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.

<ol>
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The authors declare no competing interests.

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 ...

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3.9K Views.  Boston University. 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.

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

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 ...

Measurement and Analysis of Extracellular Acid Production to Determine Glycolytic Rate

Extracellular measurement of oxygen consumption and acid production is a simple and powerful way to monitor rates of respiration and glycolysis1. Both mitochondrial (respiration) and non-mitochondrial (other redox) reactions consume oxygen, but these reactions can be easily distinguished by chemical inhibition of mitochondrial respiration. However, while mitochondrial oxygen consumption is an unambiguous and direct measurement of respiration rate2, the same is not true for extracellular acid production and its relationship to glycolytic rate 3-6. Extracellular acid produced by cells is derived from both lactate, produced by anaerobic glycolysis, and CO2, produced in the citric acid cycle during respiration. For glycolysis, the conversion of glucose to lactate- + H+ and the export of products into the assay medium is the source of glycolytic acidification. For respiration, the export of CO2, hydration to H2CO3 and dissociation to HCO3- + H+ is the source of respiratory acidification. The proportions of glycolytic and respiratory acidification depend on the experimental conditions, including cell type and substrate(s) provided, and can range from nearly 100% glycolytic acidification to nearly 100% respiratory acidification 6. Here, we demonstrate the data collection and calculation methods needed to determine respiratory and glycolytic contributions to total extracellular acidification by whole cells in culture using C2C12 myoblast cells as a model.

Glycolysis is a defining metabolic marker in multiple biological systems. Monitoring glycolysis by measuring the extracellular flux of H+ is common, but requires correction to be quantitative and unambiguous. Here, we demonstrate how to gather and correct extracellular flux data to distinguish between respiratory and glycolytic sources of extracellular acidification.

Extracellular measurement of oxygen consumption and acid production is a simple and powerful way to monitor rates of respiration and glycolysis1. Both ...

Methods Article

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