This work was supported by the grants from National Natural Science Foundation of China (31201086, 31470759 and 31671219) and Shanghai Natural Science Foundation (12ZR1436900).

C57BL/6 mice are bred in specific pathogen-free conditions. All animal experimental methods are in compliance with the guidelines approved by the Animal Care and Ethics Committee at Second Military Medical University.
1. Dissection of Postnatal Developing Pituitary Gland
<ol>
	<li>Perform anesthesia: Place neonatal mice (P0 - P5) on crushed ice to induce hypothermia. For mice older than 5 days of age, inject 5% urethane (30 &#181;L/g of body weight) intraperitoneally to induce anesthesia. As...

<ol>
	<li>Fauquier, T., Lacampagne, A., Travo, P., Bauer, K., Mollard, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hidden+face+of+the+anterior+pituitary.">Hidden face of the anterior pituitary.</a> Trends Endocrinol Metab. 13 (7), 304-309 (2002).</li><li>Haedo, M. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+pituitary+function+by+cytokines.">Regulation of pituitary function by cytokines.</a> Horm Res. 72 (5), 266-274 (2009).</li><li>Zhu, X., Gleiberman, A. S., Rosenfeld, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+physiology+of+pituitary+development:+signaling+and+transcriptional+networks.">Molecular physiology of pituitary development: signaling and transcriptional networks.</a> Physiol Rev. 87 (3), 933-963 (2007).</li><li>Bancalari, R. E., Gregory, L. C., McCabe, M. J., Dattani, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pituitary+gland+development:+an+update.">Pituitary gland development: an update.</a> Endocr Dev. 23, 1-15 (2012).</li><li>Kelberman, D., Rizzoti, K., Lovell-Badge, R., Robinson, I. C., Dattani, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+regulation+of+pituitary+gland+development+in+human+and+mouse.">Genetic regulation of pituitary gland development in human and mouse.</a> Endocr Rev. 30 (7), 790-829 (2009).</li><li>Peker, S., Kurtkaya-Yapicier, O., Kilic, T., Pamir, M. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microsurgical+anatomy+of+the+lateral+walls+of+the+pituitary+fossa.">Microsurgical anatomy of the lateral walls of the pituitary fossa.</a> Acta Neurochir (Wien). 147 (6), 641-648 (2005).</li><li>Wolpert, S. M., Molitch, M. E., Goldman, J. A., Wood, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Size,+shape,+and+appearance+of+the+normal+female+pituitary+gland.">Size, shape, and appearance of the normal female pituitary gland.</a> AJR Am J Roentgenol. 143 (2), 377-381 (1984).</li><li>Carbajo-Perez, E., Watanabe, Y. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+proliferation+in+the+anterior+pituitary+of+the+rat+during+the+postnatal+period.">Cellular proliferation in the anterior pituitary of the rat during the postnatal period.</a> Cell Tissue Res. 261 (2), 333-338 (1990).</li><li>Nantie, L. B., Himes, A. D., Getz, D. R., Raetzman, L. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Notch+signaling+in+postnatal+pituitary+expansion:+proliferation,+progenitors,+and+cell+specification.">Notch signaling in postnatal pituitary expansion: proliferation, progenitors, and cell specification.</a> Mol Endocrinol. 28 (5), 731-744 (2014).</li><li>Tzou, S. C., Landek-Salgado, M. A., Kimura, H., Caturegli, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+of+mouse+pituitary+immunogen+for+the+induction+of+experimental+autoimmune+hypophysitis.">Preparation of mouse pituitary immunogen for the induction of experimental autoimmune hypophysitis.</a> J Vis Exp. (46), (2010).</li><li>Budry, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Related+pituitary+cell+lineages+develop+into+interdigitated+3D+cell+networks.">Related pituitary cell lineages develop into interdigitated 3D cell networks.</a> Proc Natl Acad Sci U S A. 108 (30), 12515-12520 (2011).</li><li>Wilson, D. B., Wyatt, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histopathology+of+the+pituitary+gland+in+neonatal+little+(lit)+mutant+mice.">Histopathology of the pituitary gland in neonatal little (lit) mutant mice.</a> Histol Histopathol. 7 (3), 451-455 (1992).</li><li>Jonkers, B. W., Sterk, J. C., Wouterlood, F. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcardial+perfusion+fixation+of+the+CNS+by+means+of+a+compressed-air-driven+device.">Transcardial perfusion fixation of the CNS by means of a compressed-air-driven device.</a> J Neurosci Methods. 12 (2), 141-149 (1984).</li><li>Cao, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ZBTB20+is+required+for+anterior+pituitary+development+and+lactotrope+specification.">ZBTB20 is required for anterior pituitary development and lactotrope specification.</a> Nat Commun. 7, 11121 (2016).</li></ol>

For developing murine pituitaries, it has been technically difficult to obtain proper coronal sections due to their tiny and fragile features and unique anatomical characteristics6,8. Some research groups thus chose mid-sagittal sections to analyze the morphology of embryonic and neonatal pituitary11,12. Though the mid-sagittal section of pituitary is also capable of showing anterior, intermediate, and po...

The pituitary gland or hypophysis is an important endocrine organ secreting hormones essential for homeostasis1,2. Anatomically, the pituitary gland is a &#39;&#39;two-in-one&#39;&#39; structure consisting of the neurohypophysis and the adenohypophysis. These parts have different embryonic origins and function very differently. The neurohypophysis is derived from the neural ectoderm and secretes oxytocin and antidiuretic hormone. The adenohypophysis originates from Rathke&#39;s pouch and is responsible for the release of hormones including growth hormone, prolactin, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, adrenocorticotropic hormone, and melanocyte-stimulating hormone3,4,5.
The pituitary gland rests on the dorsal surface of the sphenoid bone (sella turcica) of the mouse skull and is attached to the floor of the brain by a fragile stalk. It is surrounded laterally by trigeminal nerves and anteriorly by the optic chiasm6,7. The gland has an elongated oval shape with its long axis perpendicular to that of the head. On its dorsal surface, the neurohypophysis and the adenohypophysis can easily be demarcated, with the former occupying the dorsal medial region and the latter extending laterally and ventrally. During postnatal development, the size of pituitary increases rapidly in the first month after birth8,9. Nevertheless, the mouse pituitary is still very small in size with an average weight of 1.9 mg and a long-axis diameter of ~3 mm in adult10, a long-axis diameter of 2 - 2.5 mm at postnatal day 21 (P21), and only 1 - 1.5 mm at P0.
A coronal section is preferred to display both adenohypophysis and neurohypophysis in a single slice of the mouse pituitary. However, some technical skills are required to obtain satisfying coronal sections of pituitary glands from developing mice due to its exceptionally small size and distinct anatomy. In this video article, we demonstrate how to dissect mouse pituitary glands and prepare pituitary coronal sections at different development stages.

<table>
	<tbody>
		<tr>
			<td>Tools/Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical scissors-straight</td>
			<td>JinZhong</td>
			<td>J21010</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Fine scissors-strainght</td>
			<td>JinZhong</td>
			<td>WA1010</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Blunt forceps</td>
			<td>JinZhong</td>
			<td>JD1020</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Fine forceps</td>
			<td>Dumont</td>
			<td>RS-5015</td>
			<td>for isolation of the pituitary</td>
		</tr>
		<tr>
			<td>26G (0.45mm) needle</td>
			<td>HongDa</td>
			<td></td>
			<td>for transcardial perfusion</td>
		</tr>
		<tr>
			<td>Syringe (1 mL)</td>
			<td>BD</td>
			<td>300841</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Syringe (10 mL)</td>
			<td>BD</td>
			<td></td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>35mm dish</td>
			<td>Corning</td>
			<td>430165</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Lens cleaning paper</td>
			<td>ShuangQuan</td>
			<td></td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Anatomical microscope</td>
			<td>OLYMPUS</td>
			<td>SZX-ILLB2-200</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Embedding cassette</td>
			<td>Thermo Fisher</td>
			<td>22-272423</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Tissue embedding console system</td>
			<td>KEDEE</td>
			<td>KD-BM11</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Microtome</td>
			<td>Thermo Fisher</td>
			<td>HM315R</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Superfrost-Plus slides</td>
			<td>Thermo Fisher</td>
			<td>22-037-246</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Cover glass</td>
			<td>Thermo Fisher</td>
			<td>12-543</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Fluorescence microscope</td>
			<td>OLYMPUS</td>
			<td>BH2-RFCA</td>
			<td>can be purchased from other vendors</td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Reagents</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Urethane</td>
			<td>BBI</td>
			<td>EB0448</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Sigma</td>
			<td>S9625</td>
			<td>for PBS</td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sigma</td>
			<td>P9541</td>
			<td>for PBS</td>
		</tr>
		<tr>
			<td>Na2HPO4.12H2O</td>
			<td>Sigma</td>
			<td>71650</td>
			<td>for PBS</td>
		</tr>
		<tr>
			<td>K2HPO4</td>
			<td>Sigma</td>
			<td>P2222</td>
			<td>for PBS</td>
		</tr>
		<tr>
			<td>NaNO2</td>
			<td>Sigma</td>
			<td>237213</td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin Sodium Injection</td>
			<td>SPH</td>
			<td>H31022051</td>
			<td>for perfusion saline</td>
		</tr>
		<tr>
			<td>Paraformaldehyde (PFA)</td>
			<td>Sigma</td>
			<td>P6148</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>SCR</td>
			<td>10009218</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylene</td>
			<td>SCR</td>
			<td>10023418</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraffin</td>
			<td>Thermo Fisher</td>
			<td>8330</td>
			<td></td>
		</tr>
		<tr>
			<td>Hematoxylin</td>
			<td>Sigma</td>
			<td>H9627</td>
			<td>for H&#38;E staining</td>
		</tr>
		<tr>
			<td>Eosin Y</td>
			<td>Sigma</td>
			<td>E4009</td>
			<td>for H&#38;E staining</td>
		</tr>
		<tr>
			<td>rabbit anti growth hormone (GH)</td>
			<td>National Hormone</td>
			<td></td>
			<td>for immunostaining</td>
		</tr>
		<tr>
			<td>antibody</td>
			<td>Pituitary Program</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Rabbit anti-mouse GFAP antibody</td>
			<td>Sigma</td>
			<td>G9269</td>
			<td>for immunostaining</td>
		</tr>
		<tr>
			<td>Goat anti-rabbit IgG, HRP</td>
			<td>Jackson</td>
			<td>111-035-003</td>
			<td>for immunostaining</td>
		</tr>
		<tr>
			<td>TSA system</td>
			<td>NEN Life Science Products</td>
			<td>NEL700</td>
			<td>for immunostaining</td>
		</tr>
		<tr>
			<td>Streptavidin, Alexa Fluor 594</td>
			<td>Thermo Fisher</td>
			<td>S32356</td>
			<td>for immunostaining</td>
		</tr>
		<tr>
			<td>Anti-FITC Alexa Fluor 488</td>
			<td>Thermo Fisher</td>
			<td>A11090</td>
			<td>for immunostaining</td>
		</tr>
	</tbody>
</table>

dissection and coronal slice preparation of developing mouse pituitary gland

The pituitary gland or hypophysis is an important endocrine organ secreting hormones essential for homeostasis. It consists of two glands with separate embryonic origins and functions &#8212; the neurohypophysis and the adenohypophysis. The developing mouse pituitary gland is tiny and delicate with an elongated oval shape. A coronal section is preferred to display both the adenohypophysis and neurohypophysis in a single slice of the mouse pituitary.
The goal of this protocol is to achieve proper pituitary coronal sections with well-preserved tissue architectures from developing mice. In this protocol, we describe in detail how to dissect and process pituitary glands properly from developing mice. First, mice are fixed by transcardial perfusion of formaldehyde prior to dissection. Then three different dissecting techniques are applied to obtain intact pituitary glands depending on the age of mice. For fetal mice aged embryonic days (E) 17.5 - 18.5 and neonates up to 4 days, the entire sella regions including the sphenoid bone, gland, and trigeminal nerves are dissected. For pups aged postnatal days (P) 5 - 14, the pituitary glands connected with trigeminal nerves are dissected as a whole. For mice over 3 weeks old, the pituitary glands are carefully dissected free from the surrounding tissues. We also display how to embed the pituitary glands in a proper orientation by using the surrounding tissues as landmarks to obtain satisfying coronal sections. These methods are useful in analyzing histological and developmental features of pituitary glands in developing mice.

This protocol presents a method to dissect pituitary glands from developing mice. For the neonatal mouse, the whole sella regions containing the pituitary gland, the trigeminal nerves, and the underneath sphenoid bone were dissected out from the skull base. The tiny and delicate pituitary gland remained intact during the process (Figure 1A). For mice older than 5 days, the pituitary glands attached to the lateral trigeminal nerves were then isolated. The gros...

Watch this Scientific Journal Video about Dissection and Coronal Slice Preparation of Developing Mouse Pituitary Gland at JoVE.com

Dissection and Coronal Slice Preparation of Developing Mouse Pituitary Gland

We present a protocol to dissect pituitary glands and prepare pituitary coronal sections from developing mice.

The pituitary gland or hypophysis is an important endocrine organ secreting hormones essential for homeostasis. It consists of two glands with separate ...

The overall goal of this procedure is to achieve proper pituitary coronal sections with well-preserved tissue architectures from developing mice. This procedure can help answer key questions in the field of pituitary development, such as pituitary histology, cell differentiation, proliferation, and apoptosis. The main advantage of this technique is that developing murine pituitaries can be dissected without visible damage and properly oriented for achieving coronal sections.We first had the idea for this method when we found that, for developing murine pituitaries, it was technically difficult to obtain proper coronal sections. After anesthetizing and fixing mice according to the text protocol, use scissors to cut the skull bone open. Next, with forceps, gently lift the hindbrain from the base of the skull.Then, at the first sign of the sella turcica, stop lifting but hold the hindbrain, and use fine scissors to cut the pituitary stalk and nerve fibers connected to the base of the brain. Continue to lift and remove the whole brain to fully expose the pituitary gland. The pituitary gland rests on the dorsal surface of the sphenoid bone and is surrounded laterally by trigeminal nerves.Then use scissors to cut the entire sellar region including the pituitary gland, lateral trigeminal nerves, and beneath the sphenoid bone. Put the tissue into a 35 mm dish containing 4%PFA, and incubate it at 4 degrees Celsius for 40 minutes to 3 hours, depending on the ages. Then use 10 mL of PBS to wash the fixed tissue for five changes at 15 minutes each.Transfer the fixed tissue into a 35 mm dish containing 1 mL of PBS, and under a stereo microscope, dissociate the pituitary glands. For P5 to P14 pituitaries, with fine forceps and scissors remove the connective membranes between the nerves and the bone, and carefully isolate the pituitary gland together with lateral trigeminal nerves as a whole, but leaving the sella turcica. For P21 and adult pituitaries, remove the nerves and connective membranes around the pituitary, and free the gland from the surrounding tissues.After dehydration, xylene clearing, and wax infiltration carried out according to the text protocol, on a tissue embedding console system, remove the specimen from the cassette and place it into a base mold half-filled with molten paraffin wax. For P21 and adult pituitary glands, use warmed fine forceps to position the pituitary gland with its short axis perpendicular to the bottom surface of a base mold. For P0 to P4 pituitaries, orient the specimens with their sphenoid bones perpendicular to the bottom surface of a base mold.For P5 to P14 pituitary glands, orient the specimens with their trigeminal nerves perpendicular to the bottom surface of a base mold. After positioning the gland, use warmed fine forceps to gently hold the tissue in the desired position until the wax becomes semi-solid on a cooling plate. Top up the mold with molten paraffin wax.Allow the paraffin block to cool until the wax is fully solidified. Chill the paraffin block at minus 20 degrees Celsius for 10 to 20 minutes, then use a microtome to cut it into thin slices, fine tuning the position of the paraffin block during sectioning. Carry out immunolabeling according to the text protocol.As shown here, to dissect the pituitary gland from the neonatal mouse, the whole sellar region containing the pituitary gland, the trigeminal nerves, and the sphenoid bone underneath were dissected out from the skull base. The tiny and delicate pituitary gland remained intact during the process. For mice older than five days, the pituitary glands attached to the lateral trigeminal nerves were isolated.The growth structure of the pituitary gland isolated from the P7 mouse was well-preserved. Here, the pituitary gland of the P21 mouse was successfully isolated without visible damage while removing its surrounding tissue. In this figure, H&E staining of properly-oriented coronal sections demonstrates well-preserved morphology of both adenohypophysis and neurohypophysis in P0, P7, and P21 pituitary glands.Finally, the processed slides were also compatible with immunofluorescence labeling. As an example, the adenohypophysis and neurohypophysis showed specific immunolabeling of GH and GFAP, respectively. Once mastered, the process from dissection to embedding can be done in 7.5 hours in adult mice and even less in younger mice if it's performed properly.While attempting this procedure, it's important to remember to dissect the entire sellar region to avoid touching pituitary gland with any surgical tools. Following this procedure, the pituitary that has not been prefixed can also be isolated. In that case, more caution should be taken to avoid any undesired damage.The gland should also be dissected as quickly as possible. After watching this video, you should have a good understanding of how to dissect mouse pituitary glands and prepare pituitary coronal sections at different developmental stages.

dissection-coronal-slice-preparation-developing-mouse-pituitary

Research

JoVE Journal

Developmental Biology

16.8K ビュー.  Second Military Medical University. The overall goal of this procedure is to achieve proper pituitary coronal sections with well-preserved tissue architectures from developing mice. This procedure can help answer key questions in the field of pituitary development, such as pituitary histology, cell differentiation, proliferation, and apoptosis. The main advantage of this technique is that developing murine pituitaries can be dissected without visible damage and properly oriented for achieving coronal sections.We first ha...

ビデオ: Dissection and Coronal Slice Preparation of Developing Mouse Pituitary Gland

Organotypic Slice Cultures for Studies of Postnatal Neurogenesis

Here we describe a technique for studying hippocampal postnatal neurogenesis in the rodent brain using the organotypic slice culture technique. This method maintains the characteristic topographical morphology of the hippocampus while allowing direct application of pharmacological agents to the developing hippocampal dentate gyrus. Additionally, slice cultures can be maintained for up to 4 weeks and thus, allow one to study the maturation process of newborn granule neurons. Slice cultures allow for efficient pharmacological manipulation of hippocampal slices while excluding complex variables such as uncertainties related to the deep anatomic location of the hippocampus as well as the blood brain barrier. For these reasons, we sought to optimize organotypic slice cultures specifically for postnatal neurogenesis research.

Here we describe a technique for studying hippocampal postnatal neurogenesis using the organotypic slice culture technique. This method allows for in vitro manipulation of adult neurogenesis and allows for the direct application of pharmacological agents to the cultured hippocampus.

Here we describe a technique for studying hippocampal postnatal neurogenesis in the rodent brain using the organotypic slice culture technique. This ...

Ex Utero Electroporation and Organotypic Slice Culture of Mouse Hippocampal Tissue

Mouse genetics offers a powerful tool determining the role of specific genes during development. Analyzing the resulting phenotypes by immunohistochemical and molecular methods provides information of potential target genes and signaling pathways. To further elucidate specific regulatory mechanisms requires a system allowing the manipulation of only a small number of cells of a specific tissue by either overexpression, ablation or re-introduction of specific genes and follow their fate during development. To achieve this ex utero electroporation of hippocampal structures, especially the dentate gyrus, followed by organotypic slice culture provides such a tool. Using this system to generate mosaic deletions allows determining whether the gene of interest regulates cell-autonomously developmental processes like progenitor cell proliferation or neuronal differentiation. Furthermore it facilitates the rescue of phenotypes by re-introducing the deleted gene or its target genes. In contrast to in utero electroporation the ex utero approach improves the rate of successfully targeting deeper layers of the brain like the dentate gyrus. Overall ex utero electroporation and organotypic slice culture provide a potent tool to study regulatory mechanisms in a semi-native environment mirroring endogenous conditions.

Ex Utero Electroporation and Organotypic Slice Culture of Mouse Hippocampal Tissue

Here we present a protocol providing a tool to examine regulatory mechanisms of specific genes during hippocampal development. Employing ex utero electroporation and organotypic slice culture allows the up- and down-regulation of the expression of genes of interest in single cells and follow their fate during development.

Mouse genetics offers a powerful tool determining the role of specific genes during development. Analyzing the resulting phenotypes by immunohistochemical ...

Methods to Examine the Lymph Gland and Hemocytes in Drosophila Larvae

Many parallels exist between the Drosophila and mammalian hematopoietic systems, even though Drosophila lack the lymphoid lineage that characterize mammalian adaptive immunity. Drosophila and mammalian hematopoiesis occur in spatially and temporally distinct phases to produce several blood cell lineages. Both systems maintain reservoirs of blood cell progenitors with which to expand or replace mature lineages. The hematopoietic system allows Drosophila and mammals to respond to and to adapt to immune challenges. Importantly, the transcriptional regulators and signaling pathways that control the generation, maintenance, and function of the hematopoietic system are conserved from flies to mammals. These similarities allow Drosophila to be used to genetically model hematopoietic development and disease.
Here we detail assays to examine the hematopoietic system of Drosophila larvae. In particular, we outline methods to measure blood cell numbers and concentration, visualize a specific mature lineage in vivo, and perform immunohistochemistry on blood cells in circulation and in the hematopoietic organ. These assays can reveal changes in gene expression and cellular processes including signaling, survival, proliferation, and differentiation and can be used to investigate a variety of questions concerning hematopoiesis. Combined with the genetic tools available in Drosophila, these assays can be used to evaluate the hematopoietic system upon defined genetic alterations. While not specifically outlined here, these assays can also be used to examine the effect of environmental alterations, such as infection or diet, on the hematopoietic system.

Methods to Examine the Lymph Gland and Hemocytes in Drosophila Larvae

Drosophila and mammalian hematopoietic systems share many common features, making Drosophila an attractive genetic model to study hematopoiesis. Here we demonstrate dissection and mounting of the major larval hematopoietic organ for immunohistochemistry. We also describe methods to assay various larval hematopoietic compartments including circulating hemocytes and sessile crystal cells.

Many parallels exist between the Drosophila and mammalian hematopoietic systems, even though Drosophila lack the lymphoid lineage that characterize ...

Live Confocal Imaging of Developing Arabidopsis Flowers

The study of plant growth and development has long relied on experimental techniques using dead, fixed tissues and lacking proper cellular resolution. Recent advances in confocal microscopy, combined with the development of numerous fluorophores, have overcome these issues and opened the possibility to study the expression of several genes simultaneously, with a good cellular resolution, in live samples. Live confocal imaging provides plant biologists with a powerful tool to study development, and has been extensively used to study root growth and the formation of lateral organs on the flanks of the shoot apical meristem. However, it has not been widely applied to the study of flower development, in part due to challenges that are specific to imaging flowers, such as the sepals that grow over the flower meristem, and filter out the fluorescence from underlying tissues. Here, we present a detailed protocol to perform live confocal imaging on live, developing Arabidopsis flower buds, using either an upright or an inverted microscope.

Live confocal imaging provides biologists with a powerful tool to study development. Here, we present a detailed protocol for the live confocal imaging of developing Arabidopsis flowers.

The study of plant growth and development has long relied on experimental techniques using dead, fixed tissues and lacking proper cellular resolution. ...

Dissection and Culture of Mouse Embryonic Kidney

The goal of this protocol is to describe a method for the dissection, isolation, and culture of mouse metanephric rudiments. 
During mammalian kidney development, the two progenitor tissues, the ureteric bud and the metanephric mesenchyme, communicate and reciprocally induce cellular mechanisms to eventually form the collecting system and the nephrons of the kidney. As mammalian embryos grow intrauterine and therefore are inaccessible to the observer, an organ culture has been developed. With this method, it is possible to study epithelial-mesenchymal interactions and cellular behavior during kidney organogenesis. Furthermore, the origin of congenital kidney and urogenital tract malformations can be investigated. After careful dissection, the metanephric rudiments are transferred onto a filter that floats on culture medium and can be kept in a cell culture incubator for several days. However, one must be aware that the conditions are artificial and could influence the metabolism in the tissue. Also, the penetration of test substances could be limited due to the extracellular matrix and basal membrane present in the explant.
One main advantage of organ culture is that the experimenter can gain direct access to the organ. This technology is cheap, simple, and allows a large number of modifications, such as the addition of biologically active substances, the study of genetic variants, and the application of advanced imaging techniques.

This protocol describes a method for isolating and culturing metanephric rudiments from mouse embryos.

The goal of this protocol is to describe a method for the dissection, isolation, and culture of mouse metanephric rudiments. 
During mammalian kidney ...

Dissection and Staining of Drosophila Pupal Ovaries

Unlike adult Drosophila ovaries, pupal ovaries are relatively difficult to access and examine due to their small size, translucence, and encasing within a pupal case. The challenge of dissecting pupal ovaries also lies in their physical location within the pupa: the ovaries are surrounded by fat body cells inside the pupal abdomen, and these fat cells must be removed to allow for proper antibody staining. To overcome these challenges, this protocol utilizes customized Pasteur pipets to extract fat body cells from the pupal abdomen. Moreover, a chambered coverglass is used in place of a microcentrifuge tube during the staining process to improve visibility of the pupae. However, despite these and other advantages of the tools used in this protocol, successful execution of these techniques may still involve several days of practice due to the small size of pupal ovaries. The techniques outlined in this protocol could be applied to time course experiments in which ovaries are analyzed at various stages of pupal development.

Dissection and Staining of Drosophila Pupal Ovaries

The Drosophila ovary is an excellent model system for studying stem cell niche development. Though methods for dissecting larval and adult ovaries have been published, pupal ovary dissections require different techniques that have not been published in detail. Here we outline a protocol for dissecting, staining, and mounting pupal ovaries.

Unlike adult Drosophila ovaries, pupal ovaries are relatively difficult to access and examine due to their small size, translucence, and encasing within a ...

Immunohistochemical Detection of 5-Methylcytosine and 5-Hydroxymethylcytosine in Developing and Postmitotic Mouse Retina

The epigenetics of retinal development is a well-studied research field, which promises to bring a new level of understanding about the mechanisms of a variety of human retinal degenerative diseases and pinpoint new treatment approaches. The nuclear architecture of mouse retina is organized in two different patterns: conventional and inverted. Conventional pattern is universal where heterochromatin is localized to the periphery of the nucleus, while active euchromatin resides in the nuclear interior. In contrast, inverted nuclear pattern is unique to the adult rod photoreceptor cell nuclei where heterochromatin localizes to the nuclear center, and euchromatin resides in the nuclear periphery. DNA methylation is predominantly observed in chromocenters. DNA methylation is a dynamic covalent modification on the cytosine residues (5-methylcytosine, 5mC) of CpG dinucleotides that are enriched in the promoter regions of many genes. Three DNA methyltransferases (DNMT1, DNMT3A and DNMT3B) participate in methylation of DNA during development. Detecting 5mC with immunohistochemical techniques is very challenging, contributing to variability in results, as all DNA bases including 5mC modified bases are hidden within the double-stranded DNA helix. However, detailed delineation of 5mC distribution during development is very informative. Here, we describe a reproducible technique for robust immunohistochemical detection of 5mC and another epigenetic DNA marker 5-hydroxymethylcytosine (5hmC), which colocalizes with the &#34;open&#34;, transcriptionally active chromatin in developing and postmitotic mouse retina.

The objective of this report is to describe the protocol for robust immunohistochemical detection of epigenetic markers, 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in developing and postmitotic mouse retina.

The epigenetics of retinal development is a well-studied research field, which promises to bring a new level of understanding about the mechanisms of a ...

Assessment of Ultrastructural Neuroplasticity Parameters After In Utero Transduction of the Developing Mouse Brain and Spinal Cord

The present study combines in utero transduction with transmission electron microscopy (TEM) aiming at a precise morphometrical analysis of ultrastructural parameters in unambiguously identified topographical structures, affected by a protein of interest that is introduced into the organism via viral transfer. This combined approach allows for a smooth transition from macrostructural to ultrastructural identification by following topographical navigation maps in a tissue atlas. High-resolution electron microscopy of the in-utero-transduced tissue reveals the fine ultrastructure of the neuropil and its plasticity parameters, such as cross-sectioned synaptic bouton areas, the number of synaptic vesicles and mitochondria within a bouton profile, the length of synaptic contacts, cross-sectioned axonal areas, the thickness of myelin sheaths, the number of myelin lamellae, and cross-sectioned areas of mitochondria profiles. The analysis of these parameters reveals essential insights into changes of ultrastructural plasticity in the areas of the nervous system that are affected by the viral transfer of the genetic construct. This combined method can not only be used for studying the direct effect of genetically engineered biomolecules and/or drugs on neuronal plasticity but also opens the possibility to study the in utero rescue of neuronal plasticity (e.g., in the context of neurodegenerative diseases).

The combination of transmission electron microscopy and in utero transduction is a powerful approach for studying morphological changes in the fine ultrastructure of the nervous system during development. This combined method allows deep insights into changes in structural details underlying neuroplasticity with respect to their topographical representation.

The present study combines in utero transduction with transmission electron microscopy (TEM) aiming at a precise morphometrical analysis of ...

Tissue Preparation and Immunostaining of Mouse Craniofacial Tissues and Undecalcified Bone

Tissue immunostaining provides highly specific and reliable detection of proteins of interest within a given tissue. Here we describe a complete and simple protocol to detect protein expression during craniofacial morphogenesis/pathogenesis using mouse craniofacial tissues as examples. The protocol consists of preparation and cryosectioning of tissues, indirect immunofluorescence, image acquisition, and quantification. In addition, a method for preparation and cryosectioning of undecalcified hard tissues for immunostaining is described, using craniofacial tissues and long bones as examples. Those methods are key to determine the protein expression and morphological/anatomical changes in various tissues during craniofacial morphogenesis/pathogenesis. They are also applicable to other tissues with appropriate modifications. Knowledge of the histology and high quality of sections are critical to draw scientific conclusions from experimental outcomes. Potential limitations of this methodology include but are not limited to specificity of antibodies and difficulties of quantification, which are also discussed here.

Here, we present a detailed protocol to detect and quantify protein levels during craniofacial morphogenesis/pathogenesis by immunostaining using mouse craniofacial tissues as examples. In addition, we describe a method for preparation and cryosectioning of undecalcified hard tissues from young mice for immunostaining.

Tissue immunostaining provides highly specific and reliable detection of proteins of interest within a given tissue. Here we describe a complete and ...

Transillumination-Assisted Dissection of Specific Stages of the Mouse Seminiferous Epithelial Cycle for Downstream Immunostaining Analyses

Spermatogenesis is a unique differentiation process that ultimately gives rise to one of the most distinct cell types of the body, the sperm. Differentiation of germ cells takes place in the cytoplasmic pockets of somatic Sertoli cells that host 4 to 5 generations of germ cells simultaneously and coordinate and synchronize their development. Therefore, the composition of germ cell types within a cross-section is constant, and these cell associations are also known as stages (I&#8211;XII) of the seminiferous epithelial cycle. Importantly, stages can also be identified from intact seminiferous tubules based on their differential light absorption/scatter characteristics revealed by transillumination, and the fact that the stages follow each other along the tubule in a numerical order. This article describes a transillumination-assisted microdissection method for the isolation of seminiferous tubule segments representing specific stages of mouse seminiferous epithelial cycle. The light absorption pattern of seminiferous tubules is first inspected under a dissection microscope, and then tubule segments representing specific stages are cut and used for downstream applications. Here we describe immunostaining protocols for stage-specific squash preparations and for intact tubule segments. This method allows a researcher to focus on biological events taking place at specific phases of spermatogenesis, thus providing a unique tool for developmental, toxicological, and cytological studies of spermatogenesis and underlying molecular mechanisms.

This protocol describes transillumination-assisted microdissection of segments of adult mouse seminiferous tubules representing specific stages of seminiferous epithelial cycle, and cell types therein, and subsequent immunostaining of squash preparations and intact tubule segments.