Name: in vitro reconstitution of spatial cell contact patterns with isolated caenorhabditis elegans embryo blastomeres and adhesive polystyrene beads
Uploaded: 2019-11-26T13:30:00
Description: Watch this Scientific Journal Video about In Vitro Reconstitution of Spatial Cell Contact Patterns with Isolated Caenorhabditis elegans Embryo Blastomeres and Adhesive Polystyrene Beads at JoVE.com

We thank James Priess and Bruce Bowerman for advice and providing C. elegans strains, Don Moerman, Kota Mizumoto, and Life Sciences Institute Imaging Core Facility for sharing equipment and reagents, Aoi Hiroyasu, Lisa Fernando, Min Jee Kim for the maintenance of C. elegans and critical reading of our manuscript. Our work is supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), (RGPIN-2019-04442).

1. Preparation of adhesive polystyrene bead
NOTE: This protocol does not require aseptic technique.
<ol>
	<li>Weigh 10 mg of carboxylate modified polystyrene beads in a 1.5 mL microcentrifuge tube.</li>
	<li>To wash the beads, add 1 mL of 2-(N-morpholino)ethanesulfonic acid (MES) buffer into the tube. Since MES buffer does not contain phosphate and acetate, which can reduce the reactivity of carbodiimide, it is suitable to use in protein coupling reaction. Vortex the tube to mix the beads.</...

<ol>
	<li>Herman, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hermaphrodite+cell-fate+specification.">Hermaphrodite cell-fate specification.</a> WormBook. , (2006).</li><li>Rose, L., Gonczy, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polarity+establishment,+asymmetric+division+and+segregation+of+fate+determinants+in+early+C.+elegans+embryos.">Polarity establishment, asymmetric division and segregation of fate determinants in early C. elegans embryos.</a> WormBook. , (2014).</li><li>White, J. G., Southgate, E., Thomson, J. N., Brenner, 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+structure+of+the+nervous+system+of+the+nematode+Caenorhabditis+elegans.">The structure of the nervous system of the nematode Caenorhabditis elegans.</a> Philosophical Transactions of the Royal Society of London. B, Biological Sciences. 314 (1165), 1 (1986).</li><li>Mango, 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+C.+elegans+pharynx:+a+model+for+organogenesis.">The C. elegans pharynx: a model for organogenesis.</a> WormBook. , (2007).</li><li>McGhee, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+C.+elegans+intestine.">The C. elegans intestine.</a> WormBook. , (2007).</li><li>Edgar, L. G., Goldstein, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Culture+and+Manipulation+of+Embryonic+Cells.">Culture and Manipulation of Embryonic Cells.</a> Methods in Cell Biology. 107, 151-175 (2012).</li><li>Stein, K. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+C.+elegans+eggshell.">The C. elegans eggshell.</a> WormBook. , (2018).</li><li>Quash, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+preparation+of+latex+particles+with+covalently+bound+polyamines,+IgG+and+measles+agglutinins+and+their+use+in+visual+agglutination+tests.">The preparation of latex particles with covalently bound polyamines, IgG and measles agglutinins and their use in visual agglutination tests.</a> Journal of Immunological Methods. 22 (1), 165-174 (1978).</li><li>Miller, J. V., Cuatrecasas, P., Brad, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+tyrosine+aminotransferase+by+affinity+chromatography.">Purification of tyrosine aminotransferase by affinity chromatography.</a> Biochimica et Biophysica Acta (BBA) - Enzymology. 276 (2), 407-415 (1972).</li><li>Sugioka, K., Bowerman, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combinatorial+contact+cues+specify+cell+division+orientation+by+directing+cortical+myosin+flows.">Combinatorial contact cues specify cell division orientation by directing cortical myosin flows.</a> Developmental Cell. 46 (3), 257-270 (2018).</li><li>Park, F. D., Priess, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Establishment+of+POP-1+asymmetry+in+early+C.+elegans+embryos.">Establishment of POP-1 asymmetry in early C. elegans embryos.</a> Development. 130 (15), 3547-3556 (2003).</li><li>Schneider, C. A., Rasband, W. S., Eliceiri, K. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NIH+Image+to+ImageJ:+25+years+of+image+analysis.">NIH Image to ImageJ: 25 years of image analysis.</a> Nature Methods. 9 (7), 671-675 (2012).</li><li>Thevenaz, P., Ruttimann, U. E., Unser, 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+pyramid+approach+to+subpixel+registration+based+on+intensity.">A pyramid approach to subpixel registration based on intensity.</a> IEEE Transactions on Image Processing. 7 (1), 27-41 (1998).</li><li>Gillies, T. E., Cabernard, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+Division+Orientation+in+Animals.">Cell Division Orientation in Animals.</a> Current Biology. 21 (15), 599-609 (2011).</li><li>Poulson, N. D., Lechler, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Asymmetric+cell+divisions+in+the+epidermis.">Asymmetric cell divisions in the epidermis.</a> International Review of Cell and Molecular Biology. 295, 199-232 (2012).</li><li>Knoblich, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Asymmetric+cell+division:+recent+developments+and+their+implications+for+tumour+biology.">Asymmetric cell division: recent developments and their implications for tumour biology.</a> Nature Reviews Molecular Cell Biology. 11 (12), 849-860 (2010).</li><li>Engler, A. J., Sen, S., Sweeney, H. L., Discher, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Matrix+elasticity+directs+stem+cell+lineage+specification.">Matrix elasticity directs stem cell lineage specification.</a> Cell. 126 (4), 677-689 (2006).</li><li>Dupont, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+YAP/TAZ+in+mechanotransduction.">Role of YAP/TAZ in mechanotransduction.</a> Nature. 474 (7350), 179-183 (2011).</li><li>Schierenberg, E., Junkersdorf, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+eggshell+and+underlying+vitelline+membrane+for+normal+pattern+formation+in+the+early+C.+elegans+embryo.">The role of eggshell and underlying vitelline membrane for normal pattern formation in the early C. elegans embryo.</a> Roux's Archives of Developmental Biology. 202 (1), 10-16 (1992).</li><li>Wang, Z., Wang, D., Li, H., Bao, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+neighbor+determination+in+the+metazoan+embryo+system.">Cell neighbor determination in the metazoan embryo system.</a> Proceedings of the 8th ACM International Conference on Bioinformatics, Computational Biology, and Health Informatics. , 305-312 (2017).</li><li>Shaya, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell-cell+contact+area+affects+notch+signaling+and+notch-dependent+patterning.">Cell-cell contact area affects notch signaling and notch-dependent patterning.</a> Developmental Cell. 40 (5), 505-511 (2017).</li><li>Cao, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comprehensive+single+cell+transcriptional+profiling+of+a+multicellular+organism.">Comprehensive single cell transcriptional profiling of a multicellular organism.</a> Science. 357 (6352), 661-667 (2017).</li><li>Goldstein, B., Takeshita, H., Mizumoto, K., Sawa, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wnt+signals+can+function+as+positional+cues+in+establishing+cell+polarity.">Wnt signals can function as positional cues in establishing cell polarity.</a> Developmental Cell. 10 (3), 391-396 (2006).</li><li>Priess, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Notch+signaling+in+the+C.+elegans+embryo.">Notch signaling in the C. elegans embryo.</a> WormBook. , (2005).</li><li>M&#252;ller, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oriented+cell+division+in+the+C.+elegans+embryo+is+coordinated+by+G-protein+signaling+dependent+on+the+adhesion+GPCR+LAT-1.">Oriented cell division in the C. elegans embryo is coordinated by G-protein signaling dependent on the adhesion GPCR LAT-1.</a> PLOS Genetics. 11 (10), 1005624 (2015).</li><li>Marston, D. J., Roh, M., Mikels, A. J., Nusse, R., Goldstein, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wnt+signaling+during+Caenorhabditis+elegans+embryonic+development.">Wnt signaling during Caenorhabditis elegans embryonic development.</a> Methods in Molecular Biology. 469, 103-111 (2008).</li><li>Habib, S. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+localized+Wnt+signal+orients+asymmetric+stem+cell+division+in+vitro.">A localized Wnt signal orients asymmetric stem cell division in vitro.</a> Science. 339 (6126), 1445-1448 (2013).</li></ol>

Reconstitution of simplified cell contact patterns will let researchers to test the roles of specific cell contact patterns in different aspects of morphogenesis. We have used this technique to show that cell division axis is controlled by the physical contact with adhesive beads10. As division axis specification is crucial for multicellular development by contributing to morphogenesis14, stem cell division15,16, an...

During multicellular development, the cellular behaviors (e.g., division axis) of individual cells are specified by various chemical and physical cues. To understand how individual cell interprets this information, and how they regulate multicellular assembly as an emergent property is one of the ultimate goals of morphogenesis studies. The model organism C. elegans has contributed significantly to the understanding of cellular-level regulation of morphogenesis such as cell polarity1, cell division patterning1, cell fate decision2, and tissue-scale regulations such as neuronal wiring3 and organogenesis4,5. Although there are various genetic tools available, tissue engineering methods are limited.
The most successful tissue engineering method in C. elegans study is the classical blastomere isolation6; as C. elegans embryo is surrounded by an eggshell and a permeability barrier7, their removal is one of the main procedures of this method. While this blastomere isolation method enables reconstitution of cell-cell contact in a simplified manner, it does not allow for the elimination of unwanted cues; cell contact still poses both mechanical (e.g., adhesion) and chemical cues, thereby limiting our ability to fully analyze the causal relationship between the cue and cellular behavior.
The method presented in this paper uses carboxylate modified polystyrene beads that can covalently bind to any amine-reactive molecules including proteins as ligands. Particularly, we used an amine-reactive form of Rhodamine Red-X as a ligand to make beads both visually trackable and adhesive to the cell. The carboxyl groups of bead surface and primary amine groups of ligand molecule are coupled by water-soluble carbodiimide 1-ethyl-3-(dimethylaminopropyl) carbodiimide (EDAC)8,9. Obtained adhesive beads allow for the effects of the mechanical cue on cellular dynamics10. We have used this technique to identify mechanical cues required for cell division orientation10.

<table>
	<tbody>
		<tr>
			<td>1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride</td>
			<td>Alfa Aesar</td>
			<td>AAA1080703</td>
			<td>For the bead preparation</td>
		</tr>
		<tr>
			<td>Aspirator Tube Assembly</td>
			<td>Drummond</td>
			<td>21-180-13</td>
			<td>For the blastomere isolation.</td>
		</tr>
		<tr>
			<td>Caenorhabditis elegans strain: N2, wild-type</td>
			<td>Caenorhabditis Genetics Center</td>
			<td>N2</td>
			<td>Strain used in this study</td>
		</tr>
		<tr>
			<td>Caenorhabditis elegans strain: KSG5, genotype: zuIs45; itIs37</td>
			<td>in house</td>
			<td>KSG5</td>
			<td>Strain used in this study</td>
		</tr>
		<tr>
			<td>Calibrated Mircopipets, 10 &#181;L</td>
			<td>Drummond</td>
			<td>21-180-13</td>
			<td>For the blastomere isolation</td>
		</tr>
		<tr>
			<td>Carboxylate-modified polystyrene beads (30 &#181;m diameter)</td>
			<td>KISKER Biotech</td>
			<td>PPS-30.0COOHP</td>
			<td>For the bead preparation</td>
		</tr>
		<tr>
			<td>CD Lipid Concentrate</td>
			<td>Life Technologies</td>
			<td>11905031</td>
			<td>For the blastomere isolation. Work in the tissue culture hood.</td>
		</tr>
		<tr>
			<td>Clorox</td>
			<td>Clorox</td>
			<td>N. A.</td>
			<td>For the blastomere isolation. Open a new bottle when the hypochlorite treatment does not work well.</td>
		</tr>
		<tr>
			<td>Coverslip holder</td>
			<td>In house</td>
			<td>N.A.</td>
			<td>For the blastomere isolation.</td>
		</tr>
		<tr>
			<td>Dissecting microscope: Zeiss Stemi 508 with M stand. Source of light is built-in LED. Magnification of eye piece is 10X.</td>
			<td>Carl Zeiss</td>
			<td>Stemi 508</td>
			<td>For the blastomere isolation.</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum, Qualified One Shot, Canada origin</td>
			<td>Gibco</td>
			<td>A3160701</td>
			<td>For the blastomere isolation. Work in the tissue culture hood.</td>
		</tr>
		<tr>
			<td>General Use and Precision Glide Hypodermic Needles, 25 gauge</td>
			<td>BD</td>
			<td>14-826AA</td>
			<td>For the blastomere isolation</td>
		</tr>
		<tr>
			<td>Inulin</td>
			<td>Alfa Aesar</td>
			<td>AAA1842509</td>
			<td>For the blastomere isolation</td>
		</tr>
		<tr>
			<td>MEM Vitamin Solution (100x)</td>
			<td>Gibco</td>
			<td>11120052</td>
			<td>For the blastomere isolation.</td>
		</tr>
		<tr>
			<td>MES (Fine White Crystals)</td>
			<td>Fisher BioReagents</td>
			<td>BP300-100</td>
			<td>For the bead preparation</td>
		</tr>
		<tr>
			<td>Multitest Slide 10 Well</td>
			<td>MP Biomedicals</td>
			<td>ICN6041805</td>
			<td>For the blastomere isolation</td>
		</tr>
		<tr>
			<td>PBS, Phosphate Buffered Saline, 10 x Powder</td>
			<td>Fisher BioReagents</td>
			<td>BP665-1</td>
			<td>For the bead preparation</td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin (10,000 U/mL)</td>
			<td>Gibco</td>
			<td>15140148</td>
			<td>For the blastomere isolation.</td>
		</tr>
		<tr>
			<td>Polyvinylpyrrolidone</td>
			<td>Fisher BioReagents</td>
			<td>BP431-100</td>
			<td>For the blastomere isolation</td>
		</tr>
		<tr>
			<td>Potassium Chloride</td>
			<td>Bioshop</td>
			<td>POC888</td>
			<td>For the blastomere isolation</td>
		</tr>
		<tr>
			<td>Rhodamine Red-X, Succinimidyl Ester, 5-isomer</td>
			<td>Molecular Probes</td>
			<td>R6160</td>
			<td>For the bead preparation</td>
		</tr>
		<tr>
			<td>Schneider's Drosophila Sterile Medium</td>
			<td>Gibco</td>
			<td>21720024</td>
			<td>For the blastomere isolation. Work in the tissue culture hood.</td>
		</tr>
		<tr>
			<td>Sodium Chloride</td>
			<td>Bioshop</td>
			<td>SOD001</td>
			<td>For the blastomere isolation</td>
		</tr>
		<tr>
			<td>Sodium Hydroxide Solution, 10 N</td>
			<td>Fisher Chemical</td>
			<td>SS255-1</td>
			<td>For the blastomere isolation</td>
		</tr>
		<tr>
			<td>Spinning disk confocal microscope: Yokogawa CSU-X1, Zeiss Axiovert inverted scope, Quant EM 512 camera, 63X NA 1.4 Plan apochromat objective lens. System was controlled by Slidebook 6.0.</td>
			<td>Intelligent Imaging Innovation</td>
			<td>N.A.</td>
			<td>For live-imaging</td>
		</tr>
		<tr>
			<td>Syringe Filters, PTFE, Non-Sterile</td>
			<td>Basix</td>
			<td>13100115</td>
			<td>For the blastomere isolation.</td>
		</tr>
		<tr>
			<td>Tygon S3 Laboratory Tubing,, Formulation E-3603, Inner diameter 3.175 mm</td>
			<td>Saint Gobain Performance Plastics</td>
			<td>89403-862</td>
			<td>For the blastomere isolation.</td>
		</tr>
		<tr>
			<td>Tygon S3 Laboratory Tubing,, Formulation E-3603, Inner diameter 6.35 mm</td>
			<td>Saint Gobain Performance Plastics</td>
			<td>89403-854</td>
			<td>For the blastomere isolation.</td>
		</tr>
	</tbody>
</table>

in vitro reconstitution of spatial cell contact patterns with isolated caenorhabditis elegans embryo blastomeres and adhesive polystyrene beads

In multicellular systems, individual cells are surrounded by the various physical and chemical cues coming from neighboring cells and the environment. This tissue complexity confounds the identification of causal link between extrinsic cues and cellular dynamics. A synthetically reconstituted multicellular system overcomes this problem by enabling researchers to test for a specific cue while eliminating others. Here, we present a method to reconstitute cell contact patterns with isolated Caenorhabditis elegans blastomere and adhesive polystyrene beads. The procedures involve eggshell removal, blastomere isolation by disrupting cell-cell adhesion, preparation of adhesive polystyrene beads, and reconstitution of cell-cell or cell-bead contact. Finally, we present the application of this method to investigate the orientation of cellular division axes that contributes to the regulation of spatial cellular patterning and cell fate specification in developing embryos. This robust, reproducible, and versatile in vitro method enables the study of direct relationships between spatial cell contact patterns and cellular responses.

For beads preparation, we determined the optimal amount of Rhodamine Red-X succinimidyl ester for the transgenic strain expressing GFP-myosin II and mCherry-histone (Figure 1A-D). We used mCherry tagged histone as a marker of cell cycle progression. Because both Rhodamine Red-X and mCherry will be illuminated by a 561 nm laser, the optimal intensity of Rhodamine Red-X signal is comparable to that of histone to allow simultaneous imaging of cell and bead. For example, the flu...

Watch this Scientific Journal Video about In Vitro Reconstitution of Spatial Cell Contact Patterns with Isolated Caenorhabditis elegans Embryo Blastomeres and Adhesive Polystyrene Beads at JoVE.com

In Vitro Reconstitution of Spatial Cell Contact Patterns with Isolated Caenorhabditis elegans Embryo Blastomeres and Adhesive Polystyrene Beads

Tissue complexities of multicellular systems confound the identification of causal relationship between extracellular cues and individual cellular behaviors. Here, we present a method to study the direct link between contact-dependent cues and division axes using C. elegans embryo blastomeres and adhesive polystyrene beads.

In Vitro Reconstitution of Spatial Cell Contact Patterns with Isolated Caenorhabditis elegans Embryo Blastomeres and Adhesive Polystyrene Beads

In multicellular systems, individual cells are surrounded by the various physical and chemical cues coming from neighboring cells and the environment. ...

Multicellular tissues complex, this protocol reconstitutes cellular conduct in a simplified manner. One thing is this technique to study the direct relationships between cellular conductor protons and cellular response. This protocol uses chemically functional polystyrene beads to reconstitute the cellular conductor protons.The beads can be cut with any protons of interest, to test their effects on cellular response. We have used this method in C-Elegance on mouse embryos. Therefore, this protocol can be upright to the studies of wide organisms.As embryos are fragile after high full chlorite treatment, significant practice is required before one can successfully isolate blastomere. Visual demonstration will provide a greater understanding of how one should handle capillary during blastomere-isolation methods. To begin, weigh 10 milli-grams of carboxylate modified polystyrene beads in a 1.5 milli-liter micro centrifuge tube.Add one milli-liter of MES buffer into the tube to wash. Vortex the tube to mix the beads. Spin the tube for 60 seconds at 2000XG via bench-top centrifuge.Dicard the supernatant by carefully pipetting out the buffer. Wash the beads again with one milli-liter of MES buffer. After the wash, add one milli-liter of MES buffer containing 10 milli-grams of EDAC into the tube, to activate the surface carboxyl groups.Vortex the tube to mix the beads. Rotate and incubate the tube for 15 minutes at room temperature. Spin down the beads for 60 seconds at 2000XG.Discard the supernatant by carefully pippetting out the buffer, and wash with one milli-liter of PBS. Vortex the tube to mix the beads and repeat the PBS wash one more time. Prepare one milli-liter of one, 10, 100, and one-thousandfold dilution series of Rhodamine Red-X from the 0.65 milli-liter Rhodamine Red-X stock solution.Pippette 20 micro-liters of beads into each serial dilution tube. Rotate and incubate the tubes for five minutes at room temperature. Wash the beads twice with one milli-liter of PBS.After wash, add one milli-liter of PBS into the tubes and store them at four degrees Celsius for up to six weeks. Check the fluorescence intensity of the beads under a microscope used for live imaging. Hold each end of a micro-capillary at a capacity of 10 micro-liters with right and left hand.Pull the micro-capillary towards both ends to apply tension and bring the center of the capillary over a burner to make two hand-pulled capillaries. Under the dissecting microscope, trim the tips of the hand-pulled capillaries with forceps. Make the two tip opening sizes approximately two times, and one times the short access length of C-Elegance Embryos for the embryo transfer and eggshell removal respectively.Attach the pulled capillary into a mouth-pippetting apparatus. Pippette 45 micro-liters of egg-salts solution onto a well of a multi-welled slide. Place five to 10 adult C-Elegance onto the well.To obtain early C-Elegance Embryos cut adults into pieces by positioning two needles to the right and left of C-Elegance's body, and sliding the needles past each other. Pippette 45 micro-liters of hypochlorite solution onto a well next to the well containing egg-salt solution and pippette 45 micro-liters of Shelton's Growth Medium onto the subsequent three wells. Transfer one cell stage and early two cell stage embryos into the hypochlorite solution by the mouth pippette with the larger sized opening and wait for 40 to 55 seconds.Wash the embryos by transferring them into the next three wells with Shelton's Growth Medium. With one to two seconds in each of the first two wells. Using the hand-drawn capillary with the smaller sized opening carefully repeat pippetting the embryo for eggshell removal.After that, continuously pippette with the hand-drawn capillary to separate the two-cell stage embryonic blastomeres. After eggshell removal, minimize the force in pippetting the embryos up and down to prevent burst. Prepare an imaging chamber by placing a coverslip onto a coverslip holder and tape the edges of the coverslip to stabalize it.Flip the coverslip holder, and draw a circle on the coverslip with a hydrophobic pen. Add Shelton's Growth Medium within the circle drawn by the hydrophobic marker, and transfer the isolated blastomere to the imaging chamber within the circle. Now, dispense a small volume of the chemically functionalized beads onto the coverslip using the hand-drawn capillary with the larger opening.Control the position of the beads by blowing into the hand-drawn capillary until the beads attach to the isolated blastomere. Mount the coverslip to avoid evaporation of medium and perform live imaging using an inverted microscope. In this study, the fluorescent signal from the bead treated with 0.005 micro-grams per milli-liter Rhodamine Red-X Succinimidyl Ester for the transgenic strain expressing GFP miosin-2 and M-cherihistone was too weak.On the other hand, the fluorescent signal from the beads treated with five micro-grams per milli-liter Rhodamine Red-X Succinimidyl Ester was too strong. The concentration of Rhodamine Red-X Succinimidyl Ester at 0.5 micro-grams per milli-liter was optimal for this particular transgenic strain. During the live imaging a plane was identified where two centrosomes were vertically aligned.The plane with plus or minus 90 degree angle of this plane is spindle plane. The angle of spindle orientation relative to the cell/bead contact interface after cytokinesis shows that both daughter cells were attached to the bead in a line that passes both contact sights was used as a contact orientation. One needs to learn how embryos and eggshell react to certain external forces applied by the mouth pippette.Theoretically, any cellular response can be studied, for example, sulfate specification can be studied by culturing cells and contact with adhesive beads over longer terms. This technique has been used to understand contact dependent cell division orientation mechanism. PTF filter was used to prevent inhalation of fumes of hypochlorite solution via mouth pippette.

in-vitro-reconstitution-spatial-cell-contact-patterns-with-isolated

Research

JoVE Journal

Developmental Biology

Comprehensive Assessment of Germline Chemical Toxicity Using the Nematode Caenorhabditis elegans

Identifying the reproductive toxicity of the thousands of chemicals present in our environment has been one of the most tantalizing challenges in the field of environmental health. This is due in part to the paucity of model systems that can (1) accurately recapitulate keys features of reproductive processes and (2) do so in a medium- to high-throughput fashion, without the need for a high number of vertebrate animals.
We describe here an assay in the nematode C. elegans that allows the rapid identification of germline toxicants by monitoring the induction of aneuploid embryos. By making use of a GFP reporter line, errors in chromosome segregation resulting from germline disruption are easily visualized and quantified by automated fluorescence microscopy. Thus the screening of a particular set of compounds for its toxicity can be performed in a 96- to 384-well plate format in a matter of days. Secondary analysis of positive hits can be performed to determine whether the chromosome abnormalities originated from meiotic disruption or from early embryonic chromosome segregation errors. Altogether, this assay represents a fast first-pass strategy for the rapid assessment of germline dysfunction following chemical exposure.

Comprehensive Assessment of Germline Chemical Toxicity Using the Nematode Caenorhabditis elegans

We describe the detailed steps of a high-throughput chemical assay in the nematode Caenorhabditis elegans used to assess germline toxicity. In this assay, disruption of germline function following chemical exposure is monitored using a fluorescent reporter specific to aneuploid embryos.

Identifying the reproductive toxicity of the thousands of chemicals present in our environment has been one of the most tantalizing challenges in the ...

Characterization of Thymic Settling Progenitors in the Mouse Embryo Using In Vivo and In Vitro Assays

Characterizing thymic settling progenitors is important to understand the pre-thymic stages of T cell development, essential to devise strategies for T cell replacement in lymphopenic patients. We studied thymic settling progenitors from murine embryonic day 13 and 18 thymi by two complementary in vitro and in vivo techniques, both based on the &#8220;hanging drop&#8221; method. This method allowed colonizing irradiated fetal thymic lobes with E13 and/or E18 thymic progenitors distinguished by CD45 allotypic markers and thus following their progeny. Colonization with mixed populations allows analyzing cell autonomous differences in biologic properties of the progenitors while colonization with either population removes possible competitive selective pressures. The colonized thymic lobes can also be grafted in immunodeficient male recipient mice allowing the analysis of the mature T cell progeny in vivo, such as population dynamics of the peripheral immune system and colonization of different tissues and organs. Fetal thymic organ cultures revealed that E13 progenitors developed rapidly into all mature CD3+ cells and gave rise to the canonical &#947;&#948; T cell subset, known as dendritic epithelial T cells. In comparison, E18 progenitors have a delayed differentiation and were unable to generate dendritic epithelial T cells. The monitoring of peripheral blood of thymus-grafted CD3-/- mice further showed that E18 thymic settling progenitors generate, with time, larger numbers of mature T cells than their E13 counterparts, a feature that could not be appreciated in the short term fetal thymic organ cultures.

Characterization of Thymic Settling Progenitors in the Mouse Embryo Using In Vivo and In Vitro Assays

This article describes in vivo and in vitro methodology to characterize the thymic settling progenitors by the analysis of the kinetics of generation, phenotype and numbers of their T cell progeny.

Characterizing thymic settling progenitors is important to understand the pre-thymic stages of T cell development, essential to devise strategies for T ...

Imaging Subcellular Structures in the Living Zebrafish Embryo

In vivo imaging provides unprecedented access to the dynamic behavior of cellular and subcellular structures in their natural context. Performing such imaging experiments in higher vertebrates such as mammals generally requires surgical access to the system under study. The optical accessibility of embryonic and larval zebrafish allows such invasive procedures to be circumvented and permits imaging in the intact organism. Indeed the zebrafish is now a well-established model to visualize dynamic cellular behaviors using in vivo microscopy in a wide range of developmental contexts from proliferation to migration and differentiation. A more recent development is the increasing use of zebrafish to study subcellular events including mitochondrial trafficking and centrosome dynamics. The relative ease with which these subcellular structures can be genetically labeled by fluorescent proteins and the use of light microscopy techniques to image them is transforming the zebrafish into an in vivo model of cell biology. Here we describe methods to generate genetic constructs that fluorescently label organelles, highlighting mitochondria and centrosomes as specific examples. We use the bipartite Gal4-UAS system in multiple configurations to restrict expression to specific cell-types and provide protocols to generate transiently expressing and stable transgenic fish. Finally, we provide guidelines for choosing light microscopy methods that are most suitable for imaging subcellular dynamics.

Imaging the dynamic behavior of organelles and other subcellular structures in vivo can shed light on their function in physiological and disease conditions. Here, we present methods for genetically tagging two organelles, centrosomes and mitochondria, and imaging their dynamics in living zebrafish embryos using wide-field and confocal microscopy.

In vivo imaging provides unprecedented access to the dynamic behavior of cellular and subcellular structures in their natural context. Performing such ...

Application of Impermeable Barriers Combined with Candidate Factor Soaked Beads to Study Inductive Signals in the Chick

The chick embryo provides a superb vertebrate model that can be used to dissect developmental questions in a direct way. Its accessibility and robustness following surgical intervention are key experimental strengths. Mica plates were the first barriers used to prevent chick limb bud initiation1. Protocols that use aluminum foil as an impermeable barrier to wing bud or leg bud induction and or initiation are described. We combine this technique with bead placement lateral to the barrier to exogenously supply candidate endogenous factors that have been blocked by the barrier. The results are analyzed using in situ hybridization of subsequent gene expression. Our main focus is on the role of retinoic acid signaling in the induction and later initiation of the chick embryo fore and hindlimb. We use BMS 493 (an inverse agonist of retinoic acid receptors (RAR)) soaked beads implanted in the lateral plate mesoderm (LPM) to mimic the effect of a barrier placed between the somites (a source of retinoic acid (RA)) and the LPM from which limb buds grow. Modified versions of these protocols could also be used to address other questions on the origin and timing of inductive cues. Provided the region of the chick embryo is accessible at the relevant developmental stage, a barrier could be placed between the two tissues and consequent changes in development studied. Examples may be found in the developing brain, axis extension and in organ development, such as liver or kidney induction.

Protocols using impermeable barriers to block induction events between tissues of the main body axis and flank in the chick embryo required for limb formation are described. Beads soaked in candidate inductive signals are used to overcome the effect of barrier placement and analysis of gene expression confirms this.

The chick embryo provides a superb vertebrate model that can be used to dissect developmental questions in a direct way. Its accessibility and robustness ...

Spatial and Temporal Analysis of Active ERK in the C. elegans Germline

The evolutionarily conserved&#160;extracellular signal transducing RTK-RAS-ERK pathway is an important kinase-signaling cascade that controls multiple cellular and developmental processes principally via activation of ERK, the terminal kinase of the pathway. Tight regulation of ERK activity is essential for normal development and homeostasis; overly active ERK results in excessive cellular proliferation, while underactive ERK causes cell death. C. elegans is a powerful model system that has helped characterize the function and regulation of RTK-RAS-ERK signaling pathway during development. In particular, the RTK-RAS-ERK pathway is essential for C. elegans germline development, which is the focus of this method. Using antibodies specific to the active, diphosphorylated form of ERK (dpERK), the stereotypical localization pattern can be visualized within the germline. Because this pattern is both spatially and temporally controlled, the ability to reproducibly assay dpERK is useful to identify regulators of the pathway that affect dpERK signal duration and amplitude and thus germline development. Here we demonstrate how to successfully dissect, stain, and image dpERK within the C. elegans gonad. This method can be adapted for spatial localization of any signaling or structural protein in the C. elegans gonad, provided an antibody compatible with immunofluorescence is available.

Spatial and Temporal Analysis of Active ERK in the C. elegans Germline

We present an immunofluorescence&#160;imaging-based method for spatial and temporal localization of active ERK in the dissected C. elegans gonad. The protocol described here can be adapted for visualization of any signaling or structural protein in the C. elegans gonad, provided a suitable antibody reagent is available.

The evolutionarily conserved&#160;extracellular signal transducing RTK-RAS-ERK pathway is an important kinase-signaling cascade that controls multiple ...

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

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

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

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

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

AFM and Microrheology in the Zebrafish Embryo Yolk Cell

Elucidating the factors that direct the spatio-temporal organization of evolving tissues is one of the primary purposes in the study of development. Various propositions claim to have been important contributions to the understanding of the mechanical properties of cells and tissues in their spatiotemporal organization in different developmental and morphogenetic processes. However, due to the lack of reliable and accessible tools to measure material properties and tensional parameters in vivo, validating these hypotheses has been difficult. Here we present methods employing atomic force microscopy (AFM) and particle tracking with the aim of quantifying the mechanical properties of the intact zebrafish embryo yolk cell during epiboly. Epiboly is an early conserved developmental process whose study is facilitated by the transparency of the embryo. These methods are simple to implement, reliable, and widely applicable since they overcome intrusive interventions that could affect tissue mechanics. A simple strategy was applied for the mounting of specimens, AFM recording, and nanoparticle injections and tracking. This approach makes these methods easily adaptable to other developmental times or organisms.

The lack of tools to measure material properties and tensional parameters in vivo prevents validating their roles during development. We employed atomic force microscopy (AFM) and nanoparticle-tracking to quantify mechanical features on the intact zebrafish embryo yolk cell during epiboly. These methods are reliable and widely applicable avoiding intrusive interventions.

Elucidating the factors that direct the spatio-temporal organization of evolving tissues is one of the primary purposes in the study of development. ...

Immobilization of Caenorhabditis elegans to Analyze Intracellular Transport in Neurons

Axonal transport and intraflagellar transport (IFT) are essential for axon and cilia morphogenesis and function. Kinesin superfamily proteins and dynein are molecular motors that regulate anterograde and retrograde transport, respectively. These motors use microtubule networks as rails. Caenorhabditis elegans (C. elegans) is a powerful model organism to study axonal transport and IFT in vivo. Here, I describe a protocol to observe axonal transport and IFT in living C. elegans. Transported cargo can be visualized by tagging cargo proteins using fluorescent proteins such as green fluorescent protein (GFP). C. elegans is transparent and GFP-tagged cargo proteins can be expressed in specific cells under cell-specific promoters. Living worms can be fixed by microbeads on 10% agarose gel without killing or anesthetizing the worms. Under these conditions, cargo movement can be directly observed in the axons and cilia of living C. elegans without dissection. This method can be applied to the observation of any cargo molecule in any cells by modifying the target proteins and/or the cells they are expressed in. Most basic proteins such as molecular motors and adaptor proteins that are involved in axonal transport and IFT are conserved in C. elegans. Compared to other model organisms, mutants can be obtained and maintained more easily in C. elegans. Combining this method with various C. elegans mutants can clarify the molecular mechanisms of axonal transport and IFT.

Immobilization of Caenorhabditis elegans to Analyze Intracellular Transport in Neurons

Caenorhabditis elegans (C. elegans) is a good model to study axonal and intracellular transport. Here, I describe a protocol for in vivo recording and analysis of axonal and intraflagellar transport in C. elegans.

Axonal transport and intraflagellar transport (IFT) are essential for axon and cilia morphogenesis and function. Kinesin superfamily proteins and dynein ...

Assessing Lysosomal Alkalinization in the Intestine of Live Caenorhabditis elegans

The nematode Caenorhabditis elegans (C. elegans) is a model system that is widely used to study longevity and developmental pathways. Such studies are facilitated by the transparency of the animal, the ability to do forward and reverse genetic assays, the relative ease of generating fluorescently labeled proteins, and the use of fluorescent dyes that can either be microinjected into the early embryo or incorporated into its food (E. coli strain OP50) to label cellular organelles (e.g. 9-diethylamino-5H-benzo(a)phenoxazine-5-one and (3-{2-[(1H,1&#39;H-2,2&#39;-bipyrrol-5-yl-kappaN(1))methylidene]-2H-pyrrol-5-yl-kappaN}-N-[2-(dimethylamino)ethyl]propanamidato)(difluoro)boron). Here, we present the use of a fluorescent pH-sensitive dye that stains intestinal lysosomes, providing a visual readout of dynamic, physiological changes in lysosomal acidity in live worms. This protocol does not measure lysosomal pH, but rather aims to establish a reliable method of assessing physiological relevant variations in lysosomal acidity. cDCFDA is a cell-permeant compound that is converted to the fluorescent fluorophore 5-(and-6)-carboxy-2&#39;,7&#39;-dichlorofluorescein (cDCF) upon hydrolysis by intracellular esterases. Protonation inside lysosomes traps cDCF in these organelles, where it accumulates. Due to its low pKa of 4.8, this dye has been used as a pH sensor in yeast. Here we describe the use of cDCFDA as a food supplement to assess the acidity of intestinal lysosomes in C. elegans. This technique allows for the detection of alkalinizing lysosomes in live animals, and has a broad range of experimental applications including studies on aging, autophagy, and lysosomal biogenesis.

Assessing Lysosomal Alkalinization in the Intestine of Live Caenorhabditis elegans

A step-by-step guide to probe loss of lysosomal acidity in the intestine of C. elegans using the pH-sensitive vital dye 5(6)-carboxy-2&#39;,7&#39;-dichlorofluorescein diacetate (cDCFDA)

The nematode Caenorhabditis elegans (C. elegans) is a model system that is widely used to study longevity and developmental pathways. Such studies are ...

Probing Cell Mechanics with Bead-Free Optical Tweezers in the Drosophila Embryo

Morphogenesis requires coordination between genetic patterning and mechanical forces to robustly shape the cells and tissues. Hence, a challenge to understand morphogenetic processes is to directly measure cellular forces and mechanical properties in vivo during embryogenesis. Here, we present a setup of optical tweezers coupled to a light sheet microscope, which allows to directly apply forces on cell-cell contacts of the early Drosophila embryo, while imaging at a speed of several frames per second. This technique has the advantage that it does not require the injection of beads into the embryo, usually used as intermediate probes on which optical forces are exerted. We detail step by step the implementation of the setup, and propose tools to extract mechanical information from the experiments. By monitoring the displacements of cell-cell contacts in real time, one can perform tension measurements and investigate cell contacts&#39; rheology.

Probing Cell Mechanics with Bead-Free Optical Tweezers in the Drosophila Embryo

We present a setup of optical tweezers coupled to a light sheet microscope, and its implementation to probe cell mechanics without beads in the Drosophila embryo.

Morphogenesis requires coordination between genetic patterning and mechanical forces to robustly shape the cells and tissues. Hence, a challenge to ...