Name: live imaging and analysis of muscle contractions in drosophila embryo
Uploaded: 2019-07-09T12:30:00
Description: Watch this Scientific Journal Video about Live Imaging and Analysis of Muscle Contractions in Drosophila Embryo at JoVE.com

The project was supported in part by National Institutes of Health Grants RO1 NS099409, NS075534, and CONACYT 2012-037(S) to VP.

1. Preparation
<ol>
	<li>Prepare a fly cage by making approximately 50 holes in a 100 mL capacity tri-corner plastic beaker using a hot 25 G needle (see Table of Materials).</li>
	<li>Prepare 60 mm x 15 mm Petri dishes with apple juice-agar (3% agar and 30% apple juice).</li>
	<li>Prepare fresh yeast paste by mixing dry yeast granules and water. Spread the yeast paste onto the apple agar plates to increase egg laying.</li>
	<li>Anaesthetize about 50-60 flies (use approximately equal numbers of males an...

<ol>
	<li>Pereanu, W., Spindler, S., Im, E., Buu, N., Hartenstein, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+emergence+of+patterned+movement+during+late+embryogenesis+of+Drosophila.">The emergence of patterned movement during late embryogenesis of Drosophila.</a> Developmental Neurobiology. 67, 1669-1685 (2007).</li><li>Suster, M. L., Bate, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Embryonic+assembly+of+a+central+pattern+generator+without+sensory+input.">Embryonic assembly of a central pattern generator without sensory input.</a> Nature. 416, 174-178 (2002).</li><li>Crisp, S., Evers, J. F., Fiala, A., Bate, M. <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+motor+coordination+in+Drosophila+embryos.">The development of motor coordination in Drosophila embryos.</a> Development. 135, 3707-3717 (2008).</li><li>Song, W., Onishi, M., Jan, L. Y., Jan, Y. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peripheral+multidendritic+sensory+neurons+are+necessary+for+rhythmic+locomotion+behavior+in+Drosophila+larvae.">Peripheral multidendritic sensory neurons are necessary for rhythmic locomotion behavior in Drosophila larvae.</a> Proceedings of National Academy of Science of the United States of America. 104, 5199-5204 (2007).</li><li>Hughes, C. L., Thomas, 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=A+sensory+feedback+circuit+coordinates+muscle+activity+in+Drosophila.">A sensory feedback circuit coordinates muscle activity in Drosophila.</a> Molecular and Cellular Neuroscience. 35, 383-396 (2007).</li><li>Gorczyca, D. A., 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=Identification+of+Ppk26,+a+DEG/ENaC+channel+functioning+with+Ppk1+in+a+mutually+dependent+manner+to+guide+locomotion+behavior+in+Drosophila.">Identification of Ppk26, a DEG/ENaC channel functioning with Ppk1 in a mutually dependent manner to guide locomotion behavior in Drosophila.</a> Cell Reports. 9, 1446-1458 (2014).</li><li>Baker, R., Nakamura, N., Chandel, I., 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=Protein+O-Mannosyltransferases+affect+sensory+axon+wiring+and+dynamic+chirality+of+body+posture+in+the+Drosophila+embryo.">Protein O-Mannosyltransferases affect sensory axon wiring and dynamic chirality of body posture in the Drosophila embryo.</a> Journal of Neuroscience. 38 (7), 1850-1865 (2018).</li><li>Nakamura, N., Lyalin, D., Panin, V. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protein+O-mannosylation+in+animal+development+and+physiology:+From+human+Disorders+to+Drosophila+phenotypes.">Protein O-mannosylation in animal development and physiology: From human Disorders to Drosophila phenotypes.</a> Seminars in Cell &amp; Developmental Biology. 21, 622-630 (2010).</li><li>Lyalin, D., 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=The+twisted+gene+encodes+Drosophila+protein+O-mannosyltransferase+2+and+genetically+interacts+with+the+rotated+abdomen+gene+encoding+Drosophila+protein+O-mannosyltransferase+1.">The twisted gene encodes Drosophila protein O-mannosyltransferase 2 and genetically interacts with the rotated abdomen gene encoding Drosophila protein O-mannosyltransferase 1.</a> Genetics. 172, 343-353 (2006).</li><li>Beltr&#225;n-Valero de Bernabe, D., 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=Mutations+in+the+O-Mannosyltransferase+gene+POMT1+give+rise+to+the+severe+neuronal+migration+disorder+Walker-Warburg+Syndrome.">Mutations in the O-Mannosyltransferase gene POMT1 give rise to the severe neuronal migration disorder Walker-Warburg Syndrome.</a> American Journal of Human Genetics. 71, 1033-1043 (2002).</li><li>Reeuwijk, 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=POMT2+mutations+cause+alpha-dystroglycan+hypoglycosylation+and+Walker-Warburg+syndrome.">POMT2 mutations cause alpha-dystroglycan hypoglycosylation and Walker-Warburg syndrome.</a> Journal of Medical Genetics. 42, 907-912 (2005).</li><li>Jaeken, J., Matthijs, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Congenital+disorders+of+glycosylation:+A+rapidly+expanding+disease+family.">Congenital disorders of glycosylation: A rapidly expanding disease family.</a> Annual Reviews of Genomics and Human Genetics. 8, 261-278 (2007).</li><li>Leyten, Q. H., Gabreels, F. J., Renier, W. O., ter Laak, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Congenital+muscular+dystrophy:+a+review+of+the+literature.">Congenital muscular dystrophy: a review of the literature.</a> Clinical and Neurological Neurosurgery. 98 (4), 267-280 (1996).</li><li>Roberts, D. B., Hames, B. 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:+A+Practical+Approach.+2nd+ed.">Drosophila: A Practical Approach. 2nd ed.</a> The Practical Approach Series. , 389 (1998).</li><li>Heckscher, E. S., 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=Even-Skipped++interneurons+are+core+components+of+a+sensorimotor+circuit+that+maintains+left-right+symmetric+muscle+contraction+amplitude.">Even-Skipped+ interneurons are core components of a sensorimotor circuit that maintains left-right symmetric muscle contraction amplitude.</a> Neuron. 88, 314-329 (2015).</li><li>Penjweini, R., 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=Long-term+monitoring+of+live+cell+proliferation+in+presence+of+PVP-Hypericin:+a+new+strategy+using+ms+pulses+of+LED+and+the+fluorescent+dye+CFSE.">Long-term monitoring of live cell proliferation in presence of PVP-Hypericin: a new strategy using ms pulses of LED and the fluorescent dye CFSE.</a> J. Microscopy. 245, 100-108 (2011).</li></ol>

Our method provides a quantitative way to analyze important embryo behaviors during development, such as peristaltic muscle contraction waves, including wave periodicity, amplitude and pattern, as well as wave effect on embryo rolling and posture. This can be useful in analyses of different mutants to study the role of specific genes in regulating these and other behaviors during embryonic development. We have used changes in muscle-specific GFP marker intensity to analyze muscle contraction amplitude, frequency and dire...

Peristaltic muscle contraction is a rhythmic motor behavior similar to walking and swimming in humans1,2,3. Embryonic muscle contractions seen in Drosophila late stage embryos represent an example of such a behavior. Drosophila is an excellent model organism to study various developmental processes because embryonic development in Drosophila is well characterized, relatively short, and easy to monitor. The overall goal of our method is to carefully record and analyze the wavelike pattern of contraction and relaxation of embryonic muscles. We used a simple, non-invasive approach that offers a detailed visualization, recording and analysis of muscle contractions. This method can also be potentially used to study other in vivo processes, such as embryonic rolling seen in late stage embryos just prior to hatching. In previous studies, embryonic muscle contractions were mostly analyzed in terms of frequency and direction1,2. In order to estimate the relative extent of contractions as they progress along the body axis in the anterior or posterior direction, we have used embryos expressing GFP specifically in muscles. This analysis provides a more quantitative way to analyze muscle contractions and to reveal how body posture in embryos is maintained during series of peristaltic waves of muscle contractions.
Peristaltic muscle contractions are controlled by central pattern generator (CPG) circuits and communications between neurons of the peripheral nervous system (PNS), the central nervous system (CNS), and muscles4,5. Failure to produce normal peristaltic muscle contractions can lead to defects such as failure to hatch2 and abnormal larval locomotion6 and can be indicative of neurological abnormalities. Live imaging of peristaltic waves of muscle contraction and detailed analysis of contraction phenotypes can help uncover pathogenic mechanisms associated with genetic defects affecting muscles and neural circuits involved in locomotion. We recently used that approach to investigate mechanisms that result in a body posture torsion phenotype of protein O-mannosyltransferase (POMT) mutants7.
Protein O-mannosylation (POM) is a special type of posttranslational modification, where a mannose sugar is added to serine or threonine residues of secretory pathway proteins8,9. Genetic defects in POM cause congenital muscular dystrophies (CMD) in humans10,11,12. We investigated the causative mechanisms of these diseases using Drosophila as a model system. We found that embryos with mutations in Drosophila protein O-mannosyltransferase genes POMT1 and POMT2 (a.k.a. rotated abdomen (rt) and twisted (tw)) show a displacement (&#34;rotation&#34;) of body segments, which results in an abnormal body posture7. Interestingly, this defect coincided with the developmental stage when peristaltic muscle contractions become prominent7.
Since abnormal body posture in POM mutant embryos arises when musculature and epidermis are already formed and peristaltic waves of coordinated muscle contractions have started, we hypothesized that abnormal body posture could be a result of abnormal muscle contractions rather than a defect in muscle or/and epidermis morphology7. CMDs can be associated with abnormal muscle contractions and posture defects13, and thus the analysis of the posture phenotype in Drosophila POMT mutants may elucidate pathological mechanisms associated with muscular dystrophies. In order to investigate the relationship between the body posture phenotype of Drosophila POMT mutants and possible abnormalities in peristaltic waves of muscle contractions, we decided to analyze muscle contractions in detail using a live imaging approach.
Our analysis of peristaltic contraction waves in Drosophila embryos revealed two distinct contraction modes, designated as type 1 and type 2 waves. Type 1 waves are simple waves propagating from anterior to posterior or vice versa. Type 2 waves are biphasic waves that initiate at the anterior end, propagate halfway in the posterior direction, momentarily halt, forming a temporal static contraction, and then, during the second phase, are swept by a peristaltic contraction that propagates forward from the posterior end. Wild-type embryos normally generate a series of contractions that consists of approximately 75% type 1 and 25% type 2 waves. In contrast, POMT mutant embryos generate type 1 and type 2 waves at approximately equal relative frequencies.
Our approach can provide detailed information for quantitative analysis of muscle contractions and embryo rolling7. This approach could also be adapted for analyses of other behaviors involving muscle contractions, such as hatching and crawling.

<table border="0" cellpadding="0" cellspacing="0" style="width:771px;" width="771">
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		<col />
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	</colgroup>
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Digital camera</td>
			<td style="width:155px;">Hamamatsu CMOS ORCA-Flash 4.0</td>
			<td style="width:119px;">C13440-20CU</td>
			<td style="width:283px;">With different emission filters</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Forceps</td>
			<td style="width:155px;">FST Dumont</td>
			<td style="width:119px;">11254-20</td>
			<td>Tip Dimensions 0.05 mm x 0.01 mm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">LED</td>
			<td style="width:155px;">X-cite BDX (Excelitas)</td>
			<td style="width:119px;">XLED1</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Microscope</td>
			<td style="width:155px;">Carl Ziess Examiner D1</td>
			<td style="width:119px;">491405-0005-000</td>
			<td>Epiflourescence with time lapse</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Needle</td>
			<td style="width:155px;">BD&#160;</td>
			<td align="right" style="width:119px;">305767</td>
			<td>25 G x 1-1/2 in</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Paintbrush</td>
			<td style="width:155px;">Contemporary crafts</td>
			<td style="width:119px;"></td>
			<td>Any paintbrush will work</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Petri dishes</td>
			<td style="width:155px;">VWR</td>
			<td style="width:119px;">25384-164</td>
			<td>60 mm x 15 mm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Software</td>
			<td style="width:155px;">HCImage Live</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Thread Zap Wax pen</td>
			<td style="width:155px;">Thread Zap II (by BeadSmith)(Amazon)</td>
			<td style="width:119px;">TZ1300</td>
			<td>Burner Tool</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:215px;">Tricorner plastic beaker</td>
			<td style="width:155px;">VWR</td>
			<td>25384-152</td>
			<td>100 mL</td>
		</tr>
	</tbody>
</table>

live imaging and analysis of muscle contractions in drosophila embryo

Coordinated muscle contractions are a form of rhythmic behavior seen early during development in Drosophila embryos. Neuronal sensory feedback circuits are required to control this behavior. Failure to produce the rhythmic pattern of contractions can be indicative of neurological abnormalities. We previously found that defects in protein O-mannosylation, a posttranslational protein modification, affect the axon morphology of sensory neurons and result in abnormal coordinated muscle contractions in embryos. Here, we present a relatively simple method for recording and analyzing the pattern of peristaltic muscle contractions by live imaging of late stage embryos up to the point of hatching, which we used to characterize the muscle contraction phenotype of protein O-mannosyltransferase mutants. Data obtained from these recordings can be used to analyze muscle contraction waves, including frequency, direction of propagation and relative amplitude of muscle contractions at different body segments. We have also examined body posture and taken advantage of a fluorescent marker expressed specifically in muscles to accurately determine the position of the embryo midline. A similar approach can also be utilized to study various other behaviors during development, such as embryo rolling and hatching.

Normal peristaltic muscle contractions are shown in a WT (wild-type, Canton-S) embryo in Movie 1. The average frequency of peristaltic waves of muscle contractions in our analysis was 47 contractions per hour and the average amplitude was 60% above baseline for WT embryos. Embryo rolling is shown for a WT embryo in Movie 2, with the white arrow marking the initial position of a trachea and a black arrow depicting the position of a dorsal appendage. The dorsal appendage (exterio...

Watch this Scientific Journal Video about Live Imaging and Analysis of Muscle Contractions in Drosophila Embryo at JoVE.com

Live Imaging and Analysis of Muscle Contractions in Drosophila Embryo

Here, we present a method to record embryonic muscle contractions in Drosophila embryos in a non-invasive and detail-oriented manner.

Live Imaging and Analysis of Muscle Contractions in Drosophila Embryo

Coordinated muscle contractions are a form of rhythmic behavior seen early during development in Drosophila embryos. Neuronal sensory feedback circuits ...

This method addresses how to analyze developmental processes such as muscle contractions and rolling which occur in the Drosophila embryo. Some advantages of this technique are that it is noninvasive and quite detailed, yet it is relatively simple to perform. Our method can be developed further for high-content analysis-based screening to isolate and analyze new mutations that affect embryonic muscle contractions and other developmental processes.When visualizing muscle contractions, it's important to properly time embryo collections because contractions begin only at a specific developmental stage. Step-by-step visual demonstration can greatly aid in the quantitative analysis of the developmental processes. For live imaging of mounted Drosophila embryos, place the embryos onto the stage of an epifluorescence microscope with a timelapse function and a digital camera with suitable emission filters and select a 10X water immersion objective lens.Then live video record the embryos using the appropriate microscope recording software for about one to two hours with an acquisition rate of four frames per second. At the end of the experiment, export the recorded video directly into ImageJ. Select image and crop to draw a box around each individual embryo to crop the video recordings to the size of each embryo.Click Image, Transform and Rotate to rotate the cropped images to achieve a vertical position of the embryo midline relative to the screen. To set distance measurements to micrometers, click Analyze and Set Scale, then enter the known pixel to micron ratio conversion factor for your microscope setup. All subsequent measurements will then be reported in micrometers.To analyze embryo rolling, first mark the position of one or both trachea of an embryo in the first frame of the video midway between the posterior and anterior ends and click Analyze, Tools and Region of Interest Manager. Draw an approximate seven micrometer by seven micrometer box around the trachea and click the T key on the keyboard to record this position as an XY coordinate. Mark the position of the same area of the trachea after peristaltic contractions of interest and draw a line connecting the centers of each box clicking M on the keyboard to measure the distance from the pre-contraction position to the post-contraction position.To analyze embryonic muscle contractions using embryos expressing fluorescent muscle markers, use the recording of the fluorescent readout to draw a region of interest centered around the fluorescing muscles of a particular body segment of interest. Select the Add T tab in the Region of Interest Manager to record the position of the region of interest. Click Region of Interest Manager and Measure to record the average fluorescent intensity of each region of interest selected for each frame of the video.Move the box to the centers of other body segments of interest and click Add T to record their positions to obtain regions of interest of identical size in all of the body segments to be analyzed. In the Region of Interest Manager, hold the Control key while selecting all the regions of interest recorded as XY coordinates. Click More and Multi-Measure to measure the mean fluorescent intensity of each region of interest for all of the frames of the video.This will report each measurement in a table with each region of interest as a column of the table and each frame as a row. Then transfer the table to a spreadsheet program for further analysis. Plot a graph with the frame number on the x-axis and the mean fluorescence intensity on the y-axis and convert the frame number to time using the four frames per second frame rate.The muscle contractions increase the GFP intensity as they bring more GFP into the vicinity of the focal area as more muscles get pulled in during these contractions. To determine the muscle contraction amplitude, estimate the baseline GFP intensity as the average intensity of the regions between peaks. Then assess the increase in GFP fluorescence intensity relative to this baseline.Then divide every region of interest intensity value by the baseline intensity to normalize the GFP intensity to the baseline. Compare the normalized GFP intensities at posterior, medial and anterior segments during muscle contraction wave to examine the changes in the extent of muscle contraction as the wave propagates and to determine the direction of the wave. To compare the muscle contractions on the left and right sides of the embryo, analyze the peak intensities for the same segments on both sides of the embryo.Use the contraction amplitude and the timing of the peaks to reveal the differences, if any, and the extent and the timing of the peristaltic muscle contraction waves. Here normal peristaltic muscle contractions in a wild type Drosophila embryo are shown. In this video of rolling in a wild type embryo, note that the dorsal appendage does not move while the trachea does indicating that the embryo has rolled within its shell.In this representative analysis, the muscle contraction peaks during the 165 to 178-second time period represent a single forward wave. For this embryo, no difference in the amplitude and the time of the muscle contractions was measured on the right and left sides of the embryo. A peristaltic contraction is designated as a forward type one wave if its profile has a peak that arises at the posterior region first followed by peaks at the middle and anterior regions.A backward type one wave is a peak that first arises at anterior segments and then propagates toward posterior regions. Type two waves start at one end of the embryo and proceed toward the middle regions before returning to their origin as a sweeping wave re-initiated at the opposite end. Body posture mutant embryos demonstrate an abnormal relative frequency of type one to type two wave generation that results in a body posture abnormality designated as the body torsion or rotation phenotype.To use fluorescence as a readout for the muscle contraction parameters, it is essential to use embryos with a reporter in the muscle tissue. This method can be used for the simultaneous recording of the muscle contractions of many embryos and for the assessment of the responses to various stimuli, drugs or environmental changes.

live-imaging-and-analysis-of-muscle-contractions-in-drosophila-embryo

Research

JoVE Journal

Developmental Biology

Live-imaging of the Drosophila Pupal Eye

Inherent processes of Drosophila pupal development can shift and distort the eye epithelium in ways that make individual cell behavior difficult to track during live cell imaging. These processes include: retinal rotation, cell growth and organismal movement. Additionally, irregularities in the topology of the epithelium, including subtle bumps and folds often introduced as the pupa is prepared for imaging, make it challenging to acquire in-focus images of more than a few ommatidia in a single focal plane. The workflow outlined here remedies these issues, allowing easy analysis of cellular processes during Drosophila pupal eye development. Appropriately-staged pupae are arranged in an imaging rig that can be easily assembled in most laboratories. Ubiquitin-DE-Cadherin:GFP and GMR-GAL4&#8211;driven UAS-&#945;-catenin:GFP are used to visualize cell boundaries in the eye epithelium 1-3. After deconvolution is applied to fluorescent images captured at multiple focal planes, maximum projection images are generated for each time point and enhanced using image editing software. Alignment algorithms are used to quickly stabilize superfluous motion, making individual cell behavior easier to track.

Live-imaging of the Drosophila Pupal Eye

This protocol presents an efficient method for imaging the live Drosophila pupal eye neuroepithelium. This method compensates for tissue movement and uneven topology, enhances visualization of cell boundaries through the use of multiple GFP-tagged junction proteins, and uses an easily-assembled imaging rig.

Inherent processes of Drosophila pupal development can shift and distort the eye epithelium in ways that make individual cell behavior difficult to track ...

Analysis of Zebrafish Larvae Skeletal Muscle Integrity with Evans Blue Dye

The zebrafish model is an emerging system for the study of neuromuscular disorders. In the study of neuromuscular diseases, the integrity of the muscle membrane is a critical disease determinant. To date, numerous neuromuscular conditions display degenerating muscle fibers with abnormal membrane integrity; this is most commonly observed in muscular dystrophies. Evans Blue Dye (EBD) is a vital, cell permeable dye that is rapidly taken into degenerating, damaged, or apoptotic cells; in contrast, it is not taken up by cells with an intact membrane. EBD injection is commonly employed to ascertain muscle integrity in mouse models of neuromuscular diseases. However, such EBD experiments require muscle dissection and/or sectioning prior to analysis. In contrast, EBD uptake in zebrafish is visualized in live, intact preparations. Here, we demonstrate a simple and straightforward methodology for performing EBD injections and analysis in live zebrafish. In addition, we demonstrate a co-injection strategy to increase efficacy of EBD analysis. Overall, this video article provides an outline to perform EBD injection and characterization in zebrafish models of neuromuscular disease.

In this study, we describe a straightforward method to perform Evans Blue Dye (EBD) analysis on zebrafish larvae. This technique is a powerful tool for the characterization of skeletal muscle integrity and delineation of zebrafish models of muscular dystrophy, and is a valuable method for the development of novel therapeutics.

The zebrafish model is an emerging system for the study of neuromuscular disorders.  In the study of neuromuscular diseases, the integrity of the muscle ...

Observing Mitotic Division and Dynamics in a Live Zebrafish Embryo

Mitosis is critical for organismal growth and differentiation. The process is highly dynamic and requires ordered events to accomplish proper chromatin condensation, microtubule-kinetochore attachment, chromosome segregation, and cytokinesis in a small time frame. Errors in the delicate process can result in human disease, including birth defects and cancer. Traditional approaches investigating human mitotic disease states often rely on cell culture systems, which lack the natural physiology and developmental/tissue-specific context advantageous when studying human disease. This protocol overcomes many obstacles by providing a way to visualize, with high resolution, chromosome dynamics in a vertebrate system, the zebrafish. This protocol will detail an approach that can be used to obtain dynamic images of dividing cells, which include: in vitro transcription, zebrafish breeding/collecting, embryo embedding, and time-lapse imaging. Optimization and modifications of this protocol are also explored. Using H2A.F/Z-EGFP (labels chromatin) and mCherry-CAAX (labels cell membrane) mRNA-injected embryos, mitosis in AB wild-type, auroraBhi1045, and esco2hi2865 mutant zebrafish is visualized. High resolution live imaging in zebrafish allows one to observe multiple mitoses to statistically quantify mitotic defects and timing of mitotic progression. In addition, observation of qualitative aspects that define improper mitotic processes (i.e., congression defects, missegregation of chromosomes, etc.) and improper chromosomal outcomes (i.e., aneuploidy, polyploidy, micronuclei, etc.) are observed. This assay can be applied to the observation of tissue differentiation/development and is amenable to the use of mutant zebrafish and pharmacological agents. Visualization of how defects in mitosis lead to cancer and developmental disorders will greatly enhance understanding of the pathogenesis of disease.

Mitosis is critical to every living organism and defects often lead to cancer and developmental disorders. Using this imaging protocol and zebrafish as a model system, researchers can visualize mitosis in a live vertebrate organism and the multitude of defects that arise when mitotic processes are defective.

Mitosis is critical for organismal growth and differentiation. The process is highly dynamic and requires ordered events to accomplish proper chromatin ...

Long-term Live Imaging of Drosophila Eye Disc

Live imaging provides the ability to continuously track dynamic cellular and developmental processes in real time. Drosophila larval imaginal discs have been used to study many biological processes, such as cell proliferation, differentiation, growth, migration, apoptosis, competition, cell-cell signaling, and compartmental boundary formation. However, methods for the long-term ex vivo culture and live imaging of the imaginal discs have not been satisfactory, despite many efforts. Recently, we developed a method for the long-term ex vivo culture and live imaging of imaginal discs for up to 18 h. In addition to using a high insulin concentration in the culture medium, a low-melting agarose was also used to embed the disc to prevent it from drifting during the imaging period. This report uses the eye-antennal discs as an example. Photoreceptor R3/4-specific m&#948;0.5-Ga4 expression was followed to demonstrate that photoreceptor differentiation and ommatidial rotation can be observed during a 10 h live imaging period. This is a detailed protocol describing this simple method.

Long-term Live Imaging of Drosophila Eye Disc

This protocol describes a detailed method for the long-term ex vivo culture and live imaging of a Drosophila imaginal disc. It demonstrates photoreceptor differentiation and ommatidial rotation within the 10 h period of live imaging of the eye disc. The protocol is simple and does not require expensive setup.

Live imaging provides the ability to continuously track dynamic cellular and developmental processes in real time. Drosophila larval imaginal discs have ...

In Vitro Ovule Cultivation for Live-cell Imaging of Zygote Polarization and Embryo Patterning in Arabidopsis thaliana

In most flowering plants, the zygote and embryo are hidden deep in the mother tissue, and thus it has long been a mystery of how they develop dynamically; for example, how the zygote polarizes to establish the body axis and how the embryo specifies various cell fates during organ formation. This manuscript describes an in vitro ovule culture method to perform live-cell imaging of developing zygotes and embryos of Arabidopsis thaliana. The optimized cultivation medium allows zygotes or early embryos to grow into fertile plants. By combining it with a poly(dimethylsiloxane) (PDMS) micropillar array device, the ovule is held in the liquid medium in the same position. This fixation is crucial to observe the same ovule under a microscope for several days from the zygotic division to the late embryo stage. The resulting live-cell imaging can be used to monitor the real-time dynamics of zygote polarization, such as nuclear migration and cytoskeleton rearrangement, and also the cell division timing and cell fate specification during embryo patterning. Furthermore, this ovule cultivation system can be combined with inhibitor treatments to analyze the effects of various factors on embryo development, and with optical manipulations such as laser disruption to examine the role of cell-cell communication.

In Vitro Ovule Cultivation for Live-cell Imaging of Zygote Polarization and Embryo Patterning in Arabidopsis thaliana

This manuscript describes an in vitro ovule cultivation method that enables live-cell imaging of Arabidopsis zygotes and embryos. This method is utilized to visualize the intracellular dynamics during zygote polarization and the cell fate specification in developing embryos.

In most flowering plants, the zygote and embryo are hidden deep in the mother tissue, and thus it has long been a mystery of how they develop dynamically; ...

Live Imaging of Mouse Secondary Palate Fusion

The fusion of the secondary palatal shelves to form the intact secondary palate is a key process in mammalian development and its disruption can lead to cleft secondary palate, a common congenital anomaly in humans. Secondary palate fusion has been extensively studied leading to several proposed cellular mechanisms that may mediate this process. However, these studies have been mostly performed on fixed embryonic tissues at progressive timepoints during development or in fixed explant cultures analyzed at static timepoints. Static analysis is limited for the analysis of dynamic morphogenetic processes such a palate fusion and what types of dynamic cellular behaviors mediate palatal fusion is incompletely understood. Here we describe a protocol for live imaging of ex vivo secondary palate fusion in mouse embryos. To examine cellular behaviors of palate fusion, epithelial-specific Keratin14-cre was used to label palate epithelial cells in ROSA26-mTmGflox reporter embryos. To visualize filamentous actin, Lifeact-mRFPruby reporter mice were used. Live imaging of secondary palate fusion was performed by dissecting recently-adhered secondary palatal shelves of embryonic day (E) 14.5 stage embryos and culturing in agarose-containing media on a glass bottom dish to enable imaging with an inverted confocal microscope. Using this method, we have detected a variety of novel cellular behaviors during secondary palate fusion. An appreciation of how distinct cell behaviors are coordinated in space and time greatly contributes to our understanding of this dynamic morphogenetic process. This protocol can be applied to mutant mouse lines, or cultures treated with pharmacological inhibitors to further advance understanding of how secondary palate fusion is controlled.

Here, we present a protocol for live imaging of mouse secondary palate fusion using confocal microscopy. This protocol can be used in combination with a variety of fluorescent reporter mouse lines, and with pathway inhibitors for mechanistic insight. This protocol can be adapted for live imaging in other developmental systems.

The fusion of the secondary palatal shelves to form the intact secondary palate is a key process in mammalian development and its disruption can lead to ...

In Vivo Imaging of Muscle-tendon Morphogenesis in Drosophila Pupae

Muscles together with tendons and the skeleton enable animals including humans to move their body parts. Muscle morphogenesis is highly conserved from animals to humans. Therefore, the powerful Drosophila model system can be used to study concepts of muscle-tendon development that can also be applied to human muscle biology. Here, we describe in detail how morphogenesis of the adult muscle-tendon system can be easily imaged in living, developing Drosophila pupae. Hence, the method allows investigating proteins, cells and tissues in their physiological environment. In addition to a step-by-step protocol with helpful tips, we provide a comprehensive overview of fluorescently tagged marker proteins that are suitable for studying the muscle-tendon system. To highlight the versatile applications of the protocol, we show example movies ranging from visualization of long-term morphogenetic events &#8211; occurring on the time scale of hours and days &#8211; to visualization of short-term dynamic processes like muscle twitching occurring on time scale of seconds. Taken together, this protocol should enable the reader to design and perform live-imaging experiments for investigating muscle-tendon morphogenesis in the intact organism.

In Vivo Imaging of Muscle-tendon Morphogenesis in Drosophila Pupae

Here, we present an easy-to-use and versatile method to perform live imaging of developmental processes in general and muscle-tendon morphogenesis in particular in living Drosophila pupae.

Muscles together with tendons and the skeleton enable animals including humans to move their body parts. Muscle morphogenesis is highly conserved from ...

Preparation of Drosophila Larval and Pupal Testes for Analysis of Cell Division in Live, Intact Tissue

Experimental analysis of cells dividing in living, intact tissues and organs is essential to our understanding of how cell division integrates with development, tissue homeostasis, and disease processes. Drosophila spermatocytes undergoing meiosis are ideal for this analysis because (1) whole Drosophila testes containing spermatocytes are relatively easy to prepare for microscopy, (2) the spermatocytes&#8217; large size makes them well suited for high resolution imaging, and (3) powerful Drosophila genetic tools can be integrated with in vivo analysis. Here, we present a readily accessible protocol for the preparation of whole testes from Drosophila third instar larvae and early pupae. We describe how to identify meiotic spermatocytes in prepared whole testes and how to image them live by time-lapse microscopy. Protocols for fixation and immunostaining whole testes are also provided. The use of larval testes has several advantages over available protocols that use adult testes for spermatocyte analysis. Most importantly, larval testes are smaller and less crowded with cells than adult testes, and this greatly facilitates high resolution imaging of spermatocytes. To demonstrate these advantages and the applications of the protocols, we present results showing the redistribution of the endoplasmic reticulum with respect to spindle microtubules during cell division in a single spermatocyte imaged by time-lapse confocal microscopy. The protocols can be combined with expression of any number of fluorescently tagged proteins or organelle markers, as well as gene mutations and other genetic tools, making this approach especially powerful for analysis of cell division mechanisms in the physiological context of whole tissues and organs.

Preparation of Drosophila Larval and Pupal Testes for Analysis of Cell Division in Live, Intact Tissue

The goal of this protocol is to analyze cell division in intact tissue by live and fixed cell microscopy using Drosophila meiotic spermatocytes. The protocol demonstrates how to isolate whole, intact testes from Drosophila larvae and early pupae, and how to process and mount them for microscopy.

Experimental analysis of cells dividing in living, intact tissues and organs is essential to our understanding of how cell division integrates with ...

Imaging Intranuclear Actin Rods in Live Heat Stressed Drosophila Embryos

The purpose of this protocol is to visualize intranuclear actin rods that assemble in live Drosophila melanogaster embryos following heat stress. Actin rods are a hallmark of a conserved, inducible Actin Stress Response (ASR) that accompanies human pathologies, including neurodegenerative disease. Previously, we showed that the ASR contributes to morphogenesis failures and reduced viability of developing embryos. This protocol allows the continued study of mechanisms underlying actin rod assembly and the ASR in a model system that is highly amenable to imaging, genetics and biochemistry. Embryos are collected and mounted on a coverslip to prepare them for injection. Rhodamine-conjugated globular actin (G-actinRed) is diluted and loaded into a microneedle. A single injection is made into the center of each embryo. After injection, embryos are incubated at elevated temperature and intranuclear actin rods are then visualized by confocal microscopy. Fluorescence recovery after photobleaching (FRAP) experiments may be performed on the actin rods; and other actin-rich structures in the cytoplasm can also be imaged. We find that G-actinRed polymerizes like endogenous G-actin and does not, on its own, interfere with normal embryo development. One limitation of this protocol is that care must be taken during injection to avoid serious injury to the embryo. However, with practice, injecting G-actinRed into Drosophila embryos is a fast and reliable way to visualize actin rods and can easily be used with flies of any genotype or with the introduction of other cellular stresses, including hypoxia and oxidative stress.

Imaging Intranuclear Actin Rods in Live Heat Stressed Drosophila Embryos

The goal of this protocol is to inject Rhodamine-conjugated globular actin into Drosophila embryos and image intranuclear actin rod assembly following heat stress.

The purpose of this protocol is to visualize intranuclear actin rods that assemble in live Drosophila melanogaster embryos following heat stress. Actin ...

Drosophila Embryo Preparation and Microinjection for Live Cell Microscopy Performed using an Automated High Content Analyzer

Modern approaches in quantitative live cell imaging have become an essential tool for exploring cell biology, by enabling the use of statistics and computational modeling to classify and compare biological processes. Although cell culture model systems are great for high content imaging, high throughput studies of cell morphology suggest that ex vivo cultures are limited in recapitulating the morphological complexity found in cells within living organisms. As such, there is a need for a scalable high throughput model system to image living cells within an intact organism. Described here is a protocol for using a high content image analyzer to simultaneously acquire multiple time-lapse videos of embryonic Drosophila melanogaster development during the syncytial blastoderm stage. The syncytial blastoderm has traditionally served as a great in vivo model for imaging biological events; however, obtaining a significant number of experimental replicates for quantitative and high-throughput approaches has been labor intensive and limited by the imaging of a single embryo per experimental repeat. Presented here is a method to adapt imaging and microinjection approaches to suit a high content imaging system, or any inverted microscope capable of automated multipoint acquisition. This approach enables the simultaneous acquisition of 6-12 embryos, depending on desired acquisition factors, within a single imaging session.

Presented here is a protocol to microinject and simultaneously image multiple Drosophila embryos during embryonic development using a plate-based, high content imager.

Modern approaches in quantitative live cell imaging have become an essential tool for exploring cell biology, by enabling the use of statistics and ...