Worcester Politeknik Enstitüsü Bölümü Kimya ve Biyokimya finansman için teşekkür etmek istiyorum.

1. Hücre Hatları, Transfeksiyon Transfeksiyon Yöntem 1 (Lonza, artan primer hücre transfeksiyon verimlilik için Nucleofection) <ol><li> Hücreler son geçiş ve önce transfeksiyon log fazı büyüme olmalıdır. Fosfat içinde hücreler yıkayın trypsinization tamponlu salin (PBS) ve hasat hücreleri. </li><li> 1500 xg&#39;de 5 dakika santrifüj hücreleri toplayın. </li><li> 6 plaka sterilize kapak fişleri ekleyin. Kapak fişleri gelişmiş hücre adezyon kaplı olabilir. Yeri 1.5 ml kültür ortamı (bu durumda Dulbecco&#39;nun modifiye Eagle orta (DMEM),% 10 fetal sığır serumu (FBS)) ve her kuyuya inkübatör ortam dengelenmesi. </li><li> Fosfat minimal volüm trypsinization ve tekrar süspansiyon hücreleri tarafından Hasat tamponlu salin (PBS). </li><li> Hücre sayımı ve tabanda örnek başına ~ 5x10 5 hücre sağlamak için doğru miktarda santrifüj. </li><li> Numune başına 100 mcL oda sıcaklığında Nucleofector çözüm hücreleri dikkatli bir şekilde tekrar </li><li> 5 mg plazmid DNA ile birleştirin ve hücre süspansiyonu 100 mcL Nucleofector Küvet hava kabarcıkları dahil etmek için dikkatli bir örnek aktarmak. </li><li> Uygun Nucleofector Programı (minimal mortalite ile optimal transfeksiyon etkinliğini kurmak için önceki testi gerekebilir) seçin. </li><li> Nucleofector Küvet Tutucu hücre / DNA süspansiyon içeren küvet takın ve seçilen program başlar. </li><li> Tamamlanmasının ardından, küvet kaldırmak ve (6 plaka alınan) ~ 500 mcL ön dengelenmiş kültür ortamı ekleyin. </li><li> Hemen yanı başına 1.5 mL son hacmi ile 6-plaka içine örnek aktarmak. Hücreler kontrolleri için, karma nüfuslu ya da ayrı ayrı ya kaplama olmalıdır. </li></ol> Transfeksiyon Yöntemi 2 (Qiagen Effectene transfeksiyon hücre hatları için) <ol><li> Her plazmid DNA örneği 0.8 mg 200 mcL EC tampon ekleyerek ilk Qiagen Effectene Reaktif transfeksiyon kompleksleri kullanarak hazırlayın. </li><li> Her numune için 6.4 mcL arttırıcı reaktif, tüp Flicking kısaca karıştırın ve oda sıcaklığında 2 dakika inkübe edin. </li><li> Tüp Flicking tarafından her örnek, mix 20 mcL Effectene reaktif ekleyin ve oda sıcaklığında 15 dakika inkübe edin. </li><li> Bu kuluçka sırasında, transfeksiyon için ilgi iki hücre hatları hazırlamak. Son geçişli hücreler (&lt;% 80 izdiham) yıkayın kez fosfat tamponlu salin (PBS). 1.5 ml taze ısıtılmış ve dengelenir büyüme orta Ekle (Bu durumda Dulbecco&#39;nun modifiye Eagle orta (DMEM),% 10 fetal sığır serumu (FBS)). </li><li> 15 dakika boyunca inkübe transfeksiyon kompleksleri sonra, her bir örnek 1.2 mL medya aktarın. Pipetleme, ve 6-plaka hemen her iki kuyu için yaklaşık 700 mcL kompleksleri transferi ile karıştırın. Damla damla ekleyin ve plaka dönen hafifçe karıştırın. Hücrelerin en az 3 saat transfect için izin ver (hücre tipi ile değişiklik gösterebilir). </li><li> Sterilize kapak fişleri yeni bir 6-plaka ekleyin. Kapak fişleri gelişmiş hücre adezyon kaplı olabilir. </li><li> Hücrelerin transfekte sonra, her bir kuyunun yaklaşık 100 mcL tripsin çözüm ekleyerek, kısaca her bir kuyunun tam kat plaka ajitasyon ve hemen tripsin aspire PBS ile iki kez hücreleri yıkayın ve minimal trysinization hücreleri tarafından hasat. Hücreleri kaldırdı sonra, 1.5 mL taze medya ekleyin. </li><li> Bu noktada, hücrelerin steril bir örtü fişleri üzerine karışık veya ayrı olarak nüfus (kontrol) kaplama olmalıdır. </li><li> Hücreler 12 saat kurtarmak için izin verin. </li></ol> 2. Hücre Fusion <ol><li> Hücrelerin kültür ortamları çıkarın ve PBS ile iki kez yıkayın. </li><li> Bu noktada, protein sentezini inhibe sikloheksimid (100 mg / ml) ile hücrelerin tedavisi için tavsiye edilir. Hücreler 2 saat süreyle inkübe ve sonra hücreler PBS ile iki kez yıkamak için izin verin. </li><li> 125 saniye boyunca oda sıcaklığında serum serbest DMEM% 50 polietilen glikol 1000 (PEG 1000) bir çözüm onları teşhir ederek Sigorta hücreleri. </li><li> PEG 1000 çözüm kaldırmak ve 2 ml taze ısıtılmış ve dengelenir medya eklemek hücreleri PBS ile yıkayın. </li><li> Hücreleri için 18 - 24 saat inkübe için izin verin. </li></ol> Floresan Mikroskopi <ol><li> Kültür ortamı çıkarın ve hücreler PBS içinde iki kez yıkayın. </li><li> Her iyi bir% 4 paraformaldehid solüsyonu (PBS) 1 ml ekleyerek hücreleri saptamak. 15 dakika boyunca yavaşça ajitasyon. </li><li> Sabit hücreler PBS içinde iki kez yıkayın. </li><li> Plaka kapağını dikkatlice fişleri kaldırmak, aşırı PBS kapalı fitil. Üzerine mikroskop yüklenen montaj orta (% 90 gliserol, 100 mM Tris, pH 7.5,% 2 DABCO (1,4-diazabicoyclo oktanlı) içeren DAPI (4 &#39;,6-diamidino-2-phenylindole) ile bir damla slaytlar. Haricindekileri </li><li> Slaytları fazla montaj orta çıkarın ve mühür cooje ile ver sığar. </li><li> Konfokal veya Epifloresans mikroskobu ile hücre gözünüzde canlandırın. </li></ol> 3. Temsilcisi Sonuçlar Şekil 2 birincil fibroblastlar ve H1299 küçük hücreli dışı akciğer kanseri hücreleri kullanarak bir örnek heterokaryon deney gösterir. Bu deneyde ilgi protein (Tavuk Anemisi Virüs VP3) Epifloresans mikroskopi tarafından görüntülenmiştir olarak öncelikle birincil hücre tipleri sitoplazmik yerelleştirme ve transforme hücre tipleri nükleer lokalizasyon gösterir. Protein H1299 hücrelerinde birincil sünnet derisi fibroblastlar (PFF) veya dsRed GFP ya da bir füzyon (pEGFP N1 vektör, Clontech) (dsRed-N1 vektörü, Clontech) olarak ifade edilir. Kendi füzyonlar içeren kontrol numuneleri (üst iki satır), kararlı durum lokalizasyon desen hiçbir değişiklik multinükleer hücreler gösterir. Bu tür değişiklikler aksi füzyon koşulları veya syncitia oluşumu hassasiyeti nedeniyle meydana gelebilir. Heterokaryon füzyonlar (alt sıra) nükleer GFP-erimiş birincil hücre kaynaklı protein ve transforme hücre malzeme giriş yanıt dsRed erimiş protein ile ko giriş göstermektedir. Gösterilen örnek, hem Fluoroprotein sinyallerin varlığını gösterdiği gibi, sadece iki hücre, her tür, oldukça nadir görülen bir heterokaryon füzyon. Nükleositoplazmik mekik faaliyet yerelleştirme geçişler bu tür tespit ek olarak, hem de çekirdeklerin tek bir fluorofor varlığı kolayca tespit edilebilir. Bu tip tayini 01:01 hücre füzyonlar incelenmesi ve çeviri inhibisyonuna bağlı olacaktır açıktır. <img src="/files/ftp_upload/2488/2488fig1.jpg" alt="Şekil 1" /> Şekil 1. Heterokaryon yöntemin birincil fibroblastlar ve H1299 küçük hücreli dışı karsinom hücreleri kullanarak akış şeması ilgi gen iki floresan protein genleri tek bir kare füzyon üretmek için klonlanmış. Daha sonra hücre hatları geçici ya da inşa transfekte ve kurtarmak için izin vardır. Heterokaryon oluşumu daha fazla inkübasyon polietilen glikol (PEG) ile kısa süreli tedavi ile meydana gelir. Son olarak, faiz protein alt hücresel yerleşimi floresan mikroskobu çeşitli formları kullanarak görülmektedir. <img src="/files/ftp_upload/2488/2488fig2.jpg" alt="Şekil 2" /> Şekil 2. Nükleositoplazmik kaçakçılığı ve Tavuk Anemisi Virüs VP3 proteinin aktivitesi mekik heterokaryon füzyon tarafından görüntülendi. Üst satır: dsRed-VP3 ifade kendinden erimiş H1299 hücreleri Temsilcisi Orta sıra: PEG füzyon sonra GFP-VP3 ifade birincil sünnet derisi fibroblast hücreleri (PFF) Temsilcisi Epifloresans görüntüleri Alt satır: PFF ve H1299 hücreleri Heterokaryon füzyon. Sarı GFP ve dsRed sinyaller ko gösterir. Hücreler bir Leica AF6000E floresan mikroskop ve Leica görüntüleme yazılımı kullanılarak görüntülenmiştir.

<ol>
	<li>Belaya, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FLIPing+heterokaryons+to+analyze+nucleo-cytoplasmic+shuttling+of+yeast+proteins.">FLIPing heterokaryons to analyze nucleo-cytoplasmic shuttling of yeast proteins.</a> RNA. 12, 921-930 (2006).</li><li>Bhaumik, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+target+of+a+transcriptional+activator+revealed+by+fluorescence+resonance+energy+transfer.">In vivo target of a transcriptional activator revealed by fluorescence resonance energy transfer.</a> Genes Dev. 18, 333-343 (2004).</li><li>Cohen, H. R., Panning, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=XIST+RNA+exhibits+nuclear+retention+and+exhibits+reduced+association+with+the+export+factor+TAP/NXF1.">XIST RNA exhibits nuclear retention and exhibits reduced association with the export factor TAP/NXF1.</a> Chromosoma. 116, 373-383 (2007).</li><li>Gao, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dapper1+is+a+nucleoplasmic+shuttling+protein+that+negatively+modulates+Wnt+signaling+in+the+nucleus.">Dapper1 is a nucleoplasmic shuttling protein that negatively modulates Wnt signaling in the nucleus.</a> J. Biol. Chem. 51, 35679-3588 (2008).</li><li>Grespin, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thyroid+Hormone+Receptor+&#945;1+Follows+a+Cooperative+CRM1/Calreticulin-mediated+Nuclear+Export+Pathway.">Thyroid Hormone Receptor &#945;1 Follows a Cooperative CRM1/Calreticulin-mediated Nuclear Export Pathway.</a> J. Biol. Chem. 283, 25576-25588 (2008).</li><li>Heilman, D. W., Teodoro, J. G., Green, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Apoptin+Nucleocytoplasmic+Shuttling+Is+Required+for+Cell+Type-Specific+Localization,+Apoptosis,+and+Recruitment+of+the+Anaphase-Promoting+Complex/Cyclosome+to+PML+Bodies.">Apoptin Nucleocytoplasmic Shuttling Is Required for Cell Type-Specific Localization, Apoptosis, and Recruitment of the Anaphase-Promoting Complex/Cyclosome to PML Bodies.</a> J. Virology. 80, 7535-7545 (2006).</li><li>Jeffries, S., Capobianco, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neoplastic+transformation+by+Notch+requires+nuclear+localization.">Neoplastic transformation by Notch requires nuclear localization.</a> Mol Cell Biol. 20, 3928-3941 (2000).</li><li>Keaton, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nucleocytoplasmic+trafficking+of+G2/M+regulators+in+yeast.">Nucleocytoplasmic trafficking of G2/M regulators in yeast.</a> Mol. Biol. Cell. 19, 4006-4018 (2008).</li><li>Ling, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear-Cytoplasmic+Shuttling+Is+Not+Required+for+the+Epstein-Barr+Virus+EBNA-LP+Transcriptional+Coactivation+Function.">Nuclear-Cytoplasmic Shuttling Is Not Required for the Epstein-Barr Virus EBNA-LP Transcriptional Coactivation Function.</a> J. Virology. 83, 7109-7116 (2009).</li><li>Lin, X. -. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RXR&#945;+acts+as+a+carrier+for+TR3+nuclear+export+in+a+9-cis+retinoic+acid-dependent+manner+in+gastric+cancer+cells.">RXR&#945; acts as a carrier for TR3 nuclear export in a 9-cis retinoic acid-dependent manner in gastric cancer cells.</a> J. Cell Science. 117, 5609-5621 (2004).</li><li>Vissinga, 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=Nuclear+Export+of+NBN+Is+Required+for+Normal+Cellular+Responses+to+Radiation.">Nuclear Export of NBN Is Required for Normal Cellular Responses to Radiation.</a> Mol Cell Biol. 29, 1000-1006 (2009).</li><li>Zimmerman, R. S., Rosenberg, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+p19Arf+localization+accompany+apoptotic+crisis+during+pre-B-cell+transformation+by+Abelson+murine+leukemia+virus.">Changes in p19Arf localization accompany apoptotic crisis during pre-B-cell transformation by Abelson murine leukemia virus.</a> J. Virol. 82, 8383-8391 (2008).</li></ol>

Burada sunulan heterokaryon protokol hücre tipine spesifik lokalizasyon davranış yanı sıra Nükleositoplazmik mekik faaliyet karakterizasyonu için etkin ve kolay yorumlanabilir bir yöntem sağlar. Bu yöntem, floresan analizi duyarlılık yanı sıra yetenek görüntü canlı hücreleri ve protein dinamiği çalışmaları gerçekleştirmek yararlanır. Tekniği, pek çok farklı hücre tipleri için kolayca adapte ve hem canlı ve sabit hücre görüntüleme için uygun. Örneğin, ters floresan mikroskopi canlı görüntüleme ve zaman atlamalı video yakalama için kullanılabilir. Buna karşılık, kararlı durum lokalizasyonu veya ayrık lokalizasyonları daha ayrıntılı konfokal görüntüleme belirlenmesi için iki Epifloresans mikroskopi monte hücreleri kullanılıyor olabilir. Ayrıca, bu tür photobleaching sonra floresan kurtarma (sıkı bağlamak), ya da floresan photobleaching içinde kaybı (FLIP) gibi teknikler, lokalizasyon kinetiği 1 tespitinde kullanılabilir . Protokol alternatif fluorophores birleşme 2 konser yapılacak floresan rezonans enerji transferi (FRET) gibi protein etkileşim deneyler için izin verecek. Leptomycin B veya olumsuz egemen olarak hücresel ticareti Çeşitli inhibitörleri Ran GTPaz yapıları, özellikle ithalat veya ihracat yollar 5,6,9 bağımlılığı kurmak için kullanılabilir . <ul><li> Faaliyet mekik içeren bazı deneylerde, bakım, yeni protein sentezi nedeniyle yerelleştirme etkilerinden kaçınmak için gerekli önlemler alınmalıdır. Bu durumlarda, çeviri inhibitörleri veya sınırlı bir süre noktaları kullanılmalıdır. Ancak, bir olasılık translasyonel inhibisyonu nedeniyle eserler kalır. Biri Hücre füzyonlar her hücre tipi içeren, mekik ve yerelleştirme davranışı net yorumlanması için en çok istenen. Hücre sayısı ve füzyon koşulları (zamanlama ve konsantrasyon) optimizasyonu tür olumlu 01:01 füzyon olayları teşvik etmek için gerekli olabilir. </li><li> Protokol bazı adımlar bu optimizasyon kullanılan özel hücre tipleri bağlı olarak gerekli olacaktır dikkat etmek önemlidir. Füzyon etkinlik, Transfeksiyonu verimlilik ve füzyon sonra canlılığını deneysel işlemin Yönleri hücre tipleri arasında büyük farklılık gösterebilir. Özellikle, birincil hücre tiplerinin karmaşık kültür koşulları ve düşük transfeksiyon verimliliği nedeniyle yönetmek için zor olabilir. Lonza Nucleofector cihazı gibi teknolojileri kullanımı hücrelerin hızlı bir şekilde işleme yanı sıra önemli ölçüde artmıştır transfeksiyon verimliliği izin verebilirsiniz. Ayrıca, elektroporasyon yöntemleri takip füzyon adımları askıya hücre kolay transferi için izin verir. </li></ul>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Effectene reagent</td>
<td>&nbsp;</td>
<td>Qiagen</td>
<td>301425</td>
<td>&nbsp;</td>
<tr>
<td>Phosphate buffered saline (PBS)</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>P5493</td>
<td>&nbsp;</td>
<tr>
<td>Trypsin</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>SH3023602</td>
<td>&nbsp;</td>
<tr>
<td>Dulbecco&#x2019;s modified Eagle&#x2019;s medium (DMEM)</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>SH30243FS</td>
<td>High glucose</td>
</tr>
<tr>
<td>paraformaldehyde</td>
<td>&nbsp;</td>
<td>FisherChemical</td>
<td>O4042-500</td>
<td>&nbsp;</td>
<tr>
<td>4&#x2019;,6-diamidino-2-phenylindole (DAPI)</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>D9542-10MG</td>
<td>&nbsp;</td>
<tr>
<td>Hyclone Serum (fetal bovine)</td>
<td>&nbsp;</td>
<td>Thermo Scientific</td>
<td>SH3008803HI</td>
<td>&nbsp;</td>
<tr>
<td>Falcon 6-well plates</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>08-772-1B</td>
<td>&nbsp;</td>
<tr>
<td>Polyethylene glycol 1000</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>528875-25GM</td>
<td>&nbsp;</td>
<tr>
<td>Cover slips</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>12-545-85</td>
<td>&nbsp;</td>
<tr>
<td>DABCO</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>D2522-25G</td>
<td>&nbsp;</td>
<tr>
<td>Nucleofector HDF kit</td>
<td>&nbsp;</td>
<td>Lonza</td>
<td>VPD-1001</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

heterokaryon technique for analysis of cell type-specific localization

Önemli bir sayıda proteinler, hücre içi ticareti veya nucleocytolasmic mekik tarafından düzenlenir. Bu proteinler, RNA ve protein nükleer ithalat / ihracat, transkripsiyonal yönetmelik, ve apoptosis gibi hücresel fonksiyonları çeşitli bir dizi gösterir. İlginçtir, hücre bölünmesi, farklılaşma ve dönüşüm de dahil olmak üzere önemli hücresel yeniden yapılanma, sık sık bu tür faaliyetler 3,4,8,10 içerir. Bu proteinlerin ve kendi düzenleyici mekanizmaların detaylı bir çalışma bu lokalizasyon değişiklikleri zor olabilir uyarılması ve kendilerini izlemek için oldukça dinamik ve zor olabilir hareketleri gibi zor olabilir. Hücresel karsinojeneze içeren çalışmalar, örneğin, anlayış yollar ve birincil, normal hücreleri ve transforme hücreleri 6,7,11,12 arasında farklılık protein aktiviteleri yararlanmaya devam. Birçok protein değişmiş dönüşümü sırasında veya lokalizasyonu, dönüşümün bir sonucu olarak verimli bir şekilde bu proteinlerin karakterize etmek için yöntemler ve ilaç hedef karsinojeneze ve açık yeni alanlar anlayışı geliştirmek stand katıldığı yollar gösterir. Burada protein ticareti analizi için bir yöntem mevcut ve birincil ve transforme memeli hücreleri arasındaki aktivite mekik. Bu yöntem, kararlı durum ya da dinamik protein lokalizasyonu tespit etmek için kullanılan esnek bir protokol sağlamak için floresan mikroskobu ile heterokaryon füzyonlar nesil birleştirir. Şekil 1&#39;de gösterildiği gibi, iki ayrı hücre tipleri geçici ilgi gen bağlı bir Fluoroprotein geni taşıyan plazmid yapıları ile transfekte. Ifade sonra, hücreler polietilen glikol kullanarak erimiş ve protein lokalizasyonu daha sonra çeşitli yöntemler kullanarak görüntülü olabilir. Burada sunulan protokol, özel teknikler ilave edilebilir temel bir yaklaşımdır.

Watch this Scientific Journal Video about Heterokaryon Technique for Analysis of Cell Type-specific Localization at JoVE.com

Heterokaryon Technique for Analysis of Cell Type-specific Localization

Mekik hücre tipine spesifik protein yerelleştirme ve Nükleositoplazmik karakterizasyonu için esnek ve verimli bir yöntem açıklanmıştır. Bu heterokaryon yaklaşım görüntü protein lokalizasyonu hücre füzyonu sonra floresan etiketli füzyon proteinleri kullanır. Protokol kararlı durum lokalizasyonu veya canlı hücre görüntüleme dayalı daha dinamik tespitler mükellef.

Hücre Tipi özel Yerelleştirme Analizi için Heterokaryon Tekniği

A significant number of proteins are regulated by subcellular trafficking or nucleocytolasmic shuttling.  These proteins display a diverse array of ...

heterokaryon-technique-for-analysis-of-cell-type-specific-localization

Research

JoVE Journal

Biology

16.3K Görüntüleme.  Worcester Polytechnic Institute- WPI. Mekik hücre tipine spesifik protein yerelleştirme ve Nükleositoplazmik karakterizasyonu için esnek ve verimli bir yöntem açıklanmıştır. Bu heterokaryon yaklaşım görüntü protein lokalizasyonu hücre füzyonu sonra floresan etiketli füzyon proteinleri kullanır. Protokol kararlı durum lokalizasyonu veya canlı hücre görüntüleme dayalı daha dinamik tespitler mükellef.

Video: Heterokaryon Technique for Analysis of Cell Type-specific Localization

A Neuronal and Astrocyte Co-Culture Assay for High Content Analysis of Neurotoxicity

High Content Analysis (HCA) assays combine cells and detection reagents with automated imaging and powerful image analysis algorithms, allowing measurement of multiple cellular phenotypes within a single assay. In this study, we utilized HCA to develop a novel assay for neurotoxicity. Neurotoxicity assessment represents an important part of drug safety evaluation, as well as being a significant focus of environmental protection efforts. Additionally, neurotoxicity is also a well-accepted in vitro marker of the development of neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Recently, the application of HCA to neuronal screening has been reported. By labeling neuronal cells with &beta;III-tubulin, HCA assays can provide high-throughput, non-subjective, quantitative measurements of parameters such as neuronal number, neurite count and neurite length, all of which can indicate neurotoxic effects. However, the role of astrocytes remains unexplored in these models. Astrocytes have an integral role in the maintenance of central nervous system (CNS) homeostasis, and are associated with both neuroprotection and neurodegradation when they are activated in response to toxic substances or disease states. GFAP is an intermediate filament protein expressed predominantly in the astrocytes of the CNS. Astrocytic activation (gliosis) leads to the upregulation of GFAP, commonly accompanied by astrocyte proliferation and hypertrophy. This process of reactive gliosis has been proposed as an early marker of damage to the nervous system. The traditional method for GFAP quantitation is by immunoassay. This approach is limited by an inability to provide information on cellular localization, morphology and cell number. We determined that HCA could be used to overcome these limitations and to simultaneously measure multiple features associated with gliosis - changes in GFAP expression, astrocyte hypertrophy, and astrocyte proliferation - within a single assay. In co-culture studies, astrocytes have been shown to protect neurons against several types of toxic insult and to critically influence neuronal survival. Recent studies have suggested that the use of astrocytes in an in vitro neurotoxicity test system may prove more relevant to human CNS structure and function than neuronal cells alone. Accordingly, we have developed an HCA assay for co-culture of neurons and astrocytes, comprised of protocols and validated, target-specific detection reagents for profiling &beta;III-tubulin and glial fibrillary acidic protein (GFAP). This assay enables simultaneous analysis of neurotoxicity, neurite outgrowth, gliosis, neuronal and astrocytic morphology and neuronal and astrocytic development in a wide variety of cellular models, representing a novel, non-subjective, high-throughput assay for neurotoxicity assessment. The assay holds great potential for enhanced detection of neurotoxicity and improved productivity in neuroscience research and drug discovery.

This article describes a novel protocol and reagent set designed for sensitive measurement of neurotoxic effects of compounds and treatments on co-cultures of neurons and astrocytes using high content analysis. Results demonstrate that high content analysis represents an exciting novel technology for neurotoxicity assessment.

Nörotoksisite Yüksek İçerik Analizi Nöronal ve Astrosit Hücre Co-Kültür Testi

High Content Analysis (HCA) assays combine cells and detection reagents with automated imaging and powerful image analysis algorithms, allowing ...

Biyoloji

Visualizing RNA Localization in Xenopus Oocytes

RNA localization is a conserved mechanism of establishing cell polarity. Vg1 mRNA localizes to the vegetal pole of Xenopus laevis oocytes and acts to spatially restrict gene expression of Vg1 protein. Tight control of Vg1 distribution in this manner is required for proper germ layer specification in the developing embryo. RNA sequence elements in the 3' UTR of the mRNA, the Vg1 localization element (VLE) are required and sufficient to direct transport. To study the recognition and transport of Vg1 mRNA in vivo, we have developed an imaging technique that allows extensive analysis of trans-factor directed transport mechanisms via a simple visual readout. 
To visualize RNA localization, we synthesize fluorescently labeled VLE RNA and microinject this transcript into individual oocytes. After oocyte culture to allow transport of the injected RNA, oocytes are fixed and dehydrated prior to imaging by confocal microscopy. Visualization of mRNA localization patterns provides a readout for monitoring the complete pathway of RNA transport and for identifying roles in directing RNA transport for cis-acting elements within the transcript and trans-acting factors that bind to the VLE (Lewis et al., 2008, Messitt et al., 2008). We have extended this technique through co-localization with additional RNAs and proteins (Gagnon and Mowry, 2009, Messitt et al., 2008), and in combination with disruption of motor proteins and the cytoskeleton (Messitt et al., 2008) to probe mechanisms underlying mRNA localization.

Visualizing RNA Localization in Xenopus Oocytes

Visualization of in vivo RNA transport is accomplished by microinjection of fluorescently labeled RNA transcripts into Xenopus oocytes, followed by confocal microscopy.

Görselleştirme RNA Yerelleştirme Xenopus Oosit

RNA localization is a conserved mechanism of establishing cell polarity.  Vg1 mRNA localizes to the vegetal pole of Xenopus laevis oocytes and acts to ...

Investigating Tissue- and Organ-specific Phytochrome Responses using FACS-assisted Cell-type Specific Expression Profiling in Arabidopsis thaliana

Light mediates an array of developmental and adaptive processes throughout the life cycle of a plant. Plants utilize light-absorbing molecules called photoreceptors to sense and adapt to light. The red/far-red light-absorbing phytochrome photoreceptors have been studied extensively. Phytochromes exist as a family of proteins with distinct and overlapping functions in all higher plant systems in which they have been studied1. Phytochrome-mediated light responses, which range from seed germination through flowering and senescence, are often localized to specific plant tissues or organs2. Despite the discovery and elucidation of individual and redundant phytochrome functions through mutational analyses, conclusive reports on distinct sites of photoperception and the molecular mechanisms of localized pools of phytochromes that mediate spatial-specific phytochrome responses are limited. We designed experiments based on the hypotheses that specific sites of phytochrome photoperception regulate tissue- and organ-specific aspects of photomorphogenesis, and that localized phytochrome pools engage distinct subsets of downstream target genes in cell-to-cell signaling. We developed a biochemical approach to selectively reduce functional phytochromes in an organ- or tissue-specific manner within transgenic plants. Our studies are based on a bipartite enhancer-trap approach that results in transactivation of the expression of a gene under control of the Upstream Activation Sequence (UAS) element by the transcriptional activator GAL43. The biliverdin reductase (BVR) gene under the control of the UAS is silently maintained in the absence of GAL4 transactivation in the UAS-BVR parent4. Genetic crosses between a UAS-BVR transgenic line and a GAL4-GFP enhancer trap line result in specific expression of the BVR gene in cells marked by GFP expression4. BVR accumulation in Arabidopsis plants results in phytochrome chromophore deficiency in planta5-7. Thus, transgenic plants that we have produced exhibit GAL4-dependent activation of the BVR gene, resulting in the biochemical inactivation of phytochrome, as well as GAL4-dependent GFP expression. Photobiological and molecular genetic analyses of BVR transgenic lines are yielding insight into tissue- and organ-specific phytochrome-mediated responses that have been associated with corresponding sites of photoperception4, 7, 8. Fluorescence Activated Cell Sorting (FACS) of GFP-positive, enhancer-trap-induced BVR-expressing plant protoplasts coupled with cell-type-specific gene expression profiling through microarray analysis is being used to identify putative downstream target genes involved in mediating spatial-specific phytochrome responses. This research is expanding our understanding of sites of light perception, the mechanisms through which various tissues or organs cooperate in light-regulated plant growth and development, and advancing the molecular dissection of complex phytochrome-mediated cell-to-cell signaling cascades.

Investigating Tissue- and Organ-specific Phytochrome Responses using FACS-assisted Cell-type Specific Expression Profiling in Arabidopsis thaliana

The molecular basis of spatial-specific phytochrome responses is being investigated using transgenic plants that exhibit tissue- and organ-specific phytochrome deficiencies. The isolation of specific cells exhibiting induced phytochrome chromophore depletion by Fluorescence-Activated Cell Sorting followed by microarray analyses is being utilized to identify genes involved in spatial-specific phytochrome responses.

Hücre tipi Özgül gösterilmeden FACS yardımlı kullanarak Doku ve Organ spesifik Fitokrom Yanıtları incelenmesi Arabidopsis thaliana</em

Light mediates an array of developmental and adaptive processes throughout the life cycle of a plant. Plants utilize light-absorbing molecules called ...

Single-cell Microinjection for Cell Communication Analysis

Gap junctions are intercellular channels that allow the communication of neighboring cells. This communication depends on the contribution of a hemichannel by each neighboring cell to form the gap junction. In mammalian cells, the hemichannel is formed by six connexins, monomers with four transmembrane domains and a C and N terminal within the cytoplasm. Gap junctions permit the exchange of ions, second messengers, and small metabolites. In addition, they have important roles in many forms of cellular communication within physiological processes such as synaptic transmission, heart contraction, cell growth and differentiation. We detail how to perform a single-cell microinjection of Lucifer Yellow to visualize cellular communication via gap-junctions in living cells. It is expected that in functional gap junctions, the dye will diffuse from the loaded cell to the connected cells. It is a very useful technique to study gap junctions since you can evaluate the diffusion of the fluorescence in real time. We discuss how to prepare the cells and the micropipette, how to use a micromanipulator and inject a low molecular weight fluorescent dye in an epithelial cell line.

We describe here how to perform a single-cell microinjection of Lucifer Yellow to visualize cellular communication via gap-junctions in living cells, and provide some useful tips. We expect that this paper will help everyone to evaluate the degree of cellular coupling due to functional gap junctions. Everything described here could be, in principle, adapted to other fluorescent dyes with molecular weight below 1,000 Daltons.

Hücre Haberleşme Analizi İçin Tek hücreli Mikroenjeksiyon

Gap junctions are intercellular channels that allow the communication of neighboring cells. This communication depends on the contribution of a ...

Micromanipulation Techniques Allowing Analysis of Morphogenetic Dynamics and Turnover of Cytoskeletal Regulators

Examining the spatiotemporal dynamics of proteins can reveal their functional importance in various contexts. In this article, it is discussed how fluorescent recovery after photobleaching (FRAP) and photoactivation techniques can be used to study the spatiotemporal dynamics of proteins in subcellular locations. We also show how these techniques enable straightforward determination of various parameters linked to actin cytoskeletal regulation and cell motility. Moreover, the microinjection of cells is additionally described as an alternative treatment (potentially preceding or complementing the aforementioned photomanipulation techniques) to trigger instantaneous effects of translocated proteins on cell morphology and function. Micromanipulation such as protein injection or local application of plasma membrane-permeable drugs or cytoskeletal inhibitors can serve as powerful tool to record immediate consequences of a given treatment on cell behavior at the single cell and subcellular level. This is exemplified here by immediate induction of lamellipodial cell edge protrusion by the injection of recombinant Rac1 protein, as established a quarter-century ago. In addition, we provide a protocol for determining the turnover of enhanced green fluorescent protein (EGFP)-VASP, an actin filament polymerase prominently accumulating at lamellipodial tips of B16-F1 cells, employing FRAP and including associated data analysis and curve fitting. We also present guidelines for estimating the rates of lamellipodial actin network polymerization, as exemplified by cells expressing EGFP-tagged &#946;-actin. Finally, instructions are given for how to investigate the rates of actin monomer mobility within the cell cytoplasm, followed by actin incorporation at sites of rapid filament assembly, such as the tips of protruding lamellipodia, using photoactivation approaches. None of these protocols is&#160;restricted to components or regulators of the actin cytoskeleton, but can easily be extended to explore in analogous fashion the spatiotemporal dynamics and function of proteins in various different subcellular structures or functional contexts.

We describe how micro- and photomanipulation techniques such as FRAP and photoactivation enable the determination of motility parameters and the spatiotemporal dynamics of proteins within migrating cells. Experimental readouts include subcellular dynamics and turnover of motility regulators or of the underlying actin cytoskeleton.

Morfogenetik dinamiklerini analiz ve hücre iskeleti düzenleyiciler ciro sağlayan Embriyolardan teknikleri

Examining the spatiotemporal dynamics of proteins can reveal their functional importance in various contexts. In this article, it is discussed how ...

TChIP-Seq: Cell-Type-Specific Epigenome Profiling

Epigenetic regulation plays central roles in gene expression. Since histone modification was discovered in the 1960s, its physiological and pathological functions have been extensively studied. Indeed, the advent of next-generation deep sequencing and chromatin immunoprecipitation (ChIP) via specific histone modification antibodies has revolutionized our view of epigenetic regulation across the genome. Conversely, tissues typically consist of diverse cell types, and their complex mixture poses analytic challenges to investigating the epigenome in a particular cell type. To address the cell type-specific chromatin state in a genome-wide manner, we recently developed tandem chromatin immunoprecipitation sequencing (tChIP-Seq), which is based on the selective purification of chromatin by tagged core histone proteins from cell types of interest, followed by ChIP-Seq. The goal of this protocol is the introduction of best practices of tChIP-Seq. This technique provides a versatile tool for tissue-specific epigenome investigation in diverse histone modifications and model organisms.

We describe a step-by-step protocol for tandem chromatin immunoprecipitation sequencing (tChIP-Seq) that enables the analysis of cell-type-specific genome-wide histone modification.

TChIP-Seq: Hücre türüne özgü Epigenome profil oluşturma

Epigenetic regulation plays central roles in gene expression. Since histone modification was discovered in the 1960s, its physiological and pathological ...

Assessment of Zebrafish Lens Nucleus Localization and Sutural Integrity

The zebrafish is uniquely suited to genetic manipulation and in vivo imaging, making it an increasingly popular model for reverse genetic studies and for generation of transgenics for in vivo imaging. These unique capabilities make the zebrafish an ideal platform to study ocular lens development and physiology. Our recent findings that an Aquaporin-0, Aqp0a, is required for stability of the anterior lens suture, as well as for the shift of the lens nucleus to the lens center with age led us to develop tools especially suited to analyzing the properties of zebrafish lenses. Here we outline detailed methods for lens dissection that can be applied to both larval and adult lenses, to prepare them for histological analysis, immunohistochemistry and imaging. We focus on analysis of lens suture integrity and cortical cell morphology and compare data generated from dissected lenses with data obtained from in vivo imaging of lens morphology made possible by a novel transgenic zebrafish line with a genetically encoded fluorescent marker. Analysis of dissected lenses perpendicular to their optical axis allows quantification of the relative position of the lens nucleus along the anterior-posterior axis. Movement of the lens nucleus from an initial anterior position to the center is required for normal lens optics in adult zebrafish. Thus, a quantitative measure of lens nuclear position directly correlates with its optical properties.

These protocols were developed to analyze cortical lens morphology, structural integrity of the zebrafish lens sutures in fixed and live lenses and to measure the position of the zebrafish lens nucleus along the anterior-posterior axis.

Zebrafish objektif Nucleus yerelleştirme ve sütür bütünlüğü değerlendirmesi

The zebrafish is uniquely suited to genetic manipulation and in vivo imaging, making it an increasingly popular model for reverse genetic studies and for ...

Cell Type-specific Gene Expression Profiling in the Mouse Liver

Liver repopulation after injury is a crucial feature of mammals which prevents immediate organ failure and death after exposure of environmental toxins. A deeper understanding of the changes in gene expression that occur during repopulation could help identify therapeutic targets to promote the restoration of liver function in the setting of injuries. Nonetheless, methods to isolate specifically the repopulating hepatocytes are inhibited by a lack of cell markers, limited cell numbers, and the fragility of these cells. The development of translating ribosome affinity purification (TRAP) technology in conjunction with the Fah-/- mouse model to recapitulate repopulation in the setting of liver injury allows gene expression profiling of the repopulating hepatocytes. With TRAP, cell type-specific translating mRNA is rapidly and efficiently isolated. We developed a method that utilizes TRAP with affinity-based isolation of translating mRNA from hepatocytes that selectively express the green fluorescent protein (GFP)-tagged ribosomal protein (RP), GFP:RPL10A. TRAP circumvents the long time period required for fluorescence-activated cell sorting that could change the gene expression profile. Furthermore, since only the repopulating hepatocytes express the GFP:RPL10A fusion protein, the isolated mRNA is devoid of contamination from the surrounding injured hepatocytes and other cell types in the liver. The affinity-purified mRNA is of high quality and allows downstream PCR- or high-throughput sequencing-based analysis of gene expression.

Translating ribosome affinity purification (TRAP) enables rapid and efficient isolation of cell type-specific translating mRNA. Here, we demonstrate a method that combines hydrodynamic tail-vein injection in a mouse model of liver repopulation and TRAP to examine the expression profile of repopulating hepatocytes.

Fare Karaciğerinde Hücre Tipine Özgü Gen Ekspresyonu Profiloluşturma

Liver repopulation after injury is a crucial feature of mammals which prevents immediate organ failure and death after exposure of environmental toxins. A ...

The CryoAPEX Method for Electron Microscopy Analysis of Membrane Protein Localization Within Ultrastructurally-Preserved Cells

Key cellular events like signal transduction and membrane trafficking rely on proper protein location within cellular compartments. Understanding precise subcellular localization of proteins is thus important for answering many biological questions. The quest for a robust label to identify protein localization combined with adequate cellular preservation and staining has been historically challenging. Recent advances in electron microscopy (EM) imaging have led to the development of many methods and strategies to increase cellular preservation and label target proteins. A relatively new peroxidase-based genetic tag, APEX2, is a promising leader in cloneable EM-active tags. Sample preparation for transmission electron microscopy (TEM) has also advanced in recent years with the advent of cryofixation by high pressure freezing (HPF) and low-temperature dehydration and staining via freeze substitution (FS). HPF and FS provide excellent preservation of cellular ultrastructure for TEM imaging, second only to direct cryo-imaging of vitreous samples. Here we present a protocol for the cryoAPEX method, which combines the use of the APEX2 tag with HPF and FS. In this protocol, a protein of interest is tagged with APEX2, followed by chemical fixation and the peroxidase reaction. In place of traditional staining and alcohol dehydration at room temperature, the sample is cryofixed and undergoes dehydration and staining at low temperature via FS. Using cryoAPEX, not only can a protein of interest be identified within subcellular compartments, but also additional information can be resolved with respect to its topology within a structurally preserved membrane. We show that this method can provide high enough resolution to decipher protein distribution patterns within an organelle lumen, and to distinguish the compartmentalization of a protein within one organelle in close proximity to other unlabeled organelles. Further, cryoAPEX is procedurally straightforward and amenable to cells grown in tissue culture. It is no more technically challenging than typical cryofixation and freeze substitution methods. CryoAPEX is widely applicable for TEM analysis of any membrane protein that can be genetically tagged.

This protocol describes the cryoAPEX method, in which an APEX2-tagged membrane protein can be localized by transmission electron microscopy within optimally-preserved cell ultrastructure.

Ultrayapısal Olarak Korunmuş Hücrelerde Membran Protein Lokalizasyonunun Elektron Mikroskobu Analizi için CryoAPEX Yöntemi

Key cellular events like signal transduction and membrane trafficking rely on proper protein location within cellular compartments. Understanding precise ...

Analyzing the &alpha;-Actinin Network in Human iPSC-Derived Cardiomyocytes Using Single Molecule Localization Microscopy

The maturation of iPSC-derived cardiomyocytes is a critical issue for their application in regenerative therapy, drug testing and disease modeling. Despite the development of multiple differentiation protocols, the generation of iPSC cardiomyocytes resembling an adult-like phenotype remains challenging. One major aspect of cardiomyocytes maturation involves the formation of a well-organized sarcomere network to ensure high contraction capacity. Here, we present a super resolution-based approach for semi-quantitative analysis of the &#945;-actinin network in cardiomyocytes. Using photoactivated localization microscopy a comparison of sarcomere length and z-disc thickness of iPSC-derived cardiomyocytes and cardiac cells isolated from neonatal tissue was performed. At the same time, we demonstrate the importance of proper imaging conditions to obtain reliable data. Our results show that this method is suitable to quantitatively monitor the structural maturity of cardiac cells with high spatial resolution, enabling the detection of even subtle changes of sarcomere organization.

Analyzing the &amp;#945;-Actinin Network in Human iPSC-Derived Cardiomyocytes Using Single Molecule Localization Microscopy

The formation of a proper sarcomere network is important for the maturation of iPSC-derived cardiomyocytes. We present a super resolution-based approach that allows for the quantitative evaluation of the structural maturation of stem cell derived cardiomyocytes, to improve culture conditions promoting cardiac development.

Tek Moleküllü Lokalizasyon Mikroskobu Kullanılarak İnsan iPSC Kaynaklı Kardiyomiyositlerde α-Aktinin Ağının Analizi

The maturation of iPSC-derived cardiomyocytes is a critical issue for their application in regenerative therapy, drug testing and disease modeling. ...