Name: a pipeline using bilateral in utero electroporation to interrogate genetic influences on rodent behavior
Uploaded: 2020-05-21T14:45:00
Description: Watch this Scientific Journal Video about A Pipeline using Bilateral In Utero Electroporation to Interrogate Genetic Influences on Rodent Behavior at JoVE.com

We thank Lisa Kretsge for critical feedback and editing to the manuscript. We thank all research assistants in the Cruz-Mart&#237;n lab who were invaluable in helping with perfusions and cell counting of behavior brains. We thank Andrzej Cwetsch for input on the design of the tripolar electrode, and Todd Blute and the Boston University Biology Imaging Core for use of the confocal microscope. This work was supported by a NARSAD Young Investigator Grant (AC-M, #27202), the Brenton R. Lutz Award (ALC), the I. Alden Macchi Award (ALC), the NSF NRT UtB: Neurophotonics National Research Fellowship (ALC, #DGE1633516), and the Boston University Undergraduate Research Opportunities Program (WWY). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

All experimental protocols were conducted according to the National Institutes of Health (NIH) guidelines for animal research and were approved by the Boston University Institutional Animal Care and Use Committee (IACUC).
1. DNA solution preparation
<ol>
	<li>Purchase a commercial plasmid or subclone a gene of interest into plasmid with desired promoter. Here, a plasmid containing EGFP under the CAG promoter (pCAG-EGFP) was used. 
	NOTE: Determine the desired promoter based off the leve...

<ol>
	<li>Yang, Y., 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=Genetic+association+and+meta-analysis+of+a+schizophrenia+GWAS+variant+rs10489202+in+East+Asian+populations.">Genetic association and meta-analysis of a schizophrenia GWAS variant rs10489202 in East Asian populations.</a> Translational Psychiatry. 8 (1), 144 (2018).</li><li>Schizophrenia Working Group of the Psychiatric Genomics Consortium. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biological+insights+from+108+schizophrenia-associated+genetic+loci.">Biological insights from 108 schizophrenia-associated genetic loci.</a> Nature. 511 (7510), 421-427 (2014).</li><li>Howard, D. M., 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-wide+meta-analysis+of+depression+identifies+102+independent+variants+and+highlights+the+importance+of+the+prefrontal+brain+regions.">Genome-wide meta-analysis of depression identifies 102 independent variants and highlights the importance of the prefrontal brain regions.</a> Nature Neuroscience. 22 (3), 343-352 (2019).</li><li>Grove, 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=Identification+of+common+genetic+risk+variants+for+autism+spectrum+disorder.">Identification of common genetic risk variants for autism spectrum disorder.</a> Nature Genetics. 51 (3), 431-444 (2019).</li><li>Comer, A. 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=Increased+expression+of+schizophrenia-associated+gene+C4+leads+to+hypoconnectivity+of+prefrontal+cortex+and+reduced+social+interaction.">Increased expression of schizophrenia-associated gene C4 leads to hypoconnectivity of prefrontal cortex and reduced social interaction.</a> PLoS Biology. 18 (1), 3000604 (2020).</li><li>Chini, M., 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=Resolving+and+Rescuing+Developmental+Miswiring+in+a+Mouse+Model+of+Cognitive+Impairment.">Resolving and Rescuing Developmental Miswiring in a Mouse Model of Cognitive Impairment.</a> Neuron. 105 (1), 60-74 (2020).</li><li>Clifton, N. E., 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=Dynamic+expression+of+genes+associated+with+schizophrenia+and+bipolar+disorder+across+development.">Dynamic expression of genes associated with schizophrenia and bipolar disorder across development.</a> Translational Psychiatry. 9 (1), 74 (2019).</li><li>Oberlander, V. C., Xu, X., Chini, M., Hanganu-Opatz, I. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Developmental+dysfunction+of+prefrontal-hippocampal+networks+in+mouse+models+of+mental+illness.">Developmental dysfunction of prefrontal-hippocampal networks in mouse models of mental illness.</a> European Journal of Neurosciences. 50 (6), 3072-3084 (2019).</li><li>Batista-Brito, 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=Developmental+Dysfunction+of+VIP+Interneurons+Impairs+Cortical+Circuits.">Developmental Dysfunction of VIP Interneurons Impairs Cortical Circuits.</a> Neuron. 95 (4), 884-895 (2017).</li><li>Luo, L., Callaway, E. M., Svoboda, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+Dissection+of+Neural+Circuits:+A+Decade+of+Progress.">Genetic Dissection of Neural Circuits: A Decade of Progress.</a> Neuron. 98 (2), 256-281 (2018).</li><li>DeNardo, L., Luo, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+strategies+to+access+activated+neurons.">Genetic strategies to access activated neurons.</a> Current Opinion in Neurobiology. 45, 121-129 (2017).</li><li>Huang, Z. J., Zeng, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+approaches+to+neural+circuits+in+the+mouse.">Genetic approaches to neural circuits in the mouse.</a> Annual Reviews in Neurosciences. 36, 183-215 (2013).</li><li>Wu, Z., Yang, H., Colosi, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+genome+size+on+AAV+vector+packaging.">Effect of genome size on AAV vector packaging.</a> Molecular Therapy. 18 (1), 80-86 (2010).</li><li>Callaway, E. M., Luo, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monosynaptic+Circuit+Tracing+with+Glycoprotein-Deleted+Rabies+Viruses.">Monosynaptic Circuit Tracing with Glycoprotein-Deleted Rabies Viruses.</a> Journal of Neurosciences. 35 (24), 8979-8985 (2015).</li><li>Cruz-Mart&#237;n, 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=A+dedicated+circuit+links+direction-selective+retinal+ganglion+cells+to+the+primary+visual+cortex.">A dedicated circuit links direction-selective retinal ganglion cells to the primary visual cortex.</a> Nature. 507 (7492), 358-361 (2014).</li><li>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=In+vivo+electroporation+in+the+embryonic+mouse+central+nervous+system.">In vivo electroporation in the embryonic mouse central nervous system.</a> Nature Protocols. 1 (3), 1552-1558 (2006).</li><li>Cruz-Mart&#237;n, A., Crespo, M., Portera-Cailliau, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Delayed+stabilization+of+dendritic+spines+in+fragile+X+mice.">Delayed stabilization of dendritic spines in fragile X mice.</a> Journal of Neurosciences. 30 (23), 7793-7803 (2010).</li><li>Zhang, J. H., Adikaram, P., Pandey, M., Genis, A., Simonds, W. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+genome+editing+through+CRISPR-Cas9+engineering.">Optimization of genome editing through CRISPR-Cas9 engineering.</a> Bioengineered. 7 (3), 166-174 (2016).</li><li>Strecker, 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=RNA-guided+DNA+insertion+with+CRISPR-associated+transposases.">RNA-guided DNA insertion with CRISPR-associated transposases.</a> Science. 365 (6448), 48-53 (2019).</li><li>Cruz-Mart&#237;n, A., Crespo, M., Portera-Cailliau, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glutamate+induces+the+elongation+of+early+dendritic+protrusions+via+mGluRs+in+wild+type+mice,+but+not+in+fragile+X+mice.">Glutamate induces the elongation of early dendritic protrusions via mGluRs in wild type mice, but not in fragile X mice.</a> PLoS One. 7 (2), 32446 (2012).</li><li>LoTurco, J., Manent, J. B., Sidiqi, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+and+improved+tools+for+in+utero+electroporation+studies+of+developing+cerebral+cortex.">New and improved tools for in utero electroporation studies of developing cerebral cortex.</a> Cerebral Cortex. 19, 120-125 (2009).</li><li>Kolk, S. M., de Mooij-Malsen, A. J., Martens, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatiotemporal+Molecular+Approach+of+in+utero+Electroporation+to+Functionally+Decipher+Endophenotypes+in+Neurodevelopmental+Disorders.">Spatiotemporal Molecular Approach of in utero Electroporation to Functionally Decipher Endophenotypes in Neurodevelopmental Disorders.</a> Frontiers in Molecular Neurosciences. 4, 37 (2011).</li><li>Szczurkowska, 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=Targeted+in+vivo+genetic+manipulation+of+the+mouse+or+rat+brain+by+in+utero+electroporation+with+a+triple-electrode+probe.">Targeted in vivo genetic manipulation of the mouse or rat brain by in utero electroporation with a triple-electrode probe.</a> Nature Protocols. 11 (3), 399-412 (2016).</li><li>dal Maschio, M., 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=High-performance+and+site-directed+in+utero+electroporation+by+a+triple-electrode+probe.">High-performance and site-directed in utero electroporation by a triple-electrode probe.</a> Nature Communications. 3, 960 (2012).</li><li>Zhan, Y., 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=Deficient+neuron-microglia+signaling+results+in+impaired+functional+brain+connectivity+and+social+behavior.">Deficient neuron-microglia signaling results in impaired functional brain connectivity and social behavior.</a> Nature Neurosciences. 17 (3), 400-406 (2014).</li><li>Mathis, 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=DeepLabCut:+markerless+pose+estimation+of+user-defined+body+parts+with+deep+learning.">DeepLabCut: markerless pose estimation of user-defined body parts with deep learning.</a> Nature Neurosciences. 21 (9), 1281-1289 (2018).</li><li>Bullmann, T., Arendt, T., Frey, U., Hanashima, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+transportable,+inexpensive+electroporator+for+in+utero+electroporation.">A transportable, inexpensive electroporator for in utero electroporation.</a> Development Growth and Differentiation. 57 (5), 369-377 (2015).</li><li>Li, Z., 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-wide+association+analysis+identifies+30+new+susceptibility+loci+for+schizophrenia.">Genome-wide association analysis identifies 30 new susceptibility loci for schizophrenia.</a> Nature Genetics. 49 (11), 1576-1583 (2017).</li><li>Ripke, 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=Genome-wide+association+analysis+identifies+13+new+risk+loci+for+schizophrenia.">Genome-wide association analysis identifies 13 new risk loci for schizophrenia.</a> Nature Genetics. 45 (10), 1150-1159 (2013).</li><li>De Marco Garcia, N. V., Fishell, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subtype-selective+electroporation+of+cortical+interneurons.">Subtype-selective electroporation of cortical interneurons.</a> Journal of Visualized Experiment. (90), e51518 (2014).</li><li>Borrell, V., Yoshimura, Y., Callaway, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeted+gene+delivery+to+telencephalic+inhibitory+neurons+by+directional+in+utero+electroporation.">Targeted gene delivery to telencephalic inhibitory neurons by directional in utero electroporation.</a> Journal of Neuroscience Methods. 143 (2), 151-158 (2005).</li><li>Soma, M., 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=Development+of+the+mouse+amygdala+as+revealed+by+enhanced+green+fluorescent+protein+gene+transfer+by+means+of+in+utero+electroporation.">Development of the mouse amygdala as revealed by enhanced green fluorescent protein gene transfer by means of in utero electroporation.</a> Journal of Comparative Neurology. 513 (1), 113-128 (2009).</li></ol>

Herein, a pipeline is described that combines the manipulation of novel genes of interest in large populations of frontal cortical neurons with behavioral assays in mice. Moreover, this pipeline allows for the longitudinal study of behavior in the same mice both during early postnatal development and in adulthood. This technique bypasses the need to rely on genetic animal models that can be costly in terms of time and expenses. The strength of this protocol is that it can be used to study neurodevelopmental and neuropsyc...

Genome-wide association studies (GWAS) have driven the discovery of novel candidate genes that are associated with brain pathologies1,2,3,4. These studies have been particularly beneficial in understanding devastating neuropsychiatric disorders such as schizophrenia (SCZ), where the investigation of novel genes has served as a launching point for new lines of research and therapeutic intervention5,6. Genes harboring risk for SCZ show biased expression in the prefrontal cortex (PFC) during prenatal and early postnatal development, a region implicated in the pathology of several neuropsychiatric disorders7. Additionally, mouse models of psychiatric disorders exhibit abnormal activity in PFC networks6,8,9. These results suggest that SZC-associated genes might play a role in the developmental wiring of this region. Further investigation using animal models is required to understand the contribution of these candidate genes to the establishment of connections in the PFC and to determine whether these genes have a causative role in the pathogenesis of neuropsychiatric disorders. Genetic manipulation techniques in mice that allow for the study of gene expression changes on specific neuronal circuits during prenatal and early postnatal development are a promising method to understand the molecular mechanisms that link gene expression changes to PFC dysfunction.
Genetic mouse lines offer a method to study the impact of particular genes on brain development and function. However, relying on transgenic mice can be limiting since there are not always commercially available lines to examine the effects of specific genes on developing neural circuits. Moreover, it can be extremely costly and time consuming to develop custom mouse lines. The use of intersectional genetic manipulation strategies that combine transgenic mice with viral approaches has revolutionized the understanding of the brain10,11,12. Despite much progress, viral strategies come with certain limitations depending on the viral vector type, including limits in packaging capacity that can restrict viral expression13 and cell toxicity associated with viral expression14. Furthermore, in most experimental conditions, robust gene expression using adeno-associated virus (AAVs) requires approximately 2 to 4 weeks15, making routine viral strategies unfeasible to manipulate genes during early postnatal development.
In utero electroporation (IUE) is an alternative approach that allows for a rapid and inexpensive gene transfer16,17 that, when coupled with fluorescent labeling and pharmacogenetic or optogenetic approaches, provides a powerful platform to dissect the function of neuronal circuits. Additionally, with the development of CRISPR-Cas9 genome editing genes can be overexpressed or precisely altered through cell-type specific knock-down or knock-out of specific genes or through the modulation of promoters18,19. Gene manipulation approaches using IUE are especially advantageous when the effect of genes on neuronal circuits need to be tested during narrow developmental windows20. IUE is a versatile technique and overexpression can be easily accomplished by inserting a gene into an expression vector under a specific promoter. Additional control of gene expression can be achieved by driving expression using promoters of different strengths or using inducible promoters capable of temporally controlling gene expression21,22. Additionally, IUE allows for the targeting of cells within specific cortical layers, cell types and brain regions, which isn&#8217;t always feasible using other approaches5,17. Recent advances in the IUE configuration based on the use of three electrodes, which generates a more efficient electric-field distribution, have expanded the functional repertoire of this method and allowed scientists to target new cell types and increase the efficiency, accuracy, and number of cells that can be targeted23,24. This technique was recently used to determine the causative role of complement component 4A (C4A), a gene linked to SCZ, in PFC function and early cognition5.
Presented here is an experimental pipeline that combines gene transfer approaches to target large populations of excitatory neurons in the frontal cortex, including the PFC, with behavioral paradigms that not only enables the study of cell and circuit-level changes, but also allows behavior to be monitored throughout early postnatal development and adulthood. First described is a method to bilaterally transfect large populations of layer (L) 2/3 pyramidal neurons in frontal cortical regions. Next, tasks to assay social behavior in juvenile and adult mice are outlined. Cell counts can be obtained upon the completion of behavioral tasks to quantify the extent and location of cell transfection. Furthermore, the number of cells transfected can be correlated with behavioral data to determine if a greater number of transfected cells leads to greater perturbations in behavior.

<table border="0" cellpadding="0" cellspacing="0" style="width:664px;" width="663">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">13mm Silk Black Braided Suture</td>
			<td style="width:121px;">Havel&#39;s</td>
			<td style="width:161px;">SB77D</td>
			<td style="width:167px;">Suture skin</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Adson Forceps</td>
			<td style="width:121px;">F.S.T.</td>
			<td style="width:161px;">11006-12</td>
			<td>IUE</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">C270 Webcam</td>
			<td style="width:121px;">Logitech</td>
			<td style="width:161px;">N/A</td>
			<td>Record behavior</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Electroporator</td>
			<td style="width:121px;">Custom-built</td>
			<td style="width:161px;">N/A</td>
			<td>See Figure 1 and 2 and Bullmann et al, 2015</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">EZ-500 Spin Column Plasmid DNA Maxi-preps Kit, 20preps</td>
			<td>Bio Basic Inc.</td>
			<td style="width:161px;">BS466</td>
			<td>Pladmid preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Fast Green FCF</td>
			<td style="width:121px;">Sigma</td>
			<td>F7252-5G</td>
			<td>Dye for DNA solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Fine scissors- sharp</td>
			<td style="width:121px;">F.S.T.</td>
			<td style="width:161px;">14060-09</td>
			<td>IUE</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fisherbrand Gauze Sponges</td>
			<td>Fisher Scientific</td>
			<td>1376152</td>
			<td>IUE</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Gaymar Heating/Cooling</td>
			<td style="width:121px;">Braintree</td>
			<td style="width:161px;">TP-700</td>
			<td style="width:167px;">Heating Pad</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Glass pipette puller</td>
			<td>Sutter Instrument,</td>
			<td style="width:161px;">P-97</td>
			<td>IUE</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Glass pipettes</td>
			<td>Sutter Instrument,</td>
			<td>BF150-117-10</td>
			<td>IUE</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Hair Removal Lotion</td>
			<td style="width:121px;">Nair</td>
			<td style="width:161px;">N/A</td>
			<td>Hair removal</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hartman Hemostats</td>
			<td style="width:121px;">F.S.T.</td>
			<td style="width:161px;">13002-10</td>
			<td>IUE</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Open field maze- homemade acrylic arena</td>
			<td style="width:121px;">Custom-built</td>
			<td style="width:161px;">N/A</td>
			<td>50 &#215; 50 &#215; 30 cm length-width-height</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">pCAG-GFP</td>
			<td style="width:121px;">Addgene</td>
			<td>11150</td>
			<td>Mammalian expression vector for expression of GFP</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Picospritzer III</td>
			<td>Parker Hannifin</td>
			<td style="width:161px;">N/A</td>
			<td>pressure injector</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Retractor - 2 Pronged Blunt</td>
			<td style="width:121px;">F.S.T.</td>
			<td style="width:161px;">17023-13</td>
			<td>IUE</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Ring forceps</td>
			<td style="width:121px;">F.S.T.</td>
			<td style="width:161px;">11103-09</td>
			<td>IUE</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Sterilizer, dry bead</td>
			<td style="width:121px;">Sigma</td>
			<td>Z378569</td>
			<td>sterelize surgical tools</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">SUTURE, 3/0 PGA, FS-2, VIOLET FOR VET USE ONLY</td>
			<td>Havel&#39;s</td>
			<td>HJ398</td>
			<td>Suture muscle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Water bath</td>
			<td style="width:121px;">Cole-Parmer</td>
			<td>EW-12105-84</td>
			<td style="width:167px;">warming sterile saline</td>
		</tr>
	</tbody>
</table>

a pipeline using bilateral in utero electroporation to interrogate genetic influences on rodent behavior

As genome-wide association studies shed light on the heterogeneous genetic underpinnings of many neurological diseases, the need to study the contribution of specific genes to brain development and function increases. Relying on mouse models to study the role of specific genetic manipulations is not always feasible since transgenic mouse lines are quite costly and many novel disease-associated genes do not yet have commercially available genetic lines. Additionally, it can take years of development and validation to create a mouse line. In utero electroporation offers a relatively quick and easy method to manipulate gene expression in a cell-type specific manner in vivo that only requires developing a DNA plasmid to achieve a particular genetic manipulation. Bilateral in utero electroporation can be used to target large populations of frontal cortex pyramidal neurons. Combining this gene transfer method with behavioral approaches allows one to study the effects of genetic manipulations on the function of prefrontal cortex networks and the social behavior of juvenile and adult mice.

Successful development and implementation of a custom-built electroporator and three prong- electrode. 
For IUEs, an inexpensive custom-built electroporator was built based on a previously described design27 (Figure 1A and Figure 2). A three prong electrode was made23,24 using plastic forceps with 2 negative electrodes attached to the tips of the prongs and t...

Watch this Scientific Journal Video about A Pipeline using Bilateral In Utero Electroporation to Interrogate Genetic Influences on Rodent Behavior at JoVE.com

A Pipeline using Bilateral In Utero Electroporation to Interrogate Genetic Influences on Rodent Behavior

The role of recently discovered disease-associated genes in the pathogenesis of neuropsychiatric disorders remains obscure. A modified bilateral in utero electroporation technique allows for the gene transfer in large populations of neurons and examination of the causative effects of gene expression changes on social behavior.

As genome-wide association studies shed light on the heterogeneous genetic underpinnings of many neurological diseases, the need to study the contribution ...

Using this method can allow for the discovery of how certain gene expression changes can attribute to pathologies associated with neurological diseases. The advantage of this technique is that it bypasses the need to create or purchase genetic animal lines which can take years to create and validate. This technique allows for the study of genes implicated in neurological disorders.Determining how specific genes contribute to pathology is an important step in developing novel therapies. The advantage of this protocol is learning to manipulate the embryos so that the experimenter accomplishes the gene transfer step without decreasing the survival rates. Visual demonstration of this method is important because the embryos are very fragile so it is helpful to observe how an experienced experimenter manipulates them during the procedure.Bring pregnant dams to the surgery area at least 30 minutes prior to the surgery. Sterilize the entire surgery site using sterilized germicidal wipes and then 70%ethanol. Then sterilize autoclave tools in a glass bead sterilizer.Transfer sterile PBS to 50 milliliter conical tubes and place the tubes in a water bath heated to 38 to 40 degrees Celsius. Check the sterile saline temperature with a thermometer. Turn on the water heating circulation pump so that it is warmed to 37 degrees Celsius.Then turn on the pressure injector and electroporator and ensure proper function. Briefly spin the plasma DNA solution on a tabletop centrifuge and place it on ice. Pull glass pipettes on a pipette puller so that the tip of the pulled glass pipette is about 50 micrometers in diameter.Then fill the pipette with 20 to 40 microliters of DNA solution. Set up all necessary items for surgery including hair removing lotion, iodine, 70%ethanol, cotton swabs, eye drops, sutures, and gauze. Prepare a surgery sheet and fill out the necessary information.Weigh the mouse prior to surgery and record the weight. After anesthetizing the mouse, administer preoperative analgesics and remove the fur from the abdomen using hair removal cream or a razor. Sterilize the abdomen by swabbing it with povidone iodine and 70%ethanol three times.Create a sterile field around the abdomen with sterile gauze and draping. Make a midline incision in the abdominal skin while lifting the skin up with forceps to avoid cutting through the muscle. Then lift the muscle up and cut through it taking care to avoid cutting vital organs.Carefully pull the uterine horns out of the dam using ringed forceps and place them gently onto the sterile field making sure that they are supported with padding and aren't tugging too far away from the dam. Keep the uterine horn moistened throughout the rest of the surgery with the prewarmed sterile PBS. Position an embryo with either forceps or fingers, then carefully insert the pulled glass pipette into the lateral vertical and inject two to three microliters into each ventricle by inserting the pipette into one and then the other ventricle.The ventricle has been successfully targeted if a crescent shape is present after injection. To transfect cells bilaterally in the frontal cortex, position the two negative electrodes on the sides of the embryo's head just lateral and slightly caudal to the lateral ventricles and position the positive electrode between the eyes just in front of the developing snout. Ensure the embryo is generously moistened and apply four square pulses.Inject and electroporate all embryos, going one by one so that each embryo is electroporated immediately after the DNA solution injection. Once all embryos have been electroporated, carefully insert the uterine horns back into the abdominal cavity. Coat the abdominal cavity in sterile PBS to aid uterine horn placement.Fill the abdominal cavity with sterile PBS so that no air pockets remain after suturing is complete. Suture the muscle with absorbable sutures and the skin with silk non-absorbable sutures. Allow the dam to fully recover in a heated chamber for at least one hour.Check on the dams regularly in the next 48 hours. As the dam recovers from the anesthesia and regains consciousness, it will start moving and whisking. This method was used to transfect approximately 5, 000 layer 2/3 pyramidal neurons with the pCAG-GFP plasmid.Most of these cells were localized to the frontal cortical regions. A representative example shows the rostral caudal distribution of transfected neurons in an adult control mouse, confirming the ability of bilateral IUEs to target and genetically label large populations of pyramidal neurons in the frontal cortex. The first part of the maternal interaction task tests the ability of control P18 transfected mice to find nest bedding.Control mice spent more time exploring their nest bedding than exploring fresh bedding, suggesting that they have intact sensory motor abilities and exploratory behavior. The second part of the task takes advantage of the tendency of mice to be motivated to interact with their mother. In this task, pups spent most of their time near their mother while spending significantly less time exploring the empty cup or nest bedding.Adult control mice spent approximately 35%of the time exploring a novel object. When presented with a novel and a familiar object, adult mice spent more time exploring the novel object. In the sociability task, control adult mice spent similar amounts of time exploring a novel mouse and an empty cup.This behavior was automatically tracked with DeepLabCut software by labeling various points on a mouse, including the limbs, centroid, head, and ears. The software was also used to determine when mice were rearing by examining the length of the mouse's body since this distance becomes shorter when the mouse rears. Following this procedure, many cellular molecular questions can be answered by examining the tissue and assaying different measures such as spine density or expression levels of various proteins.

a-pipeline-using-bilateral-utero-electroporation-to-interrogate

Research

JoVE Journal

Biology

In Utero Intraventricular Injection and Electroporation of E16 Rat Embryos

In-utero in-vivo injection and electroporation of the embryonic rat neocortex provides a powerful tool for the manipulation of individual progenitors lining the walls of the lateral ventricle. This technique is now widely used to study the processes involved in corticogenesis by over-expressing or knocking down genes and observing the effects on cellular proliferation, migration, and differentiation. In comparison to traditional knockout strategies, in-utero electroporation provides a rapid means to manipulate a population of cells during a specific temporal window. In this video protocol, we outline the experimental methodology for preparing rats for surgery, exposing the uterine horns through laporatomy, injecting DNA into the lateral ventricles of the developing embryo, electroporating DNA into the progenitors lining the lateral wall, and caring for animals post-surgery. Our laboratory uses this protocol for surgeries on E15-E21 rats, however it is most commonly performed at E16 as shown in this video.

In-utero in-vivo injection and electroporation of the embryonic rat neocortex provides a powerful tool for the manipulation of individual progenitors ...

In Utero Intraventricular Injection and Electroporation of E15 Mouse Embryos

In-utero in-vivo injection and electroporation of the embryonic mouse neocortex provides a powerful tool for the manipulation of individual progenitors lining the walls of the lateral ventricle. This technique is now widely used to study the processes involved in corticogenesis by over-expressing or knocking down genes and observing the effects on cellular proliferation, migration, and differentiation. In comparison to traditional knockout strategies, in-utero electroporation provides a rapid means to manipulate a population of cells during a specific temporal window. In this video protocol we outline the experimental methodology for preparing mice for surgery, exposing the uterine horns through laporatomy, injecting DNA into the lateral ventricles of the developing embryo, electroporating DNA into the progenitors lining the lateral wall, and caring for animals post-surgery. Our laboratory uses this protocol for surgeries on E13-E16 mice, however, it is most commonly performed at E15, as shown in this video. 

In-utero in-vivo injection and electroporation of the embryonic mouse neocortex provides a powerful tool for the manipulation of individual progenitors ...

Method for Culture of Early Chick Embryos ex vivo (New Culture)

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ideal tool for studying  the formation and patterning of brain, neural tube, somite and heart primordia. Applications of chick embryo culture include electroporation of DNA or RNA constructs in order to analyze gene function, grafts of growth factor coated beads such as FGFs and BMPs , as well as whole mount in situ hybridization and immunohistochemistry. This video demonstrates the different steps in chick embryo culture; First, the embryo is explanted in saline. Then, the embryo is centered on a glass ring. The membranes surrounding the embryo are lifted along the walls of the ring. The ring is then placed in a culture dish containing a pool of albumine. The culture dish is sealed and placed in a humid chamber, where the embryo is cultured for up to 24 hrs. Finally, the embryo is removed from the ring, fixed and processed for further applications. A troubleshooting guide is also presented.

Method for Culture of Early Chick Embryos ex vivo New Culture

This video demonstrates New culture, a method by which chick embryos are cultured outside the egg for up to 24 hr. This method enables one to study early development (primitive streak to 14 som.), a period corresponding to E7-9 in mouse. Applications of this technique include electroporation, in situ hybridization and immunohistochemistry.

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ...

Double Whole Mount in situ Hybridization of Early Chick Embryos

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ideal tool for studying  gene expression in brain, neural tube, somite and heart primordia formation. This video demonstrates the different steps in 2-color whole mount in situ hybridization; First, the embryo is dissected from the egg and fixed in paraformaldehyde. Second, the embryo is processed for prehybridization. The embryo is then hybridized with two different probes, one coupled to DIG, and one coupled to FITC.  Following overnight hybridization, the embryo is incubated with DIG coupled antibody. Color reaction for DIG substrate is performed, and the region of interest appears blue. The embryo is then incubated with FITC coupled antibody. The embryo is processed for color reaction with FITC, and the region of interest appears red. Finally, the embryo is fixed and processed for phtograph and sectioning. A troubleshooting guide is also presented.

This video demonstrates 2-color whole mount in situ hybridization, a method by which the spatial and temporal expression pattern of 2 different genes can be visualized in young chick embryos. This method was originally introduced by David Wilkinson, Domingos Henrique, Phil Ingham and David Ish -Horowicz.

Method for Whole Mount Antibody Staining in Chick

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ideal tool for studying antibody expression in developing brain, neural tube and somite. This video demonstrates the different steps in whole-mount antibody staining using HRP conjugated secondary antibodies; First, the embryo is dissected from the egg and fixed in paraformaldehyde. Second, endogenous peroxidase is inactivated; The embryo is then exposed to primary antibody. After several washes, the embryo is incubated with secondary antibody conjugated to HRP. Peroxidase activity is revealed using reaction with diaminobenzidine substrate. Finally, the embryo is fixed and processed for photography and sectioning. The advantage of this method over the use of fluorescent antibodies is that embryos can be processed for wax sectioning, thus enabling the study of antigen sites in cross section. This method was originally introduced by Jane Dodd and Tom Jessell 1.

This video demonstrates whole mount immunohistochemistry, a method by which the spatial and temporal expression pattern of an antigen can be visualized in young chick embryos. This method was originally introduced by Jane Dodd and Tom Jessell.

Assay for Neural Induction in the Chick Embryo

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ideal tool for studying the formation and initial patterning of the nervous system. This video demonstrates how to graft organizer tissue into a host, a method by which Hensen s node (the organizer in the chick embryo) is grafted to a host competent ectoderm. The organizer graft instructs overlying na ve tissue to adopt a neural fate via neural inducing signals. This mechanism is referred to as neural induction, and constitutes the initial step in the formation of brain and spinal cord in amniotes. This method is essentially used for the characterization of putative neural inducing molecules in chick. This video demonstrates the different steps in the assay for neural induction; First, the donnor embryo is explanted and pinned on a dish. Then, the host embryo is prepared for New culture. The graft is excised and transplanted to the host area pellucida margin. The host is cultured for 18-22 hrs. The assembly is fixed and processed for further applications (e.g. in situ hybridization). This method was originally devised by Waddington 1,2 and Gallera 3,4.

Neural induction is the first step in the formation of the brain. It is a mechanism by which Hensen's node (organizer), instructs adjacent tissue to adopt a neural fate, i.e. to give rise to the nervous system. This video demonstrates an assay for neural induction in chick embryo.

In utero and ex vivo Electroporation for Gene Expression in Mouse Retinal Ganglion Cells

The retina and its sole output neuron, the retinal ganglion cell (RGC), comprise an excellent model in which to examine biological questions such as cell differentiation, axon guidance, retinotopic organization and synapse formation[1]. One drawback is the inability to efficiently and reliably manipulate gene expression in RGCs in vivo, especially in the otherwise accessible murine visual pathways. Transgenic mice can be used to manipulate gene expression, but this approach is often expensive, time consuming, and can produce unwanted side effects. In chick, in ovo electroporation is used to manipulate gene expression in RGCs for examining retina and RGC development. Although similar electroporation techniques have been developed in neonatal mouse pups[2], adult rats[3], and embryonic murine retinae in vitro[4], none of these strategies allow full characterization of RGC development and axon projections in vivo. To this end, we have developed two applications of electroporation, one in utero and the other ex vivo, to specifically target embryonic murine RGCs[5, 6]. 
With in utero retinal electroporation, we can misexpress or downregulate specific genes in RGCs and follow their axon projections through the visual pathways in vivo, allowing examination of guidance decisions at intermediate targets, such as the optic chiasm, or at target regions, such as the lateral geniculate nucleus. Perturbing gene expression in a subset of RGCs in an otherwise wild-type background facilitates an understanding of gene function throughout the retinal pathway. Additionally, we have developed a companion technique for analyzing RGC axon growth in vitro. We electroporate embryonic heads ex vivo, collect and incubate the whole retina, then prepare explants from these retinae several days later. Retinal explants can be used in a variety of in vitro assays in order to examine the response of electroporated RGC axons to guidance cues or other factors. In sum, this set of techniques enhances our ability to misexpress or downregulate genes in RGCs and should greatly aid studies examining RGC development and axon projections.

In utero and ex vivo Electroporation for Gene Expression in Mouse Retinal Ganglion Cells

Here we present two techniques for manipulating gene expression in murine retinal ganglion cells (RGCs) by in utero and ex vivo electroporation. These techniques enable one to examine how alterations in gene expression affect RGC development, axon guidance, and functional properties.

The retina and its sole output neuron, the retinal ganglion cell (RGC), comprise an excellent model in which to examine biological questions such as cell ...

Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System 

Understanding the roles of human DNA repair proteins in genetic pathways is a formidable challenge to many researchers. Genetic studies in mammalian systems have been limited due to the lack of readily available tools including defined mutant genetic cell lines, regulatory expression systems, and appropriate selectable markers. To circumvent these difficulties, model genetic systems in lower eukaryotes have become an attractive choice for the study of functionally conserved DNA repair proteins and pathways. We have developed a model yeast system to study the poorly defined genetic functions of the Werner syndrome helicase-nuclease (WRN) in nucleic acid metabolism. Cellular phenotypes associated with defined genetic mutant backgrounds can be investigated to clarify the cellular and molecular functions of WRN through its catalytic activities and protein interactions. The human WRN gene and associated variants, cloned into DNA plasmids for expression in yeast, can be placed under the control of a regulatory plasmid element. The expression construct can then be transformed into the appropriate yeast mutant background, and genetic function assayed by a variety of methodologies. Using this approach, we determined that WRN, like its related RecQ family members BLM and Sgs1, operates in a Top3-dependent pathway that is likely to be important for genomic stability. This is described in our recent publication [1] at <a href="http://www.impactaging.com">www.impactaging.com</a>. Detailed methods of specific assays for genetic complementation studies in yeast are provided in this paper.

Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System

Genetic studies in yeast can be employed to investigate the molecular and cellular functions of human genes in cellular DNA metabolism. Methods are described for the genetic characterization of the human WRN gene product defective in the premature aging disorder Werner syndrome in functionally conserved pathways using yeast as a tractable model system.

Understanding the roles of human DNA repair proteins in genetic pathways is a formidable challenge to many researchers.  Genetic studies in mammalian ...

Using the Gene Pulser MXcell Electroporation System to Transfect Primary Cells with High Efficiency

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser MXcell electroporation system and Gene Pulser electroporation buffer (Bio-Rad) were specifically developed to easily transfect nucleic acids into mammalian cells and difficult-to-transfect cells, such as primary and stem cells. We will demonstrate how to perform a simple experiment to quickly identify the best electroporation conditions. We will demonstrate how to run several samples through a range of electroporation conditions so that an experiment can be conducted at the same time as optimization is performed. We will also show how optimal conditions identified using 96-well electroporation plates can be used with standard electroporation cuvettes, facilitating the switch from electroporation plates to electroporation cuvettes while maintaining the same electroporation efficiency. In the video, we will also discuss some of the key factors that can lead to the success or failure of electroporation experiments.

This procedure shows how to use the Gene Pulser MXcell electroporation system to rapidly and easily identify the best electroporation conditions for mouse embryonic fibroblasts (MEFs) or other primary cells. Considerations for troubleshooting are also discussed in the associated video.

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser ...

Monitoring Endoplasmic Reticulum Calcium Homeostasis Using a Gaussia Luciferase SERCaMP

The endoplasmic reticulum (ER) contains the highest level of intracellular calcium, with concentrations approximately 5,000-fold greater than cytoplasmic levels. Tight control over ER calcium is imperative for protein folding, modification and trafficking. Perturbations to ER calcium can result in the activation of the unfolded protein response, a three-prong ER stress response mechanism, and contribute to pathogenesis in a variety of diseases. The ability to monitor ER calcium alterations during disease onset and progression is important in principle, yet challenging in practice. Currently available methods for monitoring ER calcium, such as calcium-dependent fluorescent dyes and proteins, have provided insight into ER calcium dynamics in cells, however these tools are not well suited for in vivo studies. Our lab has demonstrated that a modification to the carboxy-terminus of Gaussia luciferase confers secretion of the reporter in response to ER calcium depletion. The methods for using a luciferase based, secreted ER calcium monitoring protein (SERCaMP) for in vitro and in vivo applications are described herein. This video highlights hepatic injections, pharmacological manipulation of GLuc-SERCaMP, blood collection and processing, and assay parameters for longitudinal monitoring of ER calcium.

Monitoring Endoplasmic Reticulum Calcium Homeostasis Using a Gaussia Luciferase SERCaMP

Endoplasmic reticulum calcium homeostasis is disrupted in diverse pathologies. A secreted ER calcium monitoring protein (SERCaMP) reporter can be used to detect disruptions in the ER calcium store. This protocol describes the use of a Gaussia luciferase SERCaMP to examine ER calcium homeostasis in vitro and in vivo.

The endoplasmic reticulum (ER) contains the highest level of intracellular calcium, with concentrations approximately 5,000-fold greater than cytoplasmic ...