Name: loss- and gain-of-function approach to investigate early cell fate determinants in preimplantation mouse embryos
Uploaded: 2016-06-06T13:00:00
Description: Watch this Scientific Journal Video about Loss- and Gain-of-function Approach to Investigate Early Cell Fate Determinants in Preimplantation Mouse Embryos at JoVE.com

The authors would also like to acknowledge Dr. Xiong&#39;s group at Georgia Health Sciences University for manufacturing and sharing the constructs for neogenin cDNA and shRNA vectors. This study was supported by grants from the Basic Science Research Program (2013R1A1A4A01012572) funded by the Korean Research Foundation and by a research grant from Sahmyook University.

NOTE: All procedures for animal breeding and cares were conducted according to the IACUC&#160;regulations of Sahmyook University, Seoul, S. Korea.
1. Superovulation, Breeding and Oviduct Isolation
<ol>
	<li>Maintain inbred C57BL/6 mice under the following conditions: 22 &#177; 3 &#176;C, ~60% humidity, 12 hr light/dark cycle, and water and food ad libitum.</li>
	<li>Induce superovulation of 3-5 week-old female mice by an intraperitoneal injection of 5 IU pregnant mare serum gonadotropin (PMSG) at 0.1 ml/head fol...

<ol>
	<li>Yamanaka, Y., Ralston, A., Stephenson, R. O., Rossant, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+and+molecular+regulation+of+the+mouse+blastocyst.">Cell and molecular regulation of the mouse blastocyst.</a> Dev. Dyn. 235 (9), 2301-2314 (2006).</li><li>Sasaki, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+of+trophectoderm+fate+specification+in+preimplantation+mouse+development.">Mechanisms of trophectoderm fate specification in preimplantation mouse development.</a> Dev. Growth Differ. 52 (3), 263-273 (2010).</li><li>Nishioka, N., Yamamoto, S., Kiyonari, H., Sato, H., Sawada, A., Ota, 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=Tead4+is+required+for+specification+of+trophectoderm+in+pre-implantation+mouse.">Tead4 is required for specification of trophectoderm in pre-implantation mouse.</a> Mech. Dev. 125 (3-4), 270-283 (2008).</li><li>Ovitt, C. E., Sch&#246;ler, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+molecular+biology+of+Oct-4+in+the+early+mouse+embryo.">The molecular biology of Oct-4 in the early mouse embryo.</a> Mol. Hum. Reprod. 4 (11), 1021-1031 (1998).</li><li>Stein, P., Schindler, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+Oocyte+Microinjection,+Maturation+and+Ploidy+Assessment.">Mouse Oocyte Microinjection, Maturation and Ploidy Assessment.</a> J. Vis. Exp. (53), e2851 (2011).</li><li>Shin, M. R., Cui, X. S., Jun, J. H., Jeong, Y. J., Kim, N. H. <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+mouse+blastocyst+genes+that+are+down+regulated+by+double-stranded+RNA-mediated+knockdown+of+Oct-4+expression.">Identification of mouse blastocyst genes that are down regulated by double-stranded RNA-mediated knockdown of Oct-4 expression.</a> Mol. Reprod. Dev. 70 (4), 390-396 (2005).</li><li>Khang, I., Sonn, S., Park, J. -. H., Rhee, K., Park, D., Kim, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+epithin+in+mouse+preimplantation+development:+Its+role+in+compaction.">Expression of epithin in mouse preimplantation development: Its role in compaction.</a> Dev. Biol. 281, 134-144 (2005).</li><li>Prieto, D., Aparicio, G., Machado, M., Zolessi, F. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+the+DNA-Specific+Stain+Methyl+Green+in+the+Fluorescent+Labeling+of+Embryos.">Application of the DNA-Specific Stain Methyl Green in the Fluorescent Labeling of Embryos.</a> J. Vis. Exp. (99), e52769 (2015).</li><li>Lee, J. H., Choi, S. S., Kim, H. W., Xiong, W. C., Min, C. K., Lee, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neogenin+as+a+receptor+for+early+cell+fate+determination+in+preimplantation+mouse+embryos.">Neogenin as a receptor for early cell fate determination in preimplantation mouse embryos.</a> PLoS One. 9 (7), e101989 (2014).</li><li>Gordon, J. W., Scangos, G. A., Plotkin, D. J., Barbosa, J. A., Ruddle, F. 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+transformation+of+mouse+embryos+by+microinjection+of+purified+DNA.">Genetic transformation of mouse embryos by microinjection of purified DNA.</a> Proc. Natl. Acad. Sci. USA. 77 (12), 7380-7384 (1980).</li><li>Brinster, R. L., Chen, H. Y., Trumbauer, M. E., Yagle, M. K., Palmiter, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Factors+affecting+the+efficiency+of+introducing+foreign+DNA+into+mice+by+microinjecting+eggs.">Factors affecting the efficiency of introducing foreign DNA into mice by microinjecting eggs.</a> Proc. Natl. Acad. Sci. USA. 82, 4438-4442 (1985).</li></ol>

In the present protocol, we demonstrate novel methods of microinjection of genetic materials, either cDNA or shRNA, into the 2-PN mouse embryos to explore the role of neogenin in early cell differentiation during mouse embryogenesis. Genetic modification of preimplantation embryos is a powerful technique in uncovering key information about underlying molecular mechanisms for, for example, the first cell lineage determination. Genetic modification is one of the most commonly used methods for ascertaining gene function. Wi...

Preimplantation embryonic development can be divided into several distinct stages, from the one-cell stage to the morula and the blastocyst. Much evidence suggests that polarity and positional cues play a role in early cell fate determination into the trophectoderm (TE) and the inner cell mass (ICM). However, the nature of the cues, how they are transduced into cellular signals, and the physiological contexts in which such signals are capable of initiating cell lineage differentiation are not known. These differentiated cells then undergo specialization, beginning to take on characteristic structures and functions needed for embryo proper formation and growth of the placenta1-3.
Pre-implantation embryos are particularly amenable to manipulation by direct injection of modified genetic materials like siRNA or target cDNA and thus can be utilized to study specific target molecules. There is a growing understanding that genetic analysis of vertebrate embryos is critical to advancing our understanding of embryonic development4. Precise introduction of a wild-type gene or a mutant form into an embryo in a timely context to accomplish gain- or loss-of-function of the gene has greatly facilitated the study of developmentally regulated genes. Loss- and gain-of-function via microinjection of genetic materials into individual early non-mammalian and mammalian embryos is relatively simple because of their large size and great receptivity5. Microinjection is typically performed using non-viral vectors. Particular advantage has been taken of the ease of using non-viral vectors over viral vectors and transgenes. A rapid loss- or gain-of-function expression system in mouse embryos has been developed that allows us to dissect and understand gene functions in vertebrate embryology6,7.
Fluorescent labeling of embryos would greatly facilitate the selection of microinjected or genetically manipulated embryos and at the same time grant a means to indirectly quantify the expression level of microinjected siRNA or cDNA based on fluorescent intensity8. To accomplish this labeling, fluorescent protein cDNA, GFP or RFP, are co-injected as either fusion constructs or separately. The fluorescence intensity of GFP or RFP reveals the extent of expression of siRNA or foreign DNA to ensure that loss- or gain-of-function has been accomplished.
Here, we present a micromanipulation protocol for loss- and gain-of- function technique that allowed us to identify neogenin as a receptor that relays extracellular cues important in early cell differentiation in preimplantation mouse embryos.

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			<td height="21" style="height:21px;width:496px;">M16 medium,</td>
			<td style="width:519px;">Gibco BRL (Grand Island, NY)</td>
			<td style="width:232px;">M7292 LOT# 11A832</td>
			<td style="width:261px;"></td>
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			<td height="21" style="height:21px;width:496px;">Goat serum,&#160;</td>
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			<td style="width:232px;">X0907</td>
			<td></td>
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			<td height="21" style="height:21px;width:496px;">PMSG</td>
			<td>Folligon, Intervet, Holland</td>
			<td style="width:232px;">G4877-1000IU LOT#SLBD0719V</td>
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			<td height="21" style="height:21px;width:496px;">Mineral olie</td>
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			<td height="21" style="height:21px;width:496px;">human chorionic gonadotropin and pregnant mare serum gonadotropin&#160;</td>
			<td style="width:519px;">(Intervet, Holland)</td>
			<td style="width:232px;">(invitrogen , 15596-026)</td>
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			<td height="21" style="height:21px;width:496px;">SuperScript&#174; III Reverse Transcriptase</td>
			<td style="width:519px;">lifetechnologies</td>
			<td style="width:232px;">18080-044</td>
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			<td height="21" style="height:21px;width:496px;">PCR pre mixture</td>
			<td style="width:519px;">&#160;(Bioneer, Daejon, S. Korea)</td>
			<td style="width:232px;">GenDEPOT , A0224-050</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:496px;">Agarose (molecular grade)</td>
			<td style="width:519px;">BioRad</td>
			<td style="width:232px;">161-3101</td>
			<td></td>
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			<td height="21" style="height:21px;width:496px;">Paraformaldehyde Solution, 4% in PBS</td>
			<td style="width:519px;">Affymetrix USA</td>
			<td style="width:232px;">19943</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:496px;">polyclonal rabbit anti-neogenin antibody</td>
			<td style="width:519px;">Santa Cruz Biotechnology, US</td>
			<td style="width:232px;">SC-15337</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:496px;">Alexa fluor 488 labeled anti-rabbit antibody</td>
			<td style="width:519px;">Molecular Probes (Invitrogen, USA)</td>
			<td style="width:232px;">A-11094</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:496px;">Alexa fluor 555 labeled anti-rabbit antibody</td>
			<td style="width:519px;">Molecular Probes (Invitrogen, USA)</td>
			<td style="width:232px;">A-21428</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:496px;">Alexa Fluor&#174; 555 Phalloidin</td>
			<td style="width:519px;">Molecular Probes (Invitrogen, USA)</td>
			<td style="width:232px;">A34055</td>
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			<td height="21" style="height:21px;width:496px;">DAPI (4&#39;,6-Diamidino-2-Phenylindole, Dihydrochloride)</td>
			<td style="width:519px;">Invitrogen, USA</td>
			<td style="width:232px;">D1306</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:496px;">Recombinant Human RGM-C/Hemojuvelin</td>
			<td style="width:519px;">R&#38;D systems</td>
			<td style="width:232px;">3720-RG</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:496px;">all plasmid constructs&#160;</td>
			<td style="width:519px;">Prof. Wen Cheng Xiong at Georgia Health Sciences University (Agusta, GA).</td>
			<td style="width:232px;"></td>
			<td>the present studies were kindly provided by&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:496px;">Neon&#174;&#160; Transfection System</td>
			<td style="width:519px;">lifetech</td>
			<td style="width:232px;">MPK10096</td>
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			<td height="21" style="height:21px;width:496px;">Stereo Microscrope</td>
			<td style="width:519px;">Nikon</td>
			<td style="width:232px;">SMZ1000</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:496px;">Micromainpulation system with Nikon</td>
			<td style="width:519px;">Nikon</td>
			<td style="width:232px;">Narishige ONM-1</td>
			<td></td>
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			<td height="21" style="height:21px;width:496px;">MicroInjector</td>
			<td style="width:519px;">Nikon Narishige</td>
			<td style="width:232px;">GASTIGHT #1750</td>
			<td></td>
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			<td height="21" style="height:21px;width:496px;">Holder</td>
			<td style="width:519px;">Nikon Narishige</td>
			<td style="width:232px;">Narishige IM 16</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:496px;">Microfoge</td>
			<td style="width:519px;">Nikon Narishige</td>
			<td style="width:232px;">Narishige MF-900</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:496px;">grinder</td>
			<td style="width:519px;">Narishige</td>
			<td style="width:232px;">EG400</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:496px;">Puller</td>
			<td style="width:519px;">Sutter Instrumnet company</td>
			<td style="width:232px;">P-97</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:496px;">CO2 incubator</td>
			<td style="width:519px;">Thermo Scientific Forma</td>
			<td style="width:232px;">EW-39320-16</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:496px;">Veriti&#174; 384-Well Thermal Cycler&#160;</td>
			<td style="width:519px;">lifetechnologies</td>
			<td style="width:232px;">4388444</td>
			<td></td>
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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.

We discovered that neogenin is transiently expressed during the early developmental stages of preimplantation mouse embryos, appearing as early as at the 2-cell stage and lasting until the early morula but becoming deficient at the late morula and blastocyst stages (Figure 2A). In addition, the spatial distribution of neogenin was restricted mainly to outside cells. The results of RT-PCR analysis were consistent with the early and transient nature of neogenin expression, ...

Watch this Scientific Journal Video about Loss- and Gain-of-function Approach to Investigate Early Cell Fate Determinants in Preimplantation Mouse Embryos at JoVE.com

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

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 ...

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