We would like to thank all the members of the McMahon laboratory for their assistance and support.&#160;This research was supported by grants from an NIH/NCI R01 CA176839-01 (to MM) and an Institutional Research and Academic Career Development Award (IRACDA to JS).&#160;

1. Preparation of Whole Cell Lysates from Cell Culture
<ol>
	<li>Place cell culture dishes on ice and add cold PBS with 5 mM EDTA (e.g. 5 ml of PBS with 5 mM EDTA/10 cm2 plate). Remove adherent cells from the dish using a cell scraper and then transfer the cell suspension to a cold 15 ml conical tube.</li>
	<li>Pellet the cell suspensions by low-speed centrifugation at 1,000 rpm (230 x g) for 5 min at 4 &#176;C. Place conical tubes on ice and carefully aspirate the supernatant without disrupting the...

<ol>
	<li>Burnette, W. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Western+blotting:+electrophoretic+transfer+of+proteins+from+sodium+dodecyl+sulfate--polyacrylamide+gels+to+unmodified+nitrocellulose+and+radiographic+detection+with+antibody+and+radioiodinated+protein+A.">Western blotting: electrophoretic transfer of proteins from sodium dodecyl sulfate--polyacrylamide gels to unmodified nitrocellulose and radiographic detection with antibody and radioiodinated protein A.</a> Anal. Biochem. 112, 195-203 (1981).</li><li>Renart, J., Reiser, J., Stark, G. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfer+of+proteins+from+gels+to+diazobenzyloxymethyl-paper+and+detection+with+antisera:+a+method+for+studying+antibody+specificity+and+antigen+structure.">Transfer of proteins from gels to diazobenzyloxymethyl-paper and detection with antisera: a method for studying antibody specificity and antigen structure.</a> Proc. Natl. Acad. Sci. U.S.A. 76, 3116-3120 (1979).</li><li>Towbin, H., Staehelin, T., Gordon, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophoretic+transfer+of+proteins+from+polyacrylamide+gels+to+nitrocellulose+sheets:+procedure+and+some+applications.">Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.</a> Proc. Natl. Acad. Sci. U.S.A. 76, 4350-4354 (1979).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> NuPAGE Technical Guide. Life Technologies Corporation. IM-1001. 60, (2010).</li><li>Laemmli, U. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cleavage+of+structural+proteins+during+the+assembly+of+the+head+of+bacteriophage+T4.">Cleavage of structural proteins during the assembly of the head of bacteriophage T4.</a> Nature. 227, 680-685 (1970).</li><li>Kubo, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+incubation+of+solutions+of+proteins+containing+dodecyl+sulfate+on+the+cleavage+of+peptide+bonds+by+boiling.">Effect of incubation of solutions of proteins containing dodecyl sulfate on the cleavage of peptide bonds by boiling.</a> Anal. Biochem. 225, 351-353 (1995).</li><li>Moos, M., Nguyen, N. Y., Liu, T. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reproducible+high+yield+sequencing+of+proteins+electrophoretically+separated+and+transferred+to+an+inert+support.">Reproducible high yield sequencing of proteins electrophoretically separated and transferred to an inert support.</a> J. Biol. Chem. 263, 6005-6008 (1988).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=iBlot+Dry+Blotting+System.">iBlot Dry Blotting System.</a> Life Technologies Corporation. 25-0911, 84 (2012).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Western+Blot+Analysis.">Western Blot Analysis.</a> LI-COR Biosciences. 988-12622, (2012).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odyssey+Infrared+Imaging+System+Application+Software+Version+3.030.">Odyssey Infrared Imaging System Application Software Version 3.030.</a> LI-COR Biosciences. , (2007).</li><li>Hambaeus, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+Milk+Composition.">Human Milk Composition.</a> Clin. Nutr. 54, 219-236 (1984).</li><li>DenHollander, N., Befus, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Loss+of+antigens+from+immunoblotting+membranes.">Loss of antigens from immunoblotting membranes.</a> J. Immunol. Methods. 122, 129-135 (1989).</li></ol>

The critical steps in generating high-quality, quantitative Western blots according to this protocol are the following: 1) measuring protein concentrations; 2) sample preparation; 3) blocking the membrane and; 4) quality and caliber of the primary antibody.
The accuracy of measuring total protein concentrations can have a major impact on quantifying protein bands since the exceptional sensitivity of infrared fluorescent detection will amplify any slight differences found in the protein concent...

The technique of Western blotting was first developed between 1977 and 1979 in order to create a better method for detecting proteins using antibodies1-3. This procedure utilized electrophoretic transfer of proteins to membranes from SDS-PAGE gels with target proteins visualized using secondary antibodies and detected by autoradiography, UV light, or a peroxidase reaction product3. Thus, these same basic principles are still widely used in today&#39;s Western blot protocols. However, this classic Western blotting technique does present many disadvantages, such as slow electrophoresis run times, low resolution and artificial protein bands, susceptibility to protein degradation, and limited sensitivity as well as poor data quality4. Therefore, this protocol describes significant advances and improvements to the standard Western blot procedure that generates more accurate qualitative and quantitative data.
The Laemmli system for separating a broad range of proteins using SDS-PAGE is the most widely used gel system for Western blotting5. Despite the popularity of this Western blotting system, this method can result in band distortion, loss of resolution, and spurious bands4. This may be a consequence of the deamination and alkylation of proteins due to the high pH (9.5) of the separating gel, reoxidation of reduced disulfide bonds due to the varying redox state of the gel, and cleavage of aspartyl-prolyl peptide bonds due to heating the protein in Laemmli buffer (pH 5.2)4,6. The Bis-Tris gel system, which operates at a neutral pH (7.0), provides significant benefits over the Lamemmli system. This system improves protein stability, minimizes protein modifications, maintains proteins in their reduced states, prevents aspartyl-prolyl cleavage during electrophoresis, and more importantly, the electrophoresis run time is 35 min4,6,7. In addition, the Bis-Tris gel system also produces sharper bands, higher resolution and separation, and increased sensitivity resulting in more reliable data4.
In conjunction with the Bis-Tris gel system, the iBlot dry blotting system uses high field strength and currents to significantly reduce the transfer time of proteins from gels onto membranes within 7 min8. This transfer system is based on the dry blotting method that generates a more efficient and reliable transfer of proteins8. For a detailed comparison of the efficacy of the iBlot transfer system to the conventional transfer systems please refer to the following website: <a href="http://www.invitrogen.com/site/us/en/home/Products-and-Services/Applications/Protein-Expression-and-Analysis/Western-Blotting/Western-Blot-Transfer/iBlot-Dry-Blotting-System/iBlot-Dry-Blotting-Comparison-to-Semi-Dry-and-Wet.html">http://www.invitrogen.com/site/us/en/home/Products-and-Services/Applications/Protein-Expression-and-Analysis/Western-Blotting/Western-Blot-Transfer/iBlot-Dry-Blotting-System/iBlot-Dry-Blotting-Comparison-to-Semi-Dry-and-Wet.html</a>. It utilizes an anode and cathode stack, which are comprised of a gel matrix that contains the appropriate transfer buffers, that act as ion reservoirs8. During the transfer, water electrolysis helps to prevent the generation of oxygen from the copper anode resulting in a more consistent protein transfer without causing band distortion8. Moreover, this transfer system also increases the transfer speed by reducing the distance between the electrodes8.
Although chemiluminescence is the most common and traditional technique for protein detection of Western blot analyses, two-color infrared fluorescent detection greatly improves the sensitivity, quality, and accuracy of Western blot data. This detection method uses infrared laser excitation in two optimal wavelengths, 700 nm and 800 nm, to generate a clear data image with the greatest signal-to-noise ratio and highest sensitivity9. Thus, two target proteins can be visualized simultaneously on the same membrane using the 700 nm and 800 nm fluorescent detection channels. More importantly, the linearity and dynamic range of infrared fluorescence allows for precise quantitative analysis of both strong and weak protein bands9. Furthermore, this protocol provides tremendous advantages and improvements over the classic Western blotting technique by decreasing the electrophoresis and transfer times of this experiment without compromising the efficacy of these processes and utilizing infrared fluorescent protein detection to produce greater qualitative and quantitative Western blot data.

<table border="0" cellpadding="0" cellspacing="0" width="624">
	<colgroup>
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="19">
			<td height="19" style="height:19px;width:297px;">BCA Protein Assay Kit</td>
			<td style="width:204px;">Thermo Scientific/Pierce</td>
			<td style="width:123px;">23225</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">4x NuPAGE&#174; LDS Sample Buffer&#160;</td>
			<td>Invitrogen/Life Technologies</td>
			<td>NP0007</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">10x NuPAGE&#174; Sample Reducing Agent&#160;</td>
			<td>Invitrogen/Life Technologies</td>
			<td>NP0004</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">20x NuPAGE&#174; MES SDS Running Buffer</td>
			<td>Invitrogen/Life Technologies</td>
			<td>NP0002</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">20x NuPAGE&#174; MOPS SDS Running Buffer</td>
			<td>Invitrogen/Life Technologies</td>
			<td>NP0001</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">NuPAGE&#174; Antioxidant</td>
			<td>Invitrogen/Life Technologies</td>
			<td>NP0005</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:38px;width:297px;">NuPAGE&#174; Novex&#174; 4-12% Bis-Tris Gel 1.5 mm, 10 well&#160;</td>
			<td>Invitrogen/Life Technologies</td>
			<td>NP0335BOX</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:38px;width:297px;">NuPAGE&#174; Novex&#174; 4-12% Bis-Tris Gel 1.5 mm, 15 well</td>
			<td>Invitrogen/Life Technologies</td>
			<td>NP0336BOX</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">SeeBlue&#174; Plus2 Pre-Stained Standard&#160;</td>
			<td>Invitrogen/Life Technologies</td>
			<td>LC5925</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">XCell SureLock&#174; Mini-Cell&#160;</td>
			<td>Invitrogen/Life Technologies</td>
			<td>EI0001</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">iBlot&#174; Transfer Stack, PVDF Regular</td>
			<td>Invitrogen/Life Technologies</td>
			<td>IB4010-01</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">iBlot&#174;Transfer Stack, PVDF Mini</td>
			<td>Invitrogen/Life Technologies</td>
			<td>IB4010-02</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">iBlot&#174; Transfer Stack, Nitrocellulose Regular</td>
			<td>Invitrogen/Life Technologies</td>
			<td>IB3010-01</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">iBlot&#174;Transfer Stack, Nitrocellulose Mini</td>
			<td>Invitrogen/Life Technologies</td>
			<td>IB3010-02</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">iBlot&#174; Gel Transfer Device&#160;</td>
			<td>Invitrogen/Life Technologies</td>
			<td>IB1001</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">&#946;-Actin</td>
			<td>Sigma</td>
			<td>A2228</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Phospho-BIM (S69)</td>
			<td>BD Biosciences</td>
			<td>N/A</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Total BIM</td>
			<td>Epitomics</td>
			<td>1036-1</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Phospho-ERK1/2 (T202/Y204)</td>
			<td>Cell Signaling Technology</td>
			<td>4370</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Total ERK1/2</td>
			<td>Cell Signaling Technology</td>
			<td>9107</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Odyssey&#174; Blocking Buffer&#160;</td>
			<td>LI-COR Biosciences</td>
			<td>927-40000&#160;</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">IRDye 800CW Goat anti-Rabbit IgG</td>
			<td>LI-COR Biosciences</td>
			<td>926-32211&#160;</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">IRDye 680LT Goat anti-Mouse IgG&#160;</td>
			<td>LI-COR Biosciences</td>
			<td>926-68020&#160;</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Western Incubation Box, Medium&#160;</td>
			<td>LI-COR Biosciences</td>
			<td>929-97205&#160;</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Odyssey&#174; Classic Imaging System</td>
			<td>LI-COR Biosciences</td>
			<td>N/A</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Odyssey&#174; Application Software V3.0.30</td>
			<td>LI-COR Biosciences</td>
			<td>N/A</td>
		</tr>
	</tbody>
</table>

the fastest western in town: a contemporary twist on the classic western blot analysis

The Western blot techniques that were originally established in the late 1970s are still actively utilized today. However, this traditional method of Western blotting has several drawbacks that include low quality resolution, spurious bands, decreased sensitivity, and poor protein integrity. Recent advances have drastically improved numerous aspects of the standard Western blot protocol to produce higher qualitative and quantitative data. The Bis-Tris gel system, an alternative to the conventional Laemmli system, generates better protein separation and resolution, maintains protein integrity, and reduces electrophoresis to a 35 min run time. Moreover, the iBlot dry blotting system, dramatically improves the efficacy and speed of protein transfer to the membrane in 7 min, which is in contrast to the traditional protein transfer methods that are often more inefficient with lengthy transfer times. In combination with these highly innovative modifications, protein detection using infrared fluorescent imaging results in higher-quality, more accurate and consistent data compared to the standard Western blotting technique of chemiluminescence. This technology can simultaneously detect two different antigens on the same membrane by utilizing two-color near-infrared dyes that are visualized in different fluorescent channels. Furthermore, the linearity and broad dynamic range of fluorescent imaging allows for the precise quantification of both strong and weak protein bands. Thus, this protocol describes the key improvements to the classic Western blotting method, in which these advancements significantly increase the quality of data while greatly reducing the performance time of this experiment.

Two-color infrared fluorescence detects both strong and weak bands on the same membrane with enhanced sensitivity and the highest signal-to-noise ratio to produce clear Western blot images. Typical results generated by two-color Western blot detection visualized in both the 700 nm and 800 nm fluorescent channels are exemplified in Figures 1 and 2. The uppermost Western blot in Figure 1 shows the concurrent (overlay) detection of total ERK1/2 in the 800 nm channel (green)...

Watch this Scientific Journal Video about The Fastest Western in Town: A Contemporary Twist on the Classic Western Blot Analysis at JoVE.com

The Fastest Western in Town: A Contemporary Twist on the Classic Western Blot Analysis

This protocol explores the latest advancements in performing Western blot analyses.&#160;These novel modifications employ a Bis-Tris gel system with a 35&#160;min electrophoresis run time, a 7&#160;min dry blotting transfer system, and infrared fluorescent protein detection and imaging that generates higher resolution, quality, sensitivity, and improved accuracy of Western data.

The Western blot techniques that were originally established in the late 1970s are still actively utilized today. However, this traditional method of ...

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Research

JoVE Journal

Biology

Western Blotting Using the Invitrogen NuPage Novex Bis Tris MiniGels

Western Blotting (or immunoblotting) is a standard laboratory procedure allowing investigators to verify the expression of a protein, determine the relative amount of the protein present in different samples, and analyze the results of co-immunoprecipitation experiments. In this method, a target protein is detected with a specific primary antibody in a given sample of tissue homogenate or extract. Protein separation according to molecular weight is achieved using denaturing SDS-PAGE. After transfer to a membrane, the target protein is probed with a specific primary antibody and detected by chemiluminescence.
Since its first description, the western-blotting technique has undergone several improvements, including pre-cast gels and user-friendly equipment. In our laboratory, we have chosen to use the commercially available NuPAGE electrophoresis system from Invitrogen. It is an innovative neutral pH, discontinuous SDS-PAGE, pre-cast mini-gel system. This system presents several advantages over the traditional Laemmli technique including: i) a longer shelf life of the pre-cast gels ranging from 8 months to 1 year; ii) a broad separation range of molecular weights from 1 to 400 kDa depending of the type of gel used; and iii) greater versatility (range of acrylamide percentage, the type of gel, and the ionic composition of the running buffer).
The procedure described in this video article utilizes the Bis-Tris discontinuous buffer system with 4-12% Bis-Tris gradient gels and MES running buffer, as an illustration of how to perform a western-blot using the Invitrogen NuPAGE electrophoresis system. In our laboratory, we have obtained good and reproducible results for various biochemical applications using this western-blotting method.

This technical article describes a standard western-blotting procedure using the commercially available NuPAGE electrophoresis Mini-Gel system from Invitrogen.

Western Blotting (or immunoblotting) is a standard laboratory procedure allowing investigators to verify the expression of a protein, determine the ...

Surgical Induction of Endolymphatic Hydrops by Obliteration of the Endolymphatic Duct

Surgical induction of endolymphatic hydrops (ELH) in the guinea pig by obliteration and obstruction of the endolymphatic duct is a well-accepted animal model of the condition and an important correlate for human Meniere's disease. In 1965, Robert Kimura and Harold Schuknecht first described an intradural approach for obstruction of the endolymphatic duct (Kimura 1965). Although effective, this technique, which requires penetration of the brain's protective covering, incurred an undesirable level of morbidity and mortality in the animal subjects. Consequently, Andrews and Bohmer developed an extradural approach, which predictably produces fewer of the complications associated with central nervous system (CNS) penetration.(Andrews and Bohmer 1989) 
The extradural approach described here first requires a midline incision in the region of the occiput to expose the underlying muscular layer. We operate only on the right side. After appropriate retraction of the overlying tissue, a horizontal incision is made into the musculature of the right occiput to expose the right temporo-occipital suture line. The bone immediately inferio-lateral the suture line (Fig 1) is then drilled with an otologic drill until the sigmoid sinus becomes visible. Medial retraction of the sigmoid sinus reveals the operculum of the endolymphatic duct, which houses the endolymphatic sac. Drilling medial to the operculum into the area of the endolymphatic sac reveals the endolymphatic duct, which is then packed with bone wax to produce obstruction and ultimately ELH. 
In the following weeks, the animal will demonstrate the progressive, fluctuating hearing loss and histologic evidence of ELH.

This video shows how to surgically obstruct the guinea pig's endolymphatic duct to produce endolymphatic hydrops.

Surgical induction of endolymphatic hydrops (ELH) in the guinea pig by obliteration and obstruction of the endolymphatic duct is a well-accepted animal ...

Western Blotting: Sample Preparation to Detection

Western blotting is an analytical technique used to detect specific proteins in a given sample of tissue homogenate or extract. It uses gel electrophoresis to separate native or denatured proteins by the length of the polypeptide (denaturing conditions) or by the 3-D structure of the protein (native/ non-denaturing conditions). The proteins are then transferred to a membrane (typically nitrocellulose or PVDF), where they are probed (detected) using antibodies specific to the target protein.

Western blotting is an analytical technique used to detect specific proteins in a given sample of tissue homogenate or extract.

Western blotting is an analytical technique used to detect specific proteins in a given sample of tissue homogenate or extract. It uses gel ...

Analysis of Cell Cycle Position in Mammalian Cells

The regulation of cell proliferation is central to tissue morphogenesis during the development of multicellular organisms. Furthermore, loss of control of cell proliferation underlies the pathology of diseases like cancer. As such there is great need to be able to investigate cell proliferation and quantitate the proportion of cells in each phase of the cell cycle. It is also of vital importance to indistinguishably identify cells that are replicating their DNA within a larger population. Since a cell&prime;s decision to proliferate is made in the G1 phase immediately before initiating DNA synthesis and progressing through the rest of the cell cycle, detection of DNA synthesis at this stage allows for an unambiguous determination of the status of growth regulation in cell culture experiments.
DNA content in cells can be readily quantitated by flow cytometry of cells stained with propidium iodide, a fluorescent DNA intercalating dye. Similarly, active DNA synthesis can be quantitated by culturing cells in the presence of radioactive thymidine, harvesting the cells, and measuring the incorporation of radioactivity into an acid insoluble fraction. We have considerable expertise with cell cycle analysis and recommend a different approach. We Investigate cell proliferation using bromodeoxyuridine/fluorodeoxyuridine (abbreviated simply as BrdU) staining that detects the incorporation of these thymine analogs into recently synthesized DNA. Labeling and staining cells with BrdU, combined with total DNA staining by propidium iodide and analysis by flow cytometry1 offers the most accurate measure of cells in the various stages of the cell cycle. It is our preferred method because it combines the detection of active DNA synthesis, through antibody based staining of BrdU, with total DNA content from propidium iodide. This allows for the clear separation of cells in G1 from early S phase, or late S phase from G2/M. Furthermore, this approach can be utilized to investigate the effects of many different cell stimuli and pharmacologic agents on the regulation of progression through these different cell cycle phases.
In this report we describe methods for labeling and staining cultured cells, as well as their analysis by flow cytometry. We also include experimental examples of how this method can be used to measure the effects of growth inhibiting signals from cytokines such as TGF-&beta;1, and proliferative inhibitors such as the cyclin dependent kinase inhibitor, p27KIP1. We also include an alternate protocol that allows for the analysis of cell cycle position in a sub-population of cells within a larger culture5. In this case, we demonstrate how to detect a cell cycle arrest in cells transfected with the retinoblastoma gene even when greatly outnumbered by untransfected cells in the same culture. These examples illustrate the many ways that DNA staining and flow cytometry can be utilized and adapted to investigate fundamental questions of mammalian cell cycle control.

Determining the cell cycle position of a population of cells, or understanding how signals affect proliferation, can be readily measured by flow cytometry using this protocol. We report a simple experimental approach to staining cells and quantifying their position in the cell cycle.

The regulation of cell proliferation is central to tissue morphogenesis during the development of multicellular organisms. Furthermore, loss of control of ...

Imaging and 3D Reconstruction of Cerebrovascular Structures in Embryonic Zebrafish

Zebrafish are a powerful tool to study developmental biology and pathology in vivo. The small size and relative transparency of zebrafish embryos make them particularly useful for the visual examination of processes such as heart and vascular development. In several recent studies transgenic zebrafish that express EGFP in vascular endothelial cells were used to image and analyze complex vascular networks in the brain and retina, using confocal microscopy. Descriptions are provided to prepare, treat and image zebrafish embryos that express enhanced green fluorescent protein (EGFP), and then generate comprehensive 3D renderings of the cerebrovascular system. Protocols include the treatment of embryos, confocal imaging, and fixation protocols that preserve EGFP fluorescence. Further, useful tips on obtaining high-quality images of cerebrovascular structures, such as removal the eye without damaging nearby neural tissue are provided. Potential pitfalls with confocal imaging are discussed, along with the steps necessary to generate 3D reconstructions from confocal image stacks using freely available open source software.

Imaging of cerebrovascular development in larval zebrafish is described. Techniques to facilitate 3D imaging and modify cerebrovascular development using chemical treatments are also provided.

Zebrafish are a powerful tool to study developmental biology and pathology in vivo.  The small size and relative transparency of zebrafish embryos make ...

Differentiation of Newborn Mouse Skin Derived Stem Cells into Germ-like Cells In vitro

Studying germ cell formation and differentiation has traditionally been very difficult due to low cell numbers and their location deep within developing embryos. The availability of a "closed" in vitro based system could prove invaluable for our understanding of gametogenesis. The formation of oocyte-like cells (OLCs) from somatic stem cells, isolated from newborn mouse skin, has been demonstrated and can be visualized in this video protocol. The resulting OLCs express various markers consistent with oocytes such as Oct4 , Vasa , Bmp15, and Scp3. However, they remain unable to undergo maturation or fertilization due to a failure to complete meiosis. This protocol will provide a system that is useful for studying the early stage formation and differentiation of germ cells into more mature gametes. During early differentiation the number of cells expressing Oct4 (potential germ-like cells) reaches ~5%, however currently the formation of OLCs remains relatively inefficient. The protocol is relatively straight forward though special care should be taken to ensure the starting cell population is healthy and at an early passage.

Differentiation of Newborn Mouse Skin Derived Stem Cells into Germ-like Cells In vitro

In recent years the formation of germ cells using in vitro culture methods has been demonstrated using several different types of somatic stem cells. This article will visually present the differentiation of newborn mouse derived stem cells to early oocyte-like cells.

Studying  germ cell formation and differentiation has traditionally been very difficult  due to low cell numbers and their location deep within developing ...

A Guide to Modern Quantitative Fluorescent Western Blotting with Troubleshooting Strategies

The late 1970s saw the first publicly reported use of the western blot, a technique for assessing the presence and relative abundance of specific proteins within complex biological samples. Since then, western blotting methodology has become a common component of the molecular biologists experimental repertoire. A cursory search of PubMed using the term &#8220;western blot&#8221; suggests that in excess of two hundred and twenty thousand published manuscripts have made use of this technique by the year 2014. Importantly, the last ten years have seen technical imaging advances coupled with the development of sensitive fluorescent labels which have improved sensitivity and yielded even greater ranges of linear detection. The result is a now truly Quantifiable Fluorescence based Western Blot (QFWB) that allows biologists to carry out comparative expression analysis with greater sensitivity and accuracy than ever before. Many &#8220;optimized&#8221; western blotting methodologies exist and are utilized in different laboratories. These often prove difficult to implement due to the requirement of subtle but undocumented procedural amendments. This protocol provides a comprehensive description of an established and robust QFWB method, complete with troubleshooting strategies.

The advancement of western blotting using fluorescence has allowed detection of subtle changes in protein expression enabling quantitative analyses. Here we describe a robust methodology for detection of a range of proteins across a variety of species and tissue types. A strategy to overcome common technical problems is also provided.

The late 1970s saw the first publicly reported use of the western blot, a technique for assessing the presence and relative abundance of specific proteins ...

Floral-Dip Transformation of Flax (Linum usitatissimum) to Generate Transgenic Progenies with a High Transformation Rate

Agrobacterium-mediated plant transformation via floral-dip is a widely used technique in the field of plant transformation and has been reported to be successful for many plant species. However, flax (Linum usitatissimum) transformation by floral-dip has not been reported. The goal of this protocol is to establish that Agrobacterium and the floral-dip method can be used to generate transgenic flax. We show that this technique is simple, inexpensive, efficient, and more importantly, gives a higher transformation rate than the current available methods of flax transformation.
In summary, inflorescences of flax were dipped in a solution of Agrobacterium carrying a binary vector plasmid (T-DNA fragment plus the Linum Insertion Sequence, LIS-1) for 1 - 2 min. The plants were laid flat on their side for 24 hr. Then, plants were maintained under normal growth conditions until the next treatment. The process of dipping was repeated 2 - 3 times, with approximately 10 - 14 day intervals between dipping. The T1 seeds were collected and germinated on soil. After approximately two weeks, treated progenies were tested by direct PCR; 2 - 3 leaves were used per plant plus the appropriate T-DNA primers. Positive transformants were selected and grown to maturity. The transformation rate was unexpectedly high, with 50 - 60% of the seeds from treated plants being positive transformants. This is a higher transformation rate than those reported for Arabidopsis thaliana and other plant species, using floral-dip transformation. It is also the highest, which has been reported so far, for flax transformation using other methods for transformation.

Floral-Dip Transformation of Flax Linum usitatissimum to Generate Transgenic Progenies with a High Transformation Rate

Here, we present a protocol to transform flax using Agrobacterium-mediated plant transformation via floral-dip. This protocol is simple to perform and inexpensive, yet yields a higher transformation rate than the current available methods for flax transformation.

Agrobacterium-mediated plant transformation via floral-dip is a widely used technique in the field of plant transformation and has been reported to be ...

Method for the Assessment of Effects of a Range of Wavelengths and Intensities of Red/near-infrared Light Therapy on Oxidative Stress In Vitro

Red/near-infrared light therapy (R/NIR-LT), delivered by laser or light emitting diode (LED), improves functional and morphological outcomes in a range of central nervous system injuries in vivo, possibly by reducing oxidative stress. However, effects of R/NIR-LT on oxidative stress have been shown to vary depending on wavelength or intensity of irradiation. Studies comparing treatment parameters are lacking, due to absence of commercially available devices that deliver multiple wavelengths or intensities, suitable for high through-put in vitro optimization studies. This protocol describes a technique for delivery of light at a range of wavelengths and intensities to optimize therapeutic doses required for a given injury model. We hypothesized that a method of delivering light, in which wavelength and intensity parameters could easily be altered, could facilitate determination of an optimal dose of R/NIR-LT for reducing reactive oxygen species (ROS) in vitro.
Non-coherent Xenon light was filtered through narrow-band interference filters to deliver varying wavelengths (center wavelengths of 440, 550, 670 and 810nm) and fluences (8.5 x 10-3 to 3.8 x 10-1 J/cm2) of light to cultured cells. Light output from the apparatus was calibrated to emit therapeutically relevant, equal quantal doses of light at each wavelength. Reactive species were detected in glutamate stressed cells treated with the light, using DCFH-DA and H2O2 sensitive fluorescent dyes.&#160;
We successfully delivered light at a range of physiologically and therapeutically relevant wavelengths and intensities, to cultured cells exposed to glutamate as a model of CNS injury. While the fluences of R/NIR-LT used in the current study did not exert an effect on ROS generated by the cultured cells, the method of light delivery is applicable to other systems including isolated mitochondria or more physiologically relevant organotypic slice culture models, and could be used to assess effects on a range of outcome measures of oxidative metabolism.

Method for the Assessment of Effects of a Range of Wavelengths and Intensities of Red/near-infrared Light Therapy on Oxidative Stress In Vitro

Non-coherent Xenon light was passed through narrow-band interference and neutral density filters to deliver light of varying wavelength and intensity to cultured cells. This protocol was used to assess the effects of red/near-infrared light therapy on production of reactive species in vitro: no effects were observed using the tested parameters.

Red/near-infrared light therapy (R/NIR-LT), delivered by laser or light emitting diode (LED), improves functional and morphological outcomes in a range of ...

Imaging the Intracellular Trafficking of APP with Photoactivatable GFP

Beta-amyloid (A&#946;) is the major constituent of senile plaques found in the brains of Alzheimer&#8217;s disease patients. A&#946; is derived from the sequential cleavage of Amyloid Precursor Protein (APP) by &#946; and &#947;-secretases. Despite the importance of A&#946; to AD pathology, the subcellular localization of these cleavages is not well established. Work in our laboratory and others implicate the endosomal/lysosomal system in APP processing after internalization from the cell surface. However, the intracellular trafficking of APP is relatively understudied.
While cell-surface proteins are amendable to many labeling techniques, there are no simple methods for following the trafficking of membrane proteins from the Golgi. To this end, we created APP constructs that were tagged with photo-activatable GFP (paGFP) at the C-terminus. After synthesis, paGFP has low basal fluorescence, but it can be stimulated with 413 nm light to produce a strong, stable green fluorescence. By using the Golgi marker Galactosyl transferase coupled to Cyan Fluorescent Protein (GalT-CFP) as a target, we are able to accurately photoactivate APP in the trans-Golgi network. Photo-activated APP-paGFP can then be followed as it traffics to downstream compartments identified with fluorescently tagged compartment marker proteins for the early endosome (Rab5), the late endosome (Rab9) and the lysosome (LAMP1). Furthermore, using inhibitors to APP processing including chloroquine or the &#947;-secretase inhibitor L685, 458, we are able to perform pulse-chase experiments to examine the processing of APP in single cells.
We find that a large fraction of APP moves rapidly to the lysosome without appearing at the cell surface, and is then cleared from the lysosome by secretase-like cleavages. This technique demonstrates the utility of paGFP for following the trafficking and processing of intracellular proteins from the Golgi to downstream compartments.

While the transport of cell surface proteins is relatively easily studied, visualizing the trafficking of intracellular proteins is much more difficult. Here, we use constructs incorporating photoactivatable GFP and demonstrate a method to accurately follow the amyloid precursor protein from the Golgi apparatus to down-stream compartments and follow its clearance.

Beta-amyloid (A&#946;) is the major constituent of senile plaques found in the brains of Alzheimer&#8217;s disease patients. A&#946; is derived from the ...