We would like to thank Patricia Wadsworth for the gift of the kinesin-5 construct. This work was supported by an NIH grant (5 R01 GM107026) to T.J.M. and by Research Grant No. 5-FY13-205 from the March of Dimes Foundation to T.J.M., as well as support from the Charles H. Hood Foundation, Inc., Boston, MA. to T.J.M.

1. Transfecting S2 Cells
<ol>
	<li>From a previously cultured 25 cm2 flask, add GFP-&#945;-tubulin-expressing S2 cells10 to a final volume of 2 ml at 100% confluency, and allow them to semi-adhere to the bottom of a 35 mm tissue culture dish for approximately 1 hr.</li>
	<li>Remove the media from the dish. Transfect 2 &#181;g of the Eg5-mCherry construct11 with 1 ml of Schneider&#39;s media supplemented with 10% FBS (referred to hereafter as Schneider&#39;s media) and Transfection Reagent, following the manufacturer&#39;s protocol. Seal the dish with Parafilm and incubate cells at 25 &#176;C for 16-18 hr.</li>
	<li>Add 1 ml of Schneider&#39;s media. Return cells to 25 &#176;C incubator.</li>
	<li>On day 3 post-transfection, transfer 500 &#181;l of transfected cells into a new 35 mm tissue culture dish containing 1.5 ml of Schneider&#39;s media for a test induction. Induce the expression of Eg5-mCherry by adding CuSO4 to a final concentration of 500 &#181;M. Seal the dish in Parafilm and incubate at 25 &#176;C O/N.</li>
	<li>To make concanavalin A-coated coverslips, pipette enough volume of concanavalin A solution (0.5 mg/ml dissolved in H2O) to coat an acid washed coverslip, remove the excess, and allow the coverslip to air dry.</li>
	<li>Place a 22 mm x 22 mm concanavalin A-coated coverslip in a clean 35 mm tissue culture dish, then seed 500 &#181;l at 100% confluency of the induced cells onto the coverslip and allow the cells to adhere for 1 hr at RT.</li>
	<li>To check for Eg5-mCherry expression, assemble the coverslip into a rose chamber (or appropriate imaging vessel) with media for imaging at RT on a fluorescence microscope. Use appropriate light sources and filter sets to visualize the cells. For example, the microscope used in this study has an LED white light source and EGFP (FITC/Cy2) and DSRed (TRITC/Cy3) filter cubes. Eg5-mCherry localizes to microtubules and is enriched near spindle poles.</li>
	<li>After ensuring that the cells are expressing both Eg5-mCherry and GFP-&#945;-tubulin, transfer the remainder of the transfected, uninduced cells to a 25 cm2 tissue culture flask containing 4 ml of Schneider&#39;s media.</li>
	<li>Add Blasticidin S HCL at a final concentration of 25 &#956;g/ml to the flask of transfected cells and continue splitting in the presence of 25 &#956;g/ml Blasticidin S HCl until cell death ceases being sure to check for expression of Eg5-mCherry periodically. Incubate cell lines in 25 &#176;C incubator. 
	NOTE: The percentage of cells expressing Eg5-mCherry increases over time.</li>
	<li>Once cells are stably transfected, continue to split in the absence of drug and freeze12 cells for future use.</li>
</ol>
2. RNA Interference
<ol>
	<li>PCR amplify a ~500 bp region of Klp61F from cDNA (LD15641) using primer with added T7 promoter sequence (sequence provided in Materials List) to be used as a template for dsRNA synthesis.
	<ol>
		<li>Set up four PCR reactions, 50 &#181;l each, containing 100 ng of template DNA, 25 &#181;M of each primer, appropriate buffer, and polymerase. Set the PCR protocol on the thermocycler according to the polymerase&#39;s manufacturer&#39;s protocol.</li>
		<li>Pool and clean four PCR reactions using a PCR clean up kit according to manufacturer&#39;s protocol. Store the clean template at -20 &#176;C.</li>
	</ol>
	</li>
	<li>Prepare double stranded RNA (dsRNA) from template using a T7 RNA transcription kit, following the manufacturer&#39;s instructions. Expect ~5-15 mg/ml concentration of dsRNA. Store dsRNA at -20 &#176;C.</li>
	<li>To Knockdown Klp61F with dsRNA, allow S2 cells expressing Eg5-mCherry at 25% confluency to semi-adhere to the bottom of a 35 mm tissue culture dish for 1 hr.</li>
	<li>Remove the media from the dishes and add 5 &#181;g of dsRNA against Klp61F (Drosophila kinesin-5) diluted into 1 ml of serum-free Schneider&#39;s media.</li>
	<li>Incubate at RT for 1 hr, then add 1 ml of Schneider&#39;s media with 10% FBS. Incubate cells at 25 &#176;C.</li>
	<li>24 hr after dsRNA treatment, induce expression of Eg5-mCherry by adding CuSO4 to a final concentration of 500 &#181;M. Incubate cells at 25 &#176;C for another 24 hr.&#160;</li>
</ol>
3. Live Cell Imaging
<ol>
	<li>Place a 22 mm x 22 mm concanavalin A coated coverslip into a clean 35 mm tissue culture dish.</li>
	<li>Seed 500 &#181;l of the cells that have been treated with dsRNA and induced O/N onto the concanavalin A coated coverslip and allow them to adhere for about 1 hr.</li>
	<li>Assemble the coverslip into a rose chamber (or appropriate vessel) for imaging.</li>
	<li>Find mitotic cells expressing both Eg5-mCherry and GFP-&#945;-tubulin. 
	NOTE: Mitotic cells expressing only GFP-&#945;-tubulin should have monopolar spindles since Klp61F, which is required for spindle bipolarity, is knocked down10,13.</li>
	<li>Collect time-lapse images of bipolar spindles (e.g., 1 frame per minute) in cells expressing both Eg5-mCherry and GFP-&#945;-tubulin.</li>
	<li>While imaging, remove the media from the rose chamber, and replace it with Schneider&#39;s media containing 1 &#181;M STLC over 3 consecutive media exchanges (~5 ml total) into the chamber to visualize spindle collapse.</li>
	<li>To washout the drug and reverse the spindle collapse, carefully remove the STLC-containing media from the rose chamber, and wash in Schneider&#39;s media 4x (6-8 ml total) before refilling the rose chamber one last time with fresh media. Continue imaging.</li>
</ol>
4. Error Correction Assay
<ol>
	<li>Place a 22 mm x 22 mm concanavalin A coated coverslips into clean 35 mm tissue culture dishes.</li>
	<li>Seed 500 &#181;l of cells that have been treated with Klp61F dsRNA onto the concanavalin A coated coverslip and allow them to adhere.</li>
	<li>After cells are adhered, add 1.5 ml of Schneider&#39;s media to each dish to bring the final volume up to 2 ml.</li>
	<li>To arrest cells in mitosis, add MG132 to a final concentration of 10 &#181;M to each of the dishes, and incubate for 1 hr.</li>
	<li>Add 1 &#181;M STLC and incubate for 1 hr to allow monopoles to form.</li>
	<li>Wash out the STLC by rinsing coverslips 3x with 2 ml of fresh Schneider&#39;s media each time.</li>
	<li>Incubate coverslips with Schneider&#39;s media in addition to any pharmacological drugs (e.g., Aurora kinase inhibitors) or DMSO as a control. 
	Note: Inhibitor concentrations vary and proper final concentrations must be determined by the experimenter. Stock solutions are typically made such that the inhibitor is diluted 1:1,000 into media. In this case a 1:1,000 dilution of DMSO (or appropriate solvent) serves as the vehicle control. We use the Aurora B inhibitor Binucleine 2 at a final concentration of 40 &#181;M.</li>
	<li>Fix cells at different time points to observe the progression of bipolar spindle formation and to assess kinetochore attachment states. To fix:
	<ol>
		<li>Quickly rinse the coverslips with 2 ml of 1x BRB-80.</li>
		<li>Fix cells by adding 2 ml of 10% paraformaldehyde diluted in 1x BRB-80 for 10 min. Pipet paraformaldehyde carefully in a chemical hood.</li>
		<li>Permeabilize cells with 2 ml of 1x PBS + 1% Triton-X for 8 min.</li>
		<li>Wash slides 3x with 2 ml of 1x PBS + 0.1% Triton-X.</li>
		<li>Transfer coverslips cell-side face up onto a sheet of Parafilm (use a marker to label Parafilm appropriately to keep track of the slides) in a 150 mm Petri dish.</li>
		<li>Cover the coverslips with 150 &#181;l boiled donkey serum (BDS) and incubate at RT for 1 hr to block non-specific antibody binding. 
		Note: Here, the fixation protocol can be stopped to be continued at a later point. Coverslips can be stored in a moisture chamber at 4 &#176;C for up to 24 hr. To make the moisture chamber, line the rim of a 150 mm dish with a wet laboratory wipe and cover with the Petri dish lid.</li>
		<li>Remove block, and incubate the coverslips for 1 hr at RT with 150 &#181;l of primary antibodies diluted appropriately in BDS to stain for kinetochores and microtubules to final concentrations of 2 &#181;g/ml (or according to manufacturer&#39;s recommendations) and 1 &#181;g/ml, respectively. 
		Note: Here, the fixation protocol can be stopped to be continued at a later point. Coverslips can be stored in a moisture chamber at 4 &#176;C for up to 24 hr.</li>
		<li>Wash coverslips 3x with 500 &#181;l of 1x PBS + 0.1% Triton-X.</li>
		<li>Incubate coverslips for 30-60 min at RT with the appropriate fluorophore-conjugated secondary antibodies diluted in BDS.</li>
		<li>Wash coverslips 3x with 500 &#181;l of 1x PBS + 0.1% Triton-X.</li>
		<li>Incubate coverslips with 150 &#181;l of BDS containing 1 &#181;g/ml DAPI final concentration for 5 min.</li>
		<li>Wash coverslips 2x with 1x PBS + 0.1% Triton-X, and mount coverslips cell side down on a 3x1&#34; slide with 8 &#181;l of mounting media. Paint the corners with nail polish to immobilize the coverslips onto slides.</li>
	</ol>
	</li>
	<li>Image cells with bipolar spindles that are expressing Eg5-mCherry. Take a Z series consisting of 30 planes at 0.2 &#181;m intervals in all channels using a 100X objective. Carefully analyze the kinetochores and microtubules to determine the attachment states (bioriented or syntelic attachments).</li>
</ol>

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S., Ohsugi, M., 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=Complete+kinetochore+tracking+reveals+error-prone+homologous+chromosome+biorientation+in+mammalian+oocytes.">Complete kinetochore tracking reveals error-prone homologous chromosome biorientation in mammalian oocytes.</a> Cell. 146, 568-581 (2011).</li><li>Cimini, D., Wan, X., Hirel, C. B., Salmon, E. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aurora+kinase+promotes+turnover+of+kinetochore+microtubules+to+reduce+chromosome+segregation+errors.">Aurora kinase promotes turnover of kinetochore microtubules to reduce chromosome segregation errors.</a> Curr Biol. 16, 1711-1718 (2006).</li><li>Lampson, M. A., Renduchitala, K., Khodjakov, A., Kapoor, T. 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The authors declare that they have no competing financial interests.

Visualizing error correction is a valuable technique to study the steps involved in this important and complex cellular process. To do so, erroneous attachments are generated using reversible inhibitors, and error correction is observed upon washout of the drug. This assay was originally developed using mammalian tissue culture cells5. However the presence of large number of kinetochores in many model mammalian cell types poses a challenge in observing individual error correction events. Drosophila S2 cells possess as few as 4 pairs of kinetochores, making them a more preferable cell line for observing error correction. However, a major drawback is that many inhibitors are ineffective in Drosophila S2 cells. Thus, the ability to generate a humanized Drosophila S2 cell line expressing human kinesin-5 provides a valuable tool to study error correction.
Although Drosophila S2 cells can be a better cell line to study error correction, the multiple steps involved in obtaining the cell line and knocking down essential genes poses some challenges to this technique. For instance, transfection efficiency can be quite low. If less than 20% of the cells are expressing the Eg5-mCherry, the transfection should be repeated as the selection process will take longer. Also, the percentage of cells expressing both fluorescent proteins may decrease over time. This can be overcome by splitting cells in the presence of Blasticidin S HCl and Hygromycin B to select for cells expressing Eg5-mCherry and GFP-&#945;-tubulin, respectively. It is also important to note that Drosophila S2 cells have orthologues to many human proteins and; therefore, it is critical to optimize the knockdown conditions for the endogenous proteins. Optimal knockdown conditions may vary in the amount of dsRNA and the length of treatment. Considering the emergence and rapid improvement of CRISPR-Cas9 technologies15-17, generation of a Drosophila cell line with the Klp61F gene replaced by human Eg5 presents a powerful alternative that would overcome the limitations of the transfection and knockdown approach. Our work demonstrates that fly-to-human gene replacement should be a viable option in this case although the necessary reagents to do so in Drosophila S2 cells are currently being developed.
This procedure is not limited to Eg5, but can be applied to study the function of other proteins of interest. If using inhibitors that have previously been established to be ineffective in Drosophila S2 cells, this protocol can be modified to study the direct effect of inhibitors in live cells without concerns about off target effects. The cell line produced using this protocol could also be used in high-throughput screening analyses to identify potential drugs targeting proteins involved in error correction.

Equal segregation of the genome during cell division requires correct interactions between the replicated DNA and spindle microtubules. Microtubules physically interact with chromosomes through an ensemble of proteins that assembles at centromeres known as the kinetochore1. Correct distribution of the chromosomes requires that sister kinetochores are bioriented, in which each sister is associated with microtubules originating from opposite spindle poles. Kinetochore microtubule (kt-MT) attachments that are not in the bioriented conformation are quickly and efficiently destabilized to provide the opportunity to establish biorientation in a process known as error correction. An error correction assay that was previously established in mammalian cells5 requires assembling monopolar spindles using reversible small molecule inhibitors against Eg5 (kinesin-5). The drug treatment generates a multitude of erroneous syntelic attachments in which both sister kinetochores attach to the same spindle pole. A subsequent washout of the drug allows for visualization of the error correction process. The error correction assay can be done in the presence of small molecule inhibitors or knockdowns to study the contribution of candidate proteins to correcting erroneous kt-MT attachments.
The ability to visualize error correction in living cells is a powerful tool to further understand the molecular mechanism involved in this complex process. However, the large number of chromosomes present in most cell lines poses a challenge in observing individual kt-MT attachments. Drosophila S2 cells would be ideal for applying the error correction assay as they contain as few as 4 chromosomes6, but small molecule inhibitors of kinesin 5 such as S-trityl-L-cysteine (STLC) and monastrol7-9 do not affect spindle assembly or kinesin-5 motor function in Drosophila cells. We therefore generated a Drosophila S2 cell line expressing human kinesin-5 under an inducible promoter that is sensitive to kinesin-5 inhibitors. This protocol describes how to knockdown the endogenous Drosophila kinesin-5 homologue, Klp61F, and use this cell line in the cell-based error correction assay.

<table border="0" cellpadding="0" cellspacing="0" width="826">
	<tbody>
		<tr height="61">
			<td height="61" style="height:61px;width:221px;">Effectine Transfection Reagent</td>
			<td style="width:184px;">Qiagen</td>
			<td style="width:167px;">301425</td>
			<td style="width:255px;"></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:221px;">Klp61F cDNA</td>
			<td style="width:184px;">Drosophila Genomic Resource Center</td>
			<td style="width:167px;">13690</td>
			<td style="width:255px;">Gene Name LD15641</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Schneider&#8217;s Media</td>
			<td style="width:184px;">Invitrogen</td>
			<td style="width:167px;">21720-024</td>
			<td style="width:255px;"></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:221px;">Fetal Bovine Serum, certified</td>
			<td style="width:184px;">Invitrogen</td>
			<td style="width:167px;">10082-147</td>
			<td style="width:255px;">Heat Inactivated, US origin</td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:221px;">Copper (II) Sulfate (CuSO4)</td>
			<td style="width:184px;">Sigma</td>
			<td style="width:167px;">C8027-500G</td>
			<td style="width:255px;">500mM stock&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">S-trityl-l-cysteine</td>
			<td style="width:184px;">Sigma</td>
			<td style="width:167px;">164739-5G</td>
			<td style="width:255px;">1mM stock in DMSO</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Blasticidin HCl</td>
			<td style="width:184px;">Invitrogen</td>
			<td style="width:167px;">R21001</td>
			<td style="width:255px;">5mg/ml stock in 1x PBS</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:221px;">Hygromycin B</td>
			<td style="width:184px;">Invitrogen</td>
			<td style="width:167px;">10687010</td>
			<td style="width:255px;"></td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:221px;">T7 Large scale RNA Production System</td>
			<td style="width:184px;">Promega</td>
			<td style="width:167px;">P1320</td>
			<td style="width:255px;">The approximate dsRNA concentration from each reaction is about 5-15&#181;g/&#181;l</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:221px;">Klp61F RNAi F primer</td>
			<td style="width:184px;">Invitrogen</td>
			<td style="width:167px;"></td>
			<td style="width:255px;">TAATACGACTCACTATAGGGTA-TTTGCGCATTATTTTAAAA</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:221px;">Klp61F RNAi R primer</td>
			<td style="width:184px;">Invitrogen</td>
			<td style="width:167px;"></td>
			<td style="width:255px;">TAATACGACTCACTATAGGGAT-ATTGATCAATTGAAAC</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:221px;">PCR clean-up kit</td>
			<td style="width:184px;">Mo Bio Laboratories, Inc</td>
			<td style="width:167px;">1250</td>
			<td style="width:255px;"></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:221px;">Concanavalin A</td>
			<td style="width:184px;">Sigma</td>
			<td style="width:167px;">C5275</td>
			<td style="width:255px;">0.5mg/ml solution made by dissolving in 1xPBS.&#160;</td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:221px;">Boiled Donkey Serum</td>
			<td style="width:184px;">Jackson ImmunoResearch Labs</td>
			<td style="width:167px;">017-000-121</td>
			<td style="width:255px;">5% stock solution in 1X PHEM buffer, bring solution up to boil. Stored in 4&#176;C.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:221px;">Mounting Media</td>
			<td style="width:184px;"></td>
			<td style="width:167px;"></td>
			<td style="width:255px;">20mM Tris pH 8.0,&#160; 0.5% N-propyl gallate, 90% Glycerol. Stored in 4&#176;C</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:221px;">1x BRB-80</td>
			<td dir="LTR" style="width:184px;"></td>
			<td style="width:167px;"></td>
			<td dir="LTR" style="width:255px;">80 mM PIPES pH 6.9; 1 mM EGTA; 1 mM MgCl2</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:221px;">White Light Source</td>
			<td>Lumencor Inc</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:221px;">ET EGFP Filter Cube</td>
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			<td align="right">49002</td>
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			<td height="22" style="height:22px;width:221px;">DSRed Filter Cube</td>
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			<td height="22" style="height:22px;width:221px;">anti-NDC80 antibody&#160;</td>
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			<td>Custom made by the Maresca Lab</td>
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			<td height="22" style="height:22px;width:221px;">DM1&#945; (anti-&#945;-tubulin)</td>
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			<td height="22" style="height:22px;width:221px;">anti-CID antibody</td>
			<td>AbCam</td>
			<td>ab10887</td>
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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.

Klp61F is required to form bipolar spindles. The human kinesin-5, Eg5, can rescue the function of Klp61F in Drosophila S2 cells (Figure 1A and D). Upon addition of the kinesin-5 inhibitor (STLC), microtubule-associated levels of the motor drop (Figure 1B and E), and the spindle collapses, resulting in a monopole (Figure 1C and F) in cells lacking endogenous Klp61F upon successful RNAi (Supplemental movie 1). It is noteworthy that bipolar spindles collapse upon addition of STLC in the humanized S2 cells because kinesin-5 activity is not required to maintain spindle bipolarity in human cells. This interesting discrepancy may be a result of differences in interpolar microtubule overlap and/or stability in the two model systems14. Kinesin-5 inhibition (Figure 2A and E) can be reversed by washing out the drug and recovery of a bipolar spindle can be followed over time. Upon removal of the inhibitor (Figure 2B and F), Eg5-mCherry re-associates with the microtubules as a bipolar spindle assembles (Figure 2C and G), and cells can progress into a bipolar anaphase (Figure 2D and H, Supplemental movie 2).
<img alt="Figure 1" src="/files/ftp_upload/53594/53594fig1.jpg" /> 
Figure 1. Addition of 1 &#181;M STLC leads to monopolar spindles in Drosophila S2 cells. Representative images from time-lapse imaging of a Drosophila S2 cell expressing Eg5-mCherry (A-C) and GFP-&#945;-tubulin (D-F) during addition of 1 &#181;M STLC. The Eg5 inhibitor was added at 3 min. Scale bar = 5 &#181;m. Timestamp = min:sec. <a href="https://www.jove.com/files/ftp_upload/53594/53594fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" src="/files/ftp_upload/53594/53594fig2.jpg" /> 
Figure 2. A bipolar spindle reforms upon removal of STLC. Representative images from time-lapse imaging of a Drosophila 2 cell expressing Eg5-mCherry (A-D) and GFP-&#945;-tubulin (E-H) during an STLC washout experiment. STLC was washed out at 5 min. A bipolar spindle reforms within 1 hr of removing the STLC. Scale bar = 5 &#181;m. Timestamp: min:sec. <a href="https://www.jove.com/files/ftp_upload/53594/53594fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Movie 1" src="/files/ftp_upload/53594/53594mov1.jpg" /> 
<a href="https://www.jove.com/files/ftp_upload/53594/addin.mov" target="_blank">Supplemental Movie 1. (Right click to download).</a> Widefield fluorescence imaging of a representative example of a Drosophila S2 cell expressing Eg5-mCherry (left) and GFP-&#945;-tubulin (right). 1 &#181;M STLC was added at 2 min, and the spindle forms a monopole within 10 min&#160;after addition of the inhibitor. Images were acquired every 1 min&#160;and played at a rate of 10 frames per second. Scale bar = 5 &#181;m.
<img alt="Movie 2" src="/files/ftp_upload/53594/53594mov2.jpg" /> 
<a href="https://www.jove.com/files/ftp_upload/53594/washout.mov" target="_blank">Supplemental Movie 2. (Right click to download).</a> Widefield fluorescence imaging of a representative example of a Drosophila S2 cell expressing Eg5-mCherry (left) and GFP-&#945;-tubulin (right). Media containing 1 &#181;M STLC was removed and rinsed at 5 min. A bipolar spindle reforms within 1 hr of removing the inhibitor. Images were acquired every 1 min&#160;and played at a rate of 10 frames per second. Scale bar = 5 &#181;m.

Watch this Scientific Journal Video about Generating a "Humanized" Drosophila S2 Cell Line Sensitive to Pharmacological Inhibition of Kinesin-5 at JoVE.com

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.

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 ...

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7.2K Views.  University of Massachusetts, Amherst. 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. 

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

A Gradient-generating Microfluidic Device for Cell Biology

 The fabrication and operation of a gradient-generating microfluidic device for studying cellular behavior is described.  A microfluidic platform is an enabling experimental tool, because it can precisely manipulate fluid flows, enable high-throughput experiments, and generate stable soluble concentration gradients.  Compared to conventional gradient generators, poly(dimethylsiloxane) (PDMS)-based  microfluidic devices can generate stable concentration gradients of growth factors with well-defined profiles.  Here, we developed simple gradient-generating microfluidic devices with three separate inlets.  Three microchannels combined into one microchannel to generate concentration gradients.  The stability and shape of growth factor gradients were confirmed by fluorescein isothyiocyanate (FITC)-dextran with a molecular weight similar to epidermal growth factor (EGF).  Using this microfluidic device, we demonstrated that fibroblasts exposed to concentration gradients of EGF migrated toward higher concentrations.  The directional orientation of cell migration and motility of migrating cells were quantitatively assessed by cell tracking analysis.  Thus, this gradient-generating microfluidic device might be useful for studying and analyzing the behavior of migrating cells.

We describe a protocol for the microfabrication of the gradient-generating microfluidic device that can generate spatial and temporal gradients in well-defined microenvironment. In this approach, the gradient-generating microfluidic device can be used to study directed cell migration, embryogenesis, wound healing, and cancer metastasis.

 The fabrication and operation of a gradient-generating microfluidic device for studying cellular behavior is described.  A microfluidic platform is an ...

Neurocircuit Assays for Seizures in Epilepsy Mutants of Drosophila

Drosophila melanogaster is a useful tool for studying seizure like activity. A variety of mutants in which seizures can be induced through either physical shock or electrical stimulation is available for study of various aspects of seizure activity and behavior. All flies, including wild-type, will undergo seizure-like activity if stimulated at a high enough voltage. Seizure like activity is an all-or-nothing response and each genotype has a specific seizure threshold. The seizure threshold of a specific genotype of fly can be altered either by treatment with a drug or by genetic suppression or enhancement. The threshold is easily measured by electrophysiology. Seizure-like activity can be induced via high frequency electrical stimulation delivered directly to the brain and recorded through the dorsal longitudinal muscles (DLMs) in the thorax. The DLMs are innervated by part of the giant fiber system. Starting with low voltage, high frequency stimulation, and subsequently raising the voltage in small increments, the seizure threshold for a single fly can be measured.

Neurocircuit Assays for Seizures in Epilepsy Mutants of Drosophila

Using high frequency electrical stimulation, seizure-like activity can be induced in Drosophila. This activity is easily recorded from the giant fiber system.

Drosophila melanogaster is a useful tool for studying seizure like activity. A variety of mutants in which seizures can be induced through either physical ...

Cellular Toxicity of Nanogenomedicine in MCF-7 Cell Line: MTT assay

Cytotoxicity of the futuristic nanogenomedicine (e.g., short interfering RNA and antisense) may hamper its clinical development. Of these, the gene-based medicine and/or its carrier may elicit cellular toxicity. For assessment of such cytotoxicity, a common methodology is largely dependent upon utilization of the 3-(4, 5-Dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay which has been widely used as a colorimetric approach based on the activity of mitochondrial dehydrogenase enzymes in cells. In this current investigation, MCF-7 cells were inoculated in 96-well plate and at 50% confluency they were treated with different nanopolyplexes and subjected to MTT assay after 24 hours. Water soluble yellow MTT is metabolized by the metabolically active cells to the water insoluble purple formazan, which is further dissolved in dimethylsulfoxide and Sornson s buffer pH 10.5. The resultant product can be quantified by spectrophotometry using a plate reader at 570 nm.

The MTT assay is an easy and reproducible colorimetric assay for evaluation of cell viability based on reduction of yellow MTT and production of water insoluble purple formazan. Here, the viability of MCF-7 cells upon treatment of nanogenomedicine has been evaluated.

Cytotoxicity of the futuristic nanogenomedicine (e.g., short interfering RNA and antisense) may hamper its clinical development. Of these, the gene-based ...

Preparation of Drosophila S2 cells for Light Microscopy

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 and genome sequence database. Cultured Drosophila S2 cells, the product of disassociated 20-24 hour old embryos1, possess all these properties. Consequently, S2 cells are extremely well-suited for the analysis of cellular processes, including the discovery of the genes encoding the molecular components of the process or mechanism of interest. The features of S2 cells that are most responsible for their utility are the ease with which they are maintained, their exquisite sensitivity to double-stranded (ds)RNA-mediated interference (RNAi), and their tractability to fluorescence microscopy as either live or fixed cells.
S2 cells can be grown in a variety of media, including a number of inexpensive, commercially-available, fully-defined, serum-free media2. In addition, they grow optimally and quickly at 21-24&deg;C and can be cultured in a variety of containers. Unlike mammalian cells, S2 cells do not require a regulated atmosphere, but instead do well with normal air and can even be maintained in sealed flasks.
Complementing the ease of RNAi in S2 cells is the ability to readily analyze experimentally-induced phenotypes by phase or fluorescence microscopy of fixed or live cells. S2 cells grow in culture as a single monolayer but do not display contact inhibition. Instead, cells tend to grow in colonies in dense cultures. At low density, S2 cultures grown on glass or tissue culture-treated plastic are round and loosely-attached. However, the cytology of S2 cells can be greatly improved by inducing them to flatten extensively by briefly culturing them on a surface coated with the lectin, concanavalin A (ConA)3. S2 cells can also be stably transfected with fluorescently-tagged markers to label structures or organelles of interest in live or fixed cells. Therefore, the usual scenario for the microscopic analysis of cells is this: first, S2 cells (which can possess transgenes to express tagged markers) are treated by RNAi to eliminate a target protein(s). RNAi treatment time can be adjusted to allow for differences in protein turn-over kinetics and to minimize cell trauma/death if the target protein is important for viability. Next, the treated cells are transferred to a dish containing a coverslip pre-coated with conA to induce cells to spread and tightly adhere to the glass. Finally, cells are imaged with the researcher's choice of microscopy modes. S2 cells are particularly good for studies requiring extended visualization of live cells since these cells stay healthy at room temperature and normal atmosphere.

Preparation of Drosophila S2 cells for Light Microscopy

Drosophila Schneider (S2) cells are an increasingly popular system for the discovery and functional analysis of genes. Our goal is to describe some of the microscopic techniques that make S2 cells such an increasingly important experimental system.

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 ...

Pharmacological and Functional Genetic Assays to Manipulate Regeneration of the Planarian Dugesia japonica

Free-living planarian flatworms have a long history of experimental usage owing to their remarkable regenerative abilities1. Small fragments excised from these animals reform the original body plan following regeneration of missing body structures. For example if a 'trunk' fragment is cut from an intact worm, a new 'head' will regenerate anteriorly and a 'tail' will regenerate posteriorly restoring the original 'head-to-tail' polarity of body structures prior to amputation (Figure 1A).
Regeneration is driven by planarian stem cells, known as 'neoblasts' which differentiate into ~30 different cell types during normal body homeostasis and enforced tissue regeneration. This regenerative process is robust and easy to demonstrate. Owing to the dedication of several pioneering labs, many tools and functional genetic methods have now been optimized for this model system. Consequently, considerable recent progress has been made in understanding and manipulating the molecular events underpinning planarian developmental plasticity2-9.
The planarian model system will be of interest to a broad range of scientists. For neuroscientists, the model affords the opportunity to study the regeneration of an entire nervous system, rather than simply the regrowth/repair of single nerve cell process that typically are the focus of study in many established models. Planarians express a plethora of neurotransmitters10, represent an important system for studying evolution of the central nervous system11, 12 and have behavioral screening potential13, 14. 
Regenerative outcomes are amenable to manipulation by pharmacological and genetic apparoaches. For example, drugs can be screened for effects on regeneration simply by placing body fragments in drug-containing solutions at different time points after amputation. The role of individual genes can be studied using knockdown methods (in vivo RNAi), which can be achieved either through cycles of microinjection or by feeding bacterially-expressed dsRNA constructs8, 9, 15. Both approaches can produce visually striking phenotypes at high penetrance- for example, regeneration of bipolar animals16-21. To facilitate adoption of this model and implementation of such methods, we showcase in this video article protocols for pharmacological and genetic assays (in vivo RNAi by feeding) using the planarian Dugesia japonica.

Pharmacological and Functional Genetic Assays to Manipulate Regeneration of the Planarian Dugesia japonica

An attractive model for studying stem cell differentiation within a live animal is the planarian flatworm. Regeneration is studied by simple amputation experiments that are easily performed in a basic laboratory and are amenable to pharmacological and genetic (in vivo RNAi) manipulation as detailed by protocols in this article.

Free-living planarian flatworms have a long history of experimental usage owing to their remarkable regenerative abilities1. Small fragments excised from ...

The Utility of Stage-specific Mid-to-late Drosophila Follicle Isolation

Drosophila oogenesis or follicle development has been widely used to advance the understanding of complex developmental and cell biologic processes. This methods paper describes how to isolate mid-to-late stage follicles (Stage 10B-14) and utilize them to provide new insights into the molecular and morphologic events occurring during tight windows of developmental time. Isolated follicles can be used for a variety of experimental techniques, including in vitro development assays, live imaging, mRNA expression analysis and western blot analysis of proteins. Follicles at Stage 10B (S10B) or later will complete development in culture; this allows one to combine genetic or pharmacologic perturbations with in vitro development to define the effects of such manipulations on the processes occurring during specific periods of development. Additionally, because these follicles develop in culture, they are ideally suited for live imaging studies, which often reveal new mechanisms that mediate morphological events. Isolated follicles can also be used for molecular analyses. For example, changes in gene expression that result from genetic perturbations can be defined for specific developmental windows. Additionally, protein level, stability, and/or posttranslational modification state during a particular stage of follicle development can be examined through western blot analyses. Thus, stage-specific isolation of Drosophila follicles provides a rich source of information into widely conserved processes of development and morphogenesis.

The Utility of Stage-specific Mid-to-late Drosophila Follicle Isolation

Stage-specific isolation of mid-to-late Drosophila follicles is useful for a variety of purposes. Such follicles develop in culture, which allows for genetic and/or pharmacologic manipulations to be coupled with in vitro development assays and live imaging. Additionally, follicles can be used for molecular studies, such as isolating mRNA and protein.

Drosophila oogenesis or follicle development has been widely used to advance the understanding of complex developmental and cell biologic processes. This ...

A Sensitive and Specific Quantitation Method for Determination of Serum Cardiac Myosin Binding Protein-C by Electrochemiluminescence Immunoassay

Biomarkers are becoming increasingly more important in clinical decision-making, as well as basic science. Diagnosing myocardial infarction (MI) is largely driven by detecting cardiac-specific proteins in patients' serum or plasma as an indicator of myocardial injury. Having recently shown that cardiac myosin binding protein-C (cMyBP-C) is detectable in the serum after MI, we have proposed it as a potential biomarker for MI. Biomarkers are typically detected by traditional sandwich enzyme-linked immunosorbent assays. However, this technique requires a large sample volume, has a small dynamic range, and can measure only one protein at a time.	
Here we show a multiplex immunoassay in which three cardiac proteins can be measured simultaneously with high sensitivity. Measuring cMyBP-C in uniplex or together with creatine kinase MB and cardiac troponin I showed comparable sensitivity. This technique uses the Meso Scale Discovery (MSD) method of multiplexing in a 96-well plate combined with electrochemiluminescence for detection. While only small sample volumes are required, high sensitivity and a large dynamic range are achieved. Using this technique, we measured cMyBP-C, creatine kinase MB, and cardiac troponin I levels in serum samples from 16 subjects with MI and compared the results with 16 control subjects. We were able to detect all three markers in these samples and found all three biomarkers to be increased after MI. This technique is, therefore, suitable for the sensitive detection of cardiac biomarkers in serum samples.

Measuring biomarkers in complex biological samples is increasingly guiding clinical decision-making. We describe a highly sensitive method to simultaneously measure cardiac myosin binding protein-C, creatine kinase MB, and cardiac troponin I in serum samples from subjects with myocardial infarction and healthy control subjects.

Biomarkers are becoming increasingly more  important in clinical decision-making, as well as basic science. Diagnosing  myocardial infarction (MI) is ...

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.

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

A Strategy for Sensitive, Large Scale Quantitative Metabolomics

Metabolite profiling has been a valuable asset in the study of metabolism in health and disease. However, current platforms have different limiting factors, such as labor intensive sample preparations, low detection limits, slow scan speeds, intensive method optimization for each metabolite, and the inability to measure both positively and negatively charged ions in single experiments. Therefore, a novel metabolomics protocol could advance metabolomics studies. Amide-based hydrophilic chromatography enables polar metabolite analysis without any chemical derivatization. High resolution MS using the Q-Exactive (QE-MS) has improved ion optics, increased scan speeds (256 msec at resolution 70,000), and has the capability of carrying out positive/negative switching. Using a cold methanol extraction strategy, and coupling an amide column with QE-MS enables robust detection of 168 targeted polar metabolites and thousands of additional features simultaneously.&#160; Data processing is carried out with commercially available software in a highly efficient way, and unknown features extracted from the mass spectra can be queried in databases.

Metabolite profiling has been a valuable asset in the study of metabolism in health and disease. Utilizing normal-phased liquid chromatography coupled to high-resolution mass spectrometry with polarity switching and a rapid duty cycle, we describe a protocol to analyze the polar metabolic composition of biological material with high sensitivity, accuracy, and resolution.

Metabolite profiling has been a valuable asset in the study of metabolism in health and disease. However, current platforms have different limiting ...

Ex vivo Culture of Drosophila Pupal Testis and Single Male Germ-line Cysts: Dissection, Imaging, and Pharmacological Treatment

During spermatogenesis in mammals and in Drosophila melanogaster, male germ cells develop in a series of essential developmental processes. This includes differentiation from a stem cell population, mitotic amplification, and meiosis. In addition, post-meiotic germ cells undergo a dramatic morphological reshaping process as well as a global epigenetic reconfiguration of the germ line chromatin&#8212;the histone-to-protamine switch.
Studying the role of a protein in post-meiotic spermatogenesis using mutagenesis or other genetic tools is often impeded by essential embryonic, pre-meiotic, or meiotic functions of the protein under investigation. The post-meiotic phenotype of a mutant of such a protein could be obscured through an earlier developmental block, or the interpretation of the phenotype could be complicated. The model organism Drosophila melanogaster offers a bypass to this problem: intact testes and even cysts of germ cells dissected from early pupae are able to develop ex vivo in culture medium. Making use of such cultures allows microscopic imaging of living germ cells in testes and of germ-line cysts. Importantly, the cultivated testes and germ cells also become accessible to pharmacological inhibitors, thereby permitting manipulation of enzymatic functions during spermatogenesis, including post-meiotic stages.
The protocol presented describes how to dissect and cultivate pupal testes and germ-line cysts. Information on the development of pupal testes and culture conditions are provided alongside microscope imaging data of live testes and germ-line cysts in culture. We also describe a pharmacological assay to study post-meiotic spermatogenesis, exemplified by an assay targeting the histone-to-protamine switch using the histone acetyltransferase inhibitor anacardic acid. In principle, this cultivation method could be adapted to address many other research questions in pre- and post-meiotic spermatogenesis.

Ex vivo Culture of Drosophila Pupal Testis and Single Male Germ-line Cysts: Dissection, Imaging, and Pharmacological Treatment

This protocol describes the dissection and cultivation of intact testes and germ-line cysts from Drosophila melanogaster pupae. This method allows microscopic observation of spermatogenesis ex vivo. Furthermore, we describe a pharmacological assay of the effect of inhibitors on specific stages of germ-cell development in pupal testes.

During spermatogenesis in mammals and in Drosophila melanogaster, male germ cells develop in a series of essential developmental processes. This includes ...

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

Summary

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Chapters in this video

A Gradient-generating Microfluidic Device for Cell Biology

Neurocircuit Assays for Seizures in Epilepsy Mutants of Drosophila

Cellular Toxicity of Nanogenomedicine in MCF-7 Cell Line: MTT assay

Preparation of Drosophila S2 cells for Light Microscopy

Pharmacological and Functional Genetic Assays to Manipulate Regeneration of the Planarian Dugesia japonica

The Utility of Stage-specific Mid-to-late Drosophila Follicle Isolation

A Sensitive and Specific Quantitation Method for Determination of Serum Cardiac Myosin Binding Protein-C by Electrochemiluminescence Immunoassay

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

A Strategy for Sensitive, Large Scale Quantitative Metabolomics

Ex vivo Culture of Drosophila Pupal Testis and Single Male Germ-line Cysts: Dissection, Imaging, and Pharmacological Treatment