Name: crispr-mediated loss of function analysis in cerebellar granule cells using in utero electroporation-based gene transfer
Uploaded: 2018-06-09T13:30:00
Description: Watch this Scientific Journal Video about CRISPR-mediated Loss of Function Analysis in Cerebellar Granule Cells Using In Utero Electroporation-based Gene Transfer at JoVE.com

We appreciate Laura Sieber, Anna Neuerburg, Yassin Harim, and Petra Schroeter for technical assistance. We also thank Drs. K. Reifenberg, K. Dell and P. Pr&#252;ckl&#160;for helpful assistance for animal experiments at DKFZ; the Imaging Core Facilities of the DKFZ and the Carl Zeiss Imaging Center in the DKFZ for confocal microscopy imaging. This work was supported by the Deutsche Forschungsgemeinschaft, KA 4472/1-1 (to D.K.).

All animal experiments were conducted according to animal welfare regulations and have been approved by the responsible authorities (Regierungspr&#228;sidium Karlsruhe, approval numbers: G90/13, G176/13, G32/14, G48/14, and G133/14).
1. Generate pU6-sgRNA-Cbh-Cre Plasmids
<ol>
	<li>Design the sgRNA to target a gene-of-interest according to the previously published protocol14. 
	NOTE: In this experiment, two sgRNAs are designed to target the mouse Top2b g...

<ol>
	<li>Mikuni, T., Nishiyama, J., Sun, Y., Kamasawa, N., Yasuda, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-Throughput,+High-Resolution+Mapping+of+Protein+Localization+in+Mammalian+Brain+by+In+Vivo+Genome+Editing.">High-Throughput, High-Resolution Mapping of Protein Localization in Mammalian Brain by In Vivo Genome Editing.</a> Cell. 165 (7), 1803-1817 (2016).</li><li>Zuckermann, M., Hovestadt, V., Knobbe-Thomsen, C. B., Zapatka, M., Northcott, P. A., Schramm, K., 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=Somatic+CRISPR/Cas9-mediated+tumour+suppressor+disruption+enables+versatile+brain+tumour+modelling.">Somatic CRISPR/Cas9-mediated tumour suppressor disruption enables versatile brain tumour modelling.</a> Nat Commun. 6, 7391 (2015).</li><li>Chen, F., Rosiene, J., Che, A., Becker, A., LoTurco, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tracking+and+transforming+neocortical+progenitors+by+CRISPR/Cas9+gene+targeting+and+piggyBac+transposase+lineage+labeling.">Tracking and transforming neocortical progenitors by CRISPR/Cas9 gene targeting and piggyBac transposase lineage labeling.</a> Development. 142 (20), 3601-3611 (2015).</li><li>Saito, T., Nakatsuji, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+gene+transfer+into+the+embryonic+mouse+brain+using+in+vivo+electroporation.">Efficient gene transfer into the embryonic mouse brain using in vivo electroporation.</a> Developmental biology. 240 (1), 237-246 (2001).</li><li>Matsuda, T., Cepko, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electroporation+and+RNA+interference+in+the+rodent+retina+in+vivo+and+in+vitro.">Electroporation and RNA interference in the rodent retina in vivo and in vitro.</a> Proc Natl Acad Sci U S A. 101 (1), 16-22 (2004).</li><li>Matsui, A., Yoshida, A. C., Kubota, M., Ogawa, M., Shimogori, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+in+utero+electroporation:+controlled+spatiotemporal+gene+transfection.">Mouse in utero electroporation: controlled spatiotemporal gene transfection.</a> J Vis Exp. (54), (2011).</li><li>Kawauchi, D., Taniguchi, H., Watanabe, H., Saito, T., Murakami, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+visualization+of+nucleogenesis+by+precerebellar+neurons:+involvement+of+ventricle-directed,+radial+fibre-associated+migration.">Direct visualization of nucleogenesis by precerebellar neurons: involvement of ventricle-directed, radial fibre-associated migration.</a> Development. 133 (6), 1113-1123 (2006).</li><li>Kawauchi, D., Saito, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcriptional+cascade+from+Math1+to+Mbh1+and+Mbh2+is+required+for+cerebellar+granule+cell+differentiation.">Transcriptional cascade from Math1 to Mbh1 and Mbh2 is required for cerebellar granule cell differentiation.</a> Developmental biology. 322 (2), 345-354 (2008).</li><li>Saba, R., Nakatsuji, N., Saito, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mammalian+BarH1+confers+commissural+neuron+identity+on+dorsal+cells+in+the+spinal+cord.">Mammalian BarH1 confers commissural neuron identity on dorsal cells in the spinal cord.</a> Journal of Neuroscience. 23 (6), 1987-1991 (2003).</li><li>Sato, T., Muroyama, Y., Saito, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inducible+gene+expression+in+postmitotic+neurons+by+an+in+vivo+electroporation-based+tetracycline+system.">Inducible gene expression in postmitotic neurons by an in vivo electroporation-based tetracycline system.</a> J Neurosci Methods. 214 (2), 170-176 (2013).</li><li>Kawauchi, D., Ogg, R. J., Liu, L., Shih, D. J. H., Finkelstein, D., Murphy, B. L., 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=Novel+MYC-driven+medulloblastoma+models+from+multiple+embryonic+cerebellar+cells.">Novel MYC-driven medulloblastoma models from multiple embryonic cerebellar cells.</a> Oncogene. , (2017).</li><li>Feng, W., Kawauchi, D., Korkel-Qu, H., Deng, H., Serger, E., Sieber, L., 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=Chd7+is+indispensable+for+mammalian+brain+development+through+activation+of+a+neuronal+differentiation+programme.">Chd7 is indispensable for mammalian brain development through activation of a neuronal differentiation programme.</a> Nat Commun. 8, 14758 (2017).</li><li>Platt, R. J., Chen, S., Zhou, Y., Yim, M. J., Swiech, L., Kempton, H. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CRISPR-Cas9+knockin+mice+for+genome+editing+and+cancer+modeling.">CRISPR-Cas9 knockin mice for genome editing and cancer modeling.</a> Cell. 159 (2), 440-455 (2014).</li><li>Ran, F. A., Hsu, P. D., Wright, J., Agarwala, V., Scott, D. A., Zhang, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome+engineering+using+the+CRISPR-Cas9+system.">Genome engineering using the CRISPR-Cas9 system.</a> Nat Protoc. 8 (11), 2281-2308 (2013).</li><li>Joung, J., Konermann, S., Gootenberg, J. S., Abudayyeh, O. O., Platt, R. J., Brigham, M. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-scale+CRISPR-Cas9+knockout+and+transcriptional+activation+screening.">Genome-scale CRISPR-Cas9 knockout and transcriptional activation screening.</a> Nat Protocols. 12 (4), 828-863 (2017).</li><li>Cong, L., Ran, F. A., Cox, D., Lin, S., Barretto, R., Habib, N., 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=Multiplex+genome+engineering+using+CRISPR/Cas+systems.">Multiplex genome engineering using CRISPR/Cas systems.</a> Science. 339 (6121), 819-823 (2013).</li><li>Mashiko, D., Fujihara, Y., Satouh, Y., Miyata, H., Isotani, A., Ikawa, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+mutant+mice+by+pronuclear+injection+of+circular+plasmid+expressing+Cas9+and+single+guided+RNA.">Generation of mutant mice by pronuclear injection of circular plasmid expressing Cas9 and single guided RNA.</a> Scientific Reports. 3, 3355 (2013).</li><li>Gibson, D. G., Smith, H. O., Hutchison, C. A., Venter, J. C., Merryman, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+synthesis+of+the+mouse+mitochondrial+genome.">Chemical synthesis of the mouse mitochondrial genome.</a> Nature. 7 (11), 901-903 (2010).</li><li>Baumgart, J., Baumgart, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cortex-,+Hippocampus-,+Thalamus-,+Hypothalamus-,+Lateral+Septal+Nucleus-+and+Striatum-specific+In+Utero+Electroporation+in+the+C57BL/6+Mouse.">Cortex-, Hippocampus-, Thalamus-, Hypothalamus-, Lateral Septal Nucleus- and Striatum-specific In Utero Electroporation in the C57BL/6 Mouse.</a> J Vis Exp. (107), e53303 (2016).</li><li>Martinez, S., Andreu, A., Mecklenburg, N., Echevarria, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+and+molecular+basis+of+cerebellar+development.">Cellular and molecular basis of cerebellar development.</a> Frontiers in Neuroanatomy. 7, 18 (2013).</li></ol>

Using exo utero electroporation, we have previously reported siRNA-based in vivo functional analyses of Atoh1 at an early stage of cerebellar granule cell differentiation8. Due to siRNA dilution/degradation and exposure of embryos outside the uterine wall, phenotypic analysis of the electroporated granule cells was limited to embryonic stages. However, the current method enabled analysis of the phenotype of postnatal animals.
Our previous study demonst...

Brain diseases are one of the most dreadful mortal diseases. They often result from genetic mutations and subsequent dysregulation. To understand molecular mechanisms of brain diseases, ever-lasting efforts to decipher the genomes of human patients have discovered a number of potential causative genes. So far, germline genetically engineered animal models have been utilized for in vivo gain-of-function (GOF) and loss-of-function (LOF) analyses of such candidate genes. Due to the accelerated development of functional validation studies, a more feasible and flexible in vivo gene assay system for studying gene function is desirable.
The application of an in vivo electroporation-based gene transfer system to the developing mouse brain is suitable for this purpose. In fact, several studies using in utero electroporation have shown their potential to conduct functional analyses in the developing brain1,2,3. Actually, several regions of the mouse brain, such as the cerebral cortex4, retina5, diencephalon6, hindbrain7, cerebellum8, and spinal cord9 have been targeted by somatic gene delivery approaches, so far.
Indeed, transient gene expression by in vivo electroporation on embryonic mouse brains has long been used for GOF analysis. Recent transposon-based genomic integration technologies further enabled long-term and/or conditional expression of genes of interest10,11, which is advantageous to dissect gene function in a spatial and temporal manner during development. In contrast to GOF analysis, LOF analysis has been more challenging. While transient transfection of siRNAs and shRNA-carrying plasmids was performed, long-term effects of LOF of genes are not guaranteed due to eventual degradation of exogenously introduced nucleic acids, such as plasmids and dsRNAs. However, the CRISPR/Cas technology provides a break-through in LOF analyses. Genes encoding fluorescent proteins (e.g., GFP) or bioluminescent proteins (e.g., firefly luciferase) have been co-transfected with CRISPR-Cas9 and sgRNAs to label the cells exposed to CRISPR-Cas9-mediated somatic mutations. Nevertheless, this approach might have limitations in functional studies on proliferating cells, since exogenous marker genes are diluted and degraded after long-term proliferation. While the transfected cells and their daughter cells undergo CRISPR-induced mutations in their genomes, their footprints might get lost over time. Thus, genetic labeling approaches would be suitable to overcome this issue.
We recently developed a CRISPR-based LOF method in cerebellar granule cells that undergo long-term proliferation during their differentiation12. To genetically label the transfected cells, we constructed a plasmid carrying a sgRNA together with Cre and introduced the plasmid into the cerebella of Rosa26-CAG-LSL-Cas9-P2A-EGFP mice13 using in utero electroporation. Unlike regular plasmid vectors encoding EGFP, this approach successfully labeled transfected granule neuron precursors (GNPs) and their daughter cells. This method provides great support in understanding in vivo function of genes of interest in proliferating cells in normal brain development and a tumor-prone background.

<table>
	<tbody>
		<tr>
			<td>Alexa 488 Goat anti-Chicken</td>
			<td>ThermoFisher</td>
			<td>A11039</td>
			<td>1:400 dilution</td>
		</tr>
		<tr>
			<td>Alexa 568 Donkey anti-Mouse</td>
			<td>Life Technologies</td>
			<td>A-10037</td>
			<td>1:400 dilution</td>
		</tr>
		<tr>
			<td>Alexa 594 Donkey anti-Rabbit</td>
			<td>ThermoFisher</td>
			<td>A21207</td>
			<td>1:400 dilution</td>
		</tr>
		<tr>
			<td>Alexa 647 Donkey anti-Rabbit</td>
			<td>Life Technologies</td>
			<td>A31573</td>
			<td>1:400 dilution</td>
		</tr>
		<tr>
			<td>Alkaline Phosphatase (FastAP)</td>
			<td>ThermoFisher</td>
			<td>EF0654</td>
			<td></td>
		</tr>
		<tr>
			<td>Autoclave band</td>
			<td>Kisker Biotech</td>
			<td>150262</td>
			<td></td>
		</tr>
		<tr>
			<td>BamHI (HF)</td>
			<td>NEB</td>
			<td>R3136S</td>
			<td></td>
		</tr>
		<tr>
			<td>BbsI (FastDigest)</td>
			<td>ThermoFisher</td>
			<td>FD1014</td>
			<td></td>
		</tr>
		<tr>
			<td>Cellulose Filter Paper (Whatman)</td>
			<td>Sigma-Aldrich</td>
			<td>WHA10347525</td>
			<td></td>
		</tr>
		<tr>
			<td>Cloth</td>
			<td>Tork</td>
			<td>530378</td>
			<td></td>
		</tr>
		<tr>
			<td>Confocal laser scanning microscope</td>
			<td>Zeiss</td>
			<td>LSM800</td>
			<td></td>
		</tr>
		<tr>
			<td>D-Luciferin</td>
			<td>biovision</td>
			<td>7903-1</td>
			<td></td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Sigma-Aldrich</td>
			<td>D9542</td>
			<td>1:1000 dilution</td>
		</tr>
		<tr>
			<td>Disposable plastic molds (Tissue-Tek Cyromold)</td>
			<td>VWR</td>
			<td>4566</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM Glutamax</td>
			<td>ThermoFisher</td>
			<td>31966047</td>
			<td></td>
		</tr>
		<tr>
			<td>Donkey serum</td>
			<td>Sigma-Aldrich</td>
			<td>D9663</td>
			<td></td>
		</tr>
		<tr>
			<td>EcoRI (HF)</td>
			<td>NEB</td>
			<td>R3101S</td>
			<td></td>
		</tr>
		<tr>
			<td>Electro Square Porator</td>
			<td>BTX</td>
			<td>ECM830</td>
			<td></td>
		</tr>
		<tr>
			<td>Endofree Maxi Kit</td>
			<td>Qiagen</td>
			<td>12362</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Merck</td>
			<td>107017</td>
			<td></td>
		</tr>
		<tr>
			<td>Eye ointment (Bepanthen)</td>
			<td>Bayer</td>
			<td>81552983</td>
			<td></td>
		</tr>
		<tr>
			<td>Fast Green</td>
			<td>Merck</td>
			<td>104022</td>
			<td></td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>ThermoFisher</td>
			<td>10270-016</td>
			<td></td>
		</tr>
		<tr>
			<td>Filter (0.22 &#181;m)</td>
			<td>Merck</td>
			<td>F8148</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluorescent cell imager (ZOE)</td>
			<td>Biorad</td>
			<td>1450031</td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps straight</td>
			<td>Fine Science Tools</td>
			<td>91150-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Gauze (X100 ES-pads 8f 10 x 10 cm)</td>
			<td>Fisher Scientific</td>
			<td>15387311</td>
			<td></td>
		</tr>
		<tr>
			<td>GFP antibody</td>
			<td>Abcam</td>
			<td>ab13970</td>
			<td>1:1000 dilution</td>
		</tr>
		<tr>
			<td>Gibson Assembly Master Mix</td>
			<td>NEB</td>
			<td>E2611S</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass Capillary with Filament</td>
			<td>Narishige</td>
			<td>GD1-2</td>
			<td></td>
		</tr>
		<tr>
			<td>Heating Pad</td>
			<td>ThermoLux</td>
			<td>463265 / -67</td>
			<td></td>
		</tr>
		<tr>
			<td>Image Processing software (ImageJ and Fiji)</td>
			<td>NIH</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Insulin syringe (B. Braun OMNICAN U-100)</td>
			<td>Carl Roth</td>
			<td>AKP0.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Zoetis</td>
			<td>TU061219</td>
			<td></td>
		</tr>
		<tr>
			<td>IVIS Lumina LT Series III Caliper</td>
			<td>Perkin Elmer</td>
			<td>CLS136331</td>
			<td></td>
		</tr>
		<tr>
			<td>Kalt Suture Needles</td>
			<td>Fine Science Tools</td>
			<td>12050-02</td>
			<td></td>
		</tr>
		<tr>
			<td>KAPA HIFI HOTSTART READY mix</td>
			<td>Kapa Biosystems</td>
			<td>KK2601</td>
			<td></td>
		</tr>
		<tr>
			<td>Ki67 antibody</td>
			<td>Abcam</td>
			<td>ab15580</td>
			<td>1:500 dilution</td>
		</tr>
		<tr>
			<td>Light Pointer</td>
			<td>Photonic</td>
			<td>PL3000</td>
			<td></td>
		</tr>
		<tr>
			<td>Liquid blocker pen</td>
			<td>Kisker Biotech</td>
			<td>MKP-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Metamizol</td>
			<td>WDT</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Microgrinder</td>
			<td>Narishige</td>
			<td>EG-45</td>
			<td></td>
		</tr>
		<tr>
			<td>Microinjector</td>
			<td>Narishige</td>
			<td>IM300</td>
			<td></td>
		</tr>
		<tr>
			<td>Micropipette Puller</td>
			<td>Sutter Instrument Co.</td>
			<td>P-97</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope software ZEN</td>
			<td>Zeiss</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Non-sterile Silk Suture Thread (0.12 mm)</td>
			<td>Fine Science Tools</td>
			<td>18020-50</td>
			<td></td>
		</tr>
		<tr>
			<td>O.C.T. Compound (Tissue-Tek)</td>
			<td>VWR</td>
			<td>4583</td>
			<td></td>
		</tr>
		<tr>
			<td>p27 antibody</td>
			<td>BD bioscience</td>
			<td>610241</td>
			<td>1:200 dilution</td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Roth</td>
			<td>335.3</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS (1x)</td>
			<td>Life Technologies</td>
			<td>14190169</td>
			<td></td>
		</tr>
		<tr>
			<td>pCAG-EGxxFP</td>
			<td>Addgene</td>
			<td>50716</td>
			<td></td>
		</tr>
		<tr>
			<td>Polyethylenimine</td>
			<td>Sigma-Aldrich</td>
			<td>408727</td>
			<td></td>
		</tr>
		<tr>
			<td>pX330 plasmid</td>
			<td>Addgene</td>
			<td>42230</td>
			<td></td>
		</tr>
		<tr>
			<td>QIAprep Spin Miniprep Kit</td>
			<td>Qiagen</td>
			<td>27104</td>
			<td></td>
		</tr>
		<tr>
			<td>QIAquick Gel Extraction Kit</td>
			<td>Qiagen</td>
			<td>28704</td>
			<td></td>
		</tr>
		<tr>
			<td>Quick Ligation Kit</td>
			<td>NEB</td>
			<td>M2200S</td>
			<td></td>
		</tr>
		<tr>
			<td>Ring Forceps</td>
			<td>Fine Science Tools</td>
			<td>11103-09</td>
			<td></td>
		</tr>
		<tr>
			<td>Slides (SuperFrost)</td>
			<td>ThermoFisher</td>
			<td>10417002</td>
			<td></td>
		</tr>
		<tr>
			<td>Software for biostatistics (Prism 7)</td>
			<td>GraphPad Software, Inc</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Spitacid</td>
			<td>EcoLab</td>
			<td>3003840</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereomicroscope</td>
			<td>Nikon</td>
			<td>C-PS</td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Sigma-Aldrich</td>
			<td>S5016</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical scissors</td>
			<td>Fine Science Tools</td>
			<td>91460-11</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical scissors with blunt tip</td>
			<td>Fine Science Tools</td>
			<td>14072-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Suture (Supramid schwarz DS 16, 1.5 (4/0))</td>
			<td>SMI</td>
			<td>220340</td>
			<td></td>
		</tr>
		<tr>
			<td>T4 DNA Ligation Buffer</td>
			<td>NEB</td>
			<td>B0202S</td>
			<td></td>
		</tr>
		<tr>
			<td>T4 PNK</td>
			<td>NEB</td>
			<td>M0201S</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue scissors Blunt (11.5 cm)</td>
			<td>Fine Science Tools</td>
			<td>14072-10</td>
			<td></td>
		</tr>
		<tr>
			<td>TOP2B antibody</td>
			<td>Santa Cruz</td>
			<td>sc13059</td>
			<td>1:200 dilution</td>
		</tr>
		<tr>
			<td>Trypsin (2.5 %)</td>
			<td>ThermoFisher</td>
			<td>15090046</td>
			<td></td>
		</tr>
		<tr>
			<td>Tweezers w/5mm &#216; disk electrodes Platinum</td>
			<td>Xceltis GmbH</td>
			<td>CUY650P5</td>
			<td></td>
		</tr>
		<tr>
			<td>Vaporizer</td>
			<td>Dr&#228;gerwerk AG</td>
			<td>GS186</td>
			<td></td>
		</tr>
	</tbody>
</table>

crispr-mediated loss of function analysis in cerebellar granule cells using in utero electroporation-based gene transfer

Brain malformation is often caused by genetic mutations. Deciphering the mutations in patient-derived tissues has identified potential causative factors of the diseases. To validate the contribution of a dysfunction of the mutated genes to disease development, the generation of animal models carrying the mutations is one obvious approach. While germline genetically engineered mouse models (GEMMs) are popular biological tools and exhibit reproducible results, it is restricted by time and costs. Meanwhile, non-germline GEMMs often enable exploring gene function in a more feasible manner. Since some brain diseases (e.g., brain tumors) appear to result from somatic but not germline mutations, non-germline chimeric mouse models, in which normal and abnormal cells coexist, could be helpful for disease-relevant analysis. In this study, we report a method for the induction of CRISPR-mediated somatic mutations in the cerebellum. Specifically, we utilized conditional knock-in mice, in which Cas9 and GFP are chronically activated by the CAG (CMV enhancer/chicken &#223;-actin) promoter after Cre-mediated recombination of the genome. The self-designed single-guide RNAs (sgRNAs) and the Cre recombinase sequence, both encoded in a single plasmid construct, were delivered into cerebellar stem/progenitor cells at an embryonic stage using in utero electroporation. Consequently, transfected cells and their daughter cells were labeled with green fluorescent protein (GFP), thus facilitating further phenotypic analyses. Hence, this method is not only showing electroporation-based gene delivery into embryonic cerebellar cells but also proposing a novel quantitative approach to assess CRISPR-mediated loss-of-function phenotypes.

For in vivo functional analysis, it is critical to identify the cells into which exogenous gene(s) have been introduced. While the expression of a marker, such as GFP in non-proliferating cells can be followed-up for a long period of time, the signal gets sequentially lost in proliferating cells. An illustration of this effect is demonstrated in Figure 1. To circumvent losing the footprint of transfected cells in LOF analyses, we developed a novel ap...

Watch this Scientific Journal Video about CRISPR-mediated Loss of Function Analysis in Cerebellar Granule Cells Using In Utero Electroporation-based Gene Transfer at JoVE.com

CRISPR-mediated Loss of Function Analysis in Cerebellar Granule Cells Using In Utero Electroporation-based Gene Transfer

Conventional loss-of-function studies of genes using knockout animals have often been costly and time-consuming. Electroporation-based CRISPR-mediated somatic mutagenesis is a powerful tool to understand gene functions in vivo. Here, we report a method to analyze knockout phenotypes in proliferating cells of the cerebellum.

CRISPR-mediated Loss of Function Analysis in Cerebellar Granule Cells Using In Utero Electroporation-based Gene Transfer

Brain malformation is often caused by genetic mutations. Deciphering the mutations in patient-derived tissues has identified potential causative factors ...

The overall goal of this electroporation-based in vivo gene transfer approach is to evaluate the roles of genes of interest in differentiation of cerebellar granule cells using CRISPR-mediated loss of function analyses. This method can help answer key questions in the developmental neurosciences and the neuro-oncologies, such as for identification of the molecules important for normal cerebellar development and brain tumor formations. The procedure of in-utero electroporation will be demonstrated by Dr.Lena Herbst a post-doc from Professor Peter Lichter's laboratory, and then the following immunohistochemistry will be performed by Dr.Weijun Feng, a post-doc from Dr.Haikun Di's laboratory.The main advantage of this method is to endeavor as to feasibly knock out genes of interest in the cerebellar cells, using the CRISPR-cas9 technologies, instead of the generation of the combination of knock-out animals. Although this method can give insight into gene functions during normal cerebellar development, it can also be applied to other systems, such as the development of other physical brain regions and brain tumor modeling. Begin by loading a borosilicate glass capillary into a micropipette puller and pulling to create a fine tip.Label the capillary tip with black ink for better visualization during the injection, and draw a scaling on the glass. Working under a stereomicroscope, use a ruler and sharp needle tweezers to trim the tip to a length of about six millimeters and create a sharp, one-sided beveled edge. Filter a 1%fast green stock solution through a zero-point, 22 micron filter to remove dye particles from the solution.Mix the single-guide RNA plasmids in equal parts with the luciferase reporter plasmid to a final concentration of at least one microgram per milliliter for each plasmid. Color the plasmid solution with fast green at a final concentration of 0.5%After anesthetizing a pregnant CD-1 mouse with isoflurane, place the mouse on its back on a heating pad, and administer analgesic. Apply eye ointment to prevent eye dryness during surgery.Fix the lens with tape and sterilize the abdomen with a disinfectant. Cover the mouse with gauze, leaving only the surgical area exposed. After making a skin incision of about two centimeters in length, locate the linea alba and use blunt-tip tissue scissors to make a slightly smaller second incision through the peritoneum.Moisten the opened abdominal cavity with pre-warmed sterile PBS. Next, use ring forceps to carefully extract the uterine horns from the abdominal cavity. Grasp the uterine wall at the gap between the yolk sacs of two neighboring embryos and pull gently.Avoid any pressure on the embryo while pulling it through the incision. Once the uterine horns have been extracted, aspirate approximately 10 to 15 microliters of colored plasmid solution with the prepared glass capillary. Avoid any air bubbles during this process.Gently hold the embryo with ring forceps and locate the neck area. Slowly penetrate the dorsal hindbrain with the tip of the glass capillary and move into the fourth ventricle. Inject about one microliter of the plasmid mix.Confirm that the dyed DNA has not leaked from the brain, and is visible as a diamond-shaped structure. Here it is most important to fill the entire region of the fourth ventricle with plasmid solution, to deliver DNA also to the distal part of the cerebellar primordium. At the same time, make sure not to cause any bleeding during that process.Place platinum tweezers, equipped with five millimeter diameter electrode plates laterally over the head of the embryo, with the negative pole covering the ear, and the positive pole positioned at the cerebellar primordium over the uterine wall, and apply electric square pulses. When all embryos have been electroporated, carefully place the uterine horns back into the abdominal cavity, and fill with sterile PBS. Let the uterine horns slide into a natural position.Turn off anesthesia and place the animal belly-down into a new cage to recover. Before cryosectioning, fix the cerebella overnight in five milliliters of 4%PFA in PBS per brain, at four degrees Celsius. The next day, transfer the fixed cerebella to ten milliliters of 30%sucrose in PBS per brain, and incubate overnight at four degrees Celsius.The following day, after the tissue has sunk to the bottom of the tube, remove the brains from the sucrose, and soak up the remaining sucrose solution with a piece of cellulose filter paper. Next, immerse each cerebellum in optimal cutting temperature compound in a disposable plastic mold, and freeze on dry ice. Cut the cryogenic block into 10 micron thick sections, using a cryostat, and keep the sections at minus 80 degrees Celsius until use.When ready to proceed to immunostaining, first dry the slides at room temperature for 30 minutes, and then wash twice for 10 minutes each time in PBS. Circle the sections with a liquid blocker pen and incubate the sections in blocking solution for one hour at room temperature. Add primary antibodies against the molecules of interest in the blocking solution, and incubate overnight at four degrees Celsius.Wash the slides with 0.1%Triton containing PBS three times for 10 minutes each. Then add fluorophore conjugated secondary antibody diluted in blocking solution containing DAPI, and incubate the sections for one hour at room temperature in the dark. Wash the slides in PBS-T three times for 10 minutes each time, then mount the slides, and keep at four degrees Celsius until imaging.hek293T cells stably expressing streptococcus pyogenes cas9 were transfected with sgRNA expressing and targeting plasmids. GFP expression in live cells was monitored using a fluorescent cell imager 48 hours after transfection. This image shows an affected sgRNA sequence based on GFP expression.This image shows lack of GFP expression resulting from a non-effective sgRNA sequence. These images show immunostaining of GFP, Ki67, and p27 in cerebella from a p7-rosa26-LSL-cas9 knock-in mouse with floxed stop cassette and downstream bicistronic cas9 and EGFP sequences, that was subject to electroporation at E13.5 with a Cre plasmid expressing control sgRNA. The section is counter-stained with DAPI.Note GFP-expressing cells in the outer granule cell layer marked by Ki67. Once mastered, this surgery can be done in less than 30 minutes per mouse. While attempting this procedure, it is important to remember to handle the embryo very carefully, to always use sharp-tipped capillaries, and to position the electrodes in the precise angle to ensure delivery of the electric pulses to the roof of the fourth ventricle.After its development, this technique paved the way for researchers in the field of medical sciences to explore the causal factors of the neurological disorders, including the brain tumors in the mouse cerebellum.

crispr-mediated-loss-function-analysis-cerebellar-granule-cells-using

Research

JoVE Journal

Developmental Biology

Analysis of Zebrafish Larvae Skeletal Muscle Integrity with Evans Blue Dye

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

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

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

Ex Vivo Culture of Chick Cerebellar Slices and Spatially Targeted Electroporation of Granule Cell Precursors

The cerebellar external granule layer (EGL) is the site of the largest transit amplification in the developing brain, and an excellent model for studying neuronal proliferation and differentiation. In addition, evolutionary modifications of its proliferative capability have been responsible for the dramatic expansion of cerebellar size in the amniotes, making the cerebellum an excellent model for evo-devo studies of the vertebrate brain. The constituent cells of the EGL, cerebellar granule progenitors, also represent a significant cell of origin for medulloblastoma, the most prevalent paediatric neuronal tumour. Following transit amplification, granule precursors migrate radially into the internal granular layer of the cerebellum where they represent the largest neuronal population in the mature mammalian brain. In chick, the peak of EGL proliferation occurs towards the end of the second week of gestation. In order to target genetic modification to this layer at the peak of proliferation, we have developed a method for genetic manipulation through ex vivo electroporation of cerebellum slices from embryonic Day 14 chick embryos. This method recapitulates several important aspects of in vivo granule neuron development and will be useful in generating a thorough understanding of cerebellar granule cell proliferation and differentiation, and thus of cerebellum development, evolution and disease.

Ex Vivo Culture of Chick Cerebellar Slices and Spatially Targeted Electroporation of Granule Cell Precursors

The cerebellar external granule layer is the site of the largest transit amplification in the developing brain. Here, we present a protocol to target genetic modification to this layer at the peak of proliferation using ex vivo electroporation and culture of cerebellar slices from embryonic Day 14 chick embryos.

The cerebellar external granule layer (EGL) is the site of the largest transit amplification in the developing brain, and an excellent model for studying ...

Loss- and Gain-of-function Approach to Investigate Early Cell Fate Determinants in Preimplantation Mouse Embryos

Gene silencing and overexpression techniques are instrumental for the identification of genes involved in embryonic development. Direct target gene modification in preimplantation embryos provides a means to study the underlying mechanisms of genes implicated in, for instance, cellular differentiation into the trophectoderm (TE) and the inner cell mass (ICM). Here, we describe a protocol that examines the role of neogenin as an authentic receptor for initial cell fate determination in preimplantation mouse embryos. First, we discuss the experimental manipulations that were used to produce gain and loss of neogenin function by microinjecting neogenin cDNA and shRNA; the effectiveness of this approach was confirmed by a strong correlation between the pair-wise expression levels of either red fluorescent protein (RFP) or green fluorescent protein (GFP) and the immunocytochemical quantification of neogenin expression. Secondly, overexpression of neogenin in preimplantation mouse embryos leads to normal ICM development while neogenin knockdown causes the ICM to develop abnormally, implying that neogenin could be a receptor that relays extracellular cues to drive blastomeres to early cell fates. Given the success of this detailed protocol in investigating the function of a novel embryonic developmental stage-specific receptor, we propose that it has the potential to aid in exploration and identification of other stage-specific genes during embryogenesis.

The goal of this protocol is to describe a loss- and gain-of function method that is applicable to identify neogenin as a stage-specific receptor that leads to trophectoderm and inner cell mass differentiation in preimplantation mouse embryos.

 Gene silencing and overexpression techniques are instrumental for the identification of genes involved in embryonic development. Direct target gene ...

Gene Transfer into the Chicken Auditory Organ by In Ovo Micro-electroporation

Chicken embryos are ideal model systems for studying embryonic development as manipulations of gene function can be conducted with relative ease in ovo. The inner ear auditory sensory organ is critical for our ability to hear. It houses a highly specialized sensory epithelium that consists of mechano-transducing hair cells (HCs) and surrounding glial-like supporting cells (SCs). Despite structural differences in the auditory organs, molecular mechanisms regulating the development of the auditory organ are evolutionarily conserved between mammals and aves. In ovo electroporation is largely limited to early stages at E1 - E3. Due to the relative late development of the auditory organ at E5, manipulations of the auditory organ by in ovo electroporation past E3 are difficult due to the advanced development of the chicken embryo at later stages. The method presented here is a transient gene transfer method for targeting genes of interest at stage E4 - E4.5 in the developing chicken auditory sensory organ via in ovo micro-electroporation. This method is applicable for gain- and loss-of-functions with conventional plasmid DNA-based expression vectors and can be combined with in ovo cell proliferation assay by adding EdU (5-ethynyl-2&#180;-deoxyuridine) to the whole embryo at the time of electroporation. The use of green or red fluorescent protein (GFP or RFP) expression plasmids allows the experimenter to quickly determine whether the electroporation successfully targeted the auditory portion of the developing inner ear. In this method paper, representative examples of GFP electroporated specimens are illustrated; embryos were harvested 18 - 96 hr&#160;after electroporation and targeting of GFP to the pro-sensory area of the auditory organ was confirmed by RNA in situ hybridization. The method paper also provides an optimized protocol for the use of the thymidine analog EdU to analyze cell proliferation; an example of an EdU based cell proliferation assay that combines immuno-labeling and click EdU chemistry is provided.

Gene Transfer into the Chicken Auditory Organ by In Ovo Micro-electroporation

The auditory organ mediates hearing. Here we present a modified in ovo micro-electroporation method optimized for studying auditory progenitor cell proliferation and differentiation in the developing chicken auditory organ.

Chicken embryos are ideal model systems for studying embryonic development as manipulations of gene function can be conducted with relative ease in ovo. ...

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 ...

Directed Differentiation of Primitive and Definitive Hematopoietic Progenitors from Human Pluripotent Stem Cells

One of the major goals for regenerative medicine is the generation and maintenance of hematopoietic stem cells (HSCs) derived from human pluripotent stem cells (hPSCs). Until recently, efforts to differentiate hPSCs into HSCs have predominantly generated hematopoietic progenitors that lack HSC potential, and instead resemble yolk sac hematopoiesis.&#160;These resulting hematopoietic progenitors may have limited utility for in vitro disease modeling of various adult hematopoietic disorders, particularly those of the lymphoid lineages. However, we have recently described methods to generate erythro-myelo-lymphoid multilineage definitive hematopoietic progenitors from hPSCs using a stage-specific directed differentiation protocol, which we outline here. Through enzymatic dissociation of hPSCs on basement membrane matrix-coated plasticware, embryoid bodies (EBs) are formed. EBs are differentiated to mesoderm by recombinant BMP4, which is subsequently specified to the definitive hematopoietic program by the GSK3&#946; inhibitor, CHIR99021. Alternatively, primitive hematopoiesis is specified by the PORCN inhibitor, IWP2. Hematopoiesis is further driven through the addition of recombinant VEGF and supportive hematopoietic cytokines. The resulting hematopoietic progenitors generated using this method have the potential to be used for disease and developmental modeling, in vitro.

Here, we present human pluripotent stem cell (hPSC) culture protocols, used to differentiate hPSCs into CD34+ hematopoietic progenitors. This method uses stage-specific manipulation of canonical WNT signaling to specify cells exclusively to either the definitive or primitive hematopoietic program.

One of the major goals for regenerative medicine is the generation and maintenance of hematopoietic stem cells (HSCs) derived from human pluripotent stem ...

Cell Lineage Analyses and Gene Function Studies Using Twin-spot MARCM

Mosaic analysis with a repressible cell marker (MARCM) is a positive mosaic labeling system that has been widely applied in Drosophila neurobiological studies to depict intricate morphologies and to manipulate the function of genes in subsets of neurons within otherwise unmarked and unperturbed organisms. Genetic mosaics generated in the MARCM system are mediated through site-specific recombination between homologous chromosomes within dividing precursor cells to produce both marked (MARCM clones) and unmarked daughter cells during mitosis. An extension of the MARCM method, called twin-spot MARCM (tsMARCM), labels both of the twin cells derived from a common progenitor with two distinct colors. This technique was developed to enable the retrieval of useful information from both hemi-lineages. By comprehensively analyzing different pairs of tsMARCM clones, the tsMARCM system permits high-resolution neural lineage mapping to reveal the exact birth-order of the labeled neurons produced from common progenitor cells. Furthermore, the tsMARCM system also extends gene function studies by permitting the phenotypic analysis of identical neurons of different animals. Here, we describe how to apply the tsMARCM system to facilitate studies of neural development in Drosophila.

Here, we present a protocol for a mosaic labeling technique that permits the visualization of neurons derived from a common progenitor cell in two distinct colors. This facilitates neural lineage analysis with the capability of birth-dating individual neurons and studying gene function in the same neurons of different individuals.

Mosaic analysis with a repressible cell marker (MARCM) is a positive mosaic labeling system that has been widely applied in Drosophila neurobiological ...

Structure-function Studies in Mouse Embryonic Stem Cells Using Recombinase-mediated Cassette Exchange

Gene engineering in mouse embryos or embryonic stem cells (mESCs) allows for the study of the function of a given protein. Proteins are the workhorses of the cell and often consist of multiple functional domains, which can be influenced by posttranslational modifications. The depletion of the entire protein in conditional or constitutive knock-out (KO) mice does not take into account this functional diversity and regulation. An mESC line and a derived mouse model, in which a docking site for FLPe recombination-mediated cassette exchange (RMCE) was inserted within the ROSA26 (R26) locus, was previously reported. Here, we report on a structure-function approach that allows for molecular dissection of the different functionalities of a multidomain protein. To this end, RMCE-compatible mice must be crossed with KO mice and then RMCE-compatible KO mESCs must be isolated. Next, a panel of putative rescue constructs can be introduced into the R26 locus via RMCE targeting. The candidate rescue cDNAs can be easily inserted between RMCE sites of the targeting vector using recombination cloning. Next, KO mESCs are transfected with the targeting vector in combination with an FLPe recombinase expression plasmid. RMCE reactivates the promoter-less neomycin-resistance gene in the ROSA26 docking sites and allows for the selection of the correct targeting event. In this way, high targeting efficiencies close to 100% are obtained, allowing for insertion of multiple putative rescue constructs in a semi-high throughput manner. Finally, a multitude of R26-driven rescue constructs can be tested for their ability to rescue the phenotype that was observed in parental KO mESCs. We present a proof-of-principle structure-function study in p120 catenin (p120ctn) KO mESCs using endoderm differentiation in embryoid bodies (EBs) as the phenotypic readout. This approach enables the identification of important domains, putative downstream pathways, and disease-relevant point mutations that underlie KO phenotypes for a given protein.

Proteins often contain multiple domains that can exert different cellular functions. Gene knock-outs (KO) do not consider this functional diversity. Here, we report a recombination-mediated cassette exchange (RMCE)-based structure-function approach in KO embryonic stem cells that allows for the molecular dissection of various functional domains or variants of a protein.

Gene engineering in mouse embryos or embryonic stem cells (mESCs) allows for the study of the function of a given protein. Proteins are the workhorses of ...

Identification of Skeletal Muscle Satellite Cells by Immunofluorescence with Pax7 and Laminin Antibodies

Immunofluorescence is an effective method that helps to identify different cell types on tissue sections. In order to study the desired cell population, antibodies for specific cell markers are applied on tissue sections. In adult skeletal muscle, satellite cells (SCs) are stem cells that contribute to muscle repair and regeneration. Therefore, it is important to visualize and trace the satellite cell population under different physiological conditions. In resting skeletal muscle, SCs reside between the basal lamina and myofiber plasma membrane. A commonly used marker for identifying SCs on the myofibers or in cell culture is the paired box protein Pax7. In this article, an optimized Pax7 immunofluorescence protocol on skeletal muscle sections is presented that minimizes non-specific staining and background. Another antibody that recognizes a protein (laminin) of the basal lamina was also added to help identify SCs. Similar protocols can also be used to perform double or triple labeling with Pax7 and antibodies for additional proteins of interest.

The precise identification of satellite cells is essential for studying their functions under various physiological and pathological conditions. This article presents a protocol to identify satellite cells on adult skeletal muscle sections by immunofluorescence-based staining.

Immunofluorescence is an effective method that helps to identify different cell types on tissue sections. In order to study the desired cell population, ...

Visualizing the Node and Notochordal Plate In Gastrulating Mouse Embryos Using Scanning Electron Microscopy and Whole Mount Immunofluorescence

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is the formation of the transient organizers, the node and notochordal plate, from cells that have passed through the primitive streak. The proper formation of these signaling centers is essential for the development of the body plan and techniques to visualize them are of high interest to mouse developmental biologists. The node and notochordal plate lie on the ventral surface of gastrulating mouse embryos around embryonic day (E) 7.5 of development. The node is a cup-shaped structure whose cells possess a single slender cilium each. The proper subcellular localization and rotation of the cilia in the node pit determines left-right asymmetry. The notochordal plate cells also possess single cilia albeit shorter than those of the node cells. The notochordal plate forms the notochord which acts as an important signaling organizer for somitogenesis and neural patterning. Because the cells of the node and notochordal plate are transiently present on the surface and possess cilia, they can be visualized using scanning electron microscopy (SEM). Among other techniques used to visualize these structures at the cellular level is whole mount immunofluorescence (WMIF) using the antibodies against the proteins that are highly expressed in the node and notochordal plate. In this report, we describe our optimized protocols to perform SEM and WMIF of the node and notochordal plate in developing mouse embryos to help in the assessment of tissue shape and cellular organization in wild-type and gastrulation mutant embryos.

The node and notochordal plate are transient signaling organizers in developing mouse embryos that can be visualized using several techniques. Here, we describe in detail how to perform two of the techniques to study their structure and morphogenesis: 1) scanning electron microscopy (SEM); and 2) whole mount immunofluorescence (WMIF).

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is ...