Name: Eukaryotic Polyribosome Profile Analysis (Video) | JoVE Journal
Uploaded: 2010-06-15T17:00:00.000+00:00
Duration: 9 min 16 s
Description: Learn eukaryotic polyribosome profile analysis to separate monosome and polyribosome fractions using sucrose gradient centrifugation. This method enables researchers to study translation regulation and ribosomal dynamics in vivo.

ai_agent_IP

ai_agent

maintenance

instantTrialDurationMinutes

isBiopharma

enableNewMyJoveSectionDesign

educationFeatures

seoMetaApi

ai_copilot_institution_blacklist

ai_chat_institution_blacklist

freeAccessWindow

ssoRoleCapture

scheduledMaintenanceBanner

joveLabsFeatures

disable_autoplay_for_bots

extended_trial_duration

5 minutes

playerTrialDesktop

The authors would like to acknowledge John Woolford for the initial basis of this method, TGK is supported by NIH GM057483 and AI076245 and PRC is supported by GM77073.

1. Preparation of 7-47% sucrose gradients
<ol>
	<li>Prepare sucrose gradients one day before use to allow gradients to become continuous. Make sterile 7% and 47% sucrose solutions containing 50mM NH4Cl, 50mM Tris-Acetate pH 7.0 and 12mM MgCl2 and store at 4°C 1.</li>
	<li>For 6 gradients mix the 7% and 47% sucrose stock solutions to make 48 mL of each of the following sucrose concentrations. Add DTT (1M stock) to each sucrose solution to a final concentration of 1mM. 
<table border="1" cellspacing="0" cellpadding="0">
<tbody>
 <tr>
 <td>Final Concentration</td>
 <td>7% sucrose</td>
 <td>47% sucrose</td>
 </tr>
 <tr>
 <td>7%</td>
 <td>48 mL</td>
 <td>0</td>
 </tr>
 <tr>
 <td>17%</td>
 <td>36 mL</td>
 <td>12 mL</td>
 </tr>
 <tr>
 <td>27%</td>
 <td>24 mL</td>
 <td>24 mL</td>
 </tr>
 <tr>
 <td>37%</td>
 <td>12 mL</td>
 <td>36 mL</td>
 </tr>
 <tr>
 <td>47%</td>
 <td>0</td>
 <td>48 mL</td>
 </tr>
</tbody>
</table></li>
	<li>In order to pour the gradients, attach a Pasteur pipette to a 20 mL syringe by securing and sealing with Parafilm or use a long needle. Add 7 mL of 7% sucrose to the bottom of a 1 x 3.5" polyallomer ultracentrifuge tube. Next add 7 mL of 17% sucrose solution under the 7% solution by placing the Pasteur pipette tip near bottom of tube and pipetting no faster than 0.3 mL/sec. Repeat with 7 mL each of 27%, 37% and 47% sucrose solutions. You should observe clear lines between the layers, indicating that minimal mixing has occurred. Store gradients at 4°C overnight along with the rotors, bottles and tubes that will be used to harvest samples.</li>
</ol>
2. Preparation of the yeast extract
<ol>
	<li>Grow 125 mL of yeast culture to an OD600 of 0.8-1.0. Add cycloheximide to the culture to a final concentration of 100 μg/mL and continue shaking at 30°C for 15 min.</li>
	<li>Meanwhile, prepare lysis buffer containing 80 μg/mL cycloheximide, 200 μg/mL heparin, 0.2% DEPC, and 10 mM Tris-HCl pH 7.5, 0.1M NaCl, 30mM MgCl2. Keep everything on ice from this point on.</li>
	<li>Pour the culture into a 250 mL centrifuge bottle and fill with ice. Centrifuge at 8,000 x g (7,250 rpm in a SLA-1500 rotor) for 5 min at 4°C. Wash the pellet once with 10 mL of ice cold lysis buffer and transfer to 15 mL polypropylene tubes. Centrifuge at 5,900 x g (~6,000rpm in a SLA-600TC rotor) for 3 min at 4°C. Resuspend the pellet in 0.5 mL of lysis buffer, transfer to 1.5mL tube and add 0.5 mL of chilled, baked acid-washed glass beads. Vortex the cells for four 30 sec intervals, cooling the tube on ice for 30 sec between each interval. Add another 0.5 mL of lysis buffer into the 1.5 mL tube. Centrifuge at maximum speed in a microcentrifuge (14,000 rpm in an Eppendorf 5417R microcentrifuge) for 10 min at 4°C. Transfer supernatant to a new 1.5 mL microcentrifuge tube. Remove 10 μl to a separate tube to determine the OD260 / OD280 ratio (see step 3.1 below). Store extracts at -80°C.</li>
</ol>
3. Preparation of extracts from mammalian cells
<ol>
	<li>For adherent cells, grow in 100 mm dish to ~70% confluence. You will need one 100 mm dish per 11 ml gradient (typical yield is ~20 OD260 units). Scale the amount linearly for larger or smaller gradient sizes. For non-adherent cells, approximately 1 x 107 cells are needed per 11 ml gradient.</li>
	<li>Prior to lysis, add cycloheximide to 100 μg/mL. Incubate at 37°C for 15 min. Transfer plates to ice and rinse cells twice in ice cold PBS. All future steps MUST be carried out at 0-4°C.</li>
	<li>Remove all traces of PBS by aspiration (let plates drain on an angled bed of ice) and add 1 mL lysis buffer, scrape and transfer to pre-chilled 1.5 mL tube. Lysis buffer components will need to be optimized to the cell type and growth conditions. A good starting buffer would be 20 mM HEPES-KOH, pH 7.4, 15 mM MgCl2, 200 mM KCl, 1% Triton X-100 (v/v), 100 μg/mL cycloheximide, 2 mM DTT, and 1 mg/mL heparin. The key variables are the concentrations of magnesium and potassium chloride as well as the inclusion or exclusion of non-ionic detergents to improve extraction of cytoskeletal or membrane bound polysomes. Lyse cells by passing through 27 gauge syringe needle twice or by 5-10 strokes of dounce homogenization using Type B pestle. The syringe or homogenizer should be pre-chilled prior to use.</li>
	<li>Spin at 14,000 x g for 5 min in refrigerated microcentrifuge. Transfer fresh lysate to the sucrose gradient (for mammalian cells this is made up in lysis buffer lacking Triton X-100 and heparin but otherwise as described in 1.2 and 1.3) or flash freeze in liquid nitrogen for later use.</li>
</ol>
4. Centrifugation of gradients
<ol>
	<li>Thaw polyribosome lysates on ice. Determine the concentration of nucleic acid in the lysate by adding the reserved 10 μL sample to 1 mL of water and reading the OD260/OD280 ratio with a spectrophotometer. Typical yield from a yeast culture grown as described is 50 OD units.</li>
	<li>Using a pipette with the tip placed against the wall of the tube near the surface of the gradient, gently layer 25 OD260 units of the lysate on top of the gradient. For a 35 mL gradient 500 μl of lysate is typically loaded. Lysis buffer can be used to assure all gradients are loaded with an equal volume. Lower amounts of material yield better resolution. Using forceps, carefully lower the gradients into buckets of a swinging bucket rotor.</li>
	<li>Centrifuge the gradients at 100,000 x g (23,000 rpm in a Surespin 630 rotor) for 4 hr at 4°C. This protocol can be adapted for smaller volume gradients.</li>
</ol>
5. Collection of data and fractions
<ol>
	<li>Approximately 30 min prior to the completion of the 4 hr spin attach the needle to the Model 184 tube piercer. Attach the pen to the online Isco Model UA-5 Absorbance/Fluorescence Monitor. Power on the absorbance monitor to allow a stable baseline to be reached prior to analyzing samples. Electronic acquisition of the polysome profile can easily be obtained by attaching a DI-148U data acquisition unit (DATAQ Instruments) to the chart recorder. Profiles can then be collected in real time and saved for later annotation using the accompanying WinDaq software.</li>
	<li>Fill the syringe pump with 50mL of Fluorinert using the reverse flow, rapid setting. Make sure that there are no air bubbles present. Connect the hose from the syringe to the tube piercer and briefly turn on the flow of Fluorinert at 3 mL/min in the forward direction to clear the hose of any air bubbles.</li>
	<li>Place a waste beaker or series of tubes if collecting fractions under the hose at the end of the flow cell to collect sample run off.</li>
	<li>Carefully remove the polyallomer centrifuge tubes containing the sucrose gradient from centrifuge rotor and place them on ice (pre-form the wells in the ice with an empty tube to avoid disturbing gradients).</li>
	<li>To analyze cell extracts, place the gradient tube on the tube piercer. Connect the top of the tube to the outlet and secure. Raise the bottom stage to the centrifuge tube so that the needle pierces the bottom of the tube. Once the needle has protruded through the bottom of the centrifuge tube, begin the flow of Fluorinert in the forward direction at 6mL/min.</li>
	<li>Once the Fluorinert has begun flowing into the tube, monitor the movement of the needle on the online absorbance monitor. Once the needle begins to move, turn on the chart movement to a speed setting of 60. The monitor will record the OD254 starting with the free material followed by 40S ribosomal subunit detection and continuing through to polyribosome complexes. If you are collecting fractions for RNA or protein analysis, typically 0.2 min fractions are taken (1 mL). For RNA analysis, fractions should be collected directly into tubes containing Trizol (Invitrogen), Phenol or SDS/proteinase K, depending on the preferred method of extraction.</li>
	<li>When the end of the polyribosome profile has been reached, turn off the flow of Fluorinert to the centrifuge tube and stop the chart movement of the absorbance/fluorescence monitor.</li>
	<li>Retract the Fluorinert from the centrifuge tube into the syringe by beginning the flow in the reverse direction at a rapid rate making sure not to draw sucrose from the tube into the syringe. Unscrew the centrifuge tube from the tube piercer, lower the needle, and remove the tube.</li>
	<li>Repeat steps 5.5 through 5.8 for each sucrose gradient.</li>
	<li>When all sucrose gradients have been analyzed, retract the Fluorinert from the hose back into the syringe. Remove each part of fractionator (tube piercer and flow cell) including the waste hose located at the top and rinse well with water.</li>
</ol>
6. Representative Results
<img src="/files/ftp_upload/1948/1948fig1.jpg" alt="Sedimentation profile graph; ribosomal subunits, polysomes; density vs. A254nm analysis." data-altupdatedat="1788235205000" data-alt="Figure 1"> Figure 1. Representative trace of ribosome extract prepared from yeast strain BY4741 (mata his3Δ1 leu2Δ0 met15Δ0 ura3Δ0) in the presence of cycloheximide. The ribosomal extract was fractionated utilizing a 7 47% sucrose gradient and analyzed using a pump syringe apparatus attached to a UV detector. Peaks containing polyribosomes and 80S, 60S and 40S ribosomes are indicated.

<ol><li>Baim, S. B., Pietras, D. F., Eustice, D. C., Sherman, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+mutation+allowing+an+mRNA+secondary+structure+diminishes+translation+of+Saccharomyces+cerevisiae+iso-1-cytochrome+C%5BTitle%5D)+AND+%22Mol.+Cell.+Biol%22%5BJournal%5D)">A mutation allowing an mRNA secondary structure diminishes translation of Saccharomyces cerevisiae iso-1-cytochrome C.</a> Mol. Cell. Biol. 5, 1839-1846 (1985).</li>
<li>Ripmaster, T. L., Vaughn, G. P., Woolford, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((DRS1+to+DRS7%2C+novel+genes+required+for+ribosome+assembly+and+function+in+Saccharomyces+cerevisiae%5BTitle%5D)+AND+%22Mol.+Cell.+Biol%22%5BJournal%5D)">DRS1 to DRS7, novel genes required for ribosome assembly and function in Saccharomyces cerevisiae.</a> Mol. Cell. Biol. 13, 7901-7912 (1993).</li>
<li>Anand, M., Chakraburtty, K., Marton, M. J., Hinnebusch, A. G., Kinzy, T. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Functional+interactions+between+yeast+translation+eukaryotic+elongation+factor+%28eEF%29+1A+and+eEF3%5BTitle%5D)+AND+%22J+Biol+Chem%22%5BJournal%5D)">Functional interactions between yeast translation eukaryotic elongation factor (eEF) 1A and eEF3.</a> J Biol Chem. 278, 6985-6991 (2003).</li>
<li>Serikawa, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+transcriptome+and+its+translation+during+recovery+from+cell+cycle+arrest+in+Saccharomyces+cerevisiae%5BTitle%5D)+AND+%22Mol+Cell+Proteomics%22%5BJournal%5D)">The transcriptome and its translation during recovery from cell cycle arrest in Saccharomyces cerevisiae.</a> Mol Cell Proteomics. 2, 191-204 (2003).</li>
<li>Ingolia, N. T., Ghaemmaghami, S., Newman, J. R., Weissman, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Genome-wide+analysis+in+vivo+of+translation+with+nucleotide+resolution+using+ribosome+profiling%5BTitle%5D)+AND+%22Science%22%5BJournal%5D)">Genome-wide analysis in vivo of translation with nucleotide resolution using ribosome profiling.</a> Science. 324, 218-223 (2009).</li>
<li>Valasek, L., Szamecz, B., Hinnebusch, A. G., Nielsen, K. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((In+vivo+stabilization+of+preinitiation+complexes+by+formaldehyde+cross-linking%5BTitle%5D)+AND+%22Methods+Enzymol%22%5BJournal%5D)">In vivo stabilization of preinitiation complexes by formaldehyde cross-linking.</a> Methods Enzymol. 429, 163-183 (2007).</li>
<li>Fletcher, J. E., Copeland, P. R., Driscoll, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Polysome+distribution+of+phospholipid+hydroperoxide+glutathione+peroxidase+mRNA%3A+evidence+for+a+block+in+elongation+at+the+UGA%2Fselenocysteine+codon%5BTitle%5D)+AND+%22Rna%22%5BJournal%5D)">Polysome distribution of phospholipid hydroperoxide glutathione peroxidase mRNA: evidence for a block in elongation at the UGA/selenocysteine codon.</a> Rna. 6, 1573-1584 (2000).</li>
<li>Ruan, H. J., Brown, C. Y., Morris, D. R. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aRuan%2C+HJ+%22Analysis+of+mRNA+formation+and+function%22">Analysis of mRNA formation and function</a>. Richter, J. D. , Academic Press. 305-321 (1997).</li>
<li>Martin, G. W. 3rd, Berry, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Selenocysteine+codons+decrease+polysome+association+on+endogenous+selenoprotein+mRNAs%5BTitle%5D)+AND+%22Genes+Cells%22%5BJournal%5D)">Selenocysteine codons decrease polysome association on endogenous selenoprotein mRNAs.</a> Genes Cells. 6, 121-129 (2001).</li>
<li>Lee, Y. Y., Cevallos, R. C., Jan, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((An+upstream+open+reading+frame+regulates+translation+of+GADD34+during+cellular+stresses+that+induce+eIF2alpha+phosphorylation%5BTitle%5D)+AND+%22J+Biol+Chem%22%5BJournal%5D)">An upstream open reading frame regulates translation of GADD34 during cellular stresses that induce eIF2alpha phosphorylation.</a> J Biol Chem. 284, 6661-6673 (2009).</li>
</ol>

No conflicts of interest declared.

The information obtained from the polyribosome profile can provide valuable insight into the translational status of the cell. In addition, the status of the assembly of ribosomal subunits themselves can be determined2. For example the presence of halfmers or 80S and larger peaks with a slight shoulder to the right on the profile indicates a bound 40S subunit awaiting 60S subunit joining. Performing the experiment in the absence of any added cycloheximide or other inhibitor of elongation allows for analysis of the rate of run off, which indicates whether or not elongation is altered3. The fractions themselves are a rich source of reagents for the subsequent determination of the association of a specific mRNA or protein with ribosomal subpopulations by Northern or Western blotting of the fractions. The total pool of mRNAs associated with active ribosomes can be determined via an associated microarray4 or deep sequencing analysis5. The protein associations can also be stabilized by the appropriate addition of a cross linking reagent 6.
Polyribosome analysis from mammalian cells is also worth mentioning as a distinct protocol in terms of the apparent difficulties in establishing the conditions required to obtain stable polysomes. The buffer systems reported in the literature are widely variable 7-10, thus there may be a requirement for cell-type specific optimization of the lysis buffer, or it is equally plausible that the buffer system is not as important as keen attention to working with fresh lysates kept at low temperatures. To our knowledge a systematic evaluation of the parameters affecting mammalian polysome formation has not been reported.

<table><tbody><tr><td>polyallomer ultracentrifuge tube</td><td>Beckman Coulter Inc.</td><td>326823</td><td>1 x 3.5 in. (25x89mm)</td></tr><tr><td>Fluorinert</td><td>Sigma-Aldrich</td><td>F9755</td><td></td></tr><tr><td>Cycloheximde</td><td>Sigma-Aldrich</td><td>C-7698</td><td></td></tr><tr><td>Heparin</td><td>Sigma-Aldrich</td><td>H3393</td><td></td></tr><tr><td>BY4741</td><td>Open Biosystems</td><td>YSC1048</td><td>Other strains work equally well</td></tr></tbody></table>

eukaryotic polyribosome profile analysis

Eukaryotic Polyribosome Profile Analysis

Protein synthesis is a complex cellular process that is regulated at many levels. For example, global translation can be inhibited at the initiation phase or the elongation phase by a variety of cellular stresses such as amino acid starvation or growth factor withdrawal. Alternatively, translation of individual mRNAs can be regulated by mRNA localization or the presence of cognate microRNAs. Studies of protein synthesis frequently utilize polyribosome analysis to shed light on the mechanisms of translation regulation or defects in protein synthesis. In this assay, mRNA/ribosome complexes are isolated from eukaryotic cells.  A sucrose density gradient separates mRNAs bound to multiple ribosomes known as polyribosomes from mRNAs bound to a single ribosome or monosome. Fractionation of the gradients allows isolation and quantification of the different ribosomal populations and their associated mRNAs or proteins. Differences in the ratio of polyribosomes to monosomes under defined conditions can be indicative of defects in either translation initiation or elongation/termination. Examination of the mRNAs present in the polyribosome fractions can reveal whether the cohort of individual mRNAs being translated changes with experimental conditions. In addition, ribosome assembly can be monitored by analysis of the small and large ribosomal subunit peaks which are also separated by the gradient. In this video, we present a method for the preparation of crude ribosomal extracts from yeast cells, separation of the extract by sucrose gradient and interpretation of the results.  This procedure is readily adaptable to mammalian cells.

This article describes a protocol for the extraction of translating ribosomes from eukaryotic cells. Once extracted, ribosomes are separated into monosomes and polyribosomes by sucrose gradient fractionation to allow different ribosomal populations to be analyzed. As such, this method is the gold standard for examining the regulation of translation.

Protein synthesis is a complex cellular process that is regulated at many levels. For example, global translation can be inhibited at the initiation phase ...

The overall goal of this procedure is to separate and compare the mono zone and poly ribosome fractions from cell lysates. This is accomplished by first culturing the cells of interest. The second step of the procedure is to prepare the cell lysate.The third step of the procedure is to centrifuge the lysate through a sucrose gradient. The final step of the procedure is to fractionate the gradient and visualize the different ribosomal populations through a UV trace. Ultimately, results can be obtained that show changes in translation under different experimental conditions through poly ribosome profile analysis.Hi, I am Anthony Esposito from the lab of Dr.Terry Goss Kinsey in the Molecular Genetics, microbiology and immunology department at UMD and J Robert Wood Johnson Medical School. And I'm Marcus Lewis. Also from McKinsey Lab here at R-W-J-M-S.Today we're gonna show you a procedure for poly ribosome analysis. We use this procedure in our lab to study alterations and protein synthesis that arise from mutations or environmental factors. So let's get started.Sucrose.Gradients should be prepared one day before use to allow gradients to become continuous. Mix the appropriate volumes of 7%and 47%sucrose stock solutions to make 48 milliliters of each of the following sucrose concentrations, 7%17%27%37%and 47%Add one molar DTT to each sucrose solution to a final concentration of one millimolar. In order to pour the gradients, attach a pasta pipette to a 20 milliliter syringe by securing and sealing with para film.Add seven milliliters of 7%sucrose to the bottom of a one inch by 3.5 inch poly aamer ultra centrifuge tube. Next, add seven milliliters of 17%sucrose solution under the 7%solution by placing the pasta pipette tip near the bottom of the tube pipette slowly. It should take no less than 20 seconds to pour each layer.Repeat with seven milliliters each of 27%37%and 47%sucrose solutions when the gradient has been bored. You should observe clear lines between the layers indicating that minimal mixing has occurred. Store all gradients of four degrees Celsius overnight, along with the rotors, bottles and tubes that will be used to harvest samples.To prepare extracts from yeast cells, start by growing hundred 25 milliliters of yeast culture to an OD 600 of 0.8 to one. Add cyclo heide to the culture to a final concentration of 100 micrograms per milliliter and continue shaking at 30 degrees Celsius for 15 minutes. After 15 minutes, pour the culture into a 250 milliliter centrifuge bottle and fill with ice.Keep everything on ice from this point onward centrifuge at 8, 000 times gravity for five minutes at four degrees Celsius. Resus, suspend the pellet in 10 milliliters of ice, cold lysis, buffer, and transfer to 15 milliliter polypropylene tubes. Centrifuge at 5, 900 times gravity for three minutes of four degrees Celsius Resus.Suspend the pellet in 0.5 milliliters of lysis buffer. Transfer the suspension to a 1.5 milliliter micro fuge tube and then add 0.5 milliliters of chilled baked acid washed glass beads. Vortex the cells for four 32nd intervals, calling the tube on ice for 30 seconds between each interval.Then add another 0.5 milliliters of lysis buffer into the 1.5 milliliter tube centrifuge at 5, 000 times. Gravity for five minutes at four degrees Celsius. Transfer the supernatant to a new 1.5 milliliter micro centrifuge tube and centrifuge at maximum speed for 10 minutes at four degrees Celsius.Lastly, transfer the supinate to a new 1.5 milliliter micro centri tube. The extract can be stored at minus 80 degrees Celsius to transfer the lysate to the sucrose gradient. Place the tip of the pipette against the wall of the tube near the surface of the gradient and gently layer the lysate on top of the gradient.For a 35 milliliter gradient, 500 microliters of lysate is typically loaded. Using forceps, carefully lower the gradient into the bucket of a swinging bucket rotor. Centrifuge the gradients at 100, 000 times gravity for four hours at four degrees Celsius.Approximately 30 minutes prior to the completion of the four hour spin. Attach the needle to the tube piercer and attach the pen to the online absorbance fluorescence monitor. Turn on the power for the absorbance monitor to allow a stable baseline to be reached prior to analyzing samples.Electronic acquisition of the PolyZone profile can easily be obtained in real time by attaching a DI 1 48 U data acquisition unit. To the chart recorder, fill the syringe pump with 50 milliliters of florin nuts using the reverse flow rapid setting. Make sure that there are no air bubbles present.Connect the hose from the syringe to the tube piercer. And briefly turn on the flow of Flo inert at six milliliters per minute in the forward direction. To clear the hose of any air bubbles, place a series of tubes under the hose at the end of the flow cell to collect sample runoff.Prepare an ice bucket with a preformed well for holding the centrifuge tube containing the sucrose gradient. When the four hour centrifugation is complete, carefully remove the centrifuge tubes from the centrifuge rotor and place them on ice. Taking care to avoid disturbing the gradients.To analyze cell extracts, place the gradient tube on the tube piercer and connect the top of the tube to the outlet and secure. Raise the bottom stage to the centrifuge tube so that the needle pierces the bottom of the tube. Begin the flow of Florin alert in the forward direction at six milliliters per minute.Once the flut has begun flowing into the tube, monitor the movement of the needle on the online UV absorbance monitor. Once the needle begins to move, turn on the chart movement to a speed setting of 60. When the end of the poly ribosome profile has been reached, turn off the flow of Flo inert to the centrifuge tube and stop the chart movement at the absorbance fluorescence monitor.Retract the Flo inert from the centrifuge tube into the syringe by beginning the flow in the reverse direction at a rapid rate, making sure not to draw sucrose from the tube into the syringe. Unscrew the centrifuge tube from the tube piercer, lower the needle and remove the tube. A representative trace of a ribosome extract prepared from yeast in the presence of cyclo heide is shown here.UV absorbance peaks containing polyribosomes and A TS 60 s and 40 s ribosomes are indicated. We've just shown you how to perform poly ribosome analysis When doing this procedure. It's important to remember to work quickly, keeping samples cold and RNAs free.So that's it. Thanks for watching and good luck on your experiments.

Research

JoVE Journal

Biology

Here, we describe a method to analyze changes in the initiation of mRNA translation of eukaryotic cells in response to stress conditions. This method is based on the velocity separation on sucrose gradients of translating ribosomes from non-translating ribosomes.

Analysis of Translation Initiation During Stress Conditions by Polysome Profiling

This protocol illustrates essential modifications of polyribosome fractionation in order to study the translatome of in vivo CNS samples. It allows global assessment of translation and transcription regulation through the isolation and comparison of total RNA to ribosome bound RNA fractions.

In vivo Interrogation of Central Nervous System Translatome by Polyribosome Fractionation

Ribosomes play a central role in protein synthesis. Polyribosome (polysome) fractionation by sucrose density gradient centrifugation allows direct determination of translation efficiencies of individual mRNAs on a genome-wide scale. In addition, this method can be used for biochemical analysis of ribosome- and polysome-associated factors such as chaperones and signaling molecules.

Polysome Fractionation and Analysis of Mammalian Translatomes on a Genome-wide Scale

The ability of cells to adapt to stress is crucial for their survival. Regulation of mRNA translation is one such adaptation strategy, providing for rapid regulation of the proteome. Here, we provide a standardized polysome profiling protocol to identify specific mRNAs that are selectively translated under stress conditions.

Assessment of Selective mRNA Translation in Mammalian Cells by Polysome Profiling

This protocol describes an easy method to extract and fractionate transcripts from plant tissues on the basis of the number of bound ribosomes. It allows a global estimate of translation activity and the determination of the translational status of specific mRNAs.

An Easy Method for Plant Polysome Profiling

Translational regulation plays an important role in the control of protein abundance. Here, we describe a high-throughput method for quantitative analysis of translation in the budding yeast Saccharomyces cerevisiae.

Genome-wide Quantification of Translation in Budding Yeast by Ribosome Profiling

The overall goal of polysome profiling technique is analysis of translational activity of individual mRNAs or transcriptome mRNAs during protein synthesis. The method is important for studies of protein synthesis regulation, translation activation and repression in health and multiple human diseases.

Polysome Profiling in Leishmania, Human Cells and Mouse Testis

This protocol describes how to generate a polysome profile without using automated gradient makers or gradient fractionation systems.

Polysome Profiling without Gradient Makers or Fractionation Systems

Co-translational interactions play a crucial role in nascent-chain modifications, targeting, folding, and assembly pathways. Here, we describe Selective Ribosome Profiling, a method for in vivo, direct analysis of these interactions in the model eukaryote Saccharomyces cerevisiae.

Global Identification of Co-Translational Interaction Networks by Selective Ribosome Profiling

Translating ribosomes decode three nucleotides per codon into peptides. Their movement along mRNA, captured by ribosome profiling, produces the footprints exhibiting characteristic triplet periodicity. This protocol describes how to use RiboCode to decipher this prominent feature from ribosome profiling data to identify actively translated open reading frames at the whole-transcriptome level.

De novo Identification of Actively Translated Open Reading Frames with Ribosome Profiling Data

Learn eukaryotic polyribosome profile analysis to separate monosome and polyribosome fractions using sucrose gradient centrifugation. This method enables researchers to study translation regulation and ribosomal dynamics in vivo.

Eukaryotic Polyribosome Profile Analysis

Explore More Videos