Name: ms2-affinity purification coupled with rna sequencing in gram-positive bacteria
Uploaded: 2021-02-23T15:00:00
Description: Watch this Scientific Journal Video about MS2-Affinity Purification Coupled with RNA Sequencing in Gram-Positive Bacteria at JoVE.com

This work was supported by the &#8220;Agence Nationale de la Recherche&#8221; (ANR, Grant ANR-16-CE11-0007-01, RIBOSTAPH, and ANR-18-CE12- 0025-04, CoNoCo, to PR). It has also been published under the framework of the labEx NetRNA ANR-10-LABX-0036 and of ANR-17-EURE- 0023 (to PR), as funding from the state managed by ANR as part of the investments for the future program. DL was supported by the European Union&#39;s Horizon 2020 research and innovation program under the Marie Sk&#322;odowska-Curie Grant Agreement No. 753137-SaRNAReg. Work in E. Mass&#233; Lab has been supported by operating grants from the Canadian Institutes of Health Research (CIHR), the Natural Sciences and Engineering Research Council of Canada (NSERC), and the National institutes of Health NIH Team Grant R01 GM092830-06A1.

1. Buffers and media
<ol>
	<li>For MAPS experiments, prepare the following buffers and media: 
	- Buffer A (150 mM KCl, 20 mM Tris-HCl pH 8, 1 mM MgCl2 and 1 mM DTT) 
	- Buffer E (250 mM KCl, 20 mM Tris-HCl pH 8, 12 mM maltose, 0.1% Triton, 1 mM MgCl2 and 1 mM DTT) 
	- RNA loading buffer (0.025% xylene cyanol and 0.025% bromophenol blue in 8 M urea) 
	- Brain Heart Infusion (BHI) medium (12.5 g of calf brain, 10 g of peptone, 5 g of beef heart, 5 g of NaCl, 2.5...

<ol>
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C., Masse, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DsrA+regulatory+RNA+represses+both+hns+and+rbsD+mRNAs+through+distinct+mechanisms+in+Escherichia+coli.">DsrA regulatory RNA represses both hns and rbsD mRNAs through distinct mechanisms in Escherichia coli.</a> Molecular Microbiology. 98 (2), 357-369 (2015).</li><li>Lalaouna, D., Prevost, K., Laliberte, G., Houe, V., Masse, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contrasting+silencing+mechanisms+of+the+same+target+mRNA+by+two+regulatory+RNAs+in+Escherichia+coli.">Contrasting silencing mechanisms of the same target mRNA by two regulatory RNAs in Escherichia coli.</a> Nucleic Acids Research. 46 (5), 2600-2612 (2018).</li><li>Lalaouna, D., Eyraud, A., Devinck, A., Prevost, K., Masse, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GcvB+small+RNA+uses+two+distinct+seed+regions+to+regulate+an+extensive+targetome.">GcvB small RNA uses two distinct seed regions to regulate an extensive targetome.</a> Molecular Microbiology. 111 (2), 473-486 (2019).</li><li>Silva, I. 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=SraL+sRNA+interaction+regulates+the+terminator+by+preventing+premature+transcription+termination+of+rho+mRNA.">SraL sRNA interaction regulates the terminator by preventing premature transcription termination of rho mRNA.</a> Proceedings of the National Academy of Sciences. 116 (8), 3042-3051 (2019).</li><li>Lalaouna, D., Masse, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+sRNA+interacting+with+a+transcript+of+interest+using+MS2-affinity+purification+coupled+with+RNA+sequencing+(MAPS)+technology.">Identification of sRNA interacting with a transcript of interest using MS2-affinity purification coupled with RNA sequencing (MAPS) technology.</a> Genomics Data. 5, 136-138 (2015).</li><li>Tomasini, 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+RNA+targetome+of+Staphylococcus+aureus+non-coding+RNA+RsaA:+impact+on+cell+surface+properties+and+defense+mechanisms.">The RNA targetome of Staphylococcus aureus non-coding RNA RsaA: impact on cell surface properties and defense mechanisms.</a> Nucleic Acids Research. 45 (11), 6746-6760 (2017).</li><li>Bronesky, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+multifaceted+small+RNA+modulates+gene+expression+upon+glucose+limitation+in+Staphylococcus+aureus.">A multifaceted small RNA modulates gene expression upon glucose limitation in Staphylococcus aureus.</a> The EMBO Journal. 38 (6), (2019).</li><li>Lalaouna, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RsaC+sRNA+modulates+the+oxidative+stress+response+of+Staphylococcus+aureus+during+manganese+starvation.">RsaC sRNA modulates the oxidative stress response of Staphylococcus aureus during manganese starvation.</a> Nucleic Acids Research. 47 (1), 9871-9887 (2019).</li><li>Carrier, M. 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A modified protocol for Gram-positive bacteria 
The initial protocol of MAPS was developed to study sRNA interactome in the model organism E. coli20,30. Here, we describe a modified protocol which is suitable for the characterization of sRNA-dependent regulatory networks in the opportunistic human pathogen S. aureus and is certainly transposable to other Gram-positive bacteria, pathogenic or not.
<p class="jove_content"...

Hundreds, perhaps even thousands of small regulatory RNAs (sRNAs) have been identified in most bacterial genomes, but the functions of the vast majority of them remain uncharacterized. Overall, sRNAs are short non-coding molecules, playing major roles in bacterial physiology and adaptation to fluctuating environments1,2,3. Indeed, these macromolecules are at the center of numerous intricate regulatory networks, impacting metabolic pathways, stress responses but also virulence and antibiotic resistance. Logically, their synthesis is triggered by specific environment stimuli (e.g., nutrient starvation, oxidative or membrane stresses). Most sRNAs regulate multiple target mRNAs at the post-transcriptional level through short and non-contiguous base pairing. They usually prevent translation initiation by competing with ribosomes for translation initiation regions4. The formation of sRNA:mRNA duplexes also often results in the active degradation of the target mRNA by recruitment of specific RNases.
The characterization of an sRNA targetome (i.e., the whole set of its target RNAs) allows the identification of the metabolic pathways in which it intervenes and the potential signal it answers to. Consequently, the functions of a specific sRNA can generally be inferred from its targetome. For this purpose, several in silico prediction tools have been developed such as IntaRNA and CopraRNA5,6,7. They notably rely on sequence complementarity, pairing energy and accessibility of the potential interaction site to determine putative sRNA partners. However, prediction algorithms do not integrate all factors influencing base-pairing in vivo such as the involvement of RNA chaperones8 favoring sub-optimal interactions or the co-expression of both partners. Due to their inherent limitations, the false positive rate of prediction tools remains high. Most experimental large-scale approaches are based on the co-purification of sRNA:mRNA couples interacting with a tagged RNA binding protein (RBP)6,9. For example, the RNA Interaction by Ligation and sequencing (RIL-seq) method identified RNA duplexes co-purified with RNA chaperones such as Hfq and ProQ in Escherichia coli10,11. A similar technology called UV-Crosslinking, Ligation And Sequencing of Hybrids (CLASH) was applied to RNase E- and Hfq-associated sRNAs in E. coli12,13. Despite the well-described roles of Hfq and ProQ in sRNA-mediated regulation in multiple bacteria8,14,15, sRNA-based regulation seems to be RNA chaperone-independent in several organisms like S. aureus16,17,18. Even if the purification of RNA duplexes in association with RNases is feasible as demonstrated by Waters and coworkers13, this remains tricky as RNases trigger their rapid degradation. Hence, the MS2-Affinity Purification coupled with RNA Sequencing (MAPS) approach19,20 constitutes a solid alternative in such organisms.
Unlike above-mentioned methods, MAPS uses a specific sRNA as bait to capture all interacting RNAs and hence does not rely on the involvement of an RBP. The entire process is depicted in Figure 1. In brief, the sRNA is tagged at the 5&#8217; with the MS2 RNA aptamer that is specifically recognized by the MS2 coat protein. This protein is fused with the maltose binding protein (MBP) to be immobilized on an amylose resin. Therefore, MS2-sRNA and its RNA partners are retained on the affinity chromatography column. After elution with maltose, co-purified RNAs are identified using high-throughput RNA sequencing followed by bioinformatic analysis (Figure 2). The MAPS technology ultimately draws an interacting map of all potential interactions occurring in vivo.
MAPS technology was originally implemented in the non-pathogenic Gram-negative bacterium E. coli21. Remarkably, MAPS helped identify a tRNA-derived fragment specifically interacting with both RyhB and RybB sRNAs and preventing any sRNA transcriptional noise to regulate mRNA targets in non-inducing conditions. Thereafter, MAPS has been successfully applied to other E. coli sRNAs like DsrA22, RprA23, CyaR23 and GcvB24 (Table 1). In addition to confirming previously known targets, MAPS extended the targetome of these well-known sRNAs. Recently, MAPS has been performed in Salmonella Typhimurium and revealed that SraL sRNA binds to rho mRNA, coding for a transcription termination factor25. Through this pairing, SraL protects rho mRNA from the premature transcription termination triggered by Rho itself. Interestingly, this technology is not restricted to sRNAs and can be applied to any type of cellular RNAs as exemplified by the use of a tRNA-derived fragment26 and a 5&#8217;-untranslated region of mRNA22 (Table 1).
MAPS method has been also adapted to the pathogenic Gram-positive bacterium S. aureus19. Specifically, the lysis protocol has been widely modified to efficiently break cells due to a thicker cell wall than Gram-negative bacteria and to maintain RNA integrity. This adapted protocol already unravelled the interactome of RsaA27, RsaI28 and RsaC29. This approach gave insights into the crucial role of these sRNAs in regulatory mechanisms of cell surface properties, glucose uptake, and oxidative stress responses.
The protocol developed and implemented in E. coli in 2015 has been recently described in great detail30. Here, we provide the modified MAPS protocol, which is particularly suitable for studying sRNA regulatory networks in Gram-positive (thicker cell wall) bacteria whether non-pathogenic or pathogenic (safety precautions).

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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">1.5 mL microcentrifuge tube</td>
			<td style="width:187px;">Sarstedt</td>
			<td style="width:119px;">72.690.001</td>
			<td style="width:247px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">15 mL centrifuge tubes</td>
			<td style="width:187px;">Falcon</td>
			<td style="width:119px;">352070</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">2 mL microcentrifuge tube</td>
			<td style="width:187px;">Starstedt</td>
			<td style="width:119px;">72.691</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">2100 Bioanalyzer Instrument</td>
			<td style="width:187px;">Agilent</td>
			<td style="width:119px;">G2939BA</td>
			<td>RNA quantity and quality</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">250 mL culture flask</td>
			<td style="width:187px;">Dominique Dutscher</td>
			<td style="width:119px;">2515074</td>
			<td>Bacterial cultures</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">50 mL centrifuge tubes</td>
			<td style="width:187px;">Falcon</td>
			<td style="width:119px;">352051</td>
			<td>Culture centrifugation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Absolute ethanol</td>
			<td style="width:187px;">VWR Chemicals</td>
			<td style="width:119px;">20821.321</td>
			<td>RNA extraction and purification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Allegra X-12R Centrifuge</td>
			<td style="width:187px;">Beckman Coulter</td>
			<td style="width:119px;"></td>
			<td>Bacterial pelleting</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Ampicilin (amp)</td>
			<td style="width:187px;">Sigma-Aldrich</td>
			<td style="width:119px;">A9518-5G</td>
			<td>Growth medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Amylose resin</td>
			<td style="width:187px;">New England BioLabs</td>
			<td style="width:119px;">E8021S</td>
			<td>MS2-affinity purification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Anti-dioxigenin AP Fab fragment</td>
			<td style="width:187px;">Sigma Aldrich</td>
			<td style="width:119px;">11093274910</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Autoradiography cassette</td>
			<td style="width:187px;">ThermoFisher Scientific</td>
			<td style="width:119px;">50-212-726</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">BamHI</td>
			<td style="width:187px;">ThermoFisher Scientific</td>
			<td style="width:119px;">ER0051</td>
			<td>Plasmid construction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">BHI (Brain Heart Infusion) Broth</td>
			<td style="width:187px;">Sigma-Aldrich</td>
			<td style="width:119px;">53286</td>
			<td>Growth medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Blocking reagent</td>
			<td style="width:187px;">Sigma Aldrich</td>
			<td style="width:119px;">11096176001</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">CDP-Star</td>
			<td style="width:187px;">Sigma Aldrich</td>
			<td style="width:119px;">11759051001</td>
			<td>Northern blot assays (substrate)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Centrifuge 5415 R</td>
			<td style="width:187px;">Eppendorf</td>
			<td style="width:119px;"></td>
			<td>RNA extraction and purification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Chloroform</td>
			<td style="width:187px;">Dominique Dutscher</td>
			<td style="width:119px;">508320-CER</td>
			<td>RNA extraction and purification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">DIG-RNA labelling mix</td>
			<td style="width:187px;">Sigma-Aldrich</td>
			<td style="width:119px;">11277073910</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">DNase I</td>
			<td style="width:187px;">Roche</td>
			<td style="width:119px;">4716728001</td>
			<td>DNase treatment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Erythromycin (ery)</td>
			<td style="width:187px;">Sigma-Aldrich</td>
			<td>Fluka 45673</td>
			<td>Growth medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">FastPrep device</td>
			<td style="width:187px;">MP Biomedicals</td>
			<td style="width:119px;">116004500</td>
			<td>Mechanical lysis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Guanidium Thiocyanate</td>
			<td style="width:187px;">Sigma-Aldrich</td>
			<td style="width:119px;">G9277-250G</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Hybridization Hoven Hybrigene</td>
			<td style="width:187px;">Techne</td>
			<td style="width:119px;">FHB4DD</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Hybridization tubes</td>
			<td style="width:187px;">Techne</td>
			<td style="width:119px;">FHB16</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Isoamyl alcohol</td>
			<td style="width:187px;">Fisher Scientific</td>
			<td style="width:119px;">A/6960/08</td>
			<td>RNA extraction and purification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">LB (Lysogeny Broth)</td>
			<td style="width:187px;">Sigma-Aldrich</td>
			<td style="width:119px;">L3022</td>
			<td>Growth medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lysing Matrix B Bulk</td>
			<td style="width:187px;">MP Biomedicals</td>
			<td style="width:119px;">6540-428</td>
			<td>Mechanical lysis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">MicroPulser Electroporator</td>
			<td style="width:187px;">BioRad</td>
			<td style="width:119px;">1652100</td>
			<td>Plasmid construction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Milli-Q water device</td>
			<td style="width:187px;">Millipore</td>
			<td style="width:119px;">Z00QSV0WW</td>
			<td>Ultrapure water</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">NanoDrop spectrophotometer</td>
			<td style="width:187px;">ThermoFisher Scientific</td>
			<td style="width:119px;"></td>
			<td>RNA/DNA quantity and quality</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Nitrocellulose membrane</td>
			<td style="width:187px;">Dominique Dutsher</td>
			<td style="width:119px;">10600002</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Phembact Neutre</td>
			<td style="width:187px;">PHEM Technologies</td>
			<td style="width:119px;">BAC03-5-11205</td>
			<td>Cleaning and decontamination</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Phenol</td>
			<td style="width:187px;">Carl Roth</td>
			<td style="width:119px;">38.2</td>
			<td>RNA extraction and purification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Phusion High-Fidelity DNA Polymerase</td>
			<td style="width:187px;">New England Biolabs</td>
			<td style="width:119px;">M0530</td>
			<td>Plasmid construction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">pMBP-MS2</td>
			<td style="width:187px;">Addgene</td>
			<td style="width:119px;">65104</td>
			<td>MS2-MBP production</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Poly-Prep chromatography column</td>
			<td>BioRad</td>
			<td style="width:119px;">7311550</td>
			<td>MS2-affinity purification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PstI</td>
			<td style="width:187px;">ThermoFisher Scientific</td>
			<td style="width:119px;">ER0615</td>
			<td>Plasmid construction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Qubit 3 Fluorometer</td>
			<td style="width:187px;">Invitrogen</td>
			<td style="width:119px;">15387293</td>
			<td>RNA quantity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">RNAPro Solution</td>
			<td style="width:187px;">MP Biomedicals</td>
			<td style="width:119px;">6055050</td>
			<td>Mechanical lysis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">ScriptSeq Complete Kit</td>
			<td style="width:187px;">Illumina</td>
			<td style="width:119px;">BB1224</td>
			<td>Preparation of cDNA librairies</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Spectrophotometer Genesys 20</td>
			<td style="width:187px;">ThermoFisher Scientific</td>
			<td style="width:119px;">11972278</td>
			<td>Bacterial cultures</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">SpeedVac Savant vacuum device</td>
			<td style="width:187px;">ThermoFisher Scientific</td>
			<td style="width:119px;">DNA120</td>
			<td>RNA extraction and purification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">Stratalinker UV Crosslinker 1800</td>
			<td style="width:187px;">Stratagene</td>
			<td style="width:119px;">400672</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">T4 DNA ligase</td>
			<td style="width:187px;">ThermoFisher Scientific</td>
			<td style="width:119px;">EL0014</td>
			<td>Plasmid construction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">TBE (Tris-Borate-EDTA)</td>
			<td style="width:187px;">Euromedex</td>
			<td style="width:119px;">ET020-C</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">ThermalCycler T100</td>
			<td style="width:187px;">BioRad</td>
			<td style="width:119px;">1861096</td>
			<td>Plasmid construction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tween 20</td>
			<td style="width:187px;">Sigma Aldrich</td>
			<td style="width:119px;">P9416-100ML</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">X-ray film processor</td>
			<td style="width:187px;">hu.q</td>
			<td style="width:119px;">HQ-350XT</td>
			<td>Northern blot assays</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:282px;">X-ray films Super RX-N</td>
			<td style="width:187px;">FujiFilm</td>
			<td style="width:119px;">4741019318</td>
			<td>Northern blot assays</td>
		</tr>
	</tbody>
</table>

ms2-affinity purification coupled with rna sequencing in gram-positive bacteria

Although small regulatory RNAs (sRNAs) are widespread among the bacterial domain of life, the functions of many of them remain poorly characterized notably due to the difficulty of identifying their mRNA targets. Here, we described a modified protocol of the MS2-Affinity Purification coupled with RNA Sequencing (MAPS) technology, aiming to reveal all RNA partners of a specific sRNA in vivo. Broadly, the MS2 aptamer is fused to the 5&#8217; extremity of the sRNA of interest. This construct is then expressed in vivo, allowing the MS2-sRNA to interact with its cellular partners. After bacterial harvesting, cells are mechanically lysed. The crude extract is loaded into an amylose-based chromatography column previously coated with the MS2 protein fused to the maltose binding protein. This enables the specific capture of MS2-sRNA and interacting RNAs. After elution, co-purified RNAs are identified by high-throughput RNA sequencing and subsequent bioinformatic analysis. The following protocol has been implemented in the Gram-positive human pathogen Staphylococcus aureus and is, in principle, transposable to any Gram-positive bacteria. To sum up, MAPS technology constitutes an efficient method to deeply explore the regulatory network of a particular sRNA, offering a snapshot of its whole targetome. However, it is important to keep in mind that putative targets identified by MAPS still need to be validated by complementary experimental approaches.

The representative results originate from the study of RsaC targetome in S. aureus29. RsaC is an unconventional 1,116 nt-long sRNA. Its 5&#8217; end contains several repeated regions while its 3&#8217; end (544 nt) is structurally independent and contains all predicted interaction sites with its mRNA targets. The expression of this sRNA is induced when manganese (Mn) is scarce, which is often encountered in the context of host immune response. Using MAPS technology, we identified several ...

Watch this Scientific Journal Video about MS2-Affinity Purification Coupled with RNA Sequencing in Gram-Positive Bacteria at JoVE.com

MS2-Affinity Purification Coupled with RNA Sequencing in Gram-Positive Bacteria

MAPS technology has been developed to scrutinize the targetome of a specific regulatory RNA in vivo. The sRNA of interest is tagged with a MS2 aptamer enabling the co-purification of its RNA partners and their identification by RNA sequencing. This modified protocol is particularly suited for Gram-positive bacteria.&#160;

Although small regulatory RNAs (sRNAs) are widespread among the bacterial domain of life, the functions of many of them remain poorly characterized ...

MS2-affinity purification coupled with RNA sequencing or MAPS has been developed to identify the whole targetome of any RNA of interest in bacteria. This technology makes it possible to identify any kind of sRNA partners independently of the mechanism of regulation. The characterization of sRNA-dependent regulatory networks will help understand better virulence factors production, biofilm formation, and survival of the bacteria within the host cells, and ultimately fight against staphylococcal infections.This protocol can be applied to any pathogenic or non-pathogenic gram-positive bacteria. Demonstrating the procedure will be Noemie Mercier, a PhD student from Dr.Pascal Romby's laboratory. To begin, grow one colony of strains carrying either pCN51 P3 MS2 sRNA or pCN51 P3 MS2 plasmids in three milliliters of BHI medium supplemented with 10 micrograms per microliter erythromycin in duplicates.Dilute each overnight culture in 50 milliliters of fresh BHI medium supplemented with erythromycin to reach an OD 600 of 0.05. Grow the cultures at 37 degrees Celsius with shaking at 180 RPM for six hours. Transfer each culture into a 50 milliliter centrifuge tube and centrifuge the tubes at 2, 900 times G for 15 minutes at four degrees Celsius, then discard the supernatant, freeze and store them at minus 80 degrees Celsius or keep the pellets on ice and directly perform mechanical cell lysis.To perform mechanical cell lysis, resuspend pellets in five milliliters of buffer A and transfer the resuspended cells to 15 milliliter centrifuge tubes with 3.5 grams of silica beads. Insert the tubes in a mechanical cell lysis instrument and run a cycle of 40 seconds at four meters per second. Centrifuge the tubes at 2, 900 times G for 15 minutes, then recover the supernatant and keep it on ice.Make sure that the supernatant is clear, repeating the centrifugation if it is not. Remove the column tip, then put a chromatography column in a column rack and wash the column with ultrapure water. Add 300 microliters of amylose resin and wash the column with 10 milliliters of buffer A.Dilute 1, 200 picamoles of MBP-MS2 protein in six milliliters of buffer A and load it into the column.Wash the column with 10 milliliters of buffer A.Next, perform MS2-affinity purification. Load the cell lysate into the column and collect the flow-through fraction in a clean collection tube. Wash the column three times with 10 milliliters of buffer A and collect the wash fraction, then elute the column with one milliliter of buffer E and collect the elution fraction in a two milliliter microtube.Keep all collected fractions on ice until RNA extraction. Use one milliliter of each fraction for RNA extraction. Add one volume of phenol to the RNA and mix vigorously, then centrifuge the mixture at 16, 000 times G for 10 minutes at 20 degrees Celsius.Transfer the upper phase to a clean two milliliter microtube. Add one volume of chloroform isoamyl alcohol and repeat the centrifugation, then transfer the upper phase to a new tube. Add 2.5 volumes of 100%cold ethanol and 0.1 volume of three molar sodium acetate at pH 5.2 and precipitate overnight at minus 20 degrees Celsius.On the next day, centrifuge the tubes for 15 minutes at 16, 000 times G and four degrees Celsius. Slowly remove the ethanol with a pipette, taking care not to disturb the pellet. Add 500 microliters of 80%cold ethanol and centrifuge for five minutes.Discard the ethanol by pipetting it slowly, then dry the pellet using a vacuum concentrator for five minutes on run mode. Resuspend the pellet in an appropriate volume of ultrapure water. This protocol was used to study the RsaC targetome in S.aureus.Several mRNAs interacting directly with RsaC were identified using MAPS technology, revealing its crucial role in oxidative stress and metal-related responses. To confirm the MS2 sRNA constructs and visualize their pattern of expression, cells were harvested after two, four, and six hours of growth in BHI medium. RNA was extracted and Northern blot analysis was performed using the RsaC-specific DIG probe.The level of endogenous RsaC significantly increased after six hours of growth. Importantly, the level of MS2-RsaC 544 and MS2-RsaC 1, 116 were comparable to endogenous RsaC at six hours. Affinity purification was performed and RNAs were extracted from the crude extract, flow-through, and elution fractions in the wild-type strain expressing the MS2 tag alone and the mutant RsaC strain expressing the MS2-RsaC 544 construct.The 1, 116 nucleotide long endogenous RsaC was enriched in the elution fraction, but interacted non-specifically with the affinity column due to its length and complex secondary structure. The MS2-RsaC 544 was highly enriched in the elution fraction demonstrating that it was successfully retained by the MS2-MBP fusion protein. A bioinformatic analysis revealed putative mRNA targets according to the fold change between MS2 sRNA and MS2 control, indicating that sodA was the first putative target.A Northern blot analysis performed sodA-specific DIG probe after MS2-affinity purification shows that sodA was efficiently co-enriched with MS2-RsaC 544 compared to the MS2 control. When attempting this protocol, keep in mind that the addition of the MS2 tag can affect sRNA confirmation, stability, or function. This should be carefully monitored.MAPS provides a snapshot of sRNA-RNA targets pairing. Further experimental validation will unravel their function. This technique represents a powerful tool to build sRNA regulatory networks in any bacteria.

ms2-affinity-purification-coupled-with-rna-sequencing-gram-positive

Research

JoVE Journal

Biochemistry

Thermostabilization, Expression, Purification, and Crystallization of the Human Serotonin Transporter Bound to S-citalopram

The serotonin transporter is a sodium and chloride-coupled transporter that &#34;pumps&#34; extracellular serotonin into cells. S-citalopram is a drug used to treat depression and anxiety by binding to the serotonin transporter with high-affinity, blocking serotonin reuptake. Here we report an efficient procedure and a set of tools to stabilize, express, purify, and crystallize serotonin transporter-antibody complexes bound to S-citalopram and other antidepressants. Mutations which stabilize the serotonin transporter were identified using an S-citalopram binding assay. Serotonin transporter expressed in baculovirus-transduced HEK293S GnTI- cells, was reconstituted into proteoliposomes and used to raise high-affinity antibodies. We have developed a strategy to discover antibodies that are useful for structural studies. A straightforward approach for the expression of antibody fragments in Sf9 cells has also been established. Transporter-antibody complexes purified using this procedure are well-behaved and readily crystallize, producing complexes with S-citalopram that diffract X-rays to 3-4 &#197; resolution. The strategies developed here can be utilized to determine the structure of other challenging membrane proteins.

Thermostabilization, Expression, Purification, and Crystallization of the Human Serotonin Transporter Bound to S-citalopram

This manuscript describes how to screen for thermostabilizing mutations, purify the human serotonin transporter, generate high affinity antibodies, and crystallize the serotonin transporter-antibody complex bound to the antidepressant drug S-citalopram. This protocol can be adapted to the study of other challenging membrane transporters, receptors, and channels.

The serotonin transporter is a sodium and chloride-coupled transporter that &#34;pumps&#34; extracellular serotonin into cells. S-citalopram is a drug ...

Growing Protein Crystals with Distinct Dimensions Using Automated Crystallization Coupled with In Situ Dynamic Light Scattering

The automated crystallization device is a patented technique1 especially developed for monitoring protein crystallization experiments with the aim to precisely maneuver the nucleation and crystal growth towards desired sizes of protein crystals. The controlled crystallization is based on sample investigation with in situ Dynamic Light Scattering (DLS) while all visual changes in the droplet are monitored online with the help of a microscope coupled to a CCD camera, thus enabling a full investigation of the protein droplet during all stages of crystallization. The use of in situ DLS measurements throughout the entire experiment allows a precise identification of the highly supersaturated protein solution transitioning to a new phase &#8211; the formation of crystal nuclei. By identifying the protein nucleation stage, the crystallization can be optimized from large protein crystals to the production of protein microcrystals. The experimental protocol shows an interactive crystallization approach based on precise automated steps such as precipitant addition, water evaporation for inducing high supersaturation, and sample dilution for slowing induced homogeneous nucleation or reversing phase transitions.

Growing Protein Crystals with Distinct Dimensions Using Automated Crystallization Coupled with In Situ Dynamic Light Scattering

Here we present a protocol for controlled production of protein microcrystals. The process uses an automated device allowing controlled manipulation of several crystallization parameters. The protein crystallization is carried-out by controlled and automated addition of crystallization solutions while monitoring and investigating the radius distribution of particles in the crystallization droplet.

The automated crystallization device is a patented technique1 especially developed for monitoring protein crystallization experiments with the aim to ...

Single-step Purification of Macromolecular Complexes Using RNA Attached to Biotin and a Photo-cleavable Linker

For many years, the exceptionally strong and rapidly formed interaction between biotin and streptavidin has been successfully utilized for partial purification of biologically important RNA/protein complexes. However, this strategy suffers from one major disadvantage that limits its broader utilization: the biotin/streptavidin interaction can be broken only under denaturing conditions that also disrupt the integrity of the eluted complexes, hence precluding their subsequent functional analysis and/or further purification by other methods. In addition, the eluted samples are frequently contaminated with the background proteins that nonspecifically associate with streptavidin beads, complicating the analysis of the purified complexes by silver staining and mass spectrometry. To overcome these limitations, we developed a variant of the biotin/streptavidin strategy in which biotin is attached to an RNA substrate via a photo-cleavable linker and the complexes immobilized on streptavidin beads are selectively eluted to solution in a native form by long wave UV, leaving the background proteins on the beads. Shorter RNA binding substrates can be synthesized chemically with biotin and the photo-cleavable linker covalently attached to the 5&#39; end of the RNA, whereas longer RNA substrates can be provided with the two groups by a complementary oligonucleotide. These two variants of the UV-elution method were tested for purification of the U7 snRNP-dependent processing complexes that cleave histone pre-mRNAs at the 3&#39; end and they both proved to compare favorably to other previously developed purification methods. The UV-eluted samples contained readily detectable amounts of the U7 snRNP that was free of major protein contaminants and suitable for direct analysis by mass spectrometry and functional assays. The described method can be readily adapted for purification of other RNA binding complexes and used in conjunction with single- and double-stranded DNA binding sites to purify DNA-specific proteins and macromolecular complexes.

RNA/protein complexes purified using botin-streptavidin strategy are eluted to solution under denaturing conditions in a form unsuitable for further purification and functional analysis. Here, we describe a modification of this strategy that utilizes a photo-cleavable linker in RNA and a gentle UV-elution step, yielding native and fully functional RNA/protein complexes.

For many years, the exceptionally strong and rapidly formed interaction between biotin and streptavidin has been successfully utilized for partial ...

Site-Directed Mutagenesis for In Vitro and In Vivo Experiments Exemplified with RNA Interactions in Escherichia Coli

Site-directed mutagenesis is a technique used to introduce specific mutations in DNA to investigate the interaction between small non-coding ribonucleic acid (sRNA) molecules and target messenger RNAs (mRNAs). In addition, site-directed mutagenesis is used to map specific protein binding sites to RNA. A 2-step and 3-step PCR based introduction of mutations is described. The approach is relevant to all protein-RNA and RNA-RNA interaction studies. In short, the technique relies on designing primers with the desired mutation(s), and through 2 or 3 steps of PCR synthesizing a PCR product with the mutation. The PCR product is then used for cloning. Here, we describe how to perform site-directed mutagenesis with both the 2- and 3-step approach to introduce mutations to the sRNA, McaS, and the mRNA, csgD, to investigate RNA-RNA and RNA-protein interactions. We apply this technique to investigate RNA interactions; however, the technique is applicable to all mutagenesis studies (e.g., DNA-protein interactions, amino-acid substitution/deletion/addition). It is possible to introduce any kind of mutation except for non-natural bases but the technique is only applicable if a PCR product can be used for downstream application (e.g., cloning and template for further PCR).

Site-Directed Mutagenesis for In Vitro and In Vivo Experiments Exemplified with RNA Interactions in Escherichia Coli

Site-directed mutagenesis is a technique used to introduce specific mutations in deoxyribonucleic acid (DNA). This protocol describes how to do site-directed mutagenesis with a 2-step and 3-step polymerase chain reaction (PCR) based approach, which is applicable to any DNA fragment of interest.

Site-directed mutagenesis is a technique used to introduce specific mutations in DNA to investigate the interaction between small non-coding ribonucleic ...

Translating Ribosome Affinity Purification (TRAP) for RNA Isolation from Endothelial Cells In Vivo

Many studies have been limited to using in vitro cellular assays and whole tissues or isolating of specific cell types from animals for in vitro analysis of transcriptome and gene expression by qPCR and RNA sequencing. Comprehensive transcriptome and gene expression analysis of specific cell types in complex tissues and organs will be critical to understand cellular and molecular mechanisms by which genes are regulated and their association with tissue homeostasis and organ functions. In this article, we demonstrate the methodology for isolation of ribosome-bound RNA directly in vivo in the vascular endothelia of animal lungs as an example. The specific materials and procedures for tissue processing and RNA purification will be described, including the assessment of RNA quality and yield as well as real time qPCR for arteriogenic gene assays. This approach, known as translating ribosome affinity purification (TRAP) technique, can be utilized for characterization of gene expression and transcriptome analysis of certain cell types directly in vivo in any specific type in complex tissues.

Translating Ribosome Affinity Purification TRAP for RNA Isolation from Endothelial Cells In Vivo

We present an approach to purify ribosome-bound mRNA from vascular endothelial cells (ECs) directly in mouse brain, lung and heart tissues via EC-specific genetic tag of enhanced green fluorescence protein (EGFP)in ribosomes in combination with RNA purification.

Many studies have been limited to using in vitro cellular assays and whole tissues or isolating of specific cell types from animals for in vitro analysis ...

Extremely Rapid and Specific Metabolic Labelling of RNA In Vivo with 4-Thiouracil (Ers4tU)

The nucleotide analogue, 4-thiouracil (4tU), is readily taken up by cells and incorporated into RNA as it is transcribed in vivo, allowing isolation of the RNA produced during a brief period of labelling. This is done by attaching a biotin moiety to the incorporated thio group and affinity purifying, using streptavidin coated beads. Achieving a good yield of pure, newly synthesized RNA that is free of pre-existing RNA makes shorter labelling times possible and permits increased temporal resolution in kinetic studies. This is a protocol for very specific, high yield purification of newly synthesized RNA. The protocol presented here describes how RNA is extracted from the yeast Saccharomyces cerevisiae. However, the protocol for purification of thiolated RNA from total RNA should be effective using RNA from any organism once it has been extracted from the cells. The purified RNA is suitable for analysis by many widely used techniques, such as reverse transcriptase-qPCR, RNA-seq and SLAM-seq. The specificity, sensitivity and flexibility of this technique allow unparalleled insights into RNA metabolism.

Extremely Rapid and Specific Metabolic Labelling of RNA In Vivo with 4-Thiouracil Ers4tU

The use of thiolated uracil to sensitively and specifically purify newly transcribed RNA from the yeast Saccharomyces cerevisiae.

The nucleotide analogue, 4-thiouracil (4tU), is readily taken up by cells and incorporated into RNA as it is transcribed in vivo, allowing isolation of ...

Quantitative Analysis of the Cellular Lipidome of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

Lipids are structurally diverse amphipathic molecules that are insoluble in water. Lipids are essential contributors to the organization and function of biological membranes, energy storage and production, cellular signaling, vesicular transport of proteins, organelle biogenesis, and regulated cell death. Because the budding yeast Saccharomyces cerevisiae is a unicellular eukaryote amenable to thorough molecular analyses, its use as a model organism helped uncover mechanisms linking lipid metabolism and intracellular transport to complex biological processes within eukaryotic cells. The availability of a versatile analytical method for the robust, sensitive, and accurate quantitative assessment of major classes of lipids within a yeast cell is crucial for getting deep insights into these mechanisms. Here we present a protocol to use liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for the quantitative analysis of major cellular lipids of S. cerevisiae. The LC-MS/MS method described is versatile and robust. It enables the identification and quantification of numerous species (including different isobaric or isomeric forms) within each of the 10 lipid classes. This method is sensitive and allows identification and quantitation of some lipid species at concentrations as low as 0.2 pmol/&#181;L. The method has been successfully applied to assessing lipidomes of whole yeast cells and their purified organelles. The use of alternative mobile phase additives for electrospray ionization mass spectrometry in this method can increase the efficiency of ionization for some lipid species and can be therefore used to improve their identification and quantitation.

Quantitative Analysis of the Cellular Lipidome of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

We present a protocol using liquid chromatography coupled with tandem mass spectrometry to identify and quantify major cellular lipids in Saccharomyces cerevisiae. The described method for a quantitative assessment of major lipid classes within a yeast cell is versatile, robust, and sensitive.

Lipids are structurally diverse amphipathic molecules that are insoluble in water. Lipids are essential contributors to the organization and function of ...

Rapid and Cost-Effective RNA Extraction of Rat Pancreatic Tissue

Regardless of the extraction method, optimized RNA extraction of tissues and cell lines are carried out in four stages: 1) homogenization, 2) effective denaturation of proteins from RNA, 3) ribonuclease inactivation, and 4) removal of contamination from DNA, proteins, and carbohydrates. However, it is very laborious to maintain the integrity of RNA when there are high levels of RNase in the tissue. Spontaneous autolysis makes it very difficult to extract RNA from pancreatic tissue without damaging it. Thus, a practical RNA extraction method is needed to maintain the integrity of pancreatic tissues during the extraction process. An experimental and comparative study of existing protocols was carried out by obtaining 20-30 mg of rat pancreatic tissues in less than 2 minutes and extracting the RNA. The results were assessed by electrophoresis. The experiments were carried out three times for generalization of the results. Immersing pancreatic tissue in RNA stabilization reagent at -80 &#176;C for 24 h yielded high integrity RNA, when the RNA extraction reagent was used as the reagent. The results obtained were comparable to the results obtained from commercial kits with spin column bindings.

The purity and integrity of the isolated RNA is a vital step in RNA dependent assays. Here, we present a practical, rapid, and inexpensive method to extract RNA from a small quantity of undamaged pancreatic tissue.

Regardless of the extraction method, optimized RNA extraction of tissues and cell lines are carried out in four stages: 1) homogenization, 2) effective ...

Quantitative Metabolomics of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

Metabolomics is a methodology used for the identification and quantification of many low-molecular-weight intermediates and products of metabolism within a cell, tissue, organ, biological fluid, or organism. Metabolomics traditionally focuses on water-soluble metabolites. The water-soluble metabolome is the final product of a complex cellular network that integrates various genomic, epigenomic, transcriptomic, proteomic, and environmental factors. Hence, the metabolomic analysis directly assesses the outcome of the action for all these factors in a plethora of biological processes within various organisms. One of these organisms is the budding yeast Saccharomyces cerevisiae, a unicellular eukaryote with the fully sequenced genome. Because S. cerevisiae is amenable to comprehensive molecular analyses, it is used as a model for dissecting mechanisms underlying many biological processes within the eukaryotic cell. A versatile analytical method for the robust, sensitive, and accurate quantitative assessment of the water-soluble metabolome would provide the essential methodology for dissecting these mechanisms. Here we present a protocol for the optimized conditions of metabolic activity quenching in and water-soluble metabolite extraction from S. cerevisiae cells. The protocol also describes the use of liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for the quantitative analysis of the extracted water-soluble metabolites. The LC-MS/MS method of non-targeted metabolomics described here is versatile and robust. It enables the identification and quantification of more than 370 water-soluble metabolites with diverse structural, physical, and chemical properties, including different structural isomers and stereoisomeric forms of these metabolites. These metabolites include various energy carrier molecules, nucleotides, amino acids, monosaccharides, intermediates of glycolysis, and tricarboxylic cycle intermediates. The LC-MS/MS method of non-targeted metabolomics is sensitive and allows the identification and quantitation of some water-soluble metabolites at concentrations as low as 0.05 pmol/&#181;L. The method has been successfully used for assessing water-soluble metabolomes of wild-type and mutant yeast cells cultured under different conditions.

Quantitative Metabolomics of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

We present a protocol for the identification and quantitation of major classes of water-soluble metabolites in the yeast Saccharomyces cerevisiae. The described method is versatile, robust, and sensitive. It allows the separation of structural isomers and stereoisomeric forms of water-soluble metabolites from each other.

Metabolomics is a methodology used for the identification and quantification of many low-molecular-weight intermediates and products of metabolism within ...

RIBO-seq in Bacteria: a Sample Collection and Library Preparation Protocol for NGS Sequencing

The ribosome profiling technique (RIBO-seq) is currently the most effective tool for studying the process of protein synthesis in vivo. The advantage of this method, in comparison to other approaches, is its ability to monitor translation by precisely mapping the position and number of ribosomes on a mRNA transcript.
In this article, we describe the consecutive stages of sample collection and preparation for RIBO-seq method in bacteria, highlighting the details relevant to the planning and execution of the experiment.
Since the RIBO-seq relies on intact ribosomes and related mRNAs, the key step is rapid inhibition of translation and adequate disintegration of cells. Thus, we suggest filtration and flash-freezing in liquid nitrogen for cell harvesting with an optional pretreatment with chloramphenicol to arrest translation in bacteria. For the disintegration, we propose grinding frozen cells with mortar and pestle in the presence of aluminum oxide to mechanically disrupt the cell wall. In this protocol, sucrose cushion or a sucrose gradient ultracentrifugation for monosome purification is not required. Instead, mRNA separation using polyacrylamide gel electrophoresis (PAGE) followed by the ribosomal footprint excision (28-30 nt band) is applied and provides satisfactory results. This largely simplifies the method as well as reduces the time and equipment requirements for the procedure. For library preparation, we recommend using the commercially available small RNA kit for Illumina sequencing from New England Biolabs, following manufacturer&#39;s guidelines with some degree of optimization.
The resulting cDNA libraries present appropriate quantity and quality required for next generation sequencing (NGS). Sequencing of the libraries prepared according to the described protocol results in 2 to 10 mln uniquely mapped reads per sample providing sufficient data for comprehensive bioinformatic analysis. The protocol we present is quick and relatively easy and can be performed with standard laboratory equipment.

Here we describe the stages of sample collection and preparation for RIBO-seq in bacteria. Sequencing of the libraries prepared according to these guidelines results in sufficient data for comprehensive bioinformatic analysis. The protocol we present is simple, uses standard laboratory equipment and takes seven days from lysis to obtaining libraries.

The ribosome profiling technique (RIBO-seq) is currently the most effective tool for studying the process of protein synthesis in vivo. The advantage of ...