עבודה זו נתמכה בחלקה על ידי המכון הלאומי לסרטן P30 CA23074, האגודה האמריקנית למלחמה בסרטן מחקר מוסדיים גרנט 74-001-31, ואת Univ. אריזונה GI נבג (NCI / CA9506O NIH).

<ol>
	<li>Schneider, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+lines+derived+from+late+embryonic+stages+of+Drosophila+melanogaster.">Cell lines derived from late embryonic stages of Drosophila melanogaster.</a> J Embryol Exp Morphol. 27, 353-365 (1972).</li><li>Rogers, S. L., Rogers, G. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Culture+of+Drosophila+S2+cells+and+their+use+for+RNAi-mediated+loss-of-function+studies+and+immunofluorescence+microscopy.">Culture of Drosophila S2 cells and their use for RNAi-mediated loss-of-function studies and immunofluorescence microscopy.</a> Nat Protoc. 3, 606-611 (2008).</li><li>Rogers, S. L., Rogers, G. C., Sharp, D. J., Vale, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+EB1+is+important+for+proper+assembly,+dynamics,+and+positioning+of+the+mitotic+spindle.">Drosophila EB1 is important for proper assembly, dynamics, and positioning of the mitotic spindle.</a> J Cell Biol. 158, 873-884 (2002).</li><li>Goshima, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genes+required+for+mitotic+spindle+assembly+in+Drosophila+S2+cells.">Genes required for mitotic spindle assembly in Drosophila S2 cells.</a> Science. 316, 417-421 (2007).</li></ol>

אין ניגודי אינטרסים הכריז.

עבור שדה ביולוגיה של התא, מערכת האידיאלי יהיה זול לתחזוקה, קל לתפעל, ו מקובל מגוון רחב של טכניקות. תאים תסיסנית S2 לספק את הדרישות הללו, ולכן יש להפוך במהירות את המערכת של בחירה עבור מספר הולך וגדל של התא מעבדות הביולוגיה. הצגנו סקירה קצרה של השיטות להכנת תאים S2 עבור מיקרוסקופיה. בתוקף בולט של תאים S2 היא העובדה כי הם גדלים היטב באווירה נורמלית בטמפרטורת החדר, ולכן הם יכולים שמאל על המיקרוסקופ במשך תקופות ממושכות ללא כל דרישות תחזוקה מיוחדות. למרות שהם בדרך כלל מעוגל במקצת חסיד רופף culturing בתנאים נורמליים, תאים S2 יכול להיגרם לשטח נרחב עבור הדמיה. תאים בתרבית S2 על זכוכית התחתונה מנות כי כבר מראש מצופה concanavalin יצרף ומרוחים בשכבה דקה על להחליק את המכסה, מה שהופך אותם דגימות במיקרוסקופ מעולה.

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		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>S2 cells</td>
<td>&nbsp;</td>
<td>ATCC</td>
<td>CRL-1963</td>
<td><a href="http://www.atcc.org/">http://www.atcc.org/</a></td>
</tr>
<tr>
<td>S2 cells</td>
<td>&nbsp;</td>
<td>DGRC</td>
<td>stock number 6</td>
<td><a href="https://dgrc.cgb.indiana.edu/">https://dgrc.cgb.indiana.edu/</a></td>
</tr>
<tr>
<td>S2 cells</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>R690-07</td>
<td>&nbsp;</td>
<tr>
<td>Sf900 II</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>10902-096</td>
<td>serum-free medium</td>
</tr>
<tr>
<td>HyClone SFX-Insect</td>
<td>&nbsp;</td>
<td>Thermo Scientific</td>
<td>SH30278</td>
<td>serum-free medium</td>
</tr>
<tr>
<td>Insect-Xpress</td>
<td>&nbsp;</td>
<td>BioWhittaker</td>
<td>12-730</td>
<td>serum-free medium</td>
</tr>
<tr>
<td>Schneider's S2 medium</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>11720-034</td>
<td>Add 10% (final) heat-inactivated FBS to make complete medium.</td>
</tr>
<tr>
<td>Fetal bovine serum</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>10438026</td>
<td>heat inactivated</td>
</tr>
<tr>
<td>100x antibiotic solution</td>
<td>&nbsp;</td>
<td>MP Biomedicals</td>
<td>91674049</td>
<td>contains penicillin (10000 U/mL), streptomycin (10000 &mu;g/mL), and amphotericin B (25 &mu;g/mL)</td>
</tr>
<tr>
<td>Concanavalin A</td>
<td>&nbsp;</td>
<td>MP Biomedicals</td>
<td>195283</td>
<td>&nbsp;</td>
<tr>
<td>Formaldehyde</td>
<td>&nbsp;</td>
<td>Electron Microscopy Sciences</td>
<td>15714</td>
<td>32% solution</td>
</tr>
<tr>
<td>Methanol</td>
<td>&nbsp;</td>
<td>Mallinckrodt Baker</td>
<td>9049</td>
<td>anhydrous, ACS grade</td>
</tr>
<tr>
<td>Molecular sieves</td>
<td>&nbsp;</td>
<td>Acros Organics</td>
<td>19724</td>
<td>type 3A</td>
</tr>		</tbody>
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preparation of drosophila s2 cells for light microscopy

מערכת הניסוי האידיאלי יהיה זול וקל לתחזוקה, מקובל מגוון רחב של טכניקות, יהיה נתמך על ידי ספרות ענפה רצף הגנום באתר. בתרבית תאים תסיסנית S2, תוצר של 20-24 עוברים משויך 1 שעה הישן, בעל כל התכונות האלה. כתוצאה מכך, התאים S2 הם מאוד מתאימים לניתוח של תהליכים תאיים, כולל גילוי הגנים המקודדים את המרכיבים המולקולריים של תהליך או מנגנון של עניין. התכונות של תאים S2 שאחראים ביותר עבור השירות שלהם הקלות שבה הם נשמרים, רגישות מופלאה שלהם להפרעות פעמיים תקועים RNA בתיווך (DS) (RNAi), ו נהילות שלהם מיקרוסקופ פלואורסצנטי כמו גם לחיות או קבוע תאים. תאים S2 ניתן לגדל מגוון רחב של כלי התקשורת, כולל מספר זול, זמין מסחרית, מלא מוגדרים, סרום ללא התקשורת 2. בנוסף, הם גדלים בצורה אופטימלית ובמהירות על 21-24 מעלות צלזיוס, יכול להיות מתורבת במגוון רחב של מיכלים. שלא כמו בתאי יונקים, תאים S2 אינם דורשים אווירה מוסדר, אך במקום לעשות היטב עם אוויר רגיל יכול אפילו להיות נשמר צלוחיות אטום. משלימים את הקלות של RNAi בתאים S2 היא היכולת לנתח בקלות פנוטיפים בניסוי המושרה על ידי שלב או מיקרוסקופ פלואורסצנטי של תאים קבוע או לחיות. תאים S2 לגדול בתרבות כמו בשכבה יחידה, אבל לא להציג עיכוב קשר. במקום זאת, תאים נוטים לגדול במושבות בתרבויות צפופה. באותה צפיפות נמוכה, תרבויות S2 גדל על זכוכית או תרבות שטופלו פלסטיק רקמות עגולות רופף המצורפת. עם זאת, ציטולוגיה של תאים S2 ניתן לשפר במידה ניכרת בכך שפיתה אותם לשטח נרחב על ידי culturing בקצרה אותם על משטח מצופה לקטינים, concanavalin (ConA) 3. תאים S2 יכול להיות גם transfected ביציבות עם סמנים fluorescently-tagged למבנים תווית או אברונים עניין בתאים חיים או קבוע. לכן, התרחיש הרגיל עבור ניתוח מיקרוסקופי של תאים היא זו: הראשונה, תאים S2 (אשר יכול להחזיק transgenes להביע סמנים מתויג) מטופלים על ידי RNAi לחסל את חלבון המטרה (ים). זמן RNAi הטיפול יכול להיות מותאם כדי לאפשר הבדלים חלבון להתהפך קינטיקה כדי למזער טראומה תא / מוות אם חלבון המטרה חשובה הכדאיות. בשלב הבא, בתאים שטופלו מועברים מאכל המכיל coverslip מראש מצופה conA לגרום לתאים להתפשט בחוזקה לדבוק הזכוכית. לבסוף, התאים הם צילמו עם הבחירה של החוקר מצבי במיקרוסקופ. תאים S2 טובים במיוחד ללימודי הדורשים ראיה מורחבת של תאים חיים מאז תאים אלה להישאר בריאים בטמפרטורת החדר ואת האווירה נורמלי.

Watch this Scientific Journal Video about Preparation of Drosophila S2 cells for Light Microscopy at JoVE.com

Preparation of Drosophila S2 cells for Light Microscopy

תסיסנית שניידר (S2) הם תאים מערכת פופולרי יותר ויותר על גילוי וניתוח פונקציונלי של גנים. המטרה שלנו היא לתאר כמה טכניקות להפוך תאים מיקרוסקופיים S2 כגון מערכת ניסיונית חשוב יותר ויותר.

הכנת תסיסנית תאים S2 עבור במיקרוסקופ אור

The ideal experimental system would be cheap and easy to maintain, amenable to a variety of techniques, and would be supported by an extensive literature ...

preparation-of-drosophila-s2-cells-for-light-microscopy

Nanyang Technological University

Research

JoVE Journal

Biology

Preparation of Drosophila S2 cells for Light Microscopy

22.5K Views.  University of Arizona (UOA). תסיסנית שניידר (S2) הם תאים מערכת פופולרי יותר ויותר על גילוי וניתוח פונקציונלי של גנים. המטרה שלנו היא לתאר כמה טכניקות להפוך תאים מיקרוסקופיים S2 כגון מערכת ניסיונית חשוב יותר ויותר.

Video: Preparation of Drosophila S2 cells for Light Microscopy

Preparation of embryos for Electron Microscopy of the Drosophila embryonic heart tube

The morphogenesis of the Drosophila embryonic heart tube has emerged as a valuable model system for studying cell migration, cell-cell adhesion and cell shape changes during embryonic development. One of the challenges faced in studying this structure is that the lumen of the heart tube, as well as the membrane features that are crucial to heart tube formation, are difficult to visualize in whole mount embryos, due to the small size of the heart tube and intra-lumenal space relative to the embryo. The use of transmission electron microscopy allows for higher magnification of these structures and gives the advantage of examining the embryos in cross section, which easily reveals the size and shape of the lumen. In this video, we detail the process for reliable fixation, embedding, and sectioning of late stage Drosophila embryos in order to visualize the heart tube lumen as well as important cellular structures including cell-cell junctions and the basement membrane.

Preparation of embryos for Electron Microscopy of the Drosophila embryonic heart tube

We describe a process for fixation, embedding, sectioning, and imaging of late stage Drosophila embryos for Trasmission Electron Microscopy of the embryonic heart tube. This technique allows for the visualization of the heart tube lumen as well as the basement membrane, which lines the lumen of the heart.

הכנת עוברים אלקטרונים מיקרוסקופית של תסיסנית לב עוברי צינור

The morphogenesis of the Drosophila  embryonic heart tube has emerged as a valuable model system for studying cell migration, cell-cell adhesion and cell ...

Examination of Drosophila Larval Tracheal Terminal Cells by Light Microscopy

Cell shape is critical for cell function. However, despite the importance of cell morphology, little is known about how individual cells generate specific shapes. Drosophila tracheal terminal cells have become a powerful genetic model to identify and elucidate the roles of genes required for generating cellular morphologies. Terminal cells are a component of a branched tubular network, the tracheal system that functions to supply oxygen to internal tissues. Terminal cells are an excellent model for investigating questions of cell shape as they possess two distinct cellular architectures. First, terminal cells have an elaborate branched morphology, similar to complex neurons; second, terminal cell branches are formed as thin tubes and contain a membrane-bound intracellular lumen. Quantitative analysis of terminal cell branch number, branch organization and individual branch shape, can be used to provide information about the role of specific genetic mechanisms in the making of a branched cell. Analysis of tube formation in these cells can reveal conserved mechanisms of tubulogenesis common to other tubular networks, such as the vertebrate vasculature. Here we describe techniques that can be used to rapidly fix, image, and analyze both branching patterns and tube formation in terminal cells within Drosophila larvae. These techniques can be used to analyze terminal cells in wild-type and mutant animals, or genetic mosaics. Because of the high efficiency of this protocol, it is also well suited for genetic, RNAi-based, or drug screens in the Drosophila tracheal system.

Examination of Drosophila Larval Tracheal Terminal Cells by Light Microscopy

Here, we present a method for light microscopy analysis of tracheal terminal cells in Drosophila larvae. This method allows for quick examination of branch and lumen morphology in whole animals and would be useful for analysis of individual mutants or screens for mutations affecting terminal cell development.

בחינה של<em&gt; דרוזופילה</em&gt; Terminal תאי קני הזחל על ידי מיקרוסקופ אור

Cell shape is critical for cell function. However, despite the importance of cell morphology, little is known about how individual cells generate specific ...

Organelle Transport in Cultured Drosophila Cells: S2 Cell Line and Primary Neurons.

Drosophila S2 cells plated on a coverslip in the presence of any actin-depolymerizing drug form long unbranched processes filled with uniformly polarized microtubules. Organelles move along these processes by microtubule motors. Easy maintenance, high sensitivity to RNAi-mediated protein knock-down and efficient procedure for creating stable cell lines make Drosophila S2 cells an ideal model system to study cargo transport by live imaging. The results obtained with S2 cells can be further applied to a more physiologically relevant system: axonal transport in primary neurons cultured from dissociated Drosophila embryos. Cultured neurons grow long neurites filled with bundled microtubules, very similar to S2 processes. Like in S2 cells, organelles in cultured neurons can be visualized by either organelle-specific fluorescent dyes or by using fluorescent organelle markers encoded by DNA injected into early embryos or expressed in transgenic flies. Therefore, organelle transport can be easily recorded in neurons cultured on glass coverslips using living imaging. Here we describe procedures for culturing and visualizing cargo transport in Drosophila S2 cells and primary neurons. We believe that these protocols make both systems accessible for labs studying cargo transport.

Organelle Transport in Cultured Drosophila Cells: S2 Cell Line and Primary Neurons.

Drosophila S2 cells and cultured neurons are great systems for imaging of motor-driven organelle transport in vivo. Here we describe detailed protocols for culturing both cell types, their imaging and analysis of transport.

אברון תחבורה בתרבית<em&gt; דרוזופילה</em&gt; תאים: תא קו S2 ויסודי נוירונים.

Drosophila S2 cells plated on a coverslip in the presence of any actin-depolymerizing drug form long unbranched processes filled with uniformly polarized ...

Multilayer Mounting for Long-term Light Sheet Microscopy of Zebrafish

Light sheet microscopy is the ideal imaging technique to study zebrafish embryonic development. Due to minimal photo-toxicity and bleaching, it is particularly suited for long-term time-lapse imaging over many hours up to several days. However, an appropriate sample mounting strategy is needed that offers both confinement and normal development of the sample. Multilayer mounting, a new embedding technique using low-concentration agarose in optically clear tubes, now overcomes this limitation and unleashes the full potential of light sheet microscopy for real-time developmental biology.

The development of zebrafish can be followed over days with light sheet microscopy when embryos are embedded in optically clear polymer tubes with low-concentration agarose.

רב שכבתי וההרכבה למיקרוסקופיה גיליון אור לטווח ארוך של דג הזברה

Light sheet microscopy is the ideal imaging technique to study zebrafish embryonic development. Due to minimal photo-toxicity and bleaching, it is ...

In vivo Clonal Tracking of Hematopoietic Stem and Progenitor Cells Marked by Five Fluorescent Proteins using Confocal and Multiphoton Microscopy

We developed and validated a fluorescent marking methodology for clonal tracking of hematopoietic stem and progenitor cells (HSPCs) with high spatial and temporal resolution to study in vivo hematopoiesis using the murine bone marrow transplant experimental model. Genetic combinatorial marking using lentiviral vectors encoding fluorescent proteins (FPs) enabled cell fate mapping through advanced microscopy imaging. Vectors encoding five different FPs: Cerulean, EGFP, Venus, tdTomato, and mCherry were used to concurrently transduce HSPCs, creating a diverse palette of color marked cells. Imaging using confocal/two-photon hybrid microscopy enables simultaneous high resolution assessment of uniquely marked cells and their progeny in conjunction with structural components of the tissues. Volumetric analyses over large areas reveal that spectrally coded HSPC-derived cells can be detected non-invasively in various intact tissues, including the bone marrow (BM), for extensive periods of time following transplantation. Live studies combining video-rate multiphoton and confocal time-lapse imaging in 4D demonstrate the possibility of dynamic cellular and clonal tracking in a quantitative manner.

In vivo Clonal Tracking of Hematopoietic Stem and Progenitor Cells Marked by Five Fluorescent Proteins using Confocal and Multiphoton Microscopy

Combinatorial 5 fluorescent proteins marking of hematopoietic stem and progenitor cells allows in vivo clonal tracking via confocal and two-photon microscopy, providing insights into bone marrow hematopoietic architecture during regeneration. This method allows non-invasive fate mapping of spectrally-coded HSPCs-derived cells in intact tissues for extensive periods of time following transplantation.

במשובט מעקב vivo של גזע hematopoietic ובתאים המסומנים על ידי חמישה חלבונים ניאון באמצעות Confocal וmultiphoton מיקרוסקופית

We developed and validated a fluorescent marking methodology for clonal tracking of hematopoietic stem and progenitor cells (HSPCs) with high spatial and ...

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) maintain the turnover of all mature blood cell lineages. The coordination of the complex signals leading to specific HSC fates relies upon the interaction between HSCs and the intricate bone marrow microenvironment, which is still poorly understood[1-2].
We describe how by combining a newly developed specimen holder for stable animal positioning with multi-step confocal and two-photon in vivo imaging techniques, it is possible to obtain high-resolution 3D stacks containing HSPCs and their surrounding niches and to monitor them over time through multi-point time-lapse imaging. High definition imaging allows detecting ex vivo labeled hematopoietic stem and progenitor cells (HSPCs) residing within the bone marrow. Moreover, multi-point time-lapse 3D imaging, obtained with faster acquisition settings, provides accurate information about HSPC movement and the reciprocal interactions between HSPCs and stroma cells.
Tracking of HSPCs in relation to GFP positive osteoblastic cells is shown as an exemplary application of this method. This technique can be utilized to track any appropriately labeled hematopoietic or stromal cell of interest within the mouse calvarium bone marrow space.

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

The nature of the interactions between hematopoietic stem and progenitor cells (HSPCs) and bone marrow niches is poorly understood. Custom hardware modifications and a multi-step acquisition protocol allow the use of two-photon and confocal microscopy to image ex vivo labeled HSPCs homed within bone marrow areas, tracking interactions and movement.

במעקב 4 ממדי Vivo של תאי גזע ואבות היווצרות דם במבוגרי עכבר calvarial מח עצם

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) ...

Generating a &#34;Humanized&#34; Drosophila S2 Cell Line Sensitive to Pharmacological Inhibition of Kinesin-5

Kinetochores are large protein-based structures that assemble on centromeres during cell division and link chromosomes to spindle microtubules. Proper distribution of the genetic material requires that sister kinetochores on every chromosome become bioriented by attaching to microtubules from opposite spindle poles before progressing into anaphase. However, erroneous, non-bioriented attachment states are common and cellular pathways exist to both detect and correct such attachments during cell division. The process by which improper kinetochore-microtubule interactions are destabilized is referred to as error correction. To study error correction in living cells, incorrect attachments are purposely generated via chemical inhibition of kinesin-5 motor, which leads to monopolar spindle assembly, and the transition from mal-orientation to biorientation is observed following drug washout. The large number of chromosomes in many model tissue culture cell types poses a challenge in observing individual error correction events. Drosophila S2 cells are better subjects for such studies as they possess as few as 4 pairs of chromosomes. However, small molecule kinesin-5 inhibitors are ineffective against Drosophila kinesin-5 (Klp61F). Here we describe how to build a Drosophila cell line that effectively replaces Klp61F with human kinesin-5, which renders the cells sensitive to pharmacological inhibition of the motor and suitable for use in the cell-based error correction assay.

Generating a "Humanized" Drosophila S2 Cell Line Sensitive to Pharmacological Inhibition of Kinesin-5

This protocol describes how to generate a Drosophila S2 cell line that is sensitive to small molecule inhibitors of kinesin-5. The use of these cells in a cell-based error correction assay is also outlined.

יצירה &quot;אנושי&quot;<em&gt; דרוזופילה</em&gt; S2 שורת תאים רגיש לתרופתי עיכוב של Kinesin-5

Kinetochores are large protein-based structures that assemble on centromeres during cell division and link chromosomes to spindle microtubules. Proper ...

Drosophila Preparation and Longitudinal Imaging of Heart Function In Vivo Using Optical Coherence Microscopy (OCM)

Longitudinal study of the heartbeat in small animals contributes to understanding structural and functional changes during heart development. Optical coherence microscopy (OCM) has been demonstrated to be capable of imaging small animal hearts with high spatial resolution and ultrahigh imaging speed. The high image contrast and noninvasive properties make OCM ideal for performing longitudinal studies without requiring tissue dissections or staining. Drosophila has been widely used as a model organism in cardiac developmental studies due to its high number of orthologous human disease genes, its similarity of molecular mechanisms and genetic pathways with vertebrates, its short life cycle, and its low culture cost. Here, the experimental protocols are described for the preparation of Drosophila and optical imaging of the heartbeat with a custom OCM system throughout the life cycle of the specimen. By following the steps provided in this report, transverse M-mode and 3D OCM images can be acquired to conduct longitudinal studies of the Drosophila cardiac morphology and function. The en face and axial sectional OCM images and the heart rate (HR) and cardiac activity period (CAP) histograms, were also shown to analyze the heart structural changes and to quantify the heart dynamics during Drosophila metamorphosis, combined with the videos constructed with M-mode images to trace cardiac activity intuitively. Due to the genetic similarity between Drosophila and vertebrates, longitudinal study of heart morphology and dynamics in fruit flies could help reveal the origins of human heart diseases. The protocol here would provide an effective method to perform a wide range of studies to understand the mechanisms of cardiac diseases in humans.

Drosophila Preparation and Longitudinal Imaging of Heart Function In Vivo Using Optical Coherence Microscopy OCM

Here, the experimental protocols are described for preparing Drosophila at different developmental stages and performing longitudinal optical imaging of Drosophila heartbeats using a custom optical coherence microscopy (OCM) system. The cardiac morphological and dynamical changes can be quantitatively characterized by analyzing the heart structural and functional parameters from OCM images.

הכנת תסיסנית והדמיה אורכית תפקוד הלב in vivo באמצעות מיקרוסקופית קוהרנטיות אופטית (OCM)

Longitudinal study of the heartbeat in small animals contributes to understanding structural and functional changes during heart development. Optical ...

Analysis of the Gap Junction-dependent Transfer of miRNA with 3D-FRAP Microscopy

Small antisense RNAs, like miRNA and siRNA, play an important role in cellular physiology and pathology and, moreover, can be used as therapeutic agents in the treatment of several diseases. The development of new, innovative strategies for miRNA/siRNA therapy is based on an extensive knowledge of the underlying mechanisms. Recent data suggest that small RNAs are exchanged between cells in a gap junction-dependent manner, thereby inducing gene regulatory effects in the recipient cell. Molecular biological techniques and flow cytometric analysis are commonly used to study the intercellular exchange of miRNA. However, these methods do not provide high temporal resolution, which is necessary when studying the gap junctional flux of molecules. Therefore, to investigate the impact of miRNA/siRNA as intercellular signaling molecules, novel tools are needed that will allow for the analysis of these small RNAs at the cellular level. The present protocol describes the application of three-dimensional fluorescence recovery after photobleaching (3D-FRAP) microscopy to elucidating the gap junction-dependent exchange of miRNA molecules between cardiac cells. Importantly, this straightforward and non-invasive live-cell imaging approach allows for the visualization and quantification of the gap junctional shuttling of fluorescently labeled small RNAs in real time, with high spatio-temporal resolution. The data obtained by 3D-FRAP confirm a novel pathway of intercellular gene regulation, where small RNAs act as signaling molecules within the intercellular network.

Here, we describe the application of three-dimensional fluorescence recovery after photobleaching (3D-FRAP) for the analysis of the gap junction-dependent shuttling of miRNA. In contrast to commonly applied methods, 3D-FRAP allows for the quantification of the intercellular transfer of small RNAs in real time, with high spatio-temporal resolution.

ניתוח של המעבר צומת הפער תלוי מירנה עם מיקרוסקופיה 3D-FRAP

Small antisense RNAs, like miRNA and siRNA, play an important role in cellular physiology and pathology and, moreover, can be used as therapeutic agents ...

Biological Sample Preparation by High-pressure Freezing, Microwave-assisted Contrast Enhancement, and Minimal Resin Embedding for Volume Imaging

The described sample preparation technique is designed to combine the best quality of ultrastructural preservation with the most suitable contrast for the imaging modality in a focused ion beam scanning electron microscope (FIB-SEM), which is used to obtain stacks of sequential images for 3D reconstruction and modelling. High-pressure freezing (HPF) allows close to native structural preservation, but the subsequent freeze substitution often does not provide sufficient contrast, especially for a bigger specimen, which is needed for high-quality imaging in the SEM required for 3D reconstruction. Therefore, in this protocol, after the freeze substitution, additional contrasting steps are carried out at room temperature. Although these steps are performed in a microwave, it is also possible to follow traditional bench processing, which requires longer incubation times.The subsequent embedding in minimal amounts of resin allows for faster and more precise targeting and preparation inside the FIB-SEM. This protocol is especially useful for samples that require preparation by high-pressure freezing for a reliable ultrastructural preservation but do not gain enough contrast during the freeze substitution for volume imaging using FIB-SEM. In combination with the minimal resin embedding, this protocol provides an efficient workflow for the acquisition of high-quality volume data.

Here we present a protocol for combining two sample processing techniques, high-pressure freezing and microwave-assisted sample processing, followed by minimal resin embedding for acquiring data with a focused ion beam scanning electron microscope (FIB-SEM). This is demonstrated using a mouse tibial nerve sample and Caenorhabditis elegans.

הכנת הדוגמא ביולוגית על ידי הקפאת בלחץ גבוה, שיפור ניגודיות בסיוע מיקרוגל, ושרף מינימלי הטמעה של אמצעי הדמיה

The described sample preparation technique is designed to combine the best quality of ultrastructural preservation with the most suitable contrast for the ...