This work was supported by the American Cancer Society (PF-07-103-01-CSM), the National Institutes of Health (R01 GM61275 and P30 CA042014), the Leukemia and Lymphoma Society, and the Huntsman Cancer Foundation.

siRNA transfection and cell preparation
<ol>
 <li>Prepare a 4-well LabTek II chambered coverglass by adding 0.5mL of fibronectin (10&mu;g/mL) to each well that will be used. Incubate for 10-15 minutes at room temperature. </li>
 <li>Prepare siRNA/Lipofectamine RNAiMAX (Invitrogen) complexes for reverse transfection according to manufacturer s instructions. Use the recommended amounts for one well of a 24-well dish per chamber to be used (100&mu;L total). An analogous product/protocol for siRNA transfection can be substituted.</li>
 <li>Remove the fibronectin from the wells of the chambered coverglass. Add 100&mu;L of siRNA/Lipofectamine RNAiMAX complexes to each well that will be used.</li>
 <li>Aliquot 20,000 histone H2B-mCherry-expressing cells (in 500&mu;L) per well containing transfection mixture. </li>
 <li>Allow cells to incubate for ~24 hours before replacing transfection mixture with 1mL of regular cell culture medium.</li>
 <li>Incubate cells an additional 24 hours before image acquisition (48 hours post-transfection).</li>
</ol>
Microscope setup and image acquisition
<ol start="7">
 <li>There are three main parts to the image acquisition setup: 1) a cell incubator that fits on the microscope stage and maintains a constant humid environment of 37&deg;C, and 5% CO2; 2) an inverted microscope equipped with an automated stage, automated fluorescence and brightfield shutters, and automated filter wheels; and 3) a software package that integrates and controls the stage, shutters, and filter wheels. In our imaging setup, we use a customized cell incubator from OKO Lab that can be used with the LabTek II chambered coverglass. The stage, shutters, and filter wheels are controlled by the Metamorph software. Hint: The OKO Lab stage-top incubator system includes adapters for a variety of different plate, dish, or coverslip sizes. </li>
 <li>Position the LabTek II chambered coverglass in the incubator by opening the lid of the pre-warmed and equilibrated incubator, placing the chambered coverglass in the adapter, and holding in place with modeling clay. Leave the cover on the chambered coverglass so that the cell culture medium will not dry out. Close the lid and position the entire incubator on the microscope stage, ensuring that the incubator is held firmly in place.</li>
 <li>Using Metamorph, set up your experiment by selecting "Apps/Multidimensional Acquisition" in the menu bar of the software. This will bring up a window in which you can select the frequency and length of the timelapse, the exposure time for each color (if doing multiple settings), the number and location of the stage positions, and the number of z-sections (if desired). Select where to save the data files. Hint: If using software other than Metamorph, the functions may be slightly different, but the overall concept is the same. Micromanager, an open source ImageJ-based acquisition software that is compatible with most hardware setups, is an excellent alternative. </li>
 <li>For the purposes of this protocol, we will acquire images at two wavelengths (brightfield and mCherry) every 15 minutes for 8 hours at 15 stage positions. Hint: If better time resolution is desired, then you can shorten the time interval between acquisitions; however, fewer stage positions can be used, and thus fewer mitotic cells will be available for analysis. It is important when considering time intervals to take into account the time required for the filter wheel to switch between filter sets. </li>
 <li>Determine the optimal exposure time for each wavelength by first focusing on a field of cells using brightfield illumination. In the software, adjust the autofocus function only for the brightfield channel (this will allow the software to autofocus at each stage position before each acquisition). Hint: We use a 40x dry phase-contrast objective to give excellent resolution without the need for oil. Other objectives may be used depending on the optical resolution desired. </li>
 <li>Switch to the mCherry wavelength and snap an image using a 50 msec exposure. Adjust the exposure time to the minimum required to see a good image. It is essential to limit the amount of light exposure to ensure sustained cell viability. As a general rule, this can best be achieved by using a neutral density filter (to reduce the excitation light flux) and a longer camera exposure time rather than by increasing the illumination strength. Repeat this procedure for any additional wavelengths to be used. Hint: To determine long-term cell viability at a given exposure for your experiment, you can preview the total number of images a cell can survive over the desired timelapse by temporarily adjusting the timepoint spacing from minutes to seconds (i.e., 10 min. becomes 10 seconds). If your cells survive 100-200 exposures (or the appropriate number), then your exposure is fine. If not, reduce your excitation light, exposure time, or the total number of images to simulate your full experiment. </li>
 <li>Next, select and mark an appropriate number of stage positions so that you can achieve adequate sampling of the cell population. Metamorph will record the positions and will return there for each acquisition. Hint: I generally try to find positions in which there are plenty of cells to image, but not so many that they are too dense. Also, it is important to select enough positions so that you will have a good chance of observing a large number of cells progressing through mitosis.</li>
 <li>After all timelapse, wavelength exposure time, and stage position information have been recorded, select the "Preview" button on the screen to determine if the software is controlling the equipment appropriately.</li>
 <li>Once you are satisfied, select the "Acquire" button on the screen to begin acquisition. Then sit back and allow the computer and microscope to do the work. Hint: Observe the automation through at least one full round of acquisition to ensure that everything is working properly.</li>
</ol>
Image processing and analysis
<ol start="16">
 <li>After the acquisition has finished, the next step is to transfer the image data into a form that is easier to handle. For the purposes of this protocol, I will demonstrate first how to generate movies using Metamorph, then how to generate image montages using the ImageJ program. Either format will be useful for quantification purposes.</li>
 <li>The first step is to review the data. To do so, select "Apps/Review Multidimensional Data" in the menu bar. Select the location of your files, then select "View". This will allow you to review the stack of images from each stage position individually. Select the desired stage position, then "Load Images". You will be able to advance through the data frame-by-frame. </li>
 <li>For those stage positions in which cells go through mitosis (as determined by both DNA and cellular morphology), you can make movies and montages using Metamorph, or with other programs such as ImageJ (available for free through NIH). </li>
 <li>To make a movie in Metamorph, select "Process/Save movie" in the menu bar. You will be able to select which frames to use, the speed, and file type of the movie. Then select "Save Movie". </li>
 <li>To make a montage, I save the image stack as a .stk file, which can be used in other programs such as ImageJ. </li>
 <li>Open the file in ImageJ and advance the frames until you find a cell going through mitosis. Crop the area around the cell and select "Image/Duplicate". Hint: Make sure to duplicate all frames. </li>
 <li>To make a montage, select "Image/Stacks/Make Montage" in the menu bar. Here you can specify which frames you want to include, the size and shape of the montage, and whether you want borders between the frames. Select these and hit "Okay". Save the montage as a .tif file and do any further processing in either ImageJ or Adobe Photoshop. Hint: Change montage files from the 16-bit format used by Metamorph to 8-bit format for easier image processing. </li>
 <li>To calculate time in different stages of mitosis, determine t=0 (first sign of DNA condensation or cell rounding), count the number of frames until chromosomes are aligned at the equator (time in prophase/prometaphase), frames until chromosomes begin to segregate (time in metaphase), and frames until cells begin to flatten (anaphase/telophase/cytokinesis). The calculated time in each mitotic stage depends on the time interval between each frame.</li>
</ol>
Representative Results
<img src="/files/ftp_upload/1878/1878fig1tmb.jpg" border="0" /> Figure 1 illustrates the results from a typical control siRNA transfection experiment using a HeLa cell line expressing histone H2B-mCherry. This method of has been used effectively to quantify mitotic timing, revealing an unexpected role for the nucleoporin Nup153 in the timing of late mitosis1. Please <a href="https://www.jove.com/files/ftp_upload/1878/1878fig1.jpg">click here</a> to see a larger version of figure 1.

<ol>
	<li>Mackay, D. R., Elgort, S. W., Ullman, K. 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+nucleoporin+Nup153+has+separable+roles+in+both+early+mitotic+progression+and+the+resolution+of+mitosis.">The nucleoporin Nup153 has separable roles in both early mitotic progression and the resolution of mitosis.</a> Mol Biol Cell. 20, 1652-1660 (2009).</li><li>Khodjakov, A., Rieder, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+the+division+process+in+living+tissue+culture+cells.">Imaging the division process in living tissue culture cells.</a> Methods. 38, 2-16 (2006).</li><li>Shaner, N. C., Steinbach, P. A., Tsien, R. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+guide+to+choosing+fluorescent+proteins.">A guide to choosing fluorescent proteins.</a> Nat Methods. 2, 905-909 (2005).</li><li>Meraldi, P., Draviam, V. M., Sorger, P. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Timing+and+checkpoints+in+the+regulation+of+mitotic+progression.">Timing and checkpoints in the regulation of mitotic progression.</a> Dev Cell. 7, 45-60 (2004).</li><li>Mora-Bermudez, F., Ellenberg, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+structural+dynamics+of+chromosomes+in+living+cells+by+fluorescence+microscopy.">Measuring structural dynamics of chromosomes in living cells by fluorescence microscopy.</a> Methods. 41, 158-167 (2007).</li><li>Prosser, S. L., Fry, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescence+imaging+of+the+centrosome+cycle+in+mammalian+cells.">Fluorescence imaging of the centrosome cycle in mammalian cells.</a> Methods Mol Biol. 545, 165-183 (2009).</li><li>Malureanu, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BubR1+N+terminus+acts+as+a+soluble+inhibitor+of+cyclin+B+degradation+by+APC/C(Cdc20)+in+interphase.">BubR1 N terminus acts as a soluble inhibitor of cyclin B degradation by APC/C(Cdc20) in interphase.</a> Dev Cell. 16, 118-131 (2009).</li><li>Anderson, D. J., Hetzer, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reshaping+of+the+endoplasmic+reticulum+limits+the+rate+for+nuclear+envelope+formation.">Reshaping of the endoplasmic reticulum limits the rate for nuclear envelope formation.</a> J Cell Biol. 182, 911-924 (2008).</li><li>Beaudouin, J., Gerlich, D., Daigle, N., Eils, R., Ellenberg, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+envelope+breakdown+proceeds+by+microtubule-induced+tearing+of+the+lamina.">Nuclear envelope breakdown proceeds by microtubule-induced tearing of the lamina.</a> Cell. 108, 83-96 (2002).</li><li>Marcus, A. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualization+of+spindle+behavior+using+confocal+microscopy.">Visualization of spindle behavior using confocal microscopy.</a> Methods Mol Med. 137, 125-137 (2007).</li><li>Steigemann, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aurora+B-mediated+abscission+checkpoint+protects+against+tetraploidization.">Aurora B-mediated abscission checkpoint protects against tetraploidization.</a> Cell. 136, 473-484 (2009).</li><li>Draviam, 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=A+functional+genomic+screen+identifies+a+role+for+TAO1+kinase+in+spindle-checkpoint+signalling.">A functional genomic screen identifies a role for TAO1 kinase in spindle-checkpoint signalling.</a> Nat Cell Biol. 9, 556-564 (2007).</li><li>Neumann, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-throughput+RNAi+screening+by+time-lapse+imaging+of+live+human+cells.">High-throughput RNAi screening by time-lapse imaging of live human cells.</a> Nat Methods. 3, 385-390 (2006).</li><li>Stegmeier, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anaphase+initiation+is+regulated+by+antagonistic+ubiquitination+and+deubiquitination+activities.">Anaphase initiation is regulated by antagonistic ubiquitination and deubiquitination activities.</a> Nature. 446, 876-881 (2007).</li></ol>

With recent advances in imaging and fluorescent protein technology, live imaging has become a routine aspect of cellular analysis2. A variety of GFP (and other color variants3) -tagged proteins are widely available or relatively easy to construct and can be used to track a number of cell division hallmarks including DNA/chromosome dynamics4, 5, centrosome duplication6, cyclin B dynamics7, nuclear envelope breakdown and reassembly8, 9, mitotic spindle formation10, and various stages of cytokinesis11. Tagged proteins may be used alone or in combination when the excitation/emission spectra of fluorescent tags are compatible, allowing the coordination between specific events to be assessed. If greater spatial and/or temporal resolution is/are desired, confocal microscopy whether laser scanning, spinning disk, or resonance scanning can be used, and the list of sophisticated microscopy options with ever-increasing resolution continues to grow. Live imaging of mitosis in mammalian cells has also been adapted for use in high-throughput RNAi and small molecule screens12-14. Thus, while one s initial experiments using this technique may be relatively simple, the possibilities for building on this strategy are extensive.

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		<th>Comment</th>
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<tr>
<td>Lipofectamine RNAiMAX</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>13778-075</td>
<td>&nbsp;</td>
<tr>
<td>Lab Tek II Chambered Coverglass (4-well)</td>
<td>&nbsp;</td>
<td>Thermo Scientific</td>
<td>12-565-337</td>
<td>Additional chamber sizes are available</td>
</tr>
<tr>
<td>Fibronectin</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>F1141</td>
<td>&nbsp;</td>
<tr>
<td>Stage-top cell incubator</td>
<td>&nbsp;</td>
<td>OKO Lab</td>
<td>&nbsp;</td>
<td>Can use any appropriate chamber</td>
</tr>
<tr>
<td>Automated inverted fluorescence microscope</td>
<td>&nbsp;</td>
<td>Olympus</td>
<td>&nbsp;</td>
<td>Can use any appropriate microscope</td>
</tr>
<tr>
<td>Software package</td>
<td>&nbsp;</td>
<td>Metamorph</td>
<td>&nbsp;</td>
<td>Can use any appropriate software</td>
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time-lapse imaging of mitosis after sirna transfection

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and cellular content. Hallmark events of mitosis, such as chromosome movement, can be readily tracked on an individual cell basis using time-lapse fluorescence microscopy of mammalian cell lines expressing specific GFP-tagged proteins. In combination with RNAi-based depletion, this can be a powerful method for pinpointing the stage(s) of mitosis where defects occur after levels of a particular protein have been lowered. In this protocol, we present a basic method for assessing the effect of depleting a potential mitotic regulatory protein on the timing of mitosis. Cells are transfected with siRNA, placed in a stage-top incubation chamber, and imaged using an automated fluorescence microscope. We describe how to use software to set up a time-lapse experiment, how to process the image sequences to make either still-image montages or movies, and how to quantify and analyze the timing of mitotic stages using a cell-line expressing mCherry-tagged histone H2B. Finally, we discuss important considerations for designing a time-lapse experiment. This strategy is complementary to other approaches and offers the advantages of 1) sensitivity to changes in kinetics that might not be observed when looking at cells as a population and 2) analysis of mitosis without the need to synchronize the cell cycle using drug treatments. The visual information from such imaging experiments not only allows the sub-stages of mitosis to be assessed, but can also provide unexpected insight that would not be apparent from cell cycle analysis by FACS.

Watch this Scientific Journal Video about Time-lapse Imaging of Mitosis After siRNA Transfection at JoVE.com

Time-lapse Imaging of Mitosis After siRNA Transfection

Here we describe a basic protocol to image and quantify the mitotic timing of live mammalian tissue culture cells after siRNA transfection.

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and ...

time-lapse-imaging-of-mitosis-after-sirna-transfection

Research

JoVE Journal

Biology

16.9K Views.  University of Utah. Here we describe a basic protocol to image and quantify the mitotic timing of live mammalian tissue culture cells after siRNA transfection. 

Video: Time-lapse Imaging of Mitosis After siRNA Transfection

Monitoring Actin Disassembly with Time-lapse Microscopy

Okay, so what I'd like to do today is to show you how to construct a flow chamber, a fusion chamber for imaging on an upright microscope. What then I then do is I create two spaces using film. So what I do is I take the para film, I cut it into small strips.Next I'm going to, this will basically form the channels for the, the walls, and I dry them with a tilted air. I put the cover slip on top of the para, And here's the finished. Then I heat it on a heat block to melt the param and basically create a seal.So what this is, is the, the cover glass here, and then on top of the cover glass is two layers of phim as you see right here. And then on top of this, again, there's a, it's a 22 by two two mil meter cover slip. This one right here, which I pressed against the param to fall the seal.Okay, so the liquid goes in in one direction here and I can suck it out with a filter paper here in this direction. And I'll show you how to do that in a bit. So what I like to do is I like to put it in a humidified chamber, which is very simple.Take two kind of elevated strips and have a filter of paper underneath. And to keep it noisy as I, I put the cover, cover slip on the flow chamber on. Now the way you introduce a solution to the chamber is that you just put the pipet tip at the entrance of the chamber and you just split.Now what I do is I incubate the chamber with the lid closed for 10 minutes. What I usually do to suck the liquid out from the other side is to use it, get a filter paper and cut it into thin strips like this. And I take one of these thin strips and I simultaneously apply the solution into the entrance while putting the filter paper at the exit to suck the exchange, the solution.So you'll see the liquid flowing through the solution. And then I wait for five minutes for the mid close. Now what I'm ready to do is to actually put that the actin it and the actin, I actually have to polymerize, I polymerize inside the flow chamber and it's just the same procedures before.So because like this, and then now that the action is polymerized, I wash out all the un excess un polymerized action using a large volume of just buffer. So here I have about a hundred microliters and it's a few reaction chamber volumes worth of buffer. Just, you know, when the filter paper becomes saturated, I have to change the direction.Okay?And so I'm ready to do imaging with this. So perfusion chamber with actin attached to it. Now I take the slide, mount it under the microscope, and since I'm imaging with an oil objective, I'm gonna put some immersion oil on the top surface of the cover, grass touch, such so assess solution or protein or anything on acting inside.So what I do is I can actually exchange the solution side while I'm doing the time lapse imaging. As such.

Two-photon axotomy and time-lapse confocal imaging in live zebrafish embryos

Zebrafish have long been utilized to study the cellular and molecular mechanisms of development by time-lapse imaging of the living transparent embryo. Here we describe a method to mount zebrafish embryos for long-term imaging and demonstrate how to automate the capture of time-lapse images using a confocal microscope. We also describe a method to create controlled, precise damage to individual branches of peripheral sensory axons in zebrafish using the focused power of a femtosecond laser mounted on a two-photon microscope. The parameters for successful two-photon axotomy must be optimized for each microscope. We will demonstrate two-photon axotomy on both a custom built two-photon microscope and a Zeiss 510 confocal/two-photon to provide two examples.

Zebrafish trigeminal sensory neurons can be visualized in a transgenic line expressing GFP driven by a sensory neuron specific promoter 1. We have adapted this zebrafish trigeminal model to directly observe sensory axon regeneration in living zebrafish embryos. Embryos are anesthetized with tricaine and positioned within a drop of agarose as it solidifies. Immobilized embryos are sealed within an imaging chamber filled with phenylthiourea (PTU) Ringers. We have found that embryos can be continuously imaged in these chambers for 12-48 hours. A single confocal image is then captured to determine the desired site of axotomy. The region of interest is located on the two-photon microscope by imaging the sensory axons under low, non-damaging power. After zooming in on the desired site of axotomy, the power is increased and a single scan of that defined region is sufficient to sever the axon. Multiple location time-lapse imaging is then set up on a confocal microscope to directly observe axonal recovery from injury.

Here we describe a method for mounting zebrafish embryos for long-term imaging, two-photon imaging and tissue-damage techniques, and time-lapse confocal imaging.

Zebrafish have long been utilized to study the cellular and molecular mechanisms of development by time-lapse imaging of the living transparent embryo.  ...

Multicolor Time-lapse Imaging of Transgenic Zebrafish: Visualizing Retinal Stem Cells Activated by Targeted Neuronal Cell Ablation

High-resolution time-lapse imaging of living zebrafish larvae can be utilized to visualize how biological processes unfold (for review see 1). Compound transgenic fish which express different fluorescent reporters in neighboring cell types provide a means of following cellular interactions 2 and/or tissue-level responses to experimental manipulations over time. In this video, we demonstrate methods that can be used for imaging multiple transgenically labeled cell types serially in individual fish over time courses that can span from minutes to several days. The techniques described are applicable to any study seeking to correlate the "behavior" of neighboring cells types over time, including: 1) serial 'catch and release' methods for imaging a large number of fish over successive days, 2) simplified approaches for separating fluorophores with overlapping excitation/emission profiles (e.g., GFP and YFP), 3) use of hypopigmented mutant lines to extend the time window available for high-resolution imaging into late larval stages of development, 4) use of membrane targeted fluorescent reporters to reveal fine morphological detail of individual cells as well as cellular details in larger populations of cells, and 5) a previously described method for chemically-induced ablation of transgenically targeted cell types; i.e., nitroreductase (NTR) mediated conversion of prodrug substrates, such as metronidazole (MTZ), to cytotoxic derivatives 3,5.
As an example of these approaches, we will visualize the ablation and regeneration of a subtype of retinal bipolar neuron within individual fish over several days. Simultaneously we will monitor several other retinal cell types, including neighboring non-targeted bipolar cells and potential degeneration-stimulated retinal stem cells (i.e., M&#971;ller glia). This strategy is being applied in our lab to characterize cell- and tissue-level (e.g., stem cell niche) responses to the selective loss and regeneration of targeted neuronal cell types.

In this video, techniques for multicolor confocal time-lapse imaging and targeted cell ablation are provided. Time-lapse imaging is used to monitor the behavior of multiple cell types of interest in vivo. Targeted cell ablation facilitates the study neural circuit function and cell-specific neuronal regeneration paradigms.

High-resolution time-lapse imaging of living zebrafish larvae can be utilized to visualize how biological processes unfold (for review see 1). Compound ...

Time-lapse Microscopy of Early Embryogenesis in Caenorhabditis elegans

Caenorhabditis elegans has often been used as a model system in studies of early developmental processes. The transparency of the 
embryos, the genetic resources, and the relative ease of transformation are qualities that make C. elegans an excellent model for early embryogenesis. Laser-based 
confocal microscopy and fluorescently labeled tags allow researchers to follow specific cellular structures and proteins in the developing embryo. For example, 
one can follow specific organelles, such as lysosomes or mitochondria, using fluorescently labeled dyes. These dyes can be delivered to the early embryo by means 
of microinjection into the adult gonad. Also, the localization of specific proteins can be followed using fluorescent protein tags. Examples are presented here 
demonstrating the use of a fluorescent lysosomal dye as well as fluorescently tagged histone and ubiquitin proteins. The labeled histone is used to visualize 
the DNA and thus identify the stage of the cell cycle. GFP-tagged ubiquitin reveals the dynamics of ubiquitinated vesicles in the early embryo. Observations 
of labeled lysosomes and GFP:: ubiquitin can be used to determine if there is colocalization between ubiquitinated vesicles and lysosomes. A technique for 
the microinjection of the lysosomal dye is presented. Techniques for generating transgenenic strains are presented elsewhere (1, 2). For imaging, embryos 
are cut out of adult hermaphrodite nematodes and mounted onto 2% agarose pads followed by time-lapse microscopy on a standard laser scanning confocal 
microscope or a spinning disk confocal microscope. This methodology provides for the high resolution visualization of early embryogenesis.

Time-lapse Microscopy of Early Embryogenesis in Caenorhabditis elegans

This article describes a technique for the visualization of the early events of embryogenesis in the nematode Caenorhabditis elegans.

Caenorhabditis elegans has often been used as a model system in studies of early developmental processes.  The transparency of the 
embryos, the genetic ...

Quantitative Analysis of Random Migration of Cells Using Time-lapse Video Microscopy

Cell migration is a dynamic process, which is important for embryonic development, tissue repair, immune system function, and tumor invasion 1, 2. During directional migration, cells move rapidly in response to an extracellular chemotactic signal, or in response to intrinsic cues 3 provided by the basic motility machinery. Random migration occurs when a cell possesses low intrinsic directionality, allowing the cells to explore their local environment.
Cell migration is a complex process, in the initial response cell undergoes polarization and extends protrusions in the direction of migration 2. Traditional methods to measure migration such as the Boyden chamber migration assay is an easy method to measure chemotaxis in vitro, which allows measuring migration as an end point result. However, this approach neither allows measurement of individual migration parameters, nor does it allow to visualization of morphological changes that cell undergoes during migration.
Here, we present a method that allows us to monitor migrating cells in real time using video - time lapse microscopy. Since cell migration and invasion are hallmarks of cancer, this method will be applicable in studying cancer cell migration and invasion in vitro. Random migration of platelets has been considered as one of the parameters of platelet function 4, hence this method could also be helpful in studying platelet functions. This assay has the advantage of being rapid, reliable, reproducible, and does not require optimization of cell numbers. In order to maintain physiologically suitable conditions for cells, the microscope is equipped with CO2 supply and temperature thermostat. Cell movement is monitored by taking pictures using a camera fitted to the microscope at regular intervals. Cell migration can be calculated by measuring average speed and average displacement, which is calculated by Slidebook software.

This method allows monitoring of cells in real time and quantitative measurements of different cell migration parameters such as speed, displacement, and velocity. Unlike the traditional methods, this real time approach is not based on endpoint quantitative migration measurements; instead it allows monitoring and calculating different parameters continuously.

Cell migration is a dynamic process, which is important for embryonic development, tissue repair, immune system function, and tumor invasion 1, 2. During ...

Long-term, High-resolution Confocal Time Lapse Imaging of Arabidopsis Cotyledon Epidermis during Germination

Imaging in vivo dynamics of cellular behavior throughout a developmental sequence can be a powerful technique for understanding the mechanics of tissue patterning. During animal development, key cell proliferation and patterning events occur very quickly. For instance, in Caenorhabditis elegans all cell divisions required for the larval body plan are completed within six hours after fertilization, with seven mitotic cycles1; the sixteen or more mitoses of Drosophila embryogenesis occur in less than 24 hr2. In contrast, cell divisions during plant development are slow, typically on the order of a day 3,4,5 . This imposes a unique challenge and a need for long-term live imaging for documenting dynamic behaviors of cell division and differentiation events during plant organogenesis. Arabidopsis epidermis is an excellent model system for investigating signaling, cell fate, and development in plants. In the cotyledon, this tissue consists of air- and water-resistant pavement cells interspersed with evenly distributed stomata, valves that open and close to control gas exchange and water loss. Proper spacing of these stomata is critical to their function, and their development follows a sequence of asymmetric division and cell differentiation steps to produce the organized epidermis (Fig. 1).
This protocol allows observation of cells and proteins in the epidermis over several days of development. This time frame enables precise documentation of stem-cell divisions and differentiation of epidermal cells, including stomata and epidermal pavement cells. Fluorescent proteins can be fused to proteins of interest to assess their dynamics during cell division and differentiation processes. This technique allows us to understand the localization of a novel protein, POLAR6, during the proliferation stage of stomatal-lineage cells in the Arabidopsis cotyledon epidermis, where it is expressed in cells preceding asymmetric division events and moves to a characteristic area of the cell cortex shortly before division occurs. Images can be registered and streamlined video easily produced using public domain software to visualize dynamic protein localization and cell types as they change over time.

Long-term, High-resolution Confocal Time Lapse Imaging of Arabidopsis Cotyledon Epidermis during Germination

We describe a protocol using chamber slides and media to immobilize plant cotyledons for confocal imaging of the epidermis over several days of development, documenting stomatal differentiation. Fluorophore-tagged proteins can be tracked dynamically by expression and subcellular localization, increasing understanding of their possible roles during cell division and cell-type differentiation.

Imaging in vivo dynamics of cellular behavior throughout a developmental sequence can be a powerful technique for understanding the mechanics of tissue ...

High-resolution Time-lapse Imaging and Automated Analysis of Microtubule Dynamics in Living Human Umbilical Vein Endothelial Cells

The physiological process by which new vasculature forms from existing vasculature requires specific signaling events that trigger morphological changes within individual endothelial cells (ECs). These processes are critical for homeostatic maintenance such as wound healing, and are also crucial in promoting tumor growth and metastasis. EC morphology is defined by the organization of the cytoskeleton, a tightly regulated system of actin and microtubule (MT) dynamics that is known to control EC branching, polarity and directional migration, essential components of angiogenesis. To study MT dynamics, we used high-resolution fluorescence microscopy coupled with computational image analysis of fluorescently-labeled MT plus-ends to investigate MT growth dynamics and the regulation of EC branching morphology and directional migration. Time-lapse imaging of living Human Umbilical Vein Endothelial Cells (HUVECs) was performed following transfection with fluorescently-labeled MT End Binding protein 3 (EB3) and Mitotic Centromere Associated Kinesin (MCAK)-specific cDNA constructs to evaluate effects on MT dynamics. PlusTipTracker software was used to track EB3-labeled MT plus ends in order to measure MT growth speeds and MT growth lifetimes in time-lapse images. This methodology allows for the study of MT dynamics and the identification of how localized regulation of MT dynamics within sub-cellular regions contributes to the angiogenic processes of EC branching and migration.

Protocols for Human Umbilical Vein Endothelial Cell (HUVEC) culture, transient transfection of fluorescently-labeled markers of microtubule growth, live-cell imaging and automated analysis of interphase microtubule growth dynamics are detailed.

The physiological process by which new vasculature forms from existing vasculature requires specific signaling events that trigger morphological changes ...

A Versatile Method for Mounting Arabidopsis Leaves for Intravital Time-lapse Imaging

The plant immune response associated with a genome-wide transcriptional reprogramming is initiated at the site of infection. Thus, the immune response is regulated spatially and temporally. The use of a fluorescent gene under the control of an immunity-related promoter in combination with an automated fluorescence microscopy is a simple way to understand spatiotemporal regulation of plant immunity. In contrast to the root tissues that have been used for a number of various intravital fluorescent imaging experiments, there exist few fluorescent live-imaging examples for the leaf tissues that encounter an array of airborne microbial infections. Therefore, we developed a simple method to mount leaves of Arabidopsis thaliana plants for live-cell imaging over an extended period of time. We used transgenic Arabidopsis plants expressing the yellow fluorescent protein (YFP) genefused to the nuclear localization signal (NLS) under the control of the promoter of a defense-related marker gene, Pathogenesis-Related 1 (PR1). We infiltrated a transgenic leaf with Pseudomonas syringae pv. tomato DC3000 (avrRpt2) strain (Pst_a2) and performed in vivo time-lapse imaging of the YFP signal for a total of 40 h using an automated fluorescence stereomicroscope. This method can be utilized not only for studies on plant immune responses but also for analyses of various developmental events and environmental responses occurring in leaf tissues.

A Versatile Method for Mounting Arabidopsis Leaves for Intravital Time-lapse Imaging

We report a simple and versatile method for performing fluorescent live-imaging of Arabidopsis thaliana leaves over an extended period of time. We use a transgenic Arabidopsis plant expressing a fluorescent reporter gene under the control of an immunity-related promoter as an example for gaining spatiotemporal understanding of plant immune responses.

The plant immune response associated with a genome-wide transcriptional reprogramming is initiated at the site of infection. Thus, the immune response is ...

Specific Labeling of Mitochondrial Nucleoids for Time-lapse Structured Illumination Microscopy

Mitochondrial nucleoids are compact particles formed by mitochondrial DNA molecules coated with proteins. Mitochondrial DNA encodes tRNAs, rRNAs, and several essential mitochondrial polypeptides. Mitochondrial nucleoids divide and distribute within the dynamic mitochondrial network that undergoes fission/fusion and other morphological changes. High resolution live fluorescence microscopy is a straightforward technique to characterize a nucleoid&#39;s position and motion. For this technique, nucleoids are commonly labeled through fluorescent tags of their protein components, namely transcription factor a (TFAM). However, this strategy needs overexpression of a fluorescent protein-tagged construct, which may cause artifacts (reported for TFAM), and is not feasible in many cases. Organic DNA-binding dyes do not have these disadvantages. However, they always show staining of both nuclear and mitochondrial DNAs, thus lacking specificity to mitochondrial nucleoids. By taking into account the physico-chemical properties of such dyes, we selected a nucleic acid gel stain (SYBR Gold) and achieved preferential labeling of mitochondrial nucleoids in live cells. Properties of the dye, particularly its high brightness upon binding to DNA, permit subsequent quantification of mitochondrial nucleoid motion using time series of super-resolution structured illumination images.

The protocol describes specific labeling of mitochondrial nucleoids with a commercially available DNA gel stain, acquisition of time lapse series of live labeled cells by super-resolution structured illumination microscopy (SR-SIM), and automatic tracking of nucleoid motion.

Mitochondrial nucleoids are compact particles formed by mitochondrial DNA molecules coated with proteins. Mitochondrial DNA encodes tRNAs, rRNAs, and ...

LarvaSPA, A Method for Mounting Drosophila Larva for Long-Term Time-Lapse Imaging

Live imaging is a valuable approach for investigating cell biology questions. The Drosophila larva is particularly suited for in vivo live imaging because the larval body wall and most internal organs are transparent. However, continuous live imaging of intact Drosophila larvae for longer than 30 min has been challenging because it is difficult to noninvasively immobilizeimmobilizing larvae for a long time. Here we present a larval mounting method called LarvaSPA that allows for continuous imaging of live Drosophila larvae with high temporal and spatial resolution for longer than 10 hours. This method involves partially attaching larvae to the coverslip using a UV-reactive glue and additionally restraining larval movement using a polydimethylsiloxane (PDMS) block. This method is compatible with larvae at developmental stages from second instar to wandering third instar. We demonstrate applications of this method in studying dynamic processes of Drosophila somatosensory neurons, including dendrite growth and injury-induced dendrite degeneration. This method can also be applied to study many other cellular processes that happen near the larval body wall.

LarvaSPA, A Method for Mounting Drosophila Larva for Long-Term Time-Lapse Imaging

This protocol describes a method for mounting Drosophila larvae to achieve longer than 10 h of uninterrupted time-lapse imaging in intact live animals. This method can be used to image many biological processes close to the larval body wall.

Live imaging is a valuable approach for investigating cell biology questions. The Drosophila larva is particularly suited for in vivo live imaging because ...