Name: assay to measure nucleocytoplasmic transport in real time within motor neuron-like nsc-34 cells
Uploaded: 2017-05-16T15:00:00
Description: Watch this Scientific Journal Video about Assay to Measure Nucleocytoplasmic Transport in Real Time within Motor Neuron-like NSC-34 Cells at JoVE.com

We thank all the members of the A.I. laboratory for their helpful comments and suggestions. We would like to thank Prof. Mark Hipp (Max Planck Institute for Biochemistry) for providing us with the shuttle-GFP vector. This work was supported by grants from the Israeli Science Foundation (ISF #124/14), the Binational Science Foundation (BSF #2013325), FP7 Marie Curie Career Integration Grant (CIG # 333794), and The National Institute for Psychobiology in Israel (NIPI #b133-14/15).

1. Cell Line Preparation
<ol>
	<li>Thaw approximately 1,000,000 mouse neuroblastoma spinal cord cells (NSC-34 cells) that were stored in a liquid nitrogen container. Use a 37 &#176;C water incubator until the cells are fully thawed.</li>
	<li>Add fresh, warm medium (DMEM medium containing 10% fetal bovine serum (FBS), 1% L-glutamine, and 1% pen-strep antibiotics).</li>
	<li>Centrifuge thawed cells (SL16R) at 500 x g for 5 min, forming a cell pellet. Discard the medium and add 1 mL of new medium for the cell resuspensio...

<ol>
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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=GGGGCC+repeat+expansion+in+C9orf72+compromises+nucleocytoplasmic+transport.">GGGGCC repeat expansion in C9orf72 compromises nucleocytoplasmic transport.</a> Nature. 525, 129-133 (2015).</li><li>Jovicic, 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=Modifiers+of+C9orf72+dipeptide+repeat+toxicity+connect+nucleocytoplasmic+transport+defects+to+FTD/ALS.">Modifiers of C9orf72 dipeptide repeat toxicity connect nucleocytoplasmic transport defects to FTD/ALS.</a> Nat Neurosci. 18, 1226-1229 (2015).</li><li>Kwon, I., 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=Poly-dipeptides+encoded+by+the+C9orf72+repeats+bind+nucleoli,+impede+RNA+biogenesis,+and+kill+cells.">Poly-dipeptides encoded by the C9orf72 repeats bind nucleoli, impede RNA biogenesis, and kill cells.</a> Science. 345, 1139-1145 (2014).</li><li>Rossi, 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=Nuclear+accumulation+of+mRNAs+underlies+G4C2-repeat-induced+translational+repression+in+a+cellular+model+of+C9orf72+ALS.">Nuclear accumulation of mRNAs underlies G4C2-repeat-induced translational repression in a cellular model of C9orf72 ALS.</a> J Cell Sci. 128, 1787-1799 (2015).</li><li>Shi, K. 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=Toxic+PRn+poly-dipeptides+encoded+by+the+C9orf72+repeat+expansion+block+nuclear+import+and+export.">Toxic PRn poly-dipeptides encoded by the C9orf72 repeat expansion block nuclear import and export.</a> Proc Natl Acad Sci U S A. , (2017).</li><li>Zhang, K., 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+C9orf72+repeat+expansion+disrupts+nucleocytoplasmic+transport.">The C9orf72 repeat expansion disrupts nucleocytoplasmic transport.</a> Nature. 525, 56-61 (2015).</li><li>Zhang, Y. 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=C9ORF72+poly(GA)+aggregates+sequester+and+impair+HR23+and+nucleocytoplasmic+transport+proteins.">C9ORF72 poly(GA) aggregates sequester and impair HR23 and nucleocytoplasmic transport proteins.</a> Nat Neurosci. 19, 668-677 (2016).</li><li>Cleveland, D. W., Rothstein, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=From+Charcot+to+Lou+Gehrig:+deciphering+selective+motor+neuron+death+in+ALS.">From Charcot to Lou Gehrig: deciphering selective motor neuron death in ALS.</a> Nat Rev Neurosci. 2, 806-819 (2001).</li><li>DeJesus-Hernandez, M., 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=Expanded+GGGGCC+hexanucleotide+repeat+in+noncoding+region+of+C9ORF72+causes+chromosome+9p-linked+FTD+and+ALS.">Expanded GGGGCC hexanucleotide repeat in noncoding region of C9ORF72 causes chromosome 9p-linked FTD and ALS.</a> Neuron. 72, 245-256 (2011).</li><li>Renton, A. E., 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+hexanucleotide+repeat+expansion+in+C9ORF72+is+the+cause+of+chromosome+9p21-linked+ALS-FTD.">A hexanucleotide repeat expansion in C9ORF72 is the cause of chromosome 9p21-linked ALS-FTD.</a> Neuron. 72, 257-268 (2011).</li><li>Boeve, B. F., 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=Characterization+of+frontotemporal+dementia+and/or+amyotrophic+lateral+sclerosis+associated+with+the+GGGGCC+repeat+expansion+in+C9ORF72.">Characterization of frontotemporal dementia and/or amyotrophic lateral sclerosis associated with the GGGGCC repeat expansion in C9ORF72.</a> Brain. 135, 765-783 (2012).</li><li>Haeusler, A. R., Donnelly, C. J., Rothstein, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+expanding+biology+of+the+C9orf72+nucleotide+repeat+expansion+in+neurodegenerative+disease.">The expanding biology of the C9orf72 nucleotide repeat expansion in neurodegenerative disease.</a> Nat Rev Neurosci. 17, 383-395 (2016).</li><li>Woerner, A. C., 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=Cytoplasmic+protein+aggregates+interfere+with+nucleocytoplasmic+transport+of+protein+and+RNA.">Cytoplasmic protein aggregates interfere with nucleocytoplasmic transport of protein and RNA.</a> Science. 351, 173-176 (2016).</li><li>Tao, Z., 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=Nucleolar+stress+and+impaired+stress+granule+formation+contribute+to+C9orf72+RAN+translation-induced+cytotoxicity.">Nucleolar stress and impaired stress granule formation contribute to C9orf72 RAN translation-induced cytotoxicity.</a> Hum Mol Genet. 24, 2426-2441 (2015).</li><li>Wen, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antisense+proline-arginine+RAN+dipeptides+linked+to+C9ORF72-ALS/FTD+form+toxic+nuclear+aggregates+that+initiate+in+vitro+and+in+vivo+neuronal+death.">Antisense proline-arginine RAN dipeptides linked to C9ORF72-ALS/FTD form toxic nuclear aggregates that initiate in vitro and in vivo neuronal death.</a> Neuron. 84, 1213-1225 (2014).</li></ol>

This protocol demonstrates a highly sensitive and quantitative new assay to evaluate minute changes in nucleocytoplasmic transport. Using this system, it is possible to observe and measure nucleocytoplasmic transport and its dysfunction in real time, not only large defects that result in dramatic changes in protein distribution. This assay not only has a sensitivity advantage, but it also requires little preparation, is inexpensive, and is a very easy and low-engagement assay.
To test the effi...

The nuclear pore complex (NPC) controls the import and export of large molecules into and out of the cell nucleus. In contrast to small molecules, which can enter the nucleus without regulation1, the transport of larger molecules is strongly controlled by the NPC. These large molecules, such as proteins and RNA, associate with transport factors, including importins and exportins, to be imported and exported from the nucleus2. In order to be imported, proteins must contain a small peptide motif, generally called a nuclear localization signal (NLS), which is bound by importins2. These sequences of amino acids act as a tag and are diverse in composition3,4. Proteins can be exported from the nucleus to the cytoplasm due to their association with exportins, which bind a signal sequence, generally called a nuclear export signal (NES)2. Both importins and exportins are able to transport their cargo due to the regulation of the small Ras related nuclear protein GTPase (Ran)2. Ran has been shown to exist in different conformational states depending on whether it is bound to GTP or GDP. When bound to GTP, Ran can bind to importins or exportins. Upon binding to RanGTP, importins release their cargo, while exportins must bind RanGTP to form a complex with their export cargo. The dominant nucleotide binding state of Ran depends on its location in the nucleus (RanGTP) or the cytoplasm (RanGDP).
Recently, a number of studies have shown a connection between impairments in the nucleocytoplasmic pathway and both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD)5,6,7,8,9,10,11,12. ALS is a progressive and fatal neurodegenerative disease affecting both upper and lower motor neurons (MNs)13 and resulting in paralysis and ultimately in death, within 2-5 years on average. Most cases of ALS are classified as sporadic (SALS), lacking any apparent genetic linkage, but 10% are inherited in a dominant manner (familial ALS; FALS). Recently, hexanucleotide repeat expansions (HREs) in the chromosome 9 open reading frame 72 (C9orf72) gene were identified14,15 as a genetic cause of ALS and FTD. These mutants account for 30-40% of FALS cases16, and different studies have contended that they cause toxicity by affecting nucleocytoplasmic transport5,6,7,8,9,10,11,12.
These studies have mostly shown the final outcomes and manifestations of HREs on nucleocytoplasmic transport, but they do not demonstrate nucleocytoplasmic disruption in real time. As a result, only severe nucleocytoplasmic transport deficiency has been evaluated11,17,18.
This protocol describes a new and very sensitive assay to evaluate and quantify nucleocytoplasmic transport dysfunction in real time. The rate of import of a NLS-NES-GFP protein (shuttle-GFP) can be quantified in real time using fluorescent microscopy. This is done using an exportin inhibitor, as described previously18, thus allowing the shuttle-GFP only to enter the nucleus. Using florescent microscopy and a software capable of quantifying fluorescent changes in real time, it is possible to quantify gradual changes in the fluorescence intensity of the shuttle-GFP, located in the nucleus. As a result, a Michaelis-Menten-like saturation curve of the fluorescence-to-time axis, representing the amount of nuclear shuttle-GFP at any given time, can be made. By using the initial linear rate of the curves, it is possible to generate a slope, which represents the rate of entry into the nucleus before fluorescence saturation.
To validate the assay, the translated C9orf72 dipeptide repeats, poly(GR) and poly(PR), which have been previously reported to disrupt nucleocytoplasmic transport, were used5,7,8,10,12. Using this assay, a 50% decrease in the nuclear import rate was observed compared to the control. Using this system, minute changes in nucleocytoplasmic transport can be examined. Moreover, the ability of different factors to rescue a nucleocytoplasmic transport defect can be determined.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Mouse Motor Neuron-Like hybrid Cell Line (NSC-34)</td>
			<td>tebu-bio</td>
			<td>CLU140-A</td>
		</tr>
		<tr>
			<td>DMEM 4.5g/L L-glucose</td>
			<td>Biological Industries</td>
			<td>01-055-1A</td>
		</tr>
		<tr>
			<td>FBS European Grade</td>
			<td>Biological Industries</td>
			<td>04-007-1A</td>
		</tr>
		<tr>
			<td>SL 16R Centrifuge</td>
			<td>Thermo Scientific</td>
			<td>75004030</td>
		</tr>
		<tr>
			<td>Thermo Forma Series ii Water Jacketed CO2 Incubator</td>
			<td>Thermo Scientific</td>
			<td>3111</td>
		</tr>
		<tr>
			<td>Cover glass 12mm dia. thick 0.13-0.17mm</td>
			<td>Bar Naor LTD</td>
			<td></td>
		</tr>
		<tr>
			<td><a href="https://www.thermofisher.com/order/catalog/product/R0531">TurboFect Transfection Reagent</a></td>
			<td>Thermo Scientific</td>
			<td><a href="https://www.thermofisher.com/order/catalog/product/R0531">R0531</a></td>
		</tr>
		<tr>
			<td>Axiovert 100 inverted microscope</td>
			<td>Zeiss</td>
			<td></td>
		</tr>
		<tr>
			<td>IMAGING WORKBENCH 2&#160;</td>
			<td>Axon Instruments</td>
			<td></td>
		</tr>
		<tr>
			<td>Leptomycin B</td>
			<td>Sigma</td>
			<td>L2913</td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>Biological Industries</td>
			<td>02-023-1A</td>
		</tr>
		<tr>
			<td>Homogenizer motor/control/chuck/90-degree clamp</td>
			<td>Glas-Col</td>
			<td>099C K5424CE</td>
		</tr>
		<tr>
			<td>MicroCL 17R Centrifuge, Refrigerated</td>
			<td>Thermo Scientific</td>
			<td>75002455</td>
		</tr>
	</tbody>
</table>

assay to measure nucleocytoplasmic transport in real time within motor neuron-like nsc-34 cells

Nucleocytoplasmic transport refers to the import and export of large molecules from the cell nucleus. Recently, a number of studies have shown a connection between amyotrophic lateral sclerosis (ALS) and impairments in the nucleocytoplasmic pathway. ALS is a neurodegenerative disease affecting the motor neurons and resulting in paralysis and ultimately in death, within 2-5 years on average. Most cases of ALS are sporadic, lacking any apparent genetic linkage, but 10% are inherited in a dominant manner. Recently, hexanucleotide repeat expansions (HREs) in the chromosome 9 open reading frame 72 (C9orf72) gene were identified as a genetic cause of ALS and frontotemporal dementia (FTD). Importantly, different groups have recently proposed that these mutants affect nucleocytoplasmic transport. These studies have mostly shown the final outcome and manifestations caused by HREs on nucleocytoplasmic transport, but they do not demonstrate nuclear transport dysfunction in real time. As a result, only severe nucleocytoplasmic transport deficiency can be determined, mostly due to high overexpression or exogenous protein insertion. 
This protocol describes a new and very sensitive assay to evaluate and quantify nucleocytoplasmic transport dysfunction in real time. The rate of import of a NLS-NES-GFP protein (shuttle-GFP) can be quantified in real time using fluorescent microscopy. This is performed by using an exportin inhibitor, thus allowing the shuttle GFP only to enter the nucleus. To validate the assay, the C9orf72 HRE translated dipeptide repeats, poly(GR) and poly(PR), which have been previously shown to disrupt nucleocytoplasmic transport, were used. Using the described assay, a 50% decrease in the nuclear import rate was observed compared to the control. Using this system, minute changes in nucleocytoplasmic transport can be examined and the ability of different factors to rescue (even partially) a nucleocytoplasmic transport defect can be determined.

Using the procedure presented here, motor neuron-like NSC-34 cells were transfected with a NLS-NES-GFP (shuttle-GFP) protein. This protein, which has NLS and NES signal sequences (Figure 1), can shuttle between the nucleus and the cytoplasm. Generic GFP can enter or exit the nucleus in the absence of any localization signal tag only by diffusion and is therefore distributed evenly between the nucleus and the cytoplasm (Figure 2A). In contrast, the shuttle...

Watch this Scientific Journal Video about Assay to Measure Nucleocytoplasmic Transport in Real Time within Motor Neuron-like NSC-34 Cells at JoVE.com

Assay to Measure Nucleocytoplasmic Transport in Real Time within Motor Neuron-like NSC-34 Cells

This protocol describes a method to sensitively measure the nucleocytoplasmic transport rate within motor neuron-like NSC-34 cells by quantifying the real-time change in the nuclear import of a NLS-NES-GFP protein.

Nucleocytoplasmic transport refers to the import and export of large molecules from the cell nucleus. Recently, a number of studies have shown a ...

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