Bu eser Risk değerlendirmesi (BfR) Alman Federal Enstitüsü tarafından finanse edildi.

<ol>
	<li>Seok, 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=Genomic+responses+in+mouse+models+poorly+mimic+human+inflammatory+diseases.">Genomic responses in mouse models poorly mimic human inflammatory diseases.</a> Proc Natl Acad Sci U S A. 110 (9), 3507-3512 (2013).</li><li>Takao, K., Miyakawa, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genomic+responses+in+mouse+models+greatly+mimic+human+inflammatory+diseases.">Genomic responses in mouse models greatly mimic human inflammatory diseases.</a> Proc Natl Acad Sci U S A. 112 (4), 1167-1172 (2015).</li><li>Weidner, C., Steinfath, M., Opitz, E., Oelgeschl&#228;ger, M., Sch&#246;nfelder, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defining+the+optimal+animal+model+for+translational+research+using+gene+set+enrichment+analysis.">Defining the optimal animal model for translational research using gene set enrichment analysis.</a> EMBO Mol Med. 8 (8), 831-838 (2016).</li><li>Subramanian, 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=Gene+set+enrichment+analysis:+a+knowledge-based+approach+for+interpreting+genome-wide+expression+profiles.">Gene set enrichment analysis: a knowledge-based approach for interpreting genome-wide expression profiles.</a> Proc Natl Acad Sci U S A. 102 (43), 15545-15550 (2005).</li><li>Kanehisa, M., Sato, Y., Kawashima, M., Furumichi, M., Tanabe, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=KEGG+as+a+reference+resource+for+gene+and+protein+annotation.">KEGG as a reference resource for gene and protein annotation.</a> Nucleic Acids Res. 44 (D1), D457-D462 (2016).</li><li>Kanehisa, M., Goto, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=KEGG:+kyoto+encyclopedia+of+genes+and+genomes.">KEGG: kyoto encyclopedia of genes and genomes.</a> Nucleic Acids Res. 28 (1), 27-30 (2000).</li><li>Fabregat, 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+Reactome+pathway+Knowledgebase.">The Reactome pathway Knowledgebase.</a> Nucleic Acids Res. 44 (D1), D481-D487 (2016).</li><li>Croft, 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=The+Reactome+pathway+knowledgebase.">The Reactome pathway knowledgebase.</a> Nucleic Acids Res. 42 (Database issue), D472-D477 (2014).</li><li>Nishimura, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BioCarta.">BioCarta.</a> Biotech Software &amp; Internet Report. 2 (3), 117-120 (2001).</li><li>Edgar, R., Domrachev, M., Lash, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+Expression+Omnibus:+NCBI+gene+expression+and+hybridization+array+data+repository.">Gene Expression Omnibus: NCBI gene expression and hybridization array data repository.</a> Nucleic Acids Res. 30 (1), 207-210 (2002).</li><li>Kolesnikov, N., 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=ArrayExpress+update--simplifying+data+submissions.">ArrayExpress update--simplifying data submissions.</a> Nucleic Acids Res. 43 (Database issue), D1113-D1116 (2015).</li><li>Cohen, 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=Sepsis:+a+roadmap+for+future+research.">Sepsis: a roadmap for future research.</a> Lancet Infect Dis. 15 (5), 581-614 (2015).</li><li>Spinelli, L., Carpentier, S., Montanana Sanchis, F., Dalod, M., Vu Manh, T. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BubbleGUM:+automatic+extraction+of+phenotype+molecular+signatures+and+comprehensive+visualization+of+multiple+Gene+Set+Enrichment+Analyses.">BubbleGUM: automatic extraction of phenotype molecular signatures and comprehensive visualization of multiple Gene Set Enrichment Analyses.</a> BMC Genomics. 16 (1), 814 (2015).</li></ol>

Yazarlar onlar rakip hiçbir mali çıkarları var bildirin.

Hayvan modelleri uzun hastalık mekanizmaları incelenmesi ve roman tedavi stratejilerinin geliştirilmesi için uygulandı. Ancak, şüphecilik hayvan modellerin predictivity ilgili klinik çalışmalar12sayısının yayılmaya başladı. Ayrıca, çözümlemek ve preklinik denemeler büyük omics verileri yorumlama için uygun stratejiler hakkında tartışmalı tartışmalar ters sonuçlar aynı verilerden farklı veri analizi stratejileri1 uygulandıktan sonra çizilmiş tara...

Hayvan modelleri yaygın insan hastalıkları, genetik, anatomi ve Fizyoloji bakımından insanlara kabul onların benzerlik nedeniyle incelemek için kullanılır. Ayrıca, hayvan modelleri genellikle ağ geçidi denetleyicileri için klinik tedaviler olarak hizmet ve translasyonel araştırma başarısı üzerinde büyük bir etkisi olabilir. En iyi hayvan modeli dikkatli seçimi yanıltıcı hayvan çalışmaları sayısını azaltabilirsiniz. Özellikle insan inflamatuar hastalıkları ve ilgili fare modelleri elde aynı veri kümeleri çözümleme çelişkili sonuçlara yol açtı çünkü son zamanlarda, hayvan modellerinde translasyonel araştırma uygunluğu tartışmalı, tartışıldı 1,2. Bu tartışma omics veri çözümleme sırasında temel bir sorun ortaya: sistematik veri analizi için standart yaklaşımları önyargılı gen seçim azaltmak için ve türler arası karşılaştırmalar 3sağlamlığı artırmak için ihtiyaç vardır.
Geleneksel olarak, transcriptomics veri (ve diğer omics veri) analizi tek gen düzeyinde yapılır ve gen seçim sıkı kesme parametrelere dayalı bir ilk adım içerir (örneğin, kat değişiklik &#62; 2.0, p değeri &#60; 0,05). Ancak, ilk kesme parametrelerinin ayarı kez öznel, rasgele ve biyolojik olarak haklı olduğunu ve ters sonuçlar1,2bile yol açabilir. Ayrıca, ilk gen seçim genellikle analizi birkaç son derece yukarı - ve downregulated genler için kısıtlar ve böylece differentially daha az bir ölçüde ifade edildi genler çoğunluğu dahil etmek için duyarlı değildir.
2000'lerin genomik dönemi yükselişi ve biyolojik yollar ve bağlamlarda artan bilgi ile alternatif istatistiksel yaklaşımlar tek gen düzeyinde analizler sınırlamaları aşmak için izin geliştirilmiştir. Gene transcriptomics veri analizi için yaygın olarak kabul edilen yöntemlerden biri zenginleştirme analiz (GSEA)4, ayarla, priori bir tanımlı grupların genlerin (yollar, bir kromozom vb proksimal konumunda sinyalörneğin,.) kullanır. GSEA ilk ifade onların bireysel değişiklik bakılmaksızın tüm algılanan filtre uygulanmamış genler (örneğin, yollar), hedeflenen gen kümeleri için eşleştirir. Bu yaklaşım böylece Ayrıca aksi takdirde tek gen düzeyinde analizler ile kayıp olacağını orta düzenlenmiş genden oluşmaktadır. İfade gen kümeleri içinde katkı maddesi değişikliği daha sonra çalışan toplam istatistikleri kullanılarak gerçekleştirilir.
Tıbbi araştırma rağmen geniş kullanımı, GSEA ve ilgili küme zenginleştirme yaklaşımlar bakarsanız karmaşık omics veri analizi için dikkate alınmaz. Burada, biz translasyonel çalışmaları için ideal modeli tanımlamak için bu fare modelleri ile insan örnekleri omics verileri karşılaştırmak için bir protokol tanımlamak. Biz insan enflamatuar bozuklukları taklit için kullanılan fare modelleri topluluğu dayalı İletişim Kuralı Uygulanabilirlik göstermek. Ancak, bu analiz boru hattı insan-fare karşılaştırmalar için sınırlı değildir ve daha fazla iyileştirilebilir araştırma soruları.

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a protocol for using gene set enrichment analysis to identify the appropriate animal model for translational research

İnsan hastalıkları transcriptomic veri kümeleri veri geleneksel gen gen karşılaştırma teknikleri kullanarak fare modelleri ile karşılaştırıldığında son yıllarda yapılan çalışmalarda hayvan modellerinde alaka ile ilgili çelişkili sonuçlar sonuçlandı translasyonel araştırma. Rasgele differentially ifade genler filtreleme farklı gen ifade analizleri arasındaki farklılıkları için önemli bir nedeni var. Ayrıca, farklı tür ve genellikle platformlar arasında tek gen karşılaştırılması con/uyumsuzluk yanlış yorumlanmasına yol insan ve hayvan modellerinden veri arasında önde gelen teknik farkı ile sınırlıdır. Böylece, standart yaklaşımları sistematik veri analizi için ihtiyaç vardır. Öznel gen filtreleme ve etkisiz gen gen karşılaştırma üstesinden gelmek için biz son zamanlarda gen kümesi zenginleştirme analiz (GSEA) bu sorunları önlemek için potansiyele sahip olduğunu gösterdi. Bu nedenle, biz translasyonel araştırma için uygun ve uygun olmayan hayvan modelleri arasında ayırt etmek için GSEA kullanımı için bir standart iletişim kuralı geliştirilmiştir. Bu iletişim kuralı olarak varolan deneysel omics veri gerektirir bir-priori, yeni model sistemleri nasıl tahmin etmek uygun değildir. Ancak, protokol böylece gereksiz hayvan deneyleri kaçınarak ve çevirim çalışmalar yanıltıcı en uygun hayvan modeli seçmek için standart bir şekilde varolan verileri yorumlamak açıklar.

GSEA iş akışı ve ekran örnek veri içinde gösterilen. Şekil 1 transcriptomic veri ilgi içeren gen ifade veri dosyası gösterir. Her çalışma bir açıklayıcı fenotip dosyası gerekli olduğu için bu Şekil 2' de gösterilmiştir. Ek açıklama eklenen gen kümeleri (örneğin, yollar) (şekil 3) gen küme veritabanı dosyasında tanımlanır. Şekil 4</stro...

Watch this Scientific Journal Video about A Protocol for Using Gene Set Enrichment Analysis to Identify the Appropriate Animal Model for Translational Research at JoVE.com

A Protocol for Using Gene Set Enrichment Analysis to Identify the Appropriate Animal Model for Translational Research

Gen kümesi zenginleştirme translasyonel araştırma için bir ideal fare modeli tanımlamak için transcriptomic veri analizini kullanımına ilişkin standart bir protokol sağlar. Bu iletişim kuralı ve DNA Mikroarray ve RNA sıralama veri ile kullanılabilir veri yoksa diğer omics veri için daha da uzatılabilir.

Gen kullanmak için bir protokol translasyonel araştırma için uygun hayvan modeli belirlemek için zenginleştirme çözümlemesi ayarla

Recent studies that compared transcriptomic datasets of human diseases with datasets from mouse models using traditional gene-to-gene comparison ...

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Research

JoVE Journal

Biology

17.7K Görüntüleme.  German Federal Institute for Risk Assessment (BfR). Gen kümesi zenginleştirme translasyonel araştırma için bir ideal fare modeli tanımlamak için transcriptomic veri analizini kullanımına ilişkin standart bir protokol sağlar.Bu iletişim kuralı ve DNA Mikroarray ve RNA sıralama veri ile kullanılabilir veri yoksa diğer omics veri için daha da uzatılabilir.

Video: A Protocol for Using Gene Set Enrichment Analysis to Identify the Appropriate Animal Model for Translational Research

Testing Visual Sensitivity to the Speed and Direction of Motion in Lizards

Testing visual sensitivity in any species provides basic information regarding behaviour, evolution, and ecology. However, testing specific features of the visual system provide more empirical evidence for functional applications. Investigation into the sensory system provides information about the sensory capacity, learning and memory ability, and establishes known baseline behaviour in which to gauge deviations (Burghardt, 1977). However, unlike mammalian or avian systems, testing for learning and memory in a reptile species is difficult. Furthermore, using an operant paradigm as a psychophysical measure of sensory ability is likewise as difficult. Historically, reptilian species have responded poorly to conditioning trials because of issues related to motivation, physiology, metabolism, and basic biological characteristics. Here, I demonstrate an operant paradigm used a novel model lizard species, the Jacky dragon (Amphibolurus muricatus) and describe how to test peripheral sensitivity to salient speed and motion characteristics. This method uses an innovative approach to assessing learning and sensory capacity in lizards. I employ the use of random-dot kinematograms (RDKs) to measure sensitivity to speed, and manipulate the level of signal strength by changing the proportion of dots moving in a coherent direction. RDKs do not represent a biologically meaningful stimulus, engages the visual system, and is a classic psychophysical tool used to measure sensitivity in humans and other animals. Here, RDKs are displayed to lizards using three video playback systems. Lizards are to select the direction (left or right) in which they perceive dots to be moving. Selection of the appropriate direction is reinforced by biologically important prey stimuli, simulated by computer-animated invertebrates.

Testing visual sensitivity in lizards using an operant conditioning paradigm that employs video playback of random-dot kinematograms and computer-generated invertebrates.

Kertenkeleler Hareket Hız ve Yön Visual Hassasiyet Test

Testing visual sensitivity in any species provides basic information regarding behaviour, evolution, and ecology. However, testing specific features of ...

Biyoloji

Computer-Generated Animal Model Stimuli

Communication between animals is diverse and complex. Animals may communicate using auditory, seismic, chemosensory, electrical, or visual signals. In particular, understanding the constraints on visual signal design for communication has been of great interest. Traditional methods for investigating animal interactions have used basic observational techniques, staged encounters, or physical manipulation of morphology. Less intrusive methods have tried to simulate conspecifics using crude playback tools, such as mirrors, still images, or models. As technology has become more advanced, video playback has emerged as another tool in which to examine visual communication (Rosenthal, 2000). However, to move one step further, the application of computer-animation now allows researchers to specifically isolate critical components necessary to elicit social responses from conspecifics, and manipulate these features to control interactions. Here, I provide detail on how to create an animation using the Jacky dragon as a model, but this process may be adaptable for other species. In building the animation, I elected to use Lightwave  3D to alter object morphology, add texture, install bones, and provide comparable weight shading that prevents exaggerated movement. The animation is then matched to select motor patterns to replicate critical movement features. Finally, the sequence must rendered into an individual clip for presentation. Although there are other adaptable techniques, this particular method had been demonstrated to be effective in eliciting both conspicuous and social responses in staged interactions.

Computer-generated stimuli using the Jacky dragon as a model.

Bilgisayar oluşturuldu Hayvan Modeli Uyaranlar

Communication between animals is diverse and complex. Animals may communicate using auditory, seismic, chemosensory, electrical, or visual signals. In ...

Automated Microfluidic Blood Lysis Protocol for Enrichment of Circulating Nucleated Cells

In this report the protocol for an automated microfluidic blood lysis device is detailed. Circulating nucleated cells (CNCs), including leukocytes and endothelial cells, provide an ideal platform for an updated status on the immune condition of an individual. The microfluidic protocol allows for enrichment of CNCs without selective cell loss and sample preparation variability due to user-mediated steps. Briefly, the protocol includes device fabrication, sample collection, device setup, and running blood through the microfluidic chamber. Within the device whole blood is rapidly mixed with deionized water for approximately 10 seconds in a 50 micron x 150 micron microfluidic channel. In this time span erythrocytes are lysed due to hypotonic conditions. Herringbone structures on the bottom of the channel ensure thorough mixing and exposure of cells to a constant environment. Remaining cells are returned to isotonic conditions at the exit of the device, fixed using 2% paraformaldehyde, centrifuged to separate erythrocyte debris from CNCs, and suspended in flow buffer for staining and analysis by flow cytometry. Results show clean flow cytometry scatter plots with CNC populations saved. Significance of this device and protocol comes in the study and understanding of disease pathogenesis by analysis of CNC populations. Hence, automation, effectiveness, and simplicity of the microfluidic protocol are demonstrated.

An automated microfluidic device was developed for circulating nucleated cell enrichment from peripheral blood via erythrocyte lysis that ensures isolation of high quality sample without cell loss.

Çekirdekli Hücreler Sirkülasyon zenginleştirilmesi için Otomatik mikroakışkan Kan Lizis Protokolü

In this report the protocol for an automated microfluidic blood lysis device is detailed. Circulating nucleated cells (CNCs), including leukocytes and ...

Using the Gene Pulser MXcell Electroporation System to Transfect Primary Cells with High Efficiency

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser MXcell electroporation system and Gene Pulser electroporation buffer (Bio-Rad) were specifically developed to easily transfect nucleic acids into mammalian cells and difficult-to-transfect cells, such as primary and stem cells. We will demonstrate how to perform a simple experiment to quickly identify the best electroporation conditions. We will demonstrate how to run several samples through a range of electroporation conditions so that an experiment can be conducted at the same time as optimization is performed. We will also show how optimal conditions identified using 96-well electroporation plates can be used with standard electroporation cuvettes, facilitating the switch from electroporation plates to electroporation cuvettes while maintaining the same electroporation efficiency. In the video, we will also discuss some of the key factors that can lead to the success or failure of electroporation experiments.

This procedure shows how to use the Gene Pulser MXcell electroporation system to rapidly and easily identify the best electroporation conditions for mouse embryonic fibroblasts (MEFs) or other primary cells. Considerations for troubleshooting are also discussed in the associated video.

Yüksek Verimli Primer Hücre Transfect Gen Verici MXcell Elektroporasyon Sistemi

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser ...

Genome-wide Analysis using ChIP to Identify Isoform-specific Gene Targets

Recruitment of transcriptional and epigenetic factors to their targets is a key step in their regulation. Prominently featured in recruitment are the protein domains that bind to specific histone modifications. One such domain is the plant homeodomain (PHD), found in several chromatin-binding proteins. The epigenetic factor RBP2 has multiple PHD domains, however, they have different functions (Figure 4). In particular, the C-terminal PHD domain, found in a RBP2 oncogenic fusion in human leukemia, binds to trimethylated lysine 4 in histone H3 (H3K4me3)1. The transcript corresponding to the RBP2 isoform containing the C-terminal PHD accumulates during differentiation of promonocytic, lymphoma-derived, U937 cells into monocytes2. Consistent with both sets of data, genome-wide analysis showed that in differentiated U937 cells, the RBP2 protein gets localized to genomic regions highly enriched for H3K4me33. Localization of RBP2 to its targets correlates with a decrease in H3K4me3 due to RBP2 histone demethylase activity and a decrease in transcriptional activity. In contrast, two other PHDs of RBP2 are unable to bind H3K4me3. Notably, the C-terminal domain PHD of RBP2 is absent in the smaller RBP2 isoform4. It is conceivable that the small isoform of RBP2, which lacks interaction with H3K4me3, differs from the larger isoform in genomic location. The difference in genomic location of RBP2 isoforms may account for the observed diversity in RBP2 function. Specifically, RBP2 is a critical player in cellular differentiation mediated by the retinoblastoma protein (pRB). Consistent with these data, previous genome-wide analysis, without distinction between isoforms, identified two distinct groups of RBP2 target genes: 1) genes bound by RBP2 in a manner that is independent of differentiation; 2) genes bound by RBP2 in a differentiation-dependent manner.
To identify differences in localization between the isoforms we performed genome-wide location analysis by ChIP-Seq. Using antibodies that detect both RBP2 isoforms we have located all RBP2 targets. Additionally we have antibodies that only bind large, and not small RBP2 isoform (Figure 4). After identifying the large isoform targets, one can then subtract them from all RBP2 targets to reveal the targets of small isoform. These data show the contribution of chromatin-interacting domain in protein recruitment to its binding sites in the genome.

Here we are presenting a chromatin immunoprecipitation (ChIP) procedure for genome-wide location analysis of protein isoforms that differ in a histone-binding domain. We are applying it to ChIP-Seq analysis to identify the targets of the KDM5A/JARID1A/RBP2 histone demethylase.

Izoform özel Gen Hedefler Belirlemek için ChIP kullanarak genom analizi

Recruitment of transcriptional and epigenetic factors to their targets is a key step in their regulation. Prominently featured in recruitment are the ...

Isolation of Ribosome Bound Nascent Polypeptides in vitro to Identify Translational Pause Sites Along mRNA

The rate of translational elongation is non-uniform. mRNA secondary structure, codon usage and mRNA associated proteins may alter ribosome movement on the messagefor review see 1. However, it's now widely accepted that synonymous codon usage is the primary cause of non-uniform translational elongation rates1. Synonymous codons are not used with identical frequency. A bias exists in the use of synonymous codons with some codons used more frequently than others2. Codon bias is organism as well as tissue specific2,3. Moreover, frequency of codon usage is directly proportional to the concentrations of cognate tRNAs4. Thus, a frequently used codon will have higher multitude of corresponding tRNAs, which further implies that a frequent codon will be translated faster than an infrequent one. Thus, regions on mRNA enriched in rare codons (potential pause sites) will as a rule slow down ribosome movement on the message and cause accumulation of nascent peptides of the respective sizes5-8. These pause sites can have functional impact on the protein expression, mRNA stability and protein foldingfor review see 9. Indeed, it was shown that alleviation of such pause sites can alter ribosome movement on mRNA and subsequently may affect the efficiency of co-translational (in vivo) protein folding1,7,10,11. To understand the process of protein folding in vivo, in the cell, that is ultimately coupled to the process of protein synthesis it is essential to gain comprehensive insights into the impact of codon usage/tRNA content on the movement of ribosomes along mRNA during translational elongation.
Here we describe a simple technique that can be used to locate major translation pause sites for a given mRNA translated in various cell-free systems6-8. This procedure is based on isolation of nascent polypeptides accumulating on ribosomes during in vitro translation of a target mRNA. The rationale is that at low-frequency codons, the increase in the residence time of the ribosomes results in increased amounts of nascent peptides of the corresponding sizes. In vitro transcribed mRNA is used for in vitro translational reactions in the presence of radioactively labeled amino acids to allow the detection of the nascent chains. In order to isolate ribosome bound nascent polypeptide complexes the translation reaction is layered on top of 30% glycerol solution followed by centrifugation. Nascent polypeptides in polysomal pellet are further treated with ribonuclease A and resolved by SDS PAGE. This technique can be potentially used for any protein and allows analysis of ribosome movement along mRNA and the detection of the major pause sites. Additionally, this protocol can be adapted to study factors and conditions that can alter ribosome movement and thus potentially can also alter the function/conformation of the protein.

Isolation of Ribosome Bound Nascent Polypeptides in vitro to Identify Translational Pause Sites Along mRNA

A technique to identify translational pause sites on mRNA is described. This procedure is based on isolation of nascent polypeptides accumulating on ribosomes during in vitro translation of a target mRNA, followed by the size analysis of the nascent chains using a denaturing gel electrophoresis.

Ribozom Bağlı Doğan Polipeptitler İzolasyonu<em&gt; In vitro</em&gt; MRNA boyunca Translasyonel Duraklat Siteleri Belirleme

The rate of translational elongation is non-uniform. mRNA secondary structure, codon usage and mRNA associated proteins may alter ribosome movement on the ...

Using SecM Arrest Sequence as a Tool to Isolate Ribosome Bound Polypeptides

Extensive research has provided ample evidences suggesting that protein folding in the cell is a co-translational process1-5. However, the exact pathway that polypeptide chain follows during co-translational folding to achieve its functional form is still an enigma. In order to understand this process and to determine the exact conformation of the co-translational folding intermediates, it is essential to develop techniques that allow the isolation of RNCs carrying nascent chains of predetermined sizes to allow their further structural analysis.
SecM (secretion monitor) is a 170 amino acid E. coli protein that regulates expression of the downstream SecA (secretion driving) ATPase in the secM-secA operon6. Nakatogawa and Ito originally found that a 17 amino acid long sequence (150-FSTPVWISQAQGIRAGP-166) in the C-terminal region of the SecM protein is sufficient and necessary to cause stalling of SecM elongation at Gly165, thereby producing peptidyl-glycyl-tRNA stably bound to the ribosomal P-site7-9. More importantly, it was found that this 17 amino acid long sequence can be fused to the C-terminus of virtually any full-length and/or truncated protein thus allowing the production of RNCs carrying nascent chains of predetermined sizes7. Thus, when fused or inserted into the target protein, SecM stalling sequence produces arrest of the polypeptide chain elongation and generates stable RNCs both in vivo in E. coli cells and in vitro in a cell-free system. Sucrose gradient centrifugation is further utilized to isolate RNCs.
The isolated RNCs can be used to analyze structural and functional features of the co-translational folding intermediates. Recently, this technique has been successfully used to gain insights into the structure of several ribosome bound nascent chains10,11. Here we describe the isolation of bovine Gamma-B Crystallin RNCs fused to SecM and generated in an in vitro translation system.

We describe here a technique that is now routinely used to isolate stably bound ribosome nascent chain complexes (RNCs). This technique takes advantage of the discovery that a 17 amino acid long SecM "arrest sequence" can halt translation elongation in a prokaryotic (E. coli) system, when inserted into (or fused to the C-terminus) of virtually any protein.

Ribozom Ciltli Polipeptitler izole bir aracı olarak SECM Tutuklanma sırası kullanılarak

Extensive research has provided ample evidences suggesting that protein folding in the cell is a co-translational process1-5. However, the exact pathway ...

A Protocol for Lentiviral Transduction and Downstream Analysis of Intestinal Organoids

Intestinal crypt-villus structures termed organoids, can be kept in sustained culture three dimensionally when supplemented with the appropriate growth factors. Since organoids are highly similar to the original tissue in terms of homeostatic stem cell differentiation, cell polarity and presence of all terminally differentiated cell types known to the adult intestinal epithelium, they serve as an essential resource in experimental research on the epithelium. The possibility to express transgenes or interfering RNA using lentiviral or retroviral vectors in organoids has increased opportunities for functional analysis of the intestinal epithelium and intestinal stem cells, surpassing traditional mouse transgenics in speed and cost. In the current video protocol we show how to utilize transduction of small intestinal organoids with lentiviral vectors illustrated by use of doxycylin inducible transgenes, or IPTG inducible short hairpin RNA for overexpression or gene knockdown. Furthermore, considering organoid culture yields minute cell counts that may even be reduced by experimental treatment, we explain how to process organoids for downstream analysis aimed at quantitative RT-PCR, RNA-microarray and immunohistochemistry. Techniques that enable transgene expression and gene knock down in intestinal organoids contribute to the research potential that these intestinal epithelial structures hold, establishing organoid culture as a new standard in cell culture.

In this video protocol we give a step by step explanation of lentiviral transduction in organoids of primary intestinal epithelium and of processing and downstream analysis of these cultures by quantitative RT-PCR, RNA-microarray and immunohistochemistry.

Lentiviral İletim ve Bağırsak Organoids Mansabında Analizi için Protokol

Intestinal crypt-villus structures termed organoids, can be kept in sustained culture three dimensionally when supplemented with the appropriate growth ...

Xenopus laevis as a Model to Identify Translation Impairment

Protein synthesis is a fundamental process to gene expression impacting diverse biological processes notably adaptation to environmental conditions. The initiation step, which involves the assembly of the ribosomal subunits at the mRNA initiation codon, involved initiation factor including eIF4G1. Defects in this rate limiting step of translation are linked to diverse disorders. To study the potential consequences of such deregulations, Xenopus laevis oocytes constitute an attractive model with high degrees of conservation of essential cellular and molecular mechanisms with human. In addition, during meiotic maturation, oocytes are transcriptionally repressed and all necessary proteins are translated from preexisting, maternally derived mRNAs. This inexpensive model enables exogenous mRNA to become perfectly integrated with an effective translation. Here is described a protocol for assessing translation with a factor of interest (here eIF4G1) using stored maternal mRNA that are the first to be polyadenylated and translated during oocyte maturation as a physiological readout. At first, mRNA synthetized by in vitro transcription of plasmids of interest (here eIF4G1) are injected in oocytes and kinetics of oocyte maturation by Germinal Vesicle Breakdown detection is determined. The studied maternal mRNA target is the serine/threonine-protein-kinase mos. Its polyadenylation and its subsequent translation are investigated together with the expression and phosphorylation of proteins of the mos signaling cascade involved in oocyte maturation. Variations of the current protocol to put forward translational defects are also proposed to emphasize its general applicability. In light of emerging evidence that aberrant protein synthesis may be involved in the pathogenesis of neurological disorders, such a model provides the opportunity to easily assess this impairment and identify new targets.

Xenopus laevis as a Model to Identify Translation Impairment

Protein synthesis control occurs mainly at the translation initiation step, deficiencies in which are linked to diverse disorders. To better understand their etiology, we described here a protocol using Xenopus laevis oocytes assessing the translation of mos transcript in the presence of a mutant of translation initiation factor eIF4G1.

Ksenopus Translation Düşüklüğü Belirlemek için Bir Model Olarak laevis

Protein synthesis is a fundamental process to gene expression impacting diverse biological processes notably adaptation to environmental conditions. The ...

Complete Workflow for Analysis of Histone Post-translational Modifications Using Bottom-up Mass Spectrometry: From Histone Extraction to Data Analysis

Nucleosomes are the smallest structural unit of chromatin, composed of 147 base pairs of DNA wrapped around an octamer of histone proteins. Histone function is mediated by extensive post-translational modification by a myriad of nuclear proteins. These modifications are critical for nuclear integrity as they regulate chromatin structure and recruit enzymes involved in gene regulation, DNA repair and chromosome condensation. Even though a large part of the scientific community adopts antibody-based techniques to characterize histone PTM abundance, these approaches are low throughput and biased against hypermodified proteins, as the epitope might be obstructed by nearby modifications. This protocol describes the use of nano liquid chromatography (nLC) and mass spectrometry (MS) for accurate quantification of histone modifications. This method is designed to characterize a large variety of histone PTMs and the relative abundance of several histone variants within single analyses. In this protocol, histones are derivatized with propionic anhydride followed by digestion with trypsin to generate peptides of 5 - 20 aa in length. After digestion, the newly exposed N-termini of the histone peptides are derivatized to improve chromatographic retention during nLC-MS. This method allows for the relative quantification of histone PTMs spanning four orders of magnitude.

This protocol outlines a fully integrated workflow for characterizing histone post-translational modifications using mass spectrometry (MS). The workflow includes histone purification from cell cultures or tissues, histone derivatization and digestion, MS analysis using nano-flow liquid chromatography and instructions for data analysis. The protocol is designed for completion within 2 - 3 days.

Histon Ekstraksiyon Gönderen Data Analizi: Aşağıdan yukarıya Kütle Spektrometre kullanarak histon post-translasyonel modifikasyonlar Analizi için komple iş akışı

Nucleosomes are the smallest structural unit of chromatin, composed of 147 base pairs of DNA wrapped around an octamer of histone proteins. Histone ...