Name: in situ hybridization combined with immunohistochemistry in cryosectioned zebrafish embryos
Uploaded: 2022-03-03T13:00:00
Description: Watch this Scientific Journal Video about In Situ Hybridization Combined with Immunohistochemistry in Cryosectioned Zebrafish Embryos at JoVE.com

This work was supported by the Nantong Science and Technology Foundation of China (MS12019011), the Nantong Science and Technology Foundation of China (JC2021058), and the Natural Science Foundation of the Jiangsu Higher Education Institutions (21KJB180009).

All animal protocols were approved by the Institutional Animal Care and Use Committee of Nantong University (No. S20191210-402).
1. Collection of zebrafish embryos
<ol>
	<li>Set up a pair of zebrafish in breeding tanks the night before the eggs are to be collected, one a transgenic zebrafish and the other an AB wild-type zebrafish (Tg (foxP2:egfp-caax) X AB wild-type or Tg (hb9:egfp) X AB wild-type) (see the Table of Materials</str...

<ol>
	<li>Streisinger, G., Walker, C., Dower, N., Knauber, D., Singer, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+clones+of+homozygous+diploid+zebra+fish+(Brachydanio+rerio).">Production of clones of homozygous diploid zebra fish (Brachydanio rerio).</a> Nature. 291 (5813), 293-296 (1981).</li><li>Chen, E., Ekker, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+as+a+genomics+research+model.">Zebrafish as a genomics research model.</a> Current Pharmaceutical Biotechnology. 5 (5), 409-413 (2004).</li><li>Howe, K., Clark, M. D., Torroja, C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+zebrafish+reference+genome+sequence+and+its+relationship+to+the+human+genome.">The zebrafish reference genome sequence and its relationship to the human genome.</a> Nature. 496 (7446), 498-503 (2013).</li><li>Coons, A. H., Creech, H. J., Jones, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunological+properties+of+an+antibody+containing+a+fluorescent+group.">Immunological properties of an antibody containing a fluorescent group.</a> Proceedings of the Society for Experimental Biology and Medicine. 47 (2), 200-202 (1941).</li><li>The lack of commercial antibodies for model organisms (and how you can deal with it) [Internet]. BenchSci Blog Available from: <a target="_blank" href="https://blog.benchsci.com/the-lack-of-commercial-antibodies-for-model-organisms-and-how-you-can-deal-with-it">https://blog.benchsci.com/the-lack-of-commercial-antibodies-for-model-organisms-and-how-you-can-deal-with-it</a> (2018)</li><li>Akam, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+location+of+ultrabithorax+transcripts+in+Drosophila+tissue+sections.">The location of ultrabithorax transcripts in Drosophila tissue sections.</a> EMBO Journal. 2, 2075-2084 (1983).</li><li>Hafen, E., Levine, M., Garber, R. L., Gehring, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+in+situ+hybridization+method+for+the+detection+of+cellular+RNAs+in+Drosophila+tissue+sections+and+its+application+for+localizing+transcripts+of+the+homeotic+Antennapedia+gene+complex.">An improved in situ hybridization method for the detection of cellular RNAs in Drosophila tissue sections and its application for localizing transcripts of the homeotic Antennapedia gene complex.</a> EMBO Journal. 2, 617-623 (1983).</li><li>Thisse, B., Thisse, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+situ+hybridization+on+whole-mount+zebrafish+embryos+and+young+larvae.">In situ hybridization on whole-mount zebrafish embryos and young larvae.</a> Methods in Molecular Biology. 1211, 53-67 (2014).</li><li>Clay, H., Ramakrishnan, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiplex+fluorescent+in+situ+hybridization+in+zebrafish+embryos+using+tyramide+signal+amplification.">Multiplex fluorescent in situ hybridization in zebrafish embryos using tyramide signal amplification.</a> Zebrafish. 2 (2), 105-111 (2005).</li><li>Driever, W., Stemple, D., Schier, A., Solnica-Krezel, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish:+genetic+tools+for+studying+vertebrate+development.">Zebrafish: genetic tools for studying vertebrate development.</a> Trends in Genetics. 10 (5), 152-159 (1994).</li><li>Cunningham, R. L., Monk, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole+mount+in+situ+hybridization+and+immunohistochemistry+for+zebrafish+larvae.">Whole mount in situ hybridization and immunohistochemistry for zebrafish larvae.</a> Methods in Molecular Biology. 1739, 371-384 (2018).</li><li>Thisse, C., Thisse, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-resolution+in+situ+hybridization+to+whole-mount+zebrafish+embryos.">High-resolution in situ hybridization to whole-mount zebrafish embryos.</a> Nature Protocols. 3 (1), 59-69 (2008).</li><li>Heisler, L. K., Zhou, L., Bajwa, P., Hsu, J., Tecott, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serotonin+5-HT(2C)+receptors+regulate+anxiety-like+behavior.">Serotonin 5-HT(2C) receptors regulate anxiety-like behavior.</a> Genes, Brain, and Behavior. 6 (5), 491-496 (2007).</li><li>Ferguson, J. L., Shive, 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=Sequential+immunofluorescence+and+immunohistochemistry+on+cryosectioned+zebrafish+embryos.">Sequential immunofluorescence and immunohistochemistry on cryosectioned zebrafish embryos.</a> Journal of Visualized Experiments: JoVE. (147), e59344 (2019).</li><li>Hammond-Weinberger, D. R., ZeRuth, G. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole+mount+immunohistochemistry+in+zebrafish+embryos+and+larvae.">Whole mount immunohistochemistry in zebrafish embryos and larvae.</a> Journal of Visualized Experiments: JoVE. (155), e60575 (2020).</li><li>Santos, D., Monteiro, S. M., Luzio, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=General+whole-mount+immunohistochemistry+of+zebrafish+(Danio+rerio)+embryos+and+larvae+protocol.">General whole-mount immunohistochemistry of zebrafish (Danio rerio) embryos and larvae protocol.</a> Methods in Molecular Biology. 1797, 365-371 (2018).</li><li>O'Hurley, G., Sjostedt, E., Rahman, A., Li, B., Kampf, C., Ponten, F., 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=Garbage+in,+garbage+out:+a+critical+evaluation+of+strategies+used+for+validation+of+immunohistochemical+biomarkers.">Garbage in, garbage out: a critical evaluation of strategies used for validation of immunohistochemical biomarkers.</a> Molecular Oncology. 8, 783-798 (2014).</li></ol>

This protocol proposes a combination of in situ hybridization and immunohistochemistry, an important step in the colocalization experiments on zebrafish embryos. This method serves as an easy and efficient way to simultaneously analyze one mRNA and one protein. In situ hybridization and antibody staining were performed on zebrafish embryos. In contrast to several protocols published previously14,15,16, immunofl...

The zebrafish is a powerful vertebrate model for studies of development and genetics1,2. Zebrafish and humans share high genetic homology (70% of the genes are shared with the human genome), which allows its use as a model for human diseases3. In zebrafish, it is quite common to detect the expression patterns of two genes and their spatial relationship. Immunohistochemistry was first used in 1941 to detect pathogens in infected tissues by applying FITC-labeled antibodies4. The target protein in the tissue section is first labeled with a primary antibody, and the section is then labeled with a secondary antibody against the primary antibody&#39;s host species immunoglobulin. Antibody staining is a robust approach to detect the localization of proteins, which offers high optical resolution at the intracellular level. However, the number of antibodies available is very limited in zebrafish. A recent study shows that approximately 112,000 antibodies are commercially available for mice; however, very few antibodies have been demonstrated to be reliable in zebrafish5.
Instead, in zebrafish, in situ hybridization has been widely applied for gene expression pattern analysis. This method was first used to assess gene expression in Drosophila embryos in the 1980s6,7, and since then, this technology has been continuously developed and improved. Initially, radiolabeled DNA probes were used to detect mRNA transcripts; however, the spatial resolution was relatively low, and there were potential health risks caused by the radioactivity. Subsequently, in situ hybridization relies on the RNA probes labeled with digoxigenin (DIG) or fluorescein (Fluo), which are conjugated to alkaline phosphatase (AP) or detected by fluorescent tyramide signal amplification (TSA)8,9. Although TSA has been used to detect two or three genes, DIG labeling of RNA probes and antiDIG AP-conjugated antibody are still highly sensitive, stable, and widely used approaches for in situ hybridization. Therefore, commercialized antibodies combined with DIG-labeled in situ probes are useful for providing insight into protein localization and expression of one gene.
Whole-mount embryos cannot reveal the spatial relationship between genes due to the low optical resolution, even though zebrafish embryos are small and transparent10. Hence, sectioning is necessary to analyze the expression patterns of genes at the intracellular level. Cryosectioning has been widely used in zebrafish as it is easy to perform and can effectively preserve the antigen. Therefore, in situ hybridization combined with immunohistochemistry in zebrafish cryosections offers a powerful way for analyzing the expression patterns of two genes. A combination of in situ hybridization and immunohistochemistry has been applied to zebrafish11. However, proteinase K treatment was used to enhance probe penetration at the expense of antigen integrity. To overcome this limitation, this protocol uses heating to induce antigen retrieval. This protocol is not only applicable to embryos of different stages and tissue sections of various thicknesses (14 &#181;m head sections and 20 &#181;m spinal cord sections), but it has also been verified by using genes expressed in two organs, including the head and spinal cord.
This article will describe how to combine in situ hybridization and antibody staining in zebrafish embryos in cryosections. The versatility of this protocol is demonstrated by using a number of in situ hybridization-immunohistochemistry combinations, including in situ hybridization probes for two different neurons. This method is suitable for detecting mRNA and protein in different regions and embryos of different ages, as well as the expression patterns of two genes.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Alexa Fluor 488 secondary antibody</td>
			<td>Invitrogen</td>
			<td>A21202</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Digoxigenin AP Fab fragments</td>
			<td>Roche</td>
			<td>11093274910</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-GFP antibody</td>
			<td>Millipore</td>
			<td>MAB3580</td>
			<td></td>
		</tr>
		<tr>
			<td>Blocking solution</td>
			<td>made in lab</td>
			<td>N/A</td>
			<td>0.1% Triton X-100, 3% BSA, 10% goat serum in 1x PBS</td>
		</tr>
		<tr>
			<td>BM purple</td>
			<td>Roche</td>
			<td>11442074001</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin (BSA)</td>
			<td>Sigma</td>
			<td>B2064</td>
			<td></td>
		</tr>
		<tr>
			<td>CaCl2</td>
			<td>Sigma</td>
			<td>C5670</td>
			<td></td>
		</tr>
		<tr>
			<td>Citrate buffer</td>
			<td>Leagene</td>
			<td>IH0305</td>
			<td></td>
		</tr>
		<tr>
			<td>Citric acid</td>
			<td>Sigma</td>
			<td>C2404</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryomold for tissue, 15 mm x 15 mm x 5 mm</td>
			<td>Head Biotechnology</td>
			<td>H4566</td>
			<td></td>
		</tr>
		<tr>
			<td>DEPC-Treated Water</td>
			<td>Sangon Biotech</td>
			<td>B501005</td>
			<td></td>
		</tr>
		<tr>
			<td>Digital camera, fluorescence microscope</td>
			<td>Nikon</td>
			<td>NI-SSR 931479</td>
			<td></td>
		</tr>
		<tr>
			<td>E3 embryo medium</td>
			<td>made in lab</td>
			<td>N/A</td>
			<td>5 mM NaCl, 0.17 mM KCl, 0.33 mM CaCl2, 0.33 mM MgSO4</td>
		</tr>
		<tr>
			<td>Formamide</td>
			<td>Invitrogen</td>
			<td>AM9342</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat serum</td>
			<td>Sigma</td>
			<td>G9023</td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin sodium salt</td>
			<td>J&#38;K Scientific</td>
			<td>542858</td>
			<td></td>
		</tr>
		<tr>
			<td>HYB</td>
			<td>made in lab</td>
			<td>N/A</td>
			<td>preHYB plus 50 &#181;g/mL heparin sodium salt, 100 &#181;g/mL ribonucleic acid diethylaminoethanol salt</td>
		</tr>
		<tr>
			<td>Immunohistochemical wet box</td>
			<td>Mkbio</td>
			<td>MH10002</td>
			<td></td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sigma</td>
			<td>P5405</td>
			<td></td>
		</tr>
		<tr>
			<td>Low profile leica blades</td>
			<td>Leica</td>
			<td>819</td>
			<td></td>
		</tr>
		<tr>
			<td>MABT (1x)</td>
			<td>made in lab</td>
			<td>N/A</td>
			<td>0.1 M maleic acid, 0.15 M NaCl, 0.02% Tween-20, pH 7.5</td>
		</tr>
		<tr>
			<td>Maleic acid</td>
			<td>Sigma</td>
			<td>M0375</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>J&#38;K Scientific</td>
			<td>116481</td>
			<td></td>
		</tr>
		<tr>
			<td>Methylene blue</td>
			<td>Macklin</td>
			<td>M859248</td>
			<td></td>
		</tr>
		<tr>
			<td>MgSO4</td>
			<td>Sigma</td>
			<td>M2643</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Sigma</td>
			<td>S5886</td>
			<td></td>
		</tr>
		<tr>
			<td>NTMT</td>
			<td>made in lab</td>
			<td>N/A</td>
			<td>0.1M Tris-HCl, 0.1M NaCl, 1% Tween-20</td>
		</tr>
		<tr>
			<td>OCT medium</td>
			<td>Tissue-Tek</td>
			<td>4583</td>
			<td></td>
		</tr>
		<tr>
			<td>PAP pen</td>
			<td>Enzo Life Sciences</td>
			<td>ADI-950-233</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde, 4%</td>
			<td>Abbexa</td>
			<td>abx082483</td>
			<td>made in lab in 1x PBS</td>
		</tr>
		<tr>
			<td>PBST (1x)</td>
			<td>made in lab</td>
			<td>N/A</td>
			<td>1x PBS plus 0.1% Tween-20</td>
		</tr>
		<tr>
			<td>Phenylthiourea</td>
			<td>Merck</td>
			<td>103-85-5</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate-buffered saline (10x)</td>
			<td>Invitrogen</td>
			<td>AM9624</td>
			<td></td>
		</tr>
		<tr>
			<td>preHYB</td>
			<td>made in lab</td>
			<td>N/A</td>
			<td>50% formamide, 5x SSC, 9.2 mM citric acid (pH 6.0), 0.1% Tween-20</td>
		</tr>
		<tr>
			<td>Proteinase K</td>
			<td>Roche</td>
			<td>1092766</td>
			<td></td>
		</tr>
		<tr>
			<td>Ribonucleic acid diethylaminoethanol salt</td>
			<td>Sigma</td>
			<td>R3629</td>
			<td></td>
		</tr>
		<tr>
			<td>RNase-free 1.5 mL tubes</td>
			<td>Ambion</td>
			<td>AM12400</td>
			<td></td>
		</tr>
		<tr>
			<td>SSC (20x)</td>
			<td>Invitrogen</td>
			<td>AM9770</td>
			<td></td>
		</tr>
		<tr>
			<td>SSCT (0.2x)</td>
			<td>made in lab</td>
			<td>N/A</td>
			<td>0.2x SSC plus 0.1% Tween-20</td>
		</tr>
		<tr>
			<td>SSCT (1x)</td>
			<td>made in lab</td>
			<td>N/A</td>
			<td>1x SSC plus 0.1% Tween-20</td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Invitrogen</td>
			<td>15503022</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma</td>
			<td>T9284</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween-20</td>
			<td>Sigma</td>
			<td>P1379</td>
			<td></td>
		</tr>
		<tr>
			<td>Zebrafish</td>
			<td>Laboratory Animal Center of Nantong University</td>
			<td>N/A</td>
			<td></td>
		</tr>
	</tbody>
</table>

in situ hybridization combined with immunohistochemistry in cryosectioned zebrafish embryos

As a vertebrate, the zebrafish has been widely used in biological studies. Zebrafish and humans share high genetic homology, which allows its use as a model for human diseases. Gene function study is based on the detection of gene expression patterns. Although immunohistochemistry offers a powerful way to assay protein expression, the limited number of commercially available antibodies in zebrafish restricts the application of costaining. In situ hybridization is widely used in zebrafish embryos to detect mRNA expression. This protocol describes how to obtain images by combining in situ hybridization and immunohistochemistry for zebrafish embryo sections. In situ hybridization was performed prior to cryosectioning, followed by antibody staining. Immunohistochemistry and the imaging of a single cryosection were performed after in situ hybridization. The protocol is helpful to unravel the expression pattern of two genes, first by in situ transcript detection and then by immunohistochemistry against a protein in the same section.

This protocol can be used to simultaneously examine the expression pattern of one mRNA and one protein. Figure 1 shows the experimental workflow. The 5-HT2C receptor is a subtype of the 5-HT receptor bound by the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). It is widely distributed in the central nervous system (CNS) and can significantly regulate a variety of brain functions, including appetite, mood, anxiety, and reproductive behavior13. The expression of...

Watch this Scientific Journal Video about In Situ Hybridization Combined with Immunohistochemistry in Cryosectioned Zebrafish Embryos at JoVE.com

In Situ Hybridization Combined with Immunohistochemistry in Cryosectioned Zebrafish Embryos

This protocol describes how to obtain images by combining in situ hybridization and immunohistochemistry of zebrafish embryonic sections. In situ hybridization was performed prior to cryosectioning, followed by antibody staining. It is useful to detect the expression patterns of two genes in zebrafish if there is a paucity of antibodies.

In Situ Hybridization Combined with Immunohistochemistry in Cryosectioned Zebrafish Embryos

As a vertebrate, the zebrafish has been widely used in biological studies. Zebrafish and humans share high genetic homology, which allows its use as a ...

This protocol use a combination of in situ hybridization and the immunohistochemistry, and it serves as an easy and efficient way to simultaneously analyze one mRNA and one protein. This protocol is applicable to embryos at different stages, tissue sections of various thickness, and different organs. To begin, fix approximately 10 embryos with 0.5 to 1 milliliter of fresh 4%paraformaldehyde in a 1.5 milliliter microfuge tube at four degrees Celsius overnight for 12 to 14 hours.Gradually dehydrate the embryos by washing with 25, 50, and 75%methanol in PBST successively for five minutes each at room temperature. Then, wash the embryos in 100%methanol for five minutes at room temperature. Incubate the embryos in 100%methanol at minus 20 degrees Celsius for at least overnight, for 12 to 14 hours.Gradually rehydrate the embryos by washing with 75, 50, and 25%methanol in PBST successively for five minutes each at room temperature. Again, wash the embryo thrice with PBST for five minutes each at room temperature. Digest the embryos with 10 micrograms per milliliter of proteinase K in PBST at room temperature, and wash the embryos thrice with PBST for five minutes.Then, refix the washed embryos in 4%paraformaldehyde for 15 minutes at room temperature. Again, wash the embryo thrice with PBST while incubating for five minutes during each wash. For pre-hybridizing the embryos, incubate them in pre-hybridization solution at 65 degrees Celsius for five minutes.Then, replace the pre-hybridization solution with the hybridization solution and pre-hybridize for at least four hours. Heat the probe in the hybridization solution for five minutes at 95 degrees Celsius before adding to the embryos. Remove as much pre-hybridization solution as possible without letting the embryos come into contact with the air.To the tube containing the embryos, add preheated probe in the hybridization solution and allow the probe to hybridize overnight for 12 to 14 hours at 50 to 70 degrees Celsius. On the next day, aspirate the probe solution with a pipette and store it in a tube at minus 20 degrees Celsius so that it can be reused many times. Wash the embryos with 100%hybridization solution followed by sequential washing with 75, 50, and 25%hybridization solution in twice the concentration of SSCT for 15 minutes at 65 degrees Celsius.Then, wash the embryos in twice and 0.2 times the concentration of SSCT for 15 minutes at 65 degrees Celsius. Wash the embryos twice for 10 minutes in MABT at room temperature. Block the hybridized and washed embryos for at least two hours at room temperature, with 2%blocking solution-1.Replace the blocking solution-1 with antidigoxigenin alkaline phosphatase in a fresh 2%blocking solution-1 and shake overnight for 12 to 14 hours at four degrees Celsius. Then, wash the embryos four times in MABT for 30 minutes at room temperature. Again, wash the embryos twice in NTMT and remove as much NTMT as possible from the embryos using a pipette.Replace with BM purple alkaline phosphatase substrate and stain the embryos at room temperature in the dark. Once the stain has developed, stop the reaction by briefly rinsing twice with NTMT. After in situ hybridization, rinse the embryos with PBST thrice for 20 minutes.Immerse the embryos in 5%sucrose in PBS overnight for 12 to 14 hours at four degrees Celsius. Then, change the solution covering the embryos to 15%sucrose in PBS and incubate overnight for 12 to 16 hours at four degrees Celsius. Again, change the solution covering the embryos to 30%sucrose in PBS and incubate for one to two days at four degrees Celsius.Transfer the embryos to a new cryomold for tissue and gently fill it with optimal cutting temperature medium while avoiding the formation of bubbles. Next, cut the specimens into 12 to 20 micrometer thick sections using a cryostat and quickly transfer the sections to glass slides. Allow the samples to reach room temperature and store the sections in a sealed slide box at minus 80 degrees Celsius for subsequent use.Wash the slides containing the sections with PBS for five minutes. Then, place the slides in the buffer and heat the solution for approximately 20 minutes to keep it near boiling temperature. Drain the excess solution and carefully dry the area around each section with a piece of tissue.Then, draw a circle around the section with a water-repellent pen to form a hydrophobic barrier and block the section for two hours in blocking solution-2 at room temperature. Pipette primary antibody solution per slide and incubate the slides in an immunohistochemical wet box at four degrees Celsius overnight. Wash the slides three times with PBS while incubating for 10 minutes during each wash, and drain the excess PBS.Then, incubate the slides with the appropriate secondary antibody for one hour at room temperature in PBS. Again, wash the slides thrice with PBS while incubating for 10 minutes during each wash, and drain the excess PBS. Subsequently, pipette the mounting medium onto the slide and mount with a slide coverslip.The expression of 5-HT2C receptor in the central nervous system was detected in the transgenic foxP2 egfp-caax line. The simultaneous expression of 5-HT2C was observed in the transgenic line together with foxP2 neurons, which were labeled by fluorescein green fluorescent protein. The expression of insm1a, a zinc-finger transcription factor in the zebrafish spinal cord and motor neurons, was detected in the transgenic line.The simultaneous expression of insm1a was observed in the transgenic line together with hb9 neurons, which were labeled by fluorescein green fluorescent protein. Zebrafish must be fixed with freshly-prepared paraformaldehyde.

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Neuroscience

Double Fluorescence in situ Hybridization in Fresh Brain Sections

Here we describe a modified version of a double fluorescence in situ hybridization (dFISH) method optimized for detecting two mRNAs of interest in fresh frozen brain sections. Our group has successfully used this approach to study gene co-regulation. More specifically, we have used this dFISH method to explore the anatomical organization, neurochemical properties, and the impact of sensory experience in central sensory circuits, at single cell resolution. This protocol has been validated in brain tissue from mice, rats and songbirds but is expected to be easily adaptable to other vertebrate species, as well as to an array of non-neural tissues. In this film we provide a detailed demonstration of the main steps of this procedure.

Double Fluorescence in situ Hybridization in Fresh Brain Sections

This protocol involves a non-radioactive in-situ hybridization procedure that enables the simultaneous identification of two transcript species, at a single cell resolution, in thin sections of the vertebrate brain.

Here we describe a modified version of a double fluorescence in situ hybridization (dFISH) method optimized for detecting two mRNAs of interest in fresh ...

Combining Lipophilic dye, in situ Hybridization, Immunohistochemistry, and Histology

Going beyond single gene function to cut deeper into gene regulatory networks requires multiple mutations combined in a single animal. Such analysis of two or more genes needs to be complemented with in situ hybridization of other genes, or immunohistochemistry of their proteins, both in whole mounted developing organs or sections for detailed resolution of the cellular and tissue expression alterations. Combining multiple gene alterations requires the use of cre or flipase to conditionally delete genes and avoid embryonic lethality. Required breeding schemes dramatically enhance effort and cost proportional to the number of genes mutated, with an outcome of very few animals with the full repertoire of genetic modifications desired. Amortizing the vast amount of effort and time to obtain these few precious specimens that are carrying multiple mutations necessitates tissue optimization. Moreover, investigating a single animal with multiple techniques makes it easier to correlate gene deletion defects with expression profiles. We have developed a technique to obtain a more thorough analysis of a given animal; with the ability to analyze several different histologically recognizable structures as well as gene and protein expression all from the same specimen in both whole mounted organs and sections. Although mice have been utilized to demonstrate the effectiveness of this technique it can be applied to a wide array of animals. To do this we combine lipophilic dye tracing, whole mount in situ hybridization, immunohistochemistry, and histology to extract the maximal possible amount of data.

Combining Lipophilic dye, in situ Hybridization, Immunohistochemistry, and Histology

A combination of different techniques to maximize data collection from mouse tissue is presented.

Going beyond single gene function to cut deeper into gene regulatory networks requires multiple mutations combined in a single animal.  Such analysis of ...

Time-lapse Live Imaging of Clonally Related Neural Progenitor Cells in the Developing Zebrafish Forebrain

Precise patterns of division, migration and differentiation of neural progenitor cells are crucial for proper brain development and function1,2. To understand the behavior of neural progenitor cells in the complex in vivo environment, time-lapse live imaging of neural progenitor cells in an intact brain is critically required. In this video, we exploit the unique features of zebrafish embryos to visualize the development of forebrain neural progenitor cells in vivo. We use electroporation to genetically and sparsely label individual neural progenitor cells. Briefly, DNA constructs coding for fluorescent markers were injected into the forebrain ventricle of 22 hours post fertilization (hpf) zebrafish embryos and electric pulses were delivered immediately. Six hours later, the electroporated zebrafish embryos were mounted with low melting point agarose in glass bottom culture dishes. Fluorescently labeled neural progenitor cells were then imaged for 36hours with fixed intervals under a confocal microscope using water dipping objective lens. The present method provides a way to gain insights into the in vivo development of forebrain neural progenitor cells and can be applied to other parts of the central nervous system of the zebrafish embryo.

The present video demonstrates a method which takes advantage of the combination of electroporation and confocal microscopy to perform live imaging on individual neural progenitor cells in the developing zebrafish forebrain. In vivo analysis of the development of forebrain neural progenitor cells at a clonal level can be achieved in this way.

Precise patterns of division, migration and differentiation of neural progenitor cells are crucial for proper brain development and function1,2. To ...

Detection of the Genome and Transcripts of a Persistent DNA Virus in Neuronal Tissues by Fluorescent In situ Hybridization Combined with Immunostaining

Single cell codetection of a gene, its RNA product and cellular regulatory proteins is critical to study gene expression regulation. This is a challenge in the field of virology; in particular for nuclear-replicating persistent DNA viruses that involve animal models for their study. Herpes simplex virus type 1 (HSV-1) establishes a life-long latent infection in peripheral neurons. Latent virus serves as reservoir, from which it reactivates and induces a new herpetic episode. The cell biology of HSV-1 latency remains poorly understood, in part due to the lack of methods to detect HSV-1 genomes in situ in animal models. We describe a DNA-fluorescent in situ hybridization (FISH) approach efficiently detecting low-copy viral genomes within sections of neuronal tissues from infected animal models. The method relies on heat-based antigen unmasking, and directly labeled home-made DNA probes, or commercially available probes. We developed a triple staining approach, combining DNA-FISH with RNA-FISH&#160;and immunofluorescence, using peroxidase based signal amplification to accommodate each staining requirement. A major improvement is the ability to obtain, within 10 &#181;m tissue sections, low-background signals that can be imaged at high resolution by confocal microscopy and wide-field conventional epifluorescence. Additionally, the triple staining worked with a wide range of antibodies directed against cellular and viral proteins. The complete protocol takes 2.5 days to accommodate antibody and probe penetration within the tissue.

Detection of the Genome and Transcripts of a Persistent DNA Virus in Neuronal Tissues by Fluorescent In situ Hybridization Combined with Immunostaining

We established a fluorescent in situ hybridization protocol for the detection of a persistent DNA virus genome within tissue sections of animal models. This protocol enables studying infection process by codetection of the viral genome, its RNA products, and viral or cellular proteins within single cells.

Single cell codetection of a gene, its RNA product and cellular regulatory proteins is critical to study gene expression regulation. This is a challenge ...

Complete Spinal Cord Injury and Brain Dissection Protocol for Subsequent Wholemount In Situ Hybridization in Larval Sea Lamprey

After a complete spinal cord injury, sea lampreys at first are paralyzed below the level of transection. However, they recover locomotion after several weeks, and this is accompanied by short distance regeneration (a few mm) of propriospinal axons and spinal-projecting axons from the brainstem. Among the 36 large identifiable spinal-projecting neurons, some are good regenerators and others are bad regenerators. These neurons can most easily be identified in wholemount CNS preparations. In order to understand the neuron-intrinsic mechanisms that favor or inhibit axon regeneration after injury in the vertebrates CNS, we determine differences in gene expression between the good and bad regenerators, and how expression is influenced by spinal cord transection. This paper illustrates the techniques for housing larval and recently transformed adult sea lampreys in fresh water tanks, producing complete spinal cord transections under microscopic vision, and preparing brain and spinal cord wholemounts for in situ hybridization. Briefly, animals are kept at 16&#160;&#176;C and anesthetized in 1% Benzocaine in lamprey Ringer. The spinal cord is transected with iridectomy scissors via a dorsal approach and the animal is allowed to recover in fresh water tanks at 23 &#176;C. For in situ hybridization, animals are reanesthetized and the brain and cord removed via a dorsal approach.

Complete Spinal Cord Injury and Brain Dissection Protocol for Subsequent Wholemount In Situ Hybridization in Larval Sea Lamprey

Lampreys recover locomotion after a complete spinal cord injury. However, some spinal-projecting neurons are good regenerators and others are not. This paper illustrates the techniques for housing sea lamprey larvae (and recently transformed adults), producing complete spinal cord transections and preparing wholemount brains and spinal cords for in situ hybridization.

After a complete spinal cord injury, sea lampreys at first are paralyzed below the level of transection. However, they recover locomotion after several ...

Primer for Immunohistochemistry on Cryosectioned Rat Brain Tissue: Example Staining for Microglia and Neurons

Immunohistochemistry is a widely used technique for detecting the presence, location, and relative abundance of antigens in situ. This introductory level protocol describes the reagents, equipment, and techniques required to complete immunohistochemical staining of rodent brain tissue, using markers for microglia and neuronal elements as an example. Specifically, this paper is a step-by-step protocol for fluorescent visualization of microglia and neurons via immunohistochemistry for Iba1 and Pan-neuronal, respectively. Fluorescence double-labeling is particularly useful for the localization of multiple proteins within the same sample, providing the opportunity to accurately observe interactions between cell types, receptors, ligands, and/or the extracellular matrix in relation to one another as well as protein co-localization within a single cell. Unlike other visualization techniques, fluorescence immunohistochemistry staining intensity may decrease in the weeks to months following staining, unless appropriate precautions are taken. Despite this limitation, in many applications fluorescence double-labeling is preferred over alternatives such as 3,3&#39;-diaminobenzidine tetrahydrochloride (DAB) or alkaline phosphatase (AP), as fluorescence is more time efficient and allows for more precise differentiation between two or more markers. The discussion includes troubleshooting tips and advice to promote success.

This introductory level protocol describes the reagents, equipment, and techniques required to complete immunohistochemical staining of rodent brains, using markers for microglia and neuronal elements as an example.

Immunohistochemistry is a widely used technique for detecting the presence, location, and relative abundance of antigens in situ. This introductory level ...

Detection of Axonally Localized mRNAs in Brain Sections Using High-Resolution In Situ Hybridization

mRNAs are frequently localized to vertebrate axons and their local translation is required for axon pathfinding or branching during development and for maintenance, repair or neurodegeneration in postdevelopmental periods. High throughput analyses have recently revealed that axons have a more dynamic and complex transcriptome than previously expected. These analysis, however have been mostly done in cultured neurons where axons can be isolated from the somato-dendritic compartments. It is virtually impossible to achieve such isolation in whole tissues in vivo. Thus, in order to verify the recruitment of mRNAs and their functional relevance in a whole animal, transcriptome analyses should ideally be combined with techniques that allow the visualization of mRNAs in situ. Recently, novel ISH technologies that detect RNAs at a single-molecule level have been developed. This is especially important when analyzing the subcellular localization of mRNA, since localized RNAs are typically found at low levels. Here we describe two protocols for the detection of axonally-localized mRNAs using a novel ultrasensitive RNA ISH technology. We have combined RNAscope ISH with axonal counterstain using fluorescence immunohistochemistry or histological dyes to verify the recruitment of Atf4 mRNA to axons in vivo in the mature mouse and human brains.

Detection of Axonally Localized mRNAs in Brain Sections Using High-Resolution In Situ Hybridization

RNA in situ hybridization (ISH) enables the visualization of RNAs in cells and tissues. Here we show how combination of RNAscope ISH with immunohistochemistry or histological dyes can be successfully used to detect mRNAs localized to axons in sections of mouse and human brains.

mRNAs are frequently localized to vertebrate axons and their local translation is required for axon pathfinding or branching during development and for ...

Rapid In Situ Hybridization using Oligonucleotide Probes on Paraformaldehyde-prefixed Brain of Rats with Serotonin Syndrome

3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) toxicity may cause region-specific changes in serotonergic mRNA expression due to acute serotonin (5-hydroxytryptamine; 5-HT) syndrome. This hypothesis can be tested using in situ hybridization to detect the serotonin 5-HT2A receptor gene htr2a. In the past, such procedures, utilizing radioactive riboprobe, were difficult because of the complicated workflow that needs several days to perform and the added difficulty that the technique required the use of fresh frozen tissues maintained in an RNase-free environment. Recently, the development of short oligonucleotide probes has simplified in situ hybridization procedures and allowed the use of paraformaldehyde-prefixed brain sections, which are more widely available in laboratories. Here, we describe a detailed protocol using non-radioactive oligonucleotide probes on the prefixed brain tissues. Hybridization probes used for this study include dapB (a bacterial gene coding for dihydrodipicolinate reductase), ppiB (a housekeeping gene coding for peptidylprolyl isomerase B), and htr2a (a serotonin gene coding for 5-HT2A receptors). This method is relatively simply, cheap, reproducible and requires less than two days to complete.

Rapid In Situ Hybridization using Oligonucleotide Probes on Paraformaldehyde-prefixed Brain of Rats with Serotonin Syndrome

This protocol describes a rapid and simplified in situ hybridization method ideal forparaformaldehyde-prefixed brain, thus reducing the need for prolonged complex steps while using fresh frozen tissues. The method is validated using the identification of the serotonin 5-HT2A receptor gene htr2a in rats.

3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) toxicity may cause region-specific changes in serotonergic mRNA expression due to acute serotonin ...

Combining Double Fluorescence In Situ Hybridization with Immunolabelling for Detection of the Expression of Three Genes in Mouse Brain Sections

Detection of gene expression in different types of brain cells e.g., neurons, astrocytes, oligodendrocytes, oligodendrocyte precursors and microglia, can be hampered by the lack of specific primary or secondary antibodies for immunostaining. Here we describe a protocol to detect the expression of three different genes in the same brain section using double fluorescence in situ hybridization with two gene-specific probes followed by immunostaining with an antibody of high specificity directed against the protein encoded by a third gene. The Aspartoacyclase (ASPA) gene, mutations of which can lead to a rare human white matter disease - Canavan disease - is thought to be expressed in oligodendrocytes and microglia but not in astrocytes and neurons. However, the precise expression pattern of ASPA in the brain has yet to be established. This protocol has allowed us to determine that ASPA is expressed in a subset of mature oligodendrocytes and it can be generally applied to a wide range of gene expression pattern studies.

Combining Double Fluorescence In Situ Hybridization with Immunolabelling for Detection of the Expression of Three Genes in Mouse Brain Sections

Localizing gene expression to specific cell types can be challenging due to the lack of specific antibodies. Here we describe a protocol for simultaneous triple detection of gene expression by combining double fluorescence RNA in situ hybridization with immunostaining.

Detection of gene expression in different types of brain cells e.g., neurons, astrocytes, oligodendrocytes, oligodendrocyte precursors and microglia, can ...

Localization of Odorant Receptor Genes in Locust Antennae by RNA In Situ Hybridization

Insects have evolved sophisticated olfactory reception systems to sense exogenous chemical signals. These chemical signals are transduced by Olfactory Receptor Neurons (ORNs) housed in hair-like structures, called chemosensilla, of the antennae. On the ORNs&#39; membranes, Odorant Receptors (ORs) are believed to be involved in odor coding. Thus, being able to identify genes localized to the ORNs is necessary to recognize OR genes, and provides a fundamental basis for further functional in situ studies. The RNA expression levels of specific ORs in insect antennae are very low, and preserving insect tissue for histology is challenging. Thus, it is difficult to localize an OR to a specific type of sensilla using RNA in situ hybridization. In this paper, a detailed and highly effective RNA in situ hybridization protocol particularly for lowly expressed OR genes of insects, is introduced. In addition, a specific OR gene was identified by conducting double-color fluorescent in situ hybridization experiments using a co-expressing receptor gene, Orco, as a marker.

Localization of Odorant Receptor Genes in Locust Antennae by RNA In Situ Hybridization

This paper describes a detailed and highly effective RNA in situ hybridization protocol particularly for low-level expressed Odorant Receptor (OR) genes, as well as other genes, in insect antennae using digoxigenin (DIG)-labeled or biotin-labeled probes.

Insects have evolved sophisticated olfactory reception systems to sense exogenous chemical signals. These chemical signals are transduced by Olfactory ...