National Institutes of Health grant R01 CA149976 (N.A.S) supported this work.

All procedures must be performed in accordance with institutional animal use and care guidelines. The procedure was developed for the analysis of murine hematopoietic stem and progenitor cells (HSCs and HPs), but can be adapted for the analysis of other cell populations.
1. Flow Cytometry Isolation of Murine HSCs and HPs
<ol>
	<li>Harvest murine bone marrow cells as described in the literature6. 
	NOTE: In data presented in Figure 1 ...

<ol>
	<li>Krutzik, P. O., Clutter, M. R., Nolan, G. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coordinate+analysis+of+murine+immune+cell+surface+markers+and+intracellular+phosphoproteins+by+flow+cytometry.">Coordinate analysis of murine immune cell surface markers and intracellular phosphoproteins by flow cytometry.</a> J Immunol. 175 (4), 2357-2365 (2005).</li><li>Du, J., 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=Signaling+profiling+at+the+single-cell+level+identifies+a+distinct+signaling+signature+in+murine+hematopoietic+stem+cells.">Signaling profiling at the single-cell level identifies a distinct signaling signature in murine hematopoietic stem cells.</a> Stem Cells. 30 (7), 1447-1454 (2012).</li><li>Signer, R. A., Magee, J. A., Salic, A., Morrison, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Haematopoietic+stem+cells+require+a+highly+regulated+protein+synthesis+rate.">Haematopoietic stem cells require a highly regulated protein synthesis rate.</a> Nature. 509 (7498), 49-54 (2014).</li><li>Wang, J., 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=A+differentiation+checkpoint+limits+hematopoietic+stem+cell+self-renewal+in+response+to+DNA+damage.">A differentiation checkpoint limits hematopoietic stem cell self-renewal in response to DNA damage.</a> Cell. 148 (5), 1001-1014 (2012).</li><li>Hoshii, T., 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=mTORC1+is+essential+for+leukemia+propagation+but+not+stem+cell+self-renewal.">mTORC1 is essential for leukemia propagation but not stem cell self-renewal.</a> J Clin Invest. 122 (6), 2114-2129 (2012).</li><li>Signer, R. A., 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=The+rate+of+protein+synthesis+in+hematopoietic+stem+cells+is+limited+partly+by+4E-BPs.">The rate of protein synthesis in hematopoietic stem cells is limited partly by 4E-BPs.</a> Genes Dev. 30 (15), 1698-1703 (2016).</li><li>Cai, X., 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=Runx1+deficiency+decreases+ribosome+biogenesis+and+confers+stress+resistance+to+hematopoietic+stem+and+progenitor+cells.">Runx1 deficiency decreases ribosome biogenesis and confers stress resistance to hematopoietic stem and progenitor cells.</a> Cell Stem Cell. , (2015).</li><li>Loven, J., 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=Revisiting+global+gene+expression+analysis.">Revisiting global gene expression analysis.</a> Cell. 151 (3), 476-482 (2012).</li><li>JoVE Science Education Database. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+a+Hemoacytometer+to+Count+Cells.">Using a Hemoacytometer to Count Cells.</a> Basic Methods in Cellular and Molecular Biology. , (2017).</li><li>JoVE Science Education Database. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Separating+Protein+with+SDS-PAGE.">Separating Protein with SDS-PAGE.</a> Basic Methods in Cellular and Molecular Biology. , (2017).</li><li>JoVE Science Education Database. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Western+Blot.">The Western Blot.</a> Basic Methods in Cellular and Molecular Biology. , (2017).</li><li>Jackson, R. J., Hellen, C. U., Pestova, T. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mechanism+of+eukaryotic+translation+initiation+and+principles+of+its+regulation.">The mechanism of eukaryotic translation initiation and principles of its regulation.</a> Nat Rev Mol Cell Biol. 11 (2), 113-127 (2010).</li><li>Eaton, S. 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=A+guide+to+modern+quantitative+fluorescent+western+blotting+with+troubleshooting+strategies.">A guide to modern quantitative fluorescent western blotting with troubleshooting strategies.</a> J Vis Exp. (93), e52099 (2014).</li></ol>

Western Blotting is a common technique for detecting specific proteins and the activation of signaling pathways in tissues or cells. By introducing small adjustments to a commonly used procedure, we were able to routinely detect 15 different proteins (Table of Materials) in 15,000 HSCs, and in some cases in as few as 500 HSCs. The most critical steps in this protocol are: 1) accurately counting the cells, 2) minimizing the number of transfers between tubes, and 3) lysing the cells directly with Laemmli s...

Hematopoietic stem cells (HSCs) are self-renewing cells that can give rise to all blood lineages. They are relatively rare cells in the bone marrow, rendering biochemical analyses difficult. Approaches suitable for analyzing rare cells, such as flow cytometry, have been extremely useful for quantifying relative amounts of cell surface markers and intracellular proteins. However, the analysis of intracellular proteins necessitates the use of cell permeabilization procedures to enable antibody access, and not all cell surface epitopes survive these procedures1,2. In addition, antibodies that discriminate between different protein isoforms or cleavage products are not often available for flow cytometry, and therefore investigators still rely on Western blots for certain types of analyses.
Western blot analysis of cell lysates is a routine procedure in most laboratories. Cells can be purified under native conditions that preserve the epitopes of cell surface molecules, and cell lysates can subsequently be prepared and analyzed. However, the analysis of proteins in rare primary cell populations by Western blot can require euthanizing large numbers of animals to obtain enough cells. By making small adjustments to several steps, a conventional Western blotting protocol was able to detect proteins in relatively small numbers of HSCs (500 - 15,000, depending on the protein of interest). The adjustments include accurately counting the cells, carefully handling the cell pellet, reducing transfers of cells between tubes to minimize cell loss, and lysing a defined number of cells with a concentrated loading buffer containing proteasome and phosphatase inhibitors. Many published reports include Western blots obtained with 20,000 or more HSCs3,4,5,6,7; this simple procedure will reduce the number of cells and experimental animals required to produce equivalent data by between 4 and 40 fold. The protocol is designed to normalize results on a per cell basis, rather than to an internal control. This enables detection of overall reductions in protein levels that can be overlooked if data are normalized to an internal control. The importance of normalizing on a per cell basis was described for the analysis of gene expression data8, and the same principle applies to quantifying proteins by Western blot. This optimized protocol should be useful for anyone needing to analyze small numbers of cells.

<table>
	<tbody>
		<tr>
			<td>sodium dodecyl sulfate (SDS)</td>
			<td>Fisher Scientific</td>
			<td>BP166-500</td>
			<td>&#160;SDS-PAGE</td>
		</tr>
		<tr>
			<td>TEMED</td>
			<td>Fisher Scientific</td>
			<td>BP150-20</td>
			<td>&#160;SDS-PAGE</td>
		</tr>
		<tr>
			<td>30% Acrylamidel Bis solution</td>
			<td>Bio-Rad</td>
			<td>1610158</td>
			<td>&#160;SDS-PAGE</td>
		</tr>
		<tr>
			<td>1.5M Tris-HCl pH8.8</td>
			<td>TEKNOVA</td>
			<td>T1588</td>
			<td>&#160;SDS-PAGE</td>
		</tr>
		<tr>
			<td>1.0M Tris-HCl pH6.8</td>
			<td>TEKNOVA</td>
			<td>T1068</td>
			<td>&#160;SDS-PAGE</td>
		</tr>
		<tr>
			<td>Ammonium Persulfate</td>
			<td>Fisher Scientific</td>
			<td>BP179-25</td>
			<td>&#160;SDS-PAGE</td>
		</tr>
		<tr>
			<td>mini-protean 3 comb</td>
			<td>Bio-Rad</td>
			<td>1653360</td>
			<td>&#160;SDS-PAGE</td>
		</tr>
		<tr>
			<td> 
			Mini-PROTEAN Tetra Cell</td>
			<td>Bio-Rad</td>
			<td>1658005EDU&#160;</td>
			<td>&#160;SDS-PAGE</td>
		</tr>
		<tr>
			<td>&#160;Transfer System</td>
			<td>Bio-Rad</td>
			<td>1704155EDU</td>
			<td>transfer</td>
		</tr>
		<tr>
			<td>PowerPac HC Power Supply</td>
			<td>Bio-Rad</td>
			<td>1645052EDU&#160;</td>
			<td>electrophoresis</td>
		</tr>
		<tr>
			<td>Imaging System</td>
			<td>Bio-Rad</td>
			<td>1708195&#160;</td>
			<td>signal detection</td>
		</tr>
		<tr>
			<td>4x Laemmli Sample Buffer</td>
			<td>Bio-Rad</td>
			<td>1610747EDU&#160;</td>
			<td>sample preparation</td>
		</tr>
		<tr>
			<td>10x Tris/Glycine/SDS Electrophoresis Buffer</td>
			<td>Bio-Rad</td>
			<td>1610732EDU&#160;</td>
			<td>electrophoresis</td>
		</tr>
		<tr>
			<td>2-Mercaptoethanol</td>
			<td>Bio-Rad</td>
			<td>1610710EDU</td>
			<td>sample preparation</td>
		</tr>
		<tr>
			<td>&#160;RTA Mini PVDF Transfer Kit, for 40 blots</td>
			<td>Bio-Rad</td>
			<td>1704272&#160;</td>
			<td>transfer</td>
		</tr>
		<tr>
			<td>Protease Inhibitor Cocktail</td>
			<td>Sigma</td>
			<td>11697498001</td>
			<td>sample preparation</td>
		</tr>
		<tr>
			<td>Phosphatase Inhibitor Cocktailrs</td>
			<td>Gold Biotechnology</td>
			<td>GB-450-1</td>
			<td>sample preparation</td>
		</tr>
		<tr>
			<td>EIF4G</td>
			<td>Cell signaling</td>
			<td>2469</td>
			<td>WB antibody, validated in 1000 cells 
			antibody concentration: 1:1000 
			reference(figure): Fig2</td>
		</tr>
		<tr>
			<td>p-Rps6</td>
			<td>Cell signaling</td>
			<td>4858</td>
			<td>WB antibody,validated in 1000 cells 
			antibody concentration: 1:1000 
			reference(figure): Fig2</td>
		</tr>
		<tr>
			<td>actin(HRP conjugated)</td>
			<td>abcam</td>
			<td>ab49900</td>
			<td>WB antibody,validated in 500 cells 
			antibody concentration: 1:5000 
			reference(figure): Fig1, Fig2</td>
		</tr>
		<tr>
			<td>LC-3</td>
			<td>Abcam</td>
			<td>ab48394</td>
			<td>WB antibody,validated in 15000 cells 
			antibody concentration: 1:1000 
			reference(figure): ref5 (Fig5)</td>
		</tr>
		<tr>
			<td>S6</td>
			<td>Cell Signaling</td>
			<td>2317</td>
			<td>WB antibody,validated in 15000 cells 
			antibody concentration: 1:1000 
			reference(figure): ref5 (Fig4)</td>
		</tr>
		<tr>
			<td>4EBP1</td>
			<td>Cell Signaling</td>
			<td>9644</td>
			<td>WB antibody, validated in 15000 cells 
			antibody concentration: 1:1000 
			reference(figure): ref5 (Fig4)</td>
		</tr>
		<tr>
			<td>p-4EBP1</td>
			<td>Cell Signaling</td>
			<td>2855</td>
			<td>WB antibody,validated in 15000 cells 
			antibody concentration: 1:1000 
			reference(figure): ref5 (Fig4)</td>
		</tr>
		<tr>
			<td>TSC2</td>
			<td>Cell Signaling</td>
			<td>4308</td>
			<td>WB antibody,validated in 15000 cells 
			antibody concentration: 1:1000 
			reference(figure): ref5 (Fig4)</td>
		</tr>
		<tr>
			<td>HSP90</td>
			<td>Cell Signaling</td>
			<td>4877</td>
			<td>WB antibody,validated in 15000 cells 
			antibody concentration: 1:1000 
			reference(figure): ref5 (Fig5)</td>
		</tr>
		<tr>
			<td>PTEN</td>
			<td>Cell Signaling</td>
			<td>9188</td>
			<td>WB antibody,validated in 15000 cells 
			antibody concentration: 1:1000 
			reference(figure): ref5 (FigS1)</td>
		</tr>
		<tr>
			<td>mTOR</td>
			<td>Cell Signaling</td>
			<td>2983</td>
			<td>WB antibody,validated in 15000 cells 
			antibody concentration: 1:1000 
			reference(figure): ref5 (FigS1)</td>
		</tr>
		<tr>
			<td>p-mTOR</td>
			<td>Cell Signaling</td>
			<td>5536</td>
			<td>WB antibody,validated in 15000 cells 
			antibody concentration: 1:1000 
			reference(figure): ref5 (FigS1)</td>
		</tr>
		<tr>
			<td>PP2AB</td>
			<td>Cell Signaling</td>
			<td>4953</td>
			<td>WB antibody,validated in 15000 cells 
			antibody concentration: 1:1000 
			reference(figure): ref5 (FigS1)</td>
		</tr>
		<tr>
			<td>p-AMPKa</td>
			<td>Cell Signaling</td>
			<td>2535</td>
			<td>WB antibody,validated in 15000 cells 
			antibody concentration: 1:1000 
			reference(figure): ref5 (FigS1)</td>
		</tr>
		<tr>
			<td>actin</td>
			<td>Santa Cruz</td>
			<td>sc-47778</td>
			<td>WB antibody,validated in 15000 cells 
			antibody concentration: 1:3000 
			reference(figure): ref5 (Fig4)</td>
		</tr>
		<tr>
			<td>lineage depletion kit (mouse)</td>
			<td>Miltenyi Biotec</td>
			<td>130-090-858</td>
			<td>hematopoietic stem and progenitor cells purification</td>
		</tr>
		<tr>
			<td>LS columns</td>
			<td>Miltenyi Biotec</td>
			<td>130-041-305</td>
			<td>hematopoietic stem and progenitor cells purification</td>
		</tr>
		<tr>
			<td>SCF</td>
			<td>PeproTech</td>
			<td>250-03</td>
			<td>phosphorylation stimulation</td>
		</tr>
		<tr>
			<td>APC-Cy7 c-kit antibody</td>
			<td>ThermoFisher</td>
			<td>A15423</td>
			<td>cell sorting</td>
		</tr>
		<tr>
			<td>anti-B220</td>
			<td>ThermoFisher</td>
			<td>48-0452-82</td>
			<td>cell sorting</td>
		</tr>
		<tr>
			<td>anti-CD3e</td>
			<td>ThermoFisher</td>
			<td>48-0031-82</td>
			<td>cell sorting</td>
		</tr>
		<tr>
			<td>anti-Mac1</td>
			<td>ThermoFisher</td>
			<td>48-0112-82</td>
			<td>cell sorting</td>
		</tr>
		<tr>
			<td>anti-Gr1</td>
			<td>ThermoFisher</td>
			<td>48-5931-82</td>
			<td>cell sorting</td>
		</tr>
		<tr>
			<td>anti-Ter119</td>
			<td>ThermoFisher</td>
			<td>48-5921-82</td>
			<td>cell sorting</td>
		</tr>
		<tr>
			<td>Spacer Plates with 1.0 mm Integrated Spacers</td>
			<td>Bio-Rad</td>
			<td>1653311</td>
			<td>&#160;SDS-PAGE</td>
		</tr>
		<tr>
			<td>BSA</td>
			<td>Research Products International</td>
			<td>A30075</td>
			<td>membrane blocking</td>
		</tr>
		<tr>
			<td>serum</td>
			<td>Atlanta Biologicals</td>
			<td>A12450</td>
			<td>medium supplement</td>
		</tr>
		<tr>
			<td>cell counter</td>
			<td>Invitrogen</td>
			<td>AMQAF1000</td>
			<td>cell counting</td>
		</tr>
		<tr>
			<td>hemocytometer</td>
			<td>ThermoFisher</td>
			<td>&#160;S17040</td>
			<td>cell counting</td>
		</tr>
		<tr>
			<td>flim</td>
			<td>Denville Scientific</td>
			<td>E3012</td>
			<td>signal detection</td>
		</tr>
		<tr>
			<td>medical film processor</td>
			<td>Konica</td>
			<td>SRC-101A</td>
			<td>signal detection</td>
		</tr>
		<tr>
			<td>Supersignal West Femto Maximum Sensitivity Substrate</td>
			<td>Therom Scientific</td>
			<td>34096</td>
			<td>signal detection</td>
		</tr>
		<tr>
			<td>Allegra X-15R Centrifuge (Rotor SX4750A)</td>
			<td>Beckman Coulter</td>
			<td>X-15R</td>
			<td>sample preparation</td>
		</tr>
		<tr>
			<td>BLUEstain protein ladder</td>
			<td>Gold Biotechnology</td>
			<td>P007-500</td>
			<td>electrophoresis</td>
		</tr>
		<tr>
			<td>cell sorter</td>
			<td>BD</td>
			<td>FACSAria II</td>
			<td>sample preparation</td>
		</tr>
		<tr>
			<td>Incublock</td>
			<td>Denville Scientific</td>
			<td>I0510</td>
			<td>electrophoresis</td>
		</tr>
	</tbody>
</table>

a western blotting protocol for small numbers of hematopoietic stem cells

Hematopoietic stem cells (HSCs) are rare cells, with the mouse bone marrow containing only ~25,000 phenotypic long term repopulating HSCs. A Western blotting protocol was optimized and suitable for the analysis of small numbers of HSCs (500 - 15,000 cells). Phenotypic HSCs were purified, accurately counted, and directly lysed in Laemmli sample buffer. Lysates containing equal numbers of cells were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the blot was prepared and processed following standard Western blotting protocols. Using this protocol, 2,000 - 5,000 HSCs can be routinely analyzed, and in some cases data can be obtained from as few as 500 cells, compared to the 20,000 to 40,000 cells reported in most publications. This protocol should be generally applicable to other hematopoietic cells, and enables the routine analysis of small numbers of cells using standard laboratory procedures.

Representative results from 500 - 2,000 purified HSCs and HPs are shown in Figure 1 and Figure 2. The &#946;-actin signal in Figure 1 can be detected from as few as 500 HSCs and HPs purified from the bone marrow of one mouse. Note that loading the lysates into 1.5 mm wells produced a much stronger signal from 500 HPs than loading into 3.0 mm wells. Figure 2 is a Western ...

Watch this Scientific Journal Video about A Western Blotting Protocol for Small Numbers of Hematopoietic Stem Cells at JoVE.com

A Western Blotting Protocol for Small Numbers of Hematopoietic Stem Cells

A standard Western blotting protocol was optimized for analyzing as few as 500 hematopoietic stem or progenitor cells. Optimization involves careful handling of the cell sample, limiting transfers between tubes, and directly lysing the cells in Laemmli sample buffer.

Hematopoietic stem cells (HSCs) are rare cells, with the mouse bone marrow containing only ~25,000 phenotypic long term repopulating HSCs. A Western ...

The over goal of this western blotting protocol is to Perform western blots on small numbers of cells. This method can help answer key questions in the hematopoietic stem cell field such as the presence or abundance of specific proteins or activation of signaling pathways. The main advantage of this technique is that it requires fewer than 20, 000 cells thus fewer animals are needed to analyze rare populations of primary cells.We first had the idea for this method when we were trying to find ways to reduce the number of mice we needed to use for hematopoietic stem cell analyses. Demonstrating the procedure will be Xiongwei Cai, a post doc from my laboratory. Use a swinging bucket rotor to centrifuge 1.5 milliliter tubes containing sorted hematopoietic stem and progenitor cells at 500 times gravity for five minutes at four degrees Celsius.Once the centrifugation is over, discard all but 100 microliters of supernatant, without disturbing the cell pellet. If there are less than 5, 000 cells, and the volume of the sorted sample is less than 0.2 milliliters, first transfer the cells to low binding 0.2 milliliter PCR tubes before centrifugation. However, if there are less than 5, 000 cells, but the volume of the sorted sample is more than 0.2 milliliter, then centrifuge the cells at 500 times gravity for five minutes at four degrees Celsius.After centrifugation, discard all but 200 microliters of supernatant. Then re suspend the pellet and the remaining 200 microliters of supernatant. Next, transfer the cell suspension to 0.2 milliliter PCR tubes and again, centrifuge.Then re suspend the pellet in 20 to 30 microliters of supernatant and discard the rest. If necessary, add phosphate buffered saline in 2%fetal bovine serum, or 2%bovine serum albumin to the re suspended cells. Then use an automated cell counter to determine the cellular concentration using two to five microliters of re suspended cells.Next use a 20 or 100 microliter pipette tip to transfer a volume of 500, 1, 000, and 2, 000 hematopoietic stem and progenitor cells to new 1.5 milliliter tubes. Use a swinging bucket rotor to centrifuge the cells at four degrees Celsius at 500 times gravity for five minutes. Then follow the manufacturers instructions to dissolve phosphatase and proteasome inhibitor and DMSO to prepare a 100 fold stock solution.Next dilute the four fold Laemmli sample buffer with equivalent volumes of distilled water to make a two fold Laemmli sample buffer. Then add appropriate amounts of the 100 fold stock solution of phosphatase and proteasome inhibitor to adjust the final concentration to two fold inhibitors, and two fold Laemmli sample buffer. Adjust the volume of residual supernatant in the tube such that adding equal volumes of two fold Laemmli buffer along with the phosphatase and proteasome inhibitor will achieve a final concentration of 500 cells per microliter and one fold Laemmli buffer.And then re suspend to form the lysate. Before loading the gel, heat the sample lysates at 95 degrees Celsius in a heat block for five minutes. Using standard protocols electrophoresis one to 40 microliters of lysate equivalent to 500 to 20, 000 cells through SDS page at 100 volts.After treating poly vinylidene membrane with methanol for then seconds wash the membrane with distilled water briefly. Then transfer the protein from the gel to the membrane according to the instructions provided by the manufacturer of the transfer apparatus. After transfer, block the membrane with two milliliters of 2%bovine serum albumin and phosphate buffered saline with 0.1%Tween overnight at four degrees Celsius according to standard protocals.After blocking the membrane, incubate it with diluted antibodies overnight at four degrees celsius. Then wash the membrane thrice with phosphate buffered saline with 0.1%Tween 20 for five minutes each at room temperature. Next incubate the membrane with two milliliters of enhanced chemiluminescence buffer for one minute at room temperature.Detect the signals using an imaging system. To compare the beta actin signals lysates were prepared from urine hematopoietic stem and progenitor cells and subjected to western plot analysis. It is clear form the amino blot that there is a decrease in beta actin signal from the lysates prepared from 2, 000 to 500 hematopoietic progenitor and stem cells loaded in 1.5 millimeter wells on a 12%SDS page gel.Further, to compare the beta actin signals obtained from different well sizes cast on the gel. Lysates were loaded in 1.5 and three millimeter wells on the gel and then subjected to western blot analysis. The blot shows that the beta actin signal obtained from the lysate prepared from 500 hematopoietic progenitors loaded in a 1.5 millimeter well is much stronger than when loaded in a three millimeter well.Next, to compare the signals for eucaryotic initiation factor 4G, actin and phosphorylation of ribosomal protein S6 in response to cytokine stem cell factor stimulation the lysates obtained were analyzed by amino blot. The blot shows the presence of stronger signal intensities for all three proteins in the hematopoietic re genitors with cytokine stem cell factor stimulation. In comparison to the control in vitro it is also clear that there is and increasing signal intensity for all three proteins from different hematopoietic stem cell volumes.Once mastered this technically can be done in 48 hours. If it is approached properly. While attempting this procedure it's important to remember to accurately count the cells and to direct the lysate cells with a loading buffer.After this development it is technically pelleted away for the researchers in the field of stem cell research to explore signal pathways in small number of cells. After watching this video you should have a good understanding of how to do western plotting with a small number of address pieces. Be careful with the regions you're using for SDS page.Thank you for watching. Good luck with your experiments.

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JoVE Journal

Biochemistry

10.2K visualizações.  Cincinnati Children's Hospital Medical Center. The over goal of this western blotting protocol is to Perform western blots on small numbers of cells. This method can help answer key questions in the hematopoietic stem cell field such as the presence or abundance of specific proteins or activation of signaling pathways. The main advantage of this technique is that it requires fewer than 20, 000 cells thus fewer animals are needed to analyze rare populations of primary cells.We first had the idea for this method when we were trying t...