות 4 שעות לאחר electroporation, האות EGFP הוא הנצפה אם מתחת למיקרוסקופ לנתח epifluorescent. </li><li style=";text-align:right;direction:rtl"> חמש שעות לאחר electroporation, בחר את העוברים עם פסיפס מאוד אך ביטוי EGFP חזק באזור המוח הקדמי. </li><li style=";text-align:right;direction:rtl"> העברת עוברים שנבחרו בינוני עובריים המכיל 10 מ&quot;ל PTU 0.003%. </li><li style=";text-align:right;direction:rtl"> הוסף 420 μl tricaine מניות (4mg/ml) ועד עוברי 10ml בינוני to להרדים את העוברים. </li><li style=";text-align:right;direction:rtl"> להר עוברים, לטבול 1 העובר ב 0.8% נקודת התכה נמוכה agarose. ואז להסיר לאלתר את העובר מן agarose עם טפטפת זכוכית במקום העובר על במרכזה של צלחת זכוכית 35mm התחתונה תרבות (MatTek תאגיד, חלק # P35GC-1.5-10-C, <a href="http://www.glass-bottom-dishes.com/">www.glass-bottom-dishes.com</a> ) . </li><li style=";text-align:right;direction:rtl"> להתמצא עוברים בעדינות עם בדיקה סיבים למצב הגבי-up לפני agarose מתמצק. </li><li style=";text-align:right;direction:rtl"> מניחים את צלחת כראוי על הבמה טמפרטורה מבוקרת של המיקרוסקופ confocal כפי שמוצג באיור 1C (אנו משתמשים במיקרוסקופ C1 Nikon confocal ספקטרלי עם עד הימנית יעדים). כוונו את הטמפרטורה ל 28.5 ° C. </li><li style=";text-align:right;direction:rtl"> הוסף 3ml 28.5 ° C בינוני עובריים שחומם מראש המכיל 0.003% PTU כדי לכסות את העובר. העובר מוכן כעת הדמיה. </li><li style=";text-align:right;direction:rtl"> בצעו זמן לשגות הדמיה לחיות עם מרווח קבוע באמצעות טבילה במים אובייקטיבי. </li></ol> 5. נציג תוצאות שמוצג באיור 2 נבחרות מסגרות של הדמיה זמן לשגות חי confocal של העובר electroporated של EF1α-GFF + כטב&quot;מ-E1B-EGFP ב hpf 22. <img src="/files/ftp_upload/2594/2594fig1.jpg" alt="איור 1" /> באיור 1. Apparatus הגדרת. (א) הרכבה של ציוד electroporation: גראס SD9 מרובע ממריץ הדופק (i), micromanipulator שמאל (ii), האלקטרודות (iii), Zeiss הניתוחים מיקרוסקופ (iv), המחט להזרקת (v), את הזכות micromanipulator (vi) ו-IM Narishige microinjector 300 (ז). (ב) המיקום היחסי של אלקטרודות (i), את החדר forebrain (ii) את מחט הזריקה (iii). הערה הפתרון אדום בצבע DNA כבר מוזרק לתוך החדר forebrain. (ג) הרכבה של הדמיה לחיות מיקרוסקופ C1 Nikon confocal: בקר טמפרטורה (i), טבילה במים אובייקטיבי len (ii) את העובר electroporated מוטבע נקודת התכה נמוכה agarose בתוך צלחת תחתית תרבות זכוכית (ג) (ד &#39; ) תמונה של מחט משך וחותכים עבור microinjection של ה-DNA. <img src="/files/ftp_upload/2594/2594fig2.jpg" alt="איור 2" /> איור 2. תמונות נבחרות של הדמיה זמן לשגות 18 שעות לחיות confocal של העובר electroporated עם EF1α-GFF + כטב&quot;מים-E1B-EGFP hpf ב 22. משטח החדר נמצא בצד התחתון של כל מסגרת התמונה. בר סולם מייצג 10 מיקרומטר.

<ol>
	<li>Temple, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+development+of+neural+stem+cells.">The development of neural stem cells.</a> Nature. 414, 112-117 (2001).</li><li>G#246;tz, M., Huttner, W. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cell+biology+of+neurogenesis.">The cell biology of neurogenesis.</a> Nat. Rev. Mol. Cell Biol. 6, 777-788 (2005).</li><li>Cerda, G. A., Thomas, J. E., Allende, M. L., Karlstrom, R. O., Palma, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electroporation+of+DNA,+RNA,+and+morpholinos+into+zebrafish+embryos.">Electroporation of DNA, RNA, and morpholinos into zebrafish embryos.</a> Methods. 39, 207-211 (2006).</li><li>Hendricks, M., Jesuthasan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electroporation-based+methods+for+in+vivo,+whole+mount+and+primary+culture+analysis+of+zebrafish+brain+development.">Electroporation-based methods for in vivo, whole mount and primary culture analysis of zebrafish brain development.</a> Neural. Dev. 2, 6-6 (2007).</li><li>Tawk, M., Bianco, I. H., Clarke, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Focal+electroporation+in+zebrafish+embryos+and+larvae.">Focal electroporation in zebrafish embryos and larvae.</a> Methods Mol. Biol. 546, 145-151 (2009).</li><li>Tawk, M., Tuil, D., Torrente, Y., Vriz, S., Paulin, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-efficiency+gene+transfer+into+adult+fish:+a+new+tool+to+study+fin+regeneration.">High-efficiency gene transfer into adult fish: a new tool to study fin regeneration.</a> Genesis. 32, 27-31 (2002).</li></ol>

אין ניגודי אינטרסים הכריז.

בסרטון הזה, אנחנו מדגימים את שיטת הדמיה זמן לשגות חיים של ובתאים עצביים ברמה המשובטים בקידמתו דג הזברה מתפתח. בדקנו ולשנות את הפרוטוקולים הקיימים electroporation 4-6 כדי גנטית fluorescently בודדים תווית תאים עצביים אבי. עץ היוחסין מורכב clonally התאים הצאצאים הקשורים ניתן לקבוע ?...

time-lapse live imaging of clonally related neural progenitor cells in the developing zebrafish forebrain

דפוסים מדויקים של הגירה החלוקה, ואת הבידול של ובתאים עצביים חיוניים להתפתחות המוח תקין 1,2 לתפקד. כדי להבין את ההתנהגות של ובתאים עצביים במתחם בסביבה vivo, זמן לשגות הדמיה חיה של ובתאים עצביים במוח שלם נדרש אנושות. בסרטון זה, אנו מנצלים את התכונות הייחודיות של עוברי דג הזברה כדי לחזות את התפתחותם של תאים עצביים forebrain אבי in vivo. אנו משתמשים כדי electroporation גנטית בדלילות הפרט תווית תאים עצביים אבי. בקצרה, בונה DNA המקודד סמנים ניאון הוזרקו החדר forebrain של 22 שעות שלאחר ההפריה (hpf) עוברי דג הזברה פולסים חשמליים נמסרו מיד. שש שעות מאוחר יותר, עוברי דג הזברה electroporated היו רכוב עם נקודת התכה נמוכה agarose בתרבות צלחות זכוכית התחתונה. שכותרתו fluorescently ובתאים עצביים הם צילמו אז עבור 36hours עם במרווחי זמן קבועים תחת מיקרוסקופ confocal באמצעות טבילה במים העדשה אובייקטיבי. השיטה הנוכחית מספק דרך להשיג תובנות בפיתוח vivo של תאים ובתאים forebrain עצביים יכול להיות מיושם על חלקים אחרים של מערכת העצבים המרכזית של העובר דג הזברה.

Watch this Scientific Journal Video about Time-lapse Live Imaging of Clonally Related Neural Progenitor Cells in the Developing Zebrafish Forebrain at JoVE.com

Time-lapse Live Imaging of Clonally Related Neural Progenitor Cells in the Developing Zebrafish Forebrain

הסרטון הנוכחי מדגים שיטה אשר מנצל שילוב של electroporation ו מיקרוסקופיה confocal לבצע הדמיה לחיות על הפרט ובתאים עצבית forebrain דג הזברה מתפתח.<em&gt; ב-vivo</em&gt; ניתוח של התפתחות של תאים עצביים forebrain אבי ברמה המשובטים יכולה להיות מושגת בדרך זו.

זמן לשגות הדמיה חיה של Related Clonally ובתאים עצבית של פיתוח דג הזברה forebrain

Precise patterns of division, migration and differentiation of neural progenitor cells are crucial for proper brain development and function1,2. To ...

time-lapse-live-imaging-clonally-related-neural-progenitor-cells

Research

JoVE Journal

Neuroscience

10.2K Views.  University of California San Francisco. הסרטון הנוכחי מדגים שיטה אשר מנצל שילוב של electroporation ו מיקרוסקופיה confocal לבצע הדמיה לחיות על הפרט ובתאים עצבית forebrain דג הזברה מתפתח. ב-vivo ניתוח של התפתחות של תאים עצביים forebrain אבי ברמה המשובטים יכולה להיות מושגת בדרך זו.

Video: Time-lapse Live Imaging of Clonally Related Neural Progenitor Cells in the Developing Zebrafish Forebrain

Live-cell Imaging of Sensory Organ Precursor Cells in Intact Drosophila Pupae

Since the discovery of Green Fluorescent Protein (GFP), there has been a revolutionary change in the use of live-cell imaging as a tool for understanding fundamental biological mechanisms. Striking progress has been particularly evident in Drosophila, whose extensive toolkit of mutants and transgenic lines provides a convenient model to study evolutionarily-conserved developmental and cell biological mechanisms. We are interested in understanding the mechanisms that control cell fate specification in the adult peripheral nervous system (PNS) in Drosophila. Bristles that cover the head, thorax, abdomen, legs and wings of the adult fly are individual mechanosensory organs, and have been studied as a model system for understanding mechanisms of Notch-dependent cell fate decisions. Sensory organ precursor (SOP) cells of the microchaetes (or small bristles), are distributed throughout the epithelium of the pupal thorax, and are specified during the first 12 hours after the onset of pupariation. After specification, the SOP cells begin to divide, segregating the cell fate determinant Numb to one daughter cell during mitosis. Numb functions as a cell-autonomous inhibitor of the Notch signaling pathway.
Here, we show a method to follow protein dynamics in SOP cell and its progeny within the intact pupal thorax using a combination of tissue-specific Gal4 drivers and GFP-tagged fusion proteins 1,2.This technique has the advantage over fixed tissue or cultured explants because it allows us to follow the entire development of an organ from specification of the neural precursor to growth and terminal differentiation of the organ. We can therefore directly correlate changes in cell behavior to changes in terminal differentiation. Moreover, we can combine the live imaging technique with mosaic analysis with a repressible cell marker (MARCM) system to assess the dynamics of tagged proteins in mitotic SOPs under mutant or wildtype conditions. Using this technique, we and others have revealed novel insights into regulation of asymmetric cell division and the control of Notch signaling activation in SOP cells (examples include references 1-6,7 ,8).

Live-cell Imaging of Sensory Organ Precursor Cells in Intact Drosophila Pupae

In this video, we describe a method for live cell imaging of asymmetrically dividing sensory organ progenitor cells and epidermal cells in intact Drosophila pupae

Live-תא הדמיה של תאים מבשר חושי האיברים אינטקט תסיסנית גלמים

Since the discovery of Green Fluorescent Protein (GFP), there has been a revolutionary change in the use of live-cell imaging as a tool for understanding ...

High-resolution Live Imaging of Cell Behavior in the Developing Neuroepithelium

The embryonic spinal cord consists of cycling neural progenitor cells that give rise to a large percentage of the neuronal and glial cells of the central nervous system (CNS). Although much is known about the molecular mechanisms that pattern the spinal cord and elicit neuronal differentiation1, 2, we lack a deep understanding of these early events at the level of cell behavior. It is thus critical to study the behavior of neural progenitors in real time as they undergo neurogenesis.
In the past, real-time imaging of early embryonic tissue has been limited by cell/tissue viability in culture as well as the phototoxic effects of fluorescent imaging. Here we present a novel assay for imaging such tissue for long periods of time, utilizing a novel ex vivo slice culture protocol and wide-field fluorescence microscopy (Fig. 1). This approach achieves long-term time-lapse monitoring of chick embryonic spinal cord progenitor cells with high spatial and temporal resolution.
This assay may be modified to image a range of embryonic tissues3, 4 In addition to the observation of cellular and sub-cellular behaviors, the development of novel and highly sensitive reporters for gene activity (for example, Notch signaling5) makes this assay a powerful tool with which to understand how signaling regulates cell behavior during embryonic development.

Imaging embryonic tissue in real-time is challenging over long periods of time. Here we present an assay for monitoring cellular and sub-cellular changes in chick spinal cord for long periods with high spatial and temporal resolution. This technique can be adapted for other regions of the nervous system and developing embryo.

ברזולוציה גבוהה הדמיה חיה של התנהגות התא ב Neuroepithelium פיתוח

The embryonic spinal cord consists of cycling neural progenitor cells that give rise to a large percentage of the neuronal and glial cells of the central ...

Time-lapse Imaging of Neuroblast Migration in Acute Slices of the Adult Mouse Forebrain

There is a substantial body of evidence indicating that new functional neurons are constitutively generated from an endogenous pool of neural stem cells in restricted areas of the adult mammalian brain. Newborn neuroblasts from the subventricular zone (SVZ) migrate along the rostral migratory stream (RMS) to their final destination in the olfactory bulb (OB)1. In the RMS, neuroblasts migrate tangentially in chains ensheathed by astrocytic processes2,3 using blood vessels as a structural support and a source of molecular factors required for migration4,5. In the OB, neuroblasts detach from the chains and migrate radially into the different bulbar layers where they differentiate into interneurons and integrate into the existing network1, 6.
In this manuscript we describe the procedure for monitoring cell migration in acute slices of the rodent brain. The use of acute slices allows the assessment of cell migration in the microenvironment that closely resembling to in vivo conditions and in brain regions that are difficult to access for in vivo imaging. In addition, it avoids long culturing condition as in the case of organotypic and cell cultures that may eventually alter the migration properties of the cells. Neuronal precursors in acute slices can be visualized using DIC optics or fluorescent proteins. Viral labeling of neuronal precursors in the SVZ, grafting neuroblasts from reporter mice into the SVZ of wild-type mice, and using transgenic mice that express fluorescent protein in neuroblasts are all suitable methods for visualizing neuroblasts and following their migration. The later method, however, does not allow individual cells to be tracked for long periods of time because of the high density of labeled cells. We used a wide-field fluorescent upright microscope equipped with a CCD camera to achieve a relatively rapid acquisition interval (one image every 15 or 30 sec) to reliably identify the stationary and migratory phases. A precise identification of the duration of the stationary and migratory phases is crucial for the unambiguous interpretation of results. We also performed multiple z-step acquisitions to monitor neuroblasts migration in 3D. Wide-field fluorescent imaging has been used extensively to visualize neuronal migration7-10. Here, we describe detailed protocol for labeling neuroblasts, performing real-time video-imaging of neuroblast migration in acute slices of the adult mouse forebrain, and analyzing cell migration. While the described protocol exemplified the migration of neuroblasts in the adult RMS, it can also be used to follow cell migration in embryonic and early postnatal brains.

We describe a protocol for real-time videoimaging of neuronal migration in the mouse forebrain. The migration of virally-labeled or grafted neuronal precursors was recorded in acute live slices using wide-field fluorescent imaging with a relatively rapid acquisition interval to study the different phases of cell migration, including the durations of the stationary and migration phases and the speed of migration.

הדמית זמן לשגות הגירת Neuroblast בפרוסות חריפות של המוח הקדמי המאוס למבוגרים

There is a substantial body of evidence indicating that new functional neurons are constitutively generated from an endogenous pool of neural stem cells ...

Forebrain Electrophysiological Recording in Larval Zebrafish

Epilepsy affects nearly 3 million people in the United States and up to 50 million people worldwide. Defined as the occurrence of spontaneous unprovoked seizures, epilepsy can be acquired as a result of an insult to the brain or a genetic mutation. Efforts to model seizures in animals have primarily utilized acquired insults (convulsant drugs, stimulation or brain injury) and genetic manipulations (antisense knockdown, homologous recombination or transgenesis) in rodents. Zebrafish are a vertebrate model system1-3 that could provide a valuable alternative to rodent-based epilepsy research. Zebrafish are used extensively in the study of vertebrate genetics or development, exhibit a high degree of genetic similarity to mammals and express homologs for ~85% of known human single-gene epilepsy mutations. Because of their small size (4-6 mm in length), zebrafish larvae can be maintained in fluid volumes as low as 100 &mu;l during early development and arrayed in multi-well plates. Reagents can be added directly to the solution in which embryos develop, simplifying drug administration and enabling rapid in vivo screening of test compounds4. Synthetic oligonucleotides (morpholinos), mutagenesis, zinc finger nuclease and transgenic approaches can be used to rapidly generate gene knockdown or mutation in zebrafish5-7. These properties afford zebrafish studies an unprecedented statistical power analysis advantage over rodents in the study of neurological disorders such as epilepsy. Because the "gold standard" for epilepsy research is to monitor and analyze the abnormal electrical discharges that originate in a central brain structure (i.e., seizures), a method to efficiently record brain activity in larval zebrafish is described here. This method is an adaptation of conventional extracellular recording techniques and allows for stable long-term monitoring of brain activity in intact zebrafish larvae. Sample recordings are shown for acute seizures induced by bath application of convulsant drugs and spontaneous seizures recorded in a genetically modified fish.

A simple method to record extracellular field potentials in the larval zebrafish forebrain is described. The method provides a robust in vivo read-out of seizure-like activity. This technique can be used with genetically modified zebrafish larvae carrying epilepsy-related genes or seizures evoked by administration of convulsant drugs.

הקלטת אלקטרו מוח קדמי בזחל דג זברה

Epilepsy affects nearly 3 million people in the United States and up to 50 million people worldwide. Defined as the occurrence of spontaneous unprovoked ...

Motor Nerve Transection and Time-lapse Imaging of Glial Cell Behaviors in Live Zebrafish

The nervous system is often described as a hard-wired component of the body even though it is a considerably fluid organ system that reacts to external stimuli in a consistent, stereotyped manner, while maintaining incredible flexibility and plasticity. Unlike the central nervous system (CNS), the peripheral nervous system (PNS) is capable of significant repair, but we have only just begun to understand the cellular and molecular mechanisms that govern this phenomenon. Using zebrafish as a model system, we have the unprecedented opportunity to couple regenerative studies with in vivo imaging and genetic manipulation. Peripheral nerves are composed of axons surrounded by layers of glia and connective tissue. Axons are ensheathed by myelinating or non-myelinating Schwann cells, which are in turn wrapped into a fascicle by a cellular sheath called the perineurium. Following an injury, adult peripheral nerves have the remarkable capacity to remove damaged axonal debris and re-innervate targets. To investigate the roles of all peripheral glia in PNS regeneration, we describe here an axon transection assay that uses a commercially available nitrogen-pumped dye laser to axotomize motor nerves in live transgenic zebrafish. We further describe the methods to couple these experiments to time-lapse imaging of injured and control nerves. This experimental paradigm can be used to not only assess the role that glia play in nerve regeneration, but can also be the platform for elucidating the molecular mechanisms that govern nervous system repair.

Although the peripheral nervous system (PNS) is capable of significant repair after injury, little is known about the cellular and molecular mechanisms that govern this phenomenon. Using live, transgenic zebrafish and a reproducible nerve transection assay, we can study dynamic glial cell behaviors during nerve degeneration and regeneration.

חיתוך רוחב עצב מוטורי וזמן לשגות הדמיה של התנהגויות תא גלייה בדג הזברה לחיות

The  nervous system is often described as a hard-wired component of the body even  though it is a considerably fluid organ system that reacts to external ...

In vivo Postnatal Electroporation and Time-lapse Imaging of Neuroblast Migration in Mouse Acute Brain Slices

The subventricular zone (SVZ) is one of the main neurogenic niches in the postnatal brain. Here, neural progenitors proliferate and give rise to neuroblasts able to move along the rostral migratory stream (RMS) towards the olfactory bulb (OB). This long-distance migration is required for the subsequent maturation of newborn neurons in the OB, but the molecular mechanisms regulating this process are still unclear. Investigating the signaling pathways controlling neuroblast motility may not only help understand a fundamental step in neurogenesis, but also have therapeutic regenerative potential, given the ability of these neuroblasts to target brain sites affected by injury, stroke, or degeneration.
In this manuscript we describe a detailed protocol for in vivo postnatal electroporation and subsequent time-lapse imaging of neuroblast migration in the mouse RMS. Postnatal electroporation can efficiently transfect SVZ progenitor cells, which in turn generate neuroblasts migrating along the RMS. Using confocal spinning disk time-lapse microscopy on acute brain slice cultures, neuroblast migration can be monitored in an environment closely resembling the in vivo condition. Moreover, neuroblast motility can be tracked and quantitatively analyzed. As an example, we describe how to use in vivo postnatal electroporation of a GFP-expressing plasmid to label and visualize neuroblasts migrating along the RMS. Electroporation of shRNA or CRE recombinase-expressing plasmids in conditional knockout mice employing the LoxP system can also be used to target genes of interest. Pharmacological manipulation of acute brain slice cultures can be performed to investigate the role of different signaling molecules in neuroblast migration. By coupling in vivo electroporation with time-lapse imaging, we hope to understand the molecular mechanisms controlling neuroblast motility and contribute to the development of novel approaches to promote brain repair.

In vivo Postnatal Electroporation and Time-lapse Imaging of Neuroblast Migration in Mouse Acute Brain Slices

Neuroblast migration is a fundamental event in postnatal neurogenesis. We describe a protocol for efficient labeling of neuroblasts by in vivo postnatal electroporation and subsequent visualization of their migration using time-lapse imaging of acute brain slices. We include a description for the quantitative analysis of neuroblast dynamics by video tracking.

In vivo electroporation ואחרי הלידה וזמן לשגות הדמיה של neuroblast הגירה בעכבר חריפה פרוסות המוח

The subventricular zone (SVZ) is one of the main neurogenic niches in the postnatal brain. Here, neural progenitors proliferate and give rise to ...

Assessing Cell Cycle Progression of Neural Stem and Progenitor Cells in the Mouse Developing Brain after Genotoxic Stress

Neurons of the cerebral cortex are generated during brain development from different types of neural stem and progenitor cells (NSPC), which form a pseudostratified epithelium lining the lateral ventricles of the embryonic brain. Genotoxic stresses, such as ionizing radiation, have highly deleterious effects on the developing brain related to the high sensitivity of NSPC. Elucidation of the cellular and molecular mechanisms involved depends on the characterization of the DNA damage response of these particular types of cells, which requires an accurate method to determine NSPC progression through the cell cycle in the damaged tissue. Here is shown a method based on successive intraperitoneal injections of EdU and BrdU in pregnant mice and further detection of these two thymidine analogues in coronal sections of the embryonic brain. EdU and BrdU are both incorporated in DNA of replicating cells during S phase and are detected by two different techniques (azide or a specific antibody, respectively), which facilitate their simultaneous detection. EdU and BrdU staining are then determined for each NSPC nucleus in function of its distance from the ventricular margin in a standard region of the dorsal telencephalon. Thus this dual labeling technique allows distinguishing cells that progressed through the cell cycle from those that have activated a cell cycle checkpoint leading to cell cycle arrest in response to DNA damage.
An example of experiment is presented, in which EdU was injected before irradiation and BrdU immediately after and analyzes performed within the 4 hr&#160;following irradiation. This protocol provides an accurate analysis of the acute DNA damage response of NSPC in function of the phase of the cell cycle at which they have been irradiated. This method is easily transposable to many other systems in order to determine the impact of a particular treatment on cell cycle progression in living tissues.

Administration of two analogs of thymidine, EdU and BrdU, in pregnant mice allows the analysis of cell cycle progression in neural and progenitor cells in the embryonic mouse brain. This method is useful to determine the effects of genotoxic stress, including ionizing radiation, during brain development.

התקדמות מחזור תא הערכה של גזע עצבי ובתאים במוח המתפתח העכבר, למרות מתח genotoxic

Neurons of the cerebral cortex are generated during brain development from different types of neural stem and progenitor cells (NSPC), which form a ...

Live Imaging of Mitosis in the Developing Mouse Embryonic Cortex

Although of short duration, mitosis is a complex and dynamic multi-step process fundamental for development of organs including the brain. In the developing cerebral cortex, abnormal mitosis of neural progenitors can cause defects in brain size and function. Hence, there is a critical need for tools to understand the mechanisms of neural progenitor mitosis. Cortical development in rodents is an outstanding model for studying this process. Neural progenitor mitosis is commonly examined in fixed brain sections. This protocol will describe in detail an approach for live imaging of mitosis in ex vivo embryonic brain slices. We will describe the critical steps for this procedure, which include: brain extraction, brain embedding, vibratome sectioning of brain slices, staining and culturing of slices, and time-lapse imaging. We will then demonstrate and describe in detail how to perform post-acquisition analysis of mitosis. We include representative results from this assay using the vital dye Syto11, transgenic mice (histone H2B-EGFP and centrin-EGFP), and in utero electroporation (mCherry-&#945;-tubulin). We will discuss how this procedure can be best optimized and how it can be modified for study of genetic regulation of mitosis. Live imaging of mitosis in brain slices is a flexible approach to assess the impact of age, anatomy, and genetic perturbation in a controlled environment, and to generate a large amount of data with high temporal and spatial resolution. Hence this protocol will complement existing tools for analysis of neural progenitor mitosis.

Neural progenitor mitosis is a critical parameter of neurogenesis. Much of our understanding of neural progenitor mitosis is based on analysis of fixed tissue. Live imaging in embryonic brain slices is a versatile technique to assess mitosis with high temporal and spatial resolution in a controlled environment.

הדמיה חיה של מיטוזה בCortex עכבר עוברי פיתוח

Although of short duration, mitosis is a complex and dynamic multi-step process fundamental for development of organs including the brain. In the ...

Feeder-free Derivation of Neural Crest Progenitor Cells from Human Pluripotent Stem Cells

Human pluripotent stem cells (hPSCs) have great potential for studying human embryonic development, for modeling human diseases in the dish and as a source of transplantable cells for regenerative applications after disease or accidents. Neural crest (NC) cells are the precursors for a large variety of adult somatic cells, such as cells from the peripheral nervous system and glia, melanocytes and mesenchymal cells. They are a valuable source of cells to study aspects of human embryonic development, including cell fate specification and migration. Further differentiation of NC progenitor cells into terminally differentiated cell types offers the possibility to model human diseases in vitro, investigate disease mechanisms and generate cells for regenerative medicine. This article presents the adaptation of a currently available in vitro differentiation protocol for the derivation of NC cells from hPSCs. This new protocol requires 18 days of differentiation, is feeder-free, easily scalable and highly reproducible among human embryonic stem cell (hESC) lines as well as human induced pluripotent stem cell (hiPSC) lines. Both old and new protocols yield NC cells of equal identity.

Neural crest (NC) cells derived from human pluripotent stem cells (hPSC) have great potential for modeling human development and disease and for cell replacement therapies. Here, a feeder-free adaptation of the currently widely used in vitro differentiation protocol for the derivation of NC cells from hPSCs is presented.

גזירה ללא מזין של תאים עצביים קרסט אב קדמון מפלוריפוטנטיים אדם בתאי גזע

Human pluripotent stem cells (hPSCs) have great potential for studying human embryonic development, for modeling human diseases in the dish and as a ...

Long-term Time Lapse Imaging of Mouse Cochlear Explants

Here we present a method for long-term time-lapse imaging of live embryonic mouse cochlear explants. The developmental program responsible for building the highly ordered, complex structure of the mammalian cochlea proceeds for around ten days. In order to study changes in gene expression over this period and their response to pharmaceutical or genetic manipulation, long-term imaging is necessary. Previously, live imaging has typically been limited by the viability of explanted tissue in a humidified chamber atop a standard microscope. Difficulty in maintaining optimal conditions for culture growth with regard to humidity and temperature has placed limits on the length of imaging experiments. A microscope integrated into a modified tissue culture incubator provides an excellent environment for long term-live imaging. In this method we demonstrate how to establish embryonic mouse cochlear explants and how to use an incubator microscope to conduct time lapse imaging using both bright field and fluorescent microscopy to examine the behavior of a typical embryonic day (E) 13 cochlear explant and Sox2, a marker of the prosensory cells of the cochlea, over 5 days.

Live imaging of the embryonic mammalian cochlea is challenging because the developmental processes at hand operate on a temporal gradient over ten days. Here we present a method for culturing and then imaging embryonic cochlear explant tissue taken from a fluorescent reporter mouse over five days.

לטווח ארוך זמן פקיעת הדמיה של Explants שבלול העכבר

Here we present a method for long-term time-lapse imaging of live embryonic mouse cochlear explants. The developmental program responsible for building ...