S.V. is grateful for the funding support from the NIH K22AI077353 and the Landenberger Foundation. K.R. gratefully acknowledges funding from the NIH (5SC1GM083754).

1. Adaptation of Adherent Cells into Suspension
(This is an optional step. Suspension cells generally make better nuclear extracts, however cells grown in plates may also be used.)
<ol>
	<li>Adapt adherent cells for growth in suspension using Joklik&#39;s modified MEM supplemented with 5-10% newborn calf serum or fetal bovine serum and 1% L-glutamine: penicillin-streptomycin. Propagate cells in spinner flasks with a filter cap at 37 &#176;C with 8% CO2.</li>
	<li>When adapting cel...

<ol>
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L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanism+and+regulation+of+mRNA+polyadenylation.">Mechanism and regulation of mRNA polyadenylation.</a> Genes Dev. 11, 2755-2766 (1997).</li><li>Matoulkova, E., Michalova, E., Vojtesek, B., Hrstka, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+the+3'+untranslated+region+in+post-transcriptional+regulation+of+protein+expression+in+mammalian+cells.">The role of the 3' untranslated region in post-transcriptional regulation of protein expression in mammalian cells.</a> RNA biology. 9, 563-576 (2012).</li><li>Danckwardt, S., 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+prothrombin+3'end+formation+signal+reveals+a+unique+architecture+that+is+sensitive+to+thrombophilic+gain-of-function+mutations.">The prothrombin 3'end formation signal reveals a unique architecture that is sensitive to thrombophilic gain-of-function mutations.</a> Blood. 104, 428-435 (2004).</li><li>Moreira, 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+upstream+sequence+element+of+the+C2+complement+poly(A)+signal+activates+mRNA+3'+end+formation+by+two+distinct+mechanisms.">The upstream sequence element of the C2 complement poly(A) signal activates mRNA 3' end formation by two distinct mechanisms.</a> Genes Dev. 12, 2522-2534 (1998).</li><li>Hall-Pogar, T., Zhang, H., Tian, B., Lutz, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alternative+polyadenylation+of+cyclooxygenase-2.">Alternative polyadenylation of cyclooxygenase-2.</a> Nucleic Acids Res. 33, 2565-2579 (2005).</li><li>Brackenridge, S., Proudfoot, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recruitment+of+a+basal+polyadenylation+factor+by+the+upstream+sequence+element+of+the+human+lamin+B2+polyadenylation+signal.">Recruitment of a basal polyadenylation factor by the upstream sequence element of the human lamin B2 polyadenylation signal.</a> Molecular and Cellular Biology. 20, 2660-2669 (2000).</li><li>Moore, C. L., Sharp, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accurate+cleavage+and+polyadenylation+of+exogenous+RNA+substrate.">Accurate cleavage and polyadenylation of exogenous RNA substrate.</a> Cell. 41, 845-855 (1985).</li><li>Gilmartin, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> mRNA formation and function. , 79-98 (1997).</li><li>Wahle, E., Keller, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> RNA Processing. Vol. II. , 1-34 (1994).</li><li>Chabot, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> RNA Processing Vol I. 1, 1-29 (1994).</li><li>Valente, S. 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=HIV-1+mRNA+3'+end+processing+is+distinctively+regulated+by+eIF3f,+CDK11,+and+splice+factor+9G8.">HIV-1 mRNA 3' end processing is distinctively regulated by eIF3f, CDK11, and splice factor 9G8.</a> Mol Cell. 36, 279-289 (2009).</li><li>Dignam, J. D., Lebovitz, R. M., Roeder, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accurate+transcription+initiation+by+RNA+polymerase+II+in+a+soluble+extract+from+isolated+mammalian+nuclei.">Accurate transcription initiation by RNA polymerase II in a soluble extract from isolated mammalian nuclei.</a> Nucleic Acids Res. 11, 1475-1489 (1983).</li><li>Aurup, H., Williams, D. M., Eckstein, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=2'-Fluoro-+and+2'-amino-2'-deoxynucleoside+5'-triphosphates+as+substrates+for+T7+RNA+polymerase.">2'-Fluoro- and 2'-amino-2'-deoxynucleoside 5'-triphosphates as substrates for T7 RNA polymerase.</a> Biochemistry. 31, 9636-9641 (1992).</li><li>Keller, W., Bienroth, S., Lang, K. M., Christofori, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cleavage+and+polyadenylation+factor+CPF+specifically+interacts+with+the+pre-mRNA+3'+processing+signal+AAUAAA.">Cleavage and polyadenylation factor CPF specifically interacts with the pre-mRNA 3' processing signal AAUAAA.</a> EMBO J. 10, 4241-4249 (1991).</li><li>Takagaki, Y., Ryner, L. C., Manley, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Four+factors+are+required+for+3'-end+cleavage+of+pre-mRNAs.">Four factors are required for 3'-end cleavage of pre-mRNAs.</a> Genes Dev. 3, 1711-1724 (1989).</li><li>Takagaki, Y., 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+multisubunit+factor,+CstF,+is+required+for+polyadenylation+of+mammalian+pre-mRNAs.">A multisubunit factor, CstF, is required for polyadenylation of mammalian pre-mRNAs.</a> Genes Dev. 4, 2112-2120 (1990).</li><li>Ruegsegger, U., Blank, D., Keller, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+pre-mRNA+cleavage+factor+Im+is+related+to+spliceosomal+SR+proteins+and+can+be+reconstituted+in+vitro+from+recombinant+subunits.">Human pre-mRNA cleavage factor Im is related to spliceosomal SR proteins and can be reconstituted in vitro from recombinant subunits.</a> Mol Cell. 1, 243-253 (1998).</li><li>Vries, H., 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=Human+pre-mRNA+cleavage+factor+II(m)+contains+homologs+of+yeast+proteins+and+bridges+two+other+cleavage+factors.">Human pre-mRNA cleavage factor II(m) contains homologs of yeast proteins and bridges two other cleavage factors.</a> EMBO J. 19, 5895-5904 (2000).</li><li>Gilmartin, G. M., Nevins, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+ordered+pathway+of+assembly+of+components+required+for+polyadenylation+site+recognition+and+processing.">An ordered pathway of assembly of components required for polyadenylation site recognition and processing.</a> Genes Dev. 3, 2180-2190 (1989).</li><li>Shi, Y., 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=Molecular+architecture+of+the+human+pre-mRNA+3'+processing+complex.">Molecular architecture of the human pre-mRNA 3' processing complex.</a> Mol Cell. 33, 365-376 (2009).</li><li>Bentley, D. 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The in vitro pre-mRNA 3&#8217; cleavage reaction, carried out in HeLa cell nuclear extracts or with cleavage factors fractionated from these extracts, has enabled identification of the core cleavage factors and their main complexes16-21. Many more proteins associated with these factors have recently been identified22, and the in vitro reaction may continue to shed light on how these proteins contribute to the reaction. Perhaps because the reaction in vivo appears to be cot...

The biosynthesis of most mature eukaryotic message RNAs (mRNAs) requires several post-transcriptional modifications such as capping, splicing and polyadenylation. These modifications are generally coupled to ensure correct processing1 and strongly increase the stability of the mRNA.
The 3&#8217; end formation of mammalian pre-mRNAs is generated by endonucleolytic cleavage of the nascent RNA followed by addition of adenylate residues to the 5&#8217; cleaved product by poly(A) polymerase (PAP)2-4. In mammals, cleavage is accomplished by a multicomponent protein complex, of approximately 800 kDa, which assembles on specific pre-RNA sequences. The poly(A) signal sequence, a highly conserved canonical hexanucleotide sequence AAUAAA, directs the cleavage site at approximately 10-30 nt downstream. This site is specifically recognized by the cleavage and polyadenylation specificity factor (CPSF) and the 73 kD subunit of CSPF contains the endonuclease activity. The cleavage stimulation factor (CstF) binds a more degenerate GU- or U- rich element sequence downstream of the poly(A) site. Also required for cleavage is the mammalian cleavage factor I (CFIm), and the mammalian cleavage factor II (CFII). CFIm binds the specific UGUA(N) sites in upstream sequence elements (USEs) that have been defined for a number of genes and seem to be involved in important physiological processes5-8.
In vitro, RNA processing reactions are commonly analyzed by the use of radiolabeled RNA substrates9-12. These may be synthesized by run-off transcription from the bacteriophage promoter T7 or SP6. When studying a polyadenylation site that has not been characterized before, it is necessary to use genomic DNA rather than cDNA to generate the RNA substrate, as important downstream sequences might not be present in cDNA. Design substrates to include at least 150 nt upstream and 50 nt downstream from the cleavage site/end on the mature mRNA. The cleavage product migrates faster than the substrate; however, because other fragments may be generated by non-specific nuclease action, the specificity of the reaction has to be verified by its dependence on the correct processing signal sequences. Therefore, RNA substrates with a point mutation in the AAUAAA sequence (e.g. AAGAAA) serve as a negative control for the cleavage reaction.
Given that a small amount of radiolabeled RNA is used for the cleavage reactions, RNases present in high abundance in most nuclear extracts can be problematic, and limit the choice of the starting material for extract preparation. HeLa cells tend to contain low levels of endogenous RNases, and thus perform well in these assays.
The endonucleolytic cleavage of the RNA substrates in vivo and in vitro is immediately followed by the poly(A) addition, thus the cleaved intermediate is not present in detectable quantities. Therefore, to study either a specific RNA sequence or proteins involved in a cleavage reaction, experiments are done in conditions that prevent polyadenylation from occurring. There is no dependence of cleavage on polyadenylation, or vice versa, so one can stop polyadenylation without harming the cleavage reaction. Thus, ATP is replaced with a chain terminating analogue that lacks the 3&#8217; hydroxyl group so that only a single nucleotide can be incorporated at the poly(A) site and just cleaved RNA can be detected.
Given the complexity and high degree of particularity of this type of assay, we describe a detailed video protocol to study endonucleolytic cleavage by the cleavage/Poly(A) machinery of mRNA precursors in vitro. We describe how to prepare competent nuclear extracts, generate radiolabeled RNA substrates, perform the cleavage reaction, and analyze and interpret the resulting products. Figure 1 shows an example of substrate RNAs encoding for the 3&#8217; end of HIV-1 pre-mRNAs to be used for a cleavage assay. The 3&#8216; end of the HIV RNA genome is composed of many important regulatory sequences such as the poly(A) site, a G+U rich region, and the USE element, which are all necessary for efficient maturation of the viral mRNA transcripts13. In this example we would expect the input RNA substrate to be 338 nt and upon cleavage 237 nt. If polyadenylation was allowed to occur, a smear of products would be observed between 237 and 437 nt.

<table border="0" cellpadding="0" cellspacing="0" width="757">
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			<td height="21" style="height:21px;width:216px;">1L Celstir Flask</td>
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			<td style="width:281px;">Allegra x-15R with SX4500 Rotor</td>
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			<td height="21" style="height:21px;width:216px;">Ultra Centrifuge</td>
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			<td>Optima L-100 XP Ultra with SW41 Rotor</td>
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			<td>Refridgerated</td>
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			<td height="21" style="height:21px;width:216px;">JOKLIK Modified MEM</td>
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			<td height="21" style="height:21px;width:216px;">Fetal Bovine Serum</td>
			<td style="width:141px;">Atlas&#160;</td>
			<td style="width:119px;">F-0500-A</td>
			<td>Heat inactivated</td>
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			<td height="21" style="height:21px;width:216px;">L-Glut:Pen:Strep</td>
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			<td height="21" style="height:21px;width:216px;">EDTA 0.5M Solution</td>
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			<td height="21" style="height:21px;width:216px;">EDTA</td>
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			<td height="42" style="height:42px;width:216px;">Slide-A-Lyzer Dialysis Cassettes Kit</td>
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			<td height="42" style="height:42px;width:216px;">m7G(5&#39;)ppp(5&#39;) G RNA Cap</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">DEPC treated water</td>
			<td style="width:141px;">Ambion</td>
			<td style="width:119px;">AM9906</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">10x TAE</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP13354</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">10x TBE</td>
			<td style="width:141px;">Ameresco Life Sciences</td>
			<td style="width:119px;">0658-4L</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">10x PBS</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP399-20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Urea</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP169-212</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ammonium Persulfate</td>
			<td style="width:141px;">Bio-Rad</td>
			<td style="width:119px;">161-0700</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">TEMED</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP150-20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ammonium Acetate</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">A637-500</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">40% 19:1 Acrylamide:Bis-acrylamide</td>
			<td style="width:141px;">Bio-Rad</td>
			<td style="width:119px;">161-0144</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Glycogen</td>
			<td style="width:141px;">Roche</td>
			<td style="width:119px;">10 901 393 001</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">100% Absolute Ethanol 200 Proof</td>
			<td style="width:141px;">Acros</td>
			<td style="width:119px;">61509-0040</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Acid Phenol-Chloroform</td>
			<td style="width:141px;">Ambion</td>
			<td style="width:119px;">9720</td>
			<td>For RNA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Scintilation Fluid</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">SX18-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Rnase Inhibitor</td>
			<td style="width:141px;">Promega</td>
			<td style="width:119px;">N261B</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Poly (Vinyl alcohol) PVA</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">P8136-250G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Creatine Phosphate</td>
			<td style="width:141px;">Calbiochem</td>
			<td style="width:119px;">2380</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">100mM dATP</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP2560-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">SDS</td>
			<td style="width:141px;">Acros</td>
			<td style="width:119px;">23042-5000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Proteinase K</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">BP1700-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Adjustable Sequencing Unit</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z351881-1EA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Binder Clips</td>
			<td style="width:141px;">Office Depot</td>
			<td style="width:119px;">838-056</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">20cmx42cm glass plates</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z352543</td>
			<td>1SET</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">20cmx22cm glass plates</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z35252-7</td>
			<td>1SET</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">20cmx42cm Aluminum Cooling Plates</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z352667</td>
			<td>1EA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">0.4mmx22cm Spacers</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z35230-6</td>
			<td>1SET</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">0.4mmx42cm Spacers</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z352314-1</td>
			<td>1SET</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">8-well Comb</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z35195-4</td>
			<td>1EA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">16-well Comb</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z351962</td>
			<td>1EA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">32-well Comb</td>
			<td style="width:141px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z351970</td>
			<td>1EA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gel Repel Coating</td>
			<td style="width:141px;">C.B.S. Scientific</td>
			<td style="width:119px;">SGR-0401</td>
			<td>or SGR-0101 for individual bottle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gel Loading Tips</td>
			<td style="width:141px;">Rainin</td>
			<td style="width:119px;">GT-10-4</td>
			<td>0.1-10uL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sequencing PowerPac HV</td>
			<td style="width:141px;">Bio-Rad</td>
			<td style="width:119px;">PowerPac HV</td>
			<td>5000V/500mA/400W</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gel Dryer Model 583</td>
			<td style="width:141px;">Bio-Rad</td>
			<td style="width:119px;">Model 583</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Hydrotech Vacuum Pump for gel dryer</td>
			<td style="width:141px;">Bio-Rad</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Glogos II Glow-in-the-dark Markers</td>
			<td style="width:141px;">Agilent</td>
			<td style="width:119px;">420201</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Film 8x10</td>
			<td style="width:141px;">Midsci</td>
			<td style="width:119px;">BX810</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Film 14x17</td>
			<td style="width:141px;">Phenix</td>
			<td style="width:119px;">F-BX1417</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Autoradiography Cassette</td>
			<td style="width:141px;">Fisher</td>
			<td style="width:119px;">FBCA 1417</td>
			<td>8x10 size available</td>
		</tr>
	</tbody>
</table>

analysis of rna processing reactions using cell free systems: 3' end cleavage of pre-mrna substrates in vitro

The 3&#8217; end of mammalian mRNAs is not formed by abrupt termination of transcription by RNA polymerase II (RNPII). Instead, RNPII synthesizes precursor mRNA beyond the end of mature RNAs, and an active process of endonuclease activity is required at a specific site. Cleavage of the precursor RNA normally occurs 10-30 nt downstream from the consensus polyA site (AAUAAA) after the CA dinucleotides. Proteins from the cleavage complex, a multifactorial protein complex of approximately 800 kDa, accomplish this specific nuclease activity. Specific RNA sequences upstream and downstream of the polyA site control the recruitment of the cleavage complex. Immediately after cleavage, pre-mRNAs are polyadenylated by the polyA polymerase (PAP) to produce mature stable RNA messages.
Processing of the 3&#8217; end of an RNA transcript may be studied using cellular nuclear extracts with specific radiolabeled RNA substrates. In sum, a long 32P-labeled uncleaved precursor RNA is incubated with nuclear extracts in vitro, and cleavage is assessed by gel electrophoresis and autoradiography. When proper cleavage occurs, a shorter 5&#8217; cleaved product is detected and quantified. Here, we describe the cleavage assay in detail using, as an example, the 3&#8217; end processing of HIV-1 mRNAs.

Representative results of a cleavage assay of the RNA poly(A) sites of HIV-1 (Figure 2). We can observe the uncleaved RNA substrate, which is the slowest migrating band at the top of the gel. The specific cleaved product is the most intense shorter fragment band that runs faster in the gel at the expected size, and is specifically absent from the cleavage assay of the mutpoly(A) control that contains a point mutation in the polyA sequence (mutPolyA) RNA substrate. Degradation products of the input substr...

Watch this Scientific Journal Video about Analysis of RNA Processing Reactions Using Cell Free Systems: 3' End Cleavage of Pre-mRNA Substrates in vitro at JoVE.com

Analysis of RNA Processing Reactions Using Cell Free Systems: 3&#039; End Cleavage of Pre-mRNA Substrates in vitro

RNA polymerase II synthesizes a precursor RNA that extends beyond the 3' end of the mature mRNA. The end of the mature RNA is generated cotranscriptionally, at a site dictated by RNA sequences, via the endonuclease activity of the cleavage complex. Here, we detail the method to study cleavage reactions in vitro.

Analysis of RNA Processing Reactions Using Cell Free Systems: 3' End Cleavage of Pre-mRNA Substrates in vitro

The 3&#8217; end of mammalian mRNAs is not formed by abrupt termination of transcription by RNA polymerase II (RNPII). Instead, RNPII synthesizes ...

analysis-rna-processing-reactions-using-cell-free-systems-3-end

Research

JoVE Journal

Biology

12.7K ビュー.  The Scripps Research Institute.  RNAポリメラーゼIIは、成熟mRNAの3 '末端を越えて延びる前駆体RNAを合成する。成熟したRNAの末端が切断複合体のエンドヌクレアーゼ活性を経由して、RNA配列によって決定されるサイトで、cotranscriptionally生成されます。ここでは、in vitroでの切断反応を研究する方法を詳細に私たち。 

ビデオ: Analysis of RNA Processing Reactions Using Cell Free Systems: 3' End Cleavage of Pre-mRNA Substrates in vitro

RNA polymerase II synthesizes a precursor RNA that extends beyond the 3' end of the mature mRNA. The end of the mature RNA is generated cotranscriptionally, at a site dictated by RNA sequences, via the endonuclease activity of the cleavage complex. Here, we detail the method to study cleavage reactions in...

quantitative analysis of alternative pre-mrna splicing in mouse brain sections using rna in situ hybridization assay

Quantitative Analysis of Alternative Pre-mRNA Splicing in Mouse Brain Sections Using RNA In Situ Hybridization Assay

An in situ hybridization (ISH) protocol that uses short antisense oligonucleotides to detect alternative pre-mRNA splicing patterns in mouse brain sections is...

Quantitative Analysis of Alternative Pre-mRNA Splicing in Mouse Brain Sections Using RNA In Situ Hybridization Assay

using in vitro and in-cell shape to investigate small molecule induced pre-mrna structural changes

Using In Vitro and In-cell SHAPE to Investigate Small Molecule Induced Pre-mRNA Structural Changes

Detailed protocols for both in vitro and in-cell selective 2&#39;-hydroxyl acylation analyzed by primer extension (SHAPE) experiments to determine the secondary structure of pre-mRNA sequences of interest in the presence of an RNA-targeting small molecule are presented in this...

real-time monitoring of reactions performed using continuous-flow processing: the preparation of 3-acetylcoumarin as an example

Real-time Monitoring of Reactions Performed Using Continuous-flow Processing: The Preparation of 3-Acetylcoumarin as an Example

Real-time monitoring allows for fast optimization of reactions performed using continuous-flow processing. Here the preparation of 3-acetylcoumarin is used as an example. The apparatus for performing in-situ Raman monitoring is described, as are the steps required to optimize the...

cell-free protein synthesis system for building synthetic cells

Author Spotlight: Optimizing CFPS Systems for Synthetic Cell Construction

This protocol describes the Cell-Free Protein Synthesis (CFPS) system used in constructing synthetic cells. It outlines key stages with representative results in different micro-compartments. The protocol aims to establish best practices for diverse laboratories in the synthetic cell community, advancing progress in synthetic cell...

CFPS Protocols for Micro-Compartmentalized Synthetic Cells

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single read and paired end mrna-seq illumina libraries from 10 nanograms total rna

Single Read and Paired End mRNA-Seq Illumina Libraries from 10 Nanograms Total RNA

Here we describe a method for preparation of both single read and paired end Illumina mRNA-Seq sequencing libraries for gene expression analysis based on T7 linear RNA amplification. This protocol requires only 10 nanograms of starting total RNA and generates highly consistent libraries representing whole...

preparation of extracts and t7 rna polymerase for cell-free protein synthesis systems

Preparation of Extracts and T7 RNA Polymerase for Cell-Free Protein Synthesis Systems

increasing cdna yields from single-cell quantities of mrna in standard laboratory reverse transcriptase reactions using acoustic microstreaming

Increasing cDNA Yields from Single-cell Quantities of mRNA in Standard Laboratory Reverse Transcriptase Reactions using Acoustic Microstreaming

We describe a novel method for increasing cDNA yield from single-cell quantities of mRNA in otherwise standard laboratory reverse transcription reactions.  The novelty resides in the use of a micromixer, which utilizes the phenomenon of acoustic microstreaming, to mix fluids at microliter scales more effectively than shaking, vortexing or...

3' end sequencing library preparation with a-seq2

3&#039; End Sequencing Library Preparation with A-seq2

This protocol describes a method for mapping pre-mRNA 3&#39; end processing...

3' End Sequencing Library Preparation with A-seq2

in vitro cleavage assays using purified recombinant drosophila caspases for substrate screening

In Vitro Cleavage Assays using Purified Recombinant Drosophila Caspases for Substrate Screening

Here we present a protocol to express and purify recombinant Drosophila caspases Dronc and Drice, and their use in in vitro cleavage...

In Vitro Cleavage Assays using Purified Recombinant Drosophila Caspases for Substrate Screening

in vitro transcription and capping of gaussia luciferase mrna followed by hela cell transfection

In vitro Transcription and Capping of Gaussia Luciferase mRNA Followed by HeLa Cell Transfection

This method describes high yield in vitro synthesis of both capped and uncapped mRNA from a linearized plasmid containing the Gaussia luciferase (GLuc) gene. The RNA is purified and a fraction of the uncapped RNA is enzymatically capped using the Vaccinia virus capping enzyme. In the final step, the mRNA is transfected into HeLa cells and cell culture supernatants are assayed for luciferase...

In vitro Transcription and Capping of Gaussia Luciferase mRNA Followed by HeLa Cell Transfection

analysis of nonhomologous end joining and homologous recombination efficiency in hek-293t cells using gfp-based reporter systems

Author Spotlight: Decoding DNA Repair by Extrachromosomal NHEJ Assay and HR Assays

This protocol describes an extrachromosomal nonhomologous end joining (NHEJ) assay and homologous recombination (HR) assay to quantify the efficiency of NHEJ and HR in HEK-293T...

Analysis of Nonhomologous End Joining and Homologous Recombination Efficiency in HEK-293T Cells Using GFP-Based Reporter Systems

rapid characterization of genetic parts with cell-free systems

Rapid Characterization of Genetic Parts with Cell-Free Systems

Well-characterized genetic parts are necessary for the design of novel genetic circuits. Here we describe a cost-effective, high-throughput method for rapidly characterizing genetic parts. Our method reduces cost and time by combining cell-free lysates, linear DNA to avoid cloning, and acoustic liquid handling to increase throughput and reduce reaction...

antibody-free assay for rna methyltransferase activity analysis

Antibody-Free Assay for RNA Methyltransferase Activity Analysis

Here, an antibody-free in vitro assay for direct analysis of methyltransferase activity on synthetic or in vitro transcribed RNA is...

efficient transfection of in vitro transcribed mrna in cultured cells using peptide-poloxamine nanoparticles

Efficient Transfection of In vitro Transcribed mRNA in Cultured Cells Using Peptide-Poloxamine Nanoparticles

A self-assembled peptide-poloxamine nanoparticle (PP-sNp) is developed using a microfluidic mixing device to encapsulate and deliver in vitro transcribed messenger RNA. The described mRNA/PP-sNp could efficiently transfect cultured cells in...

Efficient Transfection of In vitro Transcribed mRNA in Cultured Cells Using Peptide-Poloxamine Nanoparticles

visualization of mg53-mediated cell membrane repair using in vivo and in vitro systems

Visualization of MG53-mediated Cell Membrane Repair Using in vivo and in vitro Systems

Described here are protocols used to visualize the dynamic process of MG53-mediated cell membrane repair in whole animals and at the cellular level. These methods can be applied to investigate the cell biology of plasma membrane resealing and regenerative...

Visualization of MG53-mediated Cell Membrane Repair Using in vivo and in vitro Systems

rapid, enzymatic methods for amplification of minimal, linear templates for protein prototyping using cell-free systems

Rapid, Enzymatic Methods for Amplification of Minimal, Linear Templates for Protein Prototyping using Cell-Free Systems

The study describes a protocol for creating large (&#181;g-mg) quantities of DNA for protein screening campaigns from synthetic gene fragments without cloning or using living cells. The minimal template is enzymatically digested and circularized and then amplified using isothermal rolling circle amplification. Cell-free expression reactions could be performed with the unpurified...

hela based cell free expression systems for expression of plasmodium rhoptry proteins

HeLa Based Cell Free Expression Systems for Expression of Plasmodium Rhoptry Proteins

Expression of malarial proteins in cell based systems remains challenging. We demonstrate two step and one step IVT (in vitro translation) cell free expression systems for expressing malarial recombinant rhoptry proteins from HeLa cells. We use a Ni-resin affinity based purification system to purify the rhoptry...

HeLa Based Cell Free Expression Systems for Expression of Plasmodium Rhoptry Proteins

Video Bioinformatics Analysis of Human Embryonic Stem Cell Colony Growth

Because video data are complex and are comprised of many images, mining information from video material is difficult to do without the aid of computer software.  Video bioinformatics is a powerful quantitative approach for extracting spatio-temporal data from video images using computer software to perform dating mining and analysis. In this article, we introduce a video bioinformatics method for quantifying the growth of human embryonic stem cells (hESC) by analyzing time-lapse videos collected in a Nikon BioStation CT incubator equipped with a camera for video imaging. In our experiments, hESC colonies that were attached to Matrigel were filmed for 48 hours in the BioStation CT.  To determine the rate of growth of these colonies, recipes were developed using CL-Quant software which enables users to extract various types of data from video images.  To accurately evaluate colony growth, three recipes were created. The first segmented the image into the colony and background, the second enhanced the image to define colonies throughout the video sequence accurately, and the third measured the number of pixels in the colony over time.  The three recipes were run in sequence on video data collected in a BioStation CT to analyze the rate of growth of individual hESC colonies over 48 hours. To verify the truthfulness of the CL-Quant recipes, the same data were analyzed manually using Adobe Photoshop software. When the data obtained using the CL-Quant recipes and Photoshop were compared, results were virtually identical, indicating the CL-Quant recipes were truthful. The method described here could be applied to any video data to measure growth rates of hESC or other cells that grow in colonies. In addition, other video bioinformatics recipes can be developed in the future for other cell processes such as migration, apoptosis, and cell adhesion.  

Video bioinformatics is the automated processing, analysis, understanding, and data mining of biological spatio-temporal data extracted from microscopic videos. The purpose of this article is to demonstrate a method for measuring human embryonic stem cell colony growth using a video bioinformatics method.

Because video data are complex and are comprised of many images, mining information from video material is difficult to do without the aid of computer ...

Repair of acute injury to the cell membrane is an elemental process of normal cellular physiology, and defective membrane repair has been linked to many degenerative human diseases. The recent discovery of MG53 as a key component of the membrane resealing machinery allows for a better molecular understanding of the basic biology of tissue repair, as well as for potential translational applications in regenerative medicine. Here we detail the experimental protocols for exploring the in vivo function of MG53 in repair of muscle injury using treadmill exercise protocols on mouse models, for testing the ex vivo membrane repair capacity by measuring dye entry into isolated muscle fibers, and for monitoring the dynamic process of MG53-mediated vesicle trafficking and cell membrane repair in cultured cells using live cell confocal microscopy.

Described here are protocols used to visualize the dynamic process of MG53-mediated cell membrane repair in whole animals and at the cellular level. These methods can be applied to investigate the cell biology of plasma membrane resealing and regenerative medicine.

Repair of acute injury to the cell membrane is an elemental process of normal cellular physiology, and defective membrane repair has been linked to many ...

Whole transcriptome sequencing by mRNA-Seq is now used extensively to perform global gene expression, mutation, allele-specific expression and other genome-wide analyses. mRNA-Seq even opens the gate for gene expression analysis of non-sequenced genomes. mRNA-Seq offers high sensitivity, a large dynamic range and allows measurement of transcript copy numbers in a sample. Illumina&#x2019;s genome analyzer performs sequencing of a large number (&gt; 107) of relatively short sequence reads (&lt; 150 bp).The &quot;paired end&quot; approach, wherein a single long read is sequenced at both its ends, allows for tracking alternate splice junctions, insertions and deletions, and is useful for de novo transcriptome assembly.
One of the major challenges faced by researchers is a limited amount of starting material. For example, in experiments where cells are harvested by laser micro-dissection, available starting total RNA may measure in nanograms. Preparation of mRNA-Seq libraries from such samples have been described1, 2 but involves significant PCR amplification that may introduce bias. Other RNA-Seq library construction procedures with minimal PCR amplification have been published3, 4 but require microgram amounts of starting total RNA.
Here we describe a protocol for the Illumina Genome Analyzer II platform for mRNA-Seq sequencing for library preparation that avoids significant PCR amplification and requires only 10 nanograms of total RNA. While this protocol has been described previously and validated for single-end sequencing5, where it was shown to produce directional libraries without introducing significant amplification bias, here we validate it further for use as a paired end protocol. We selectively amplify polyadenylated messenger RNAs from starting total RNA using the T7 based Eberwine linear amplification method, coined &quot;T7LA&quot; (T7 linear amplification). The amplified poly-A mRNAs are fragmented, reverse transcribed and adapter ligated to produce the final sequencing library. For both single read and paired end runs, sequences are mapped to the human transcriptome6 and normalized so that data from multiple runs can be compared. We report the gene expression measurement in units of transcripts per million (TPM), which is a superior measure to RPKM when comparing samples7.

Here we describe a method for preparation of both single read and paired end Illumina mRNA-Seq sequencing libraries for gene expression analysis based on T7 linear RNA amplification. This protocol requires only 10 nanograms of starting total RNA and generates highly consistent libraries representing whole transcripts.

Whole transcriptome sequencing by mRNA-Seq is now used extensively to perform global gene expression, mutation, allele-specific expression and other ...

In vitro transcription is the synthesis of RNA transcripts by RNA polymerase from a linear DNA template containing the corresponding promoter sequence (T7, T3, SP6) and the gene to be transcribed (Figure 1A). A typical transcription reaction consists of the template DNA, RNA polymerase, ribonucleotide triphosphates, RNase inhibitor and buffer containing Mg2+ ions.
Large amounts of high quality RNA are often required for a variety of applications. Use of in vitro transcription has been reported for RNA structure and function studies such as splicing1, RNAi experiments in mammalian cells2, antisense RNA amplification by the "Eberwine method"3, microarray analysis4 and for RNA vaccine studies5. The technique can also be used for producing radiolabeled and dye labeled probes6. Warren, et al. recently reported reprogramming of human cells by transfection with in vitro transcribed capped RNA7. The T7 High Yield RNA Synthesis Kit from New England Biolabs has been designed to synthesize up to 180 &mu;g RNA per 20 &mu;l reaction. RNA of length up to 10kb has been successfully transcribed using this kit. Linearized plasmid DNA, PCR products and synthetic DNA oligonucleotides can be used as templates for transcription as long as they have the T7 promoter sequence upstream of the gene to be transcribed.
Addition of a 5' end cap structure to the RNA is an important process in eukaryotes. It is essential for RNA stability8, efficient translation9, nuclear transport10 and splicing11. The process involves addition of a 7-methylguanosine cap at the 5' triphosphate end of the RNA. RNA capping can be carried out post-transcriptionally using capping enzymes or co-transcriptionally using cap analogs. In the enzymatic method, the mRNA is capped using the Vaccinia virus capping enzyme12,13. The enzyme adds on a 7-methylguanosine cap at the 5' end of the RNA using GTP and S-adenosyl methionine as donors (cap 0 structure). Both methods yield functionally active capped RNA suitable for transfection or other applications14 such as generating viral genomic RNA for reverse-genetic systems15 and crystallographic studies of cap binding proteins such as eIF4E16.
In the method described below, the T7 High Yield RNA Synthesis Kit from NEB is used to synthesize capped and uncapped RNA transcripts of Gaussia luciferase (GLuc) and Cypridina luciferase (CLuc). A portion of the uncapped GLuc RNA is capped using the Vaccinia Capping System (NEB). A linearized plasmid containing the GLuc or CLuc gene and T7 promoter is used as the template DNA. The transcribed RNA is transfected into HeLa cells and cell culture supernatants are assayed for luciferase activity. Capped CLuc RNA is used as the internal control to normalize GLuc expression.

This method describes high yield in vitro synthesis of both capped and uncapped mRNA from a linearized plasmid containing the Gaussia luciferase (GLuc) gene. The RNA is purified and a fraction of the uncapped RNA is enzymatically capped using the Vaccinia virus capping enzyme. In the final step, the mRNA is transfected into HeLa cells and cell culture supernatants are assayed for luciferase activity.

In vitro transcription is the synthesis of RNA transcripts by RNA polymerase from a linear DNA template containing the corresponding promoter sequence ...

Cell Specific Analysis of Arabidopsis Leaves Using Fluorescence Activated Cell Sorting

After initiation of the leaf primordium, biomass accumulation is controlled mainly by cell proliferation and expansion in the leaves1. However, the Arabidopsis leaf is a complex organ made up of many different cell types and several structures. At the same time, the growing leaf contains cells at different stages of development, with the cells furthest from the petiole being the first to stop expanding and undergo senescence1. Different cells within the leaf are therefore dividing, elongating or differentiating; active, stressed or dead; and/or responding to stimuli in sub-sets of their cellular type at any one time. This makes genomic study of the leaf challenging: for example when analyzing expression data from whole leaves, signals from genetic networks operating in distinct cellular response zones or cell types will be confounded, resulting in an inaccurate profile being generated.
To address this, several methods have been described which enable studies of cell specific gene expression. These include laser-capture microdissection (LCM)2 or GFP expressing plants used for protoplast generation and subsequent fluorescence activated cell sorting (FACS)3,4, the recently described INTACT system for nuclear precipitation5 and immunoprecipitation of polysomes6.
FACS has been successfully used for a number of studies, including showing that the cell identity and distance from the root tip had a significant effect on the expression profiles of a large number of genes3,7. FACS of GFP lines have also been used to demonstrate cell-specific transcriptional regulation during root nitrogen responses and lateral root development8, salt stress9 auxin distribution in the root10 and to create a gene expression map of the Arabidopsis shoot apical meristem11. Although FACS has previously been used to sort Arabidopsis leaf derived protoplasts based on autofluorescence12,13, so far the use of FACS on Arabidopsis lines expressing GFP in the leaves has been very limited4. In the following protocol we describe a method for obtaining Arabidopsis leaf protoplasts that are compatible with FACS while minimizing the impact of the protoplast generation regime. We demonstrate the method using the KC464 Arabidopsis line, which express GFP in the adaxial epidermis14, the KC274 line, which express GFP in the vascular tissue14 and the TP382 Arabidopsis line, which express a double GFP construct linked to a nuclear localization signal in the guard cells (data not shown; Figure 2). We are currently using this method to study both cell-type specific expression during development and stress, as well as heterogeneous cell populations at various stages of senescence.

Cell Specific Analysis of Arabidopsis Leaves Using Fluorescence Activated Cell Sorting

A method for producing Arabidopsis leaf protoplasts that are compatible with fluorescence activated cell sorting (FACS), allowing for studies of specific cell populations. This method is compatible with any Arabidopsis line that expresses GFP in a subset of cells.

After initiation of the leaf primordium, biomass accumulation is controlled mainly by cell proliferation and expansion in the leaves1. However, the ...

Substrate Generation for Endonucleases of CRISPR/Cas Systems

The interaction of viruses and their prokaryotic hosts shaped the evolution of bacterial and archaeal life. Prokaryotes developed several strategies to evade viral attacks that include restriction modification, abortive infection and CRISPR/Cas systems. These adaptive immune systems found in many Bacteria and most Archaea consist of clustered regularly interspaced short palindromic repeat (CRISPR) sequences and a number of CRISPR associated (Cas) genes (Fig. 1) 1-3. Different sets of Cas proteins and repeats define at least three major divergent types of CRISPR/Cas systems 4. The universal proteins Cas1 and Cas2 are proposed to be involved in the uptake of viral DNA that will generate a new spacer element between two repeats at the 5' terminus of an extending CRISPR cluster 5. The entire cluster is transcribed into a precursor-crRNA containing all spacer and repeat sequences and is subsequently processed by an enzyme of the diverse Cas6 family into smaller crRNAs 6-8. These crRNAs consist of the spacer sequence flanked by a 5' terminal (8 nucleotides) and a 3' terminal tag derived from the repeat sequence 9. A repeated infection of the virus can now be blocked as the new crRNA will be directed by a Cas protein complex (Cascade) to the viral DNA and identify it as such via base complementarity10. Finally, for CRISPR/Cas type 1 systems, the nuclease Cas3 will destroy the detected invader DNA 11,12 .
These processes define CRISPR/Cas as an adaptive immune system of prokaryotes and opened a fascinating research field for the study of the involved Cas proteins. The function of many Cas proteins is still elusive and the causes for the apparent diversity of the CRISPR/Cas systems remain to be illuminated. Potential activities of most Cas proteins were predicted via detailed computational analyses. A major fraction of Cas proteins are either shown or proposed to function as endonucleases 4.
Here, we present methods to generate crRNAs and precursor-cRNAs for the study of Cas endoribonucleases. Different endonuclease assays require either short repeat sequences that can directly be synthesized as RNA oligonucleotides or longer crRNA and pre-crRNA sequences that are generated via in vitro T7 RNA polymerase run-off transcription. This methodology allows the incorporation of radioactive nucleotides for the generation of internally labeled endonuclease substrates and the creation of synthetic or mutant crRNAs. Cas6 endonuclease activity is utilized to mature pre-crRNAs into crRNAs with 5'-hydroxyl and a 2',3'-cyclic phosphate termini.

CRISPR/Cas systems mediate adaptive immunity in Bacteria and Archaea. Many Cas proteins are proposed to act as endoribonucleases acting on crRNA precursors of varying length. Here we illustrate three different approaches to generate pre-crRNA substrates for the biochemical analysis of Cas endonuclease activity.

The  interaction of viruses and their prokaryotic hosts shaped the evolution of  bacterial and archaeal life. Prokaryotes developed several strategies to ...

Malaria causes significant global morbidity and mortality. No routine vaccine is currently available. One of the major reasons for lack of a vaccine is the challenge of identifying suitable vaccine candidates. Malarial proteins expressed using prokaryotic and eukaryotic cell based expression systems are poorly glycosylated, generally insoluble and undergo improper folding leading to reduced immunogenicity. The wheat germ, rabbit reticulocyte lysate and Escherichia coli lysate cell free expression systems are currently used for expression of malarial proteins. However, the length of expression time and improper glycosylation of proteins still remains a challenge. We demonstrate expression of Plasmodium proteins in vitro using HeLa based cell free expression systems, termed &#8220;in vitro human cell free expression systems&#8221;. The 2 HeLa based cell free expression systems transcribe mRNA in 75 min and 3 &#181;l of transcribed mRNA is sufficient to translate proteins in 90 min. The 1-step expression system is a transcription and translation coupled expression system; the transcription and co-translation occurs in 3 hr. The process can also be extended for 6 hr by providing additional energy. In the 2-step expression system, mRNA is first transcribed and then added to the translation mix for protein expression. We describe how to express malaria proteins; a hydrophobic PF3D7_0114100 Maurer&#8217;s Cleft &#8211; 2 transmembrane (PfMC-2TM) protein, a hydrophilic PF3D7_0925900 protein and an armadillo repeats containing protein PF3D7_1361800, using the HeLa based cell free expression system. The proteins are expressed in micro volumes employing 2-step and 1-step expression strategies. An affinity purification method to purify 25 &#181;l of proteins expressed using the in vitro human cell free expression system is also described. Protein yield is determined by Bradford&#8217;s assay and the expressed and purified proteins can be confirmed by western blotting analysis. Expressed recombinant proteins can be used for immunizations, immunoassays and protein sequencing.

Expression of malarial proteins in cell based systems remains challenging. We demonstrate two step and one step IVT (in vitro translation) cell free expression systems for expressing malarial recombinant rhoptry proteins from HeLa cells. We use a Ni-resin affinity based purification system to purify the rhoptry proteins.

Malaria causes significant global morbidity and mortality. No routine vaccine is currently available. One of the major reasons for lack of a vaccine is ...

A Cell Free Assay to Study Chromatin Decondensation at the End of Mitosis

During the vertebrate cell cycle chromatin undergoes extensive structural and functional changes. Upon mitotic entry, it massively condenses into rod shaped chromosomes which are moved individually by the mitotic spindle apparatus. Mitotic chromatin condensation yields chromosomes compacted fifty-fold denser as in interphase. During exit from mitosis, chromosomes have to re-establish their functional interphase state, which is enclosed by a nuclear envelope and is competent for replication and transcription. The decondensation process is morphologically well described, but in molecular terms poorly understood: We lack knowledge about the underlying molecular events and to a large extent the factors involved as well as their regulation. We describe here a cell-free system that faithfully recapitulates chromatin decondensation in vitro, based on mitotic chromatin clusters purified from synchronized HeLa cells and X. laevis egg extract. Our cell-free system provides an important tool for further molecular characterization of chromatin decondensation and its co-ordination with processes simultaneously occurring during mitotic exit such as nuclear envelope and pore complex re-assembly.

The molecular mechanisms of the decondensation of highly compacted mitotic chromatin are ill-defined. We present a cell-free assay based on mitotic chromatin clusters isolated from HeLa cells and Xenopus laevis egg extract that faithfully reconstitutes the decondensation process in vitro.

During the vertebrate cell cycle chromatin undergoes extensive structural and functional changes. Upon mitotic entry, it massively condenses into rod ...

Detection of RNA-binding Proteins by In Vitro RNA Pull-down in Adipocyte Culture

RNA-binding proteins (RBPs) are emerging as a regulatory layer in the development and function of adipose. RBPs play a key role in the gene expression regulation at posttranscriptional levels by affecting the stability and translational efficiency of target mRNAs. RNA pull-down technique has been widely used to study RNA-protein interaction, which is necessary to elucidate the mechanism underlying RBPs&#39; as well as long non-coding RNAs&#39; (lncRNAs) function. However, the high lipid abundance in adipocytes poses a technical challenge in conducting this experiment. Here a detailed RNA pull-down protocol is optimized for primary adipocyte culture. An RNA fragment from androgen receptor&#39;s (AR) 3&#39; untranslated region (3&#39;UTR) containing an adenylate-uridylate-rich elementwas used as an example to demonstrate how to retrieve its RBP partner, HuR protein, from adipocyte lystate. The method described here can be applied to detect the interactions between RBPs and noncoding RNAs, as well as between RBPs and coding RNAs.

Detection of RNA-binding Proteins by In Vitro RNA Pull-down in Adipocyte Culture

An RNA pull-down protocol is optimized here for detection of interactions between RNA-binding proteins (RBPs) and noncoding as well as coding RNAs. An RNA fragment from androgen receptor (AR) was used as an example to demonstrate how to retrieve its RBP from lystate of primary brown adipocytes.

RNA-binding proteins (RBPs) are emerging as a regulatory layer in the development and function of adipose. RBPs play a key role in the gene expression ...

Studies in the last decade have revealed a complex and dynamic variety of pre-mRNA cleavage and polyadenylation reactions. mRNAs with long 3&#39; untranslated regions (UTRs) are generated in differentiated cells whereas proliferating cells preferentially express transcripts with short 3&#39;UTRs. We describe the A-seq protocol, now at its second version, which was developed to map polyadenylation sites genome-wide and study the regulation of pre-mRNA 3&#39; end processing. Also this current protocol takes advantage of the polyadenylate (poly(A)) tails that are added during the biogenesis of most mammalian mRNAs to enrich for fully processed mRNAs. A DNA adaptor with deoxyuracil at its fourth position allows the precise processing of mRNA 3&#39; end fragments for sequencing. Not including the cell culture and the overnight ligations, the protocol requires about 8 h hands-on time. Along with it, an easy-to-use software package for the analysis of the derived sequencing data is provided. A-seq2 and the associated analysis software provide an efficient and reliable solution to the mapping of pre-mRNA 3&#39; ends in a wide range of conditions, from 106 or fewer cells.

This protocol describes a method for mapping pre-mRNA 3&#39; end processing sites.