Name: a cell-free assay using xenopus laevis embryo extracts to study mechanisms of nuclear size regulation
Uploaded: 2016-08-08T14:00:00.000+00:00
Duration: 14 min 27 s
Description: Watch this Scientific Journal Video about A Cell-Free Assay Using Xenopus laevis Embryo Extracts to Study Mechanisms of Nuclear Size Regulation at JoVE.com

Members of the Levy and Gatlin labs as well as colleagues in the Department of Molecular Biology offered helpful advice and discussions. Rebecca Heald provided support in the early stages of developing this protocol. This work was supported by the NIH/NIGMS (R15GM106318) and the American Cancer Society (RSG-15-035-01-DDC).

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The authors have nothing to disclose.

Here is presented a novel method to study mechanisms of nuclear size regulation during X. laevis development. Developmental progression is associated with dramatic changes in cell physiology, metabolism, division rates, and migration, as well as alterations in the sizes of cells and intracellular structures. These varied processes are complex and essential, so it is difficult to study just one of these aspects of development in an in vivo setting. The X. laevis embryo extract and nuclear shrink...

أحجام العضيات الخلوية تحجيم عادة مع حجم الخلية، وهذا قد ربما أفضل موثقة لتدرج حجم النووي مع حجم الخلية 1-10. هذا صحيح بشكل خاص خلال مرحلة التطور الجنيني وتمايز الخلايا، عندما غالبا ما يلاحظ تخفيضات كبيرة في كل خلية وحجم النووي 11،12 هذا. وعلاوة على ذلك، تغيير حجم النووي معلمة رئيسية في تشخيص السرطان والتشخيص 13-17. الآليات التي تساهم في تنظيم حجم النووي غير معروفة إلى حد كبير، ويرجع ذلك جزئيا إلى التعقيد والطبيعة الأساسية للبنية النووي وظيفة. وقد تم تطوير هذا الأسلوب هو موضح هنا بمثابة فحص في المختبر لحجم النووي التحجيم التي هي قابلة للتلاعب البيوكيميائية وتوضيح آليات التنظيم حجم النووي. القيطم المورق البيض استخراج هو نظام راسخ أن ألخص ودراسة العمليات الخلوية المعقدة في في المختبر </em&gt; السياق. وقد كشفت هذه مقتطفات المعلومات الأساسية الجديدة عن العديد من العمليات الخلوية بما في ذلك تجميع ووظيفة المغزل الإنقسامية، الشبكة الإندوبلازمية، ونواة 18-22. واحد الميزة الرئيسية لنظام استخراج هي أن اكس. تمثل المورق مقتطفات بيضة السيتوبلازم مخفف تقريبا التي يمكن تغييرها بسهولة، على سبيل المثال من خلال إضافة بروتينات المؤتلف أو immunodepletion التكوين. وعلاوة على ذلك، هو واحد قادرا على التعامل مع العمليات الأساسية عن طريق استخدام العلاجات التي قد تكون على خلاف ذلك قاتلة في سياق في الجسم الحي. إدخال تعديلات على إجراءات استخراج البيض تسمح لعزل مقتطفات من X. الأجنة المورق بدلا من البيض، وهذه مقتطفات الجنين قابلة بالتساوي للتلاعب البيوكيميائية 23. خلال X. المورق التنمية، والمخصبة جنين وحيدة الخلية (~ مم 1) يخضع لسلسلة من اثني عشر الانقسامات الخلوية السريعة (المراحل 1-8) لتوليد عدة آلاف من 50 μم وقطرها أصغر الخلايا وصلت إلى مرحلة تنموية يطلق الانتقال midblastula (MBT) أو مرحلة 24-26 أغسطس. تتميز الدبابة مع بداية النسخ اقحي، الهجرة الخلية، الانقسامات الخلوية غير متزامن، واقتناء مراحل الفجوة، وإنشاء أحجام ثابتة للدولة نووية بدلا من التوسع النووي المستمر كما هو الحال في الجنين قبل الدبابة. من المرحلة 4 إلى المعيدة (مراحل 10،5 حتي 12)، وحجم النواة الفردية ينخفض ​​بأكثر من 10 أضعاف (11). هنا، فإن الهدف هو تحديد الآليات المسؤولة عن هذه التخفيضات في حجم النووي خلال التقدم التنموي. هذا النهج هو لتجميع أول نواة في اكس. المورق استخراج البيض وعزل تلك النواة من بويضة السيتوبلازم / استخراج. ثم يتم معلق هذه النوى في السيتوبلازم من الأجنة مرحلة متأخرة المعيدة. بعد فترة الحضانة، ونوى من استخراج البيض تصبح أصغر في أواخر استخراج مرحلة الجنين. نحن مسبب أن هذا عواد يكون فحص مفيدة لتحديد مكونات هيولية الموجودة في الأجنة المرحلة المتأخرة التي تساهم في تنموي حجم النووي التحجيم. باستخدام هذا الاختبار، بالإضافة إلى التحقق من صحة في الجسم الحي، أثبتنا أن بروتين كيناز C (بي كي سي) يساهم في خفض النمو في حجم النووي في اكس. المورق 23.

<table><tbody><tr><td>Alexa Fluor 568 Donkey anti-mouse IgG</td><td>Molecular Probes</td><td>A10037</td><td></td></tr><tr><td>ATP disodium salt</td><td>Sigma Aldrich</td><td>A2383</td><td></td></tr><tr><td>Benzocaine</td><td>Sigma Aldrich</td><td>E1501</td><td></td></tr><tr><td>Bovine Serum Albumin</td><td>Sigma Aldrich</td><td>A3059</td><td></td></tr><tr><td>CaCl&lt;sub&gt;2&lt;/sub&gt;</td><td>Sigma Aldrich</td><td>C3306</td><td></td></tr><tr><td>Centrifuge</td><td>Beckman</td><td>J2-21M</td><td></td></tr><tr><td>Centrifuge rotor</td><td>Beckman</td><td>JS 13.1</td><td></td></tr><tr><td>chymostatin</td><td>Sigma Aldrich</td><td>C7268</td><td></td></tr><tr><td>creatine phosphate disodium</td><td>Calbiochem</td><td>2380</td><td></td></tr><tr><td>cycloheximide</td><td>Sigma Aldrich</td><td>C6255</td><td></td></tr><tr><td>cytochalasin D</td><td>Sigma Aldrich</td><td>C8273</td><td></td></tr><tr><td>disposable wipes (kimwipes)</td><td>Sigma Aldrich</td><td>Z188956</td><td></td></tr><tr><td>L-cysteine</td><td>Sigma Aldrich</td><td>W326306</td><td></td></tr><tr><td>EGTA</td><td>Sigma Aldrich</td><td>E4378</td><td></td></tr><tr><td>Formaldehyde</td><td>Sigma Aldrich</td><td>F8775</td><td></td></tr><tr><td>Glass crystallizing dish (150 x 75 mm)</td><td>VWR</td><td>89090-662</td><td></td></tr><tr><td>Glycerol</td><td>Macron</td><td>5094-16</td><td></td></tr><tr><td>HEPES</td><td>Sigma Aldrich</td><td>H4034</td><td></td></tr><tr><td>Hoechst - bisBenzimide H 33342 trihydrochloride</td><td>Sigma Aldrich</td><td>B2261</td><td></td></tr><tr><td>HCG - Human Chorionic Gonadotropin&amp;nbsp;</td><td>Prospec</td><td>hor-250-c</td><td></td></tr><tr><td>L15 Media</td><td>Sigma Aldrich</td><td>L4386</td><td></td></tr><tr><td>leupeptin</td><td>Sigma Aldrich</td><td>L2884</td><td></td></tr><tr><td>Lysolecithin</td><td>Sigma Aldrich</td><td>L1381</td><td></td></tr><tr><td>mAb414</td><td>Abcam</td><td>ab24609</td><td></td></tr><tr><td>MgCl&lt;sub&gt;2&lt;/sub&gt;</td><td>EMD</td><td>MX0045-2</td><td></td></tr><tr><td>MgSO&lt;sub&gt;4&lt;/sub&gt;</td><td>Sigma Aldrich</td><td>M9397</td><td></td></tr><tr><td>Maltose</td><td>Sigma Aldrich</td><td>M5885</td><td></td></tr><tr><td>NP40</td><td>BDH</td><td>56009</td><td></td></tr><tr><td>Paraformaldehyde</td><td>Electron Microscopy Sciences</td><td>15710</td><td></td></tr><tr><td>Penicillin + Streptomycin</td><td>Sigma Aldrich</td><td>Pp0781</td><td></td></tr><tr><td>pepstatin</td><td>Sigma Aldrich</td><td>P5318</td><td></td></tr><tr><td>PIPES</td><td>Sigma Aldrich</td><td>P6757</td><td></td></tr><tr><td>Plastic paraffin film (parafilm)</td><td>Sigma Aldrich</td><td>P7793</td><td></td></tr><tr><td>KCl</td><td>Sigma Aldrich</td><td>P9541</td><td></td></tr><tr><td>KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;</td><td>Mallinckrodt</td><td>70100</td><td></td></tr><tr><td>KOH</td><td>Baker</td><td>5 3140</td><td></td></tr><tr><td>PMSG - Pregnant Mare Serum Gonadotropin</td><td>Prospec</td><td>hor-272-a</td><td></td></tr><tr><td>NaCl</td><td>Sigma Aldrich</td><td>S3014</td><td></td></tr><tr><td>NaHCO&lt;sub&gt;3&lt;/sub&gt;</td><td>Fisher</td><td>BP328</td><td></td></tr><tr><td>Na&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt;</td><td>EMD</td><td>SX0720-1</td><td></td></tr><tr><td>NaOH</td><td>EMD</td><td>SX0590</td><td></td></tr><tr><td>Pestle</td><td>Thomas Scientific</td><td>3411D56</td><td></td></tr><tr><td>Round bottom glass tubes, 15 ml</td><td>Corex</td><td>8441</td><td></td></tr><tr><td>Secondary antibody (Alexa Fluor 568 donkey anti-mouse IgG)</td><td>ThermoFisher</td><td>A10037</td><td></td></tr><tr><td>sucrose</td><td>Calbiochem</td><td>8550</td><td></td></tr><tr><td>thermal cycler</td><td>Bio-Rad</td><td>T100</td><td></td></tr><tr><td>Ultracentrifuge</td><td>Beckman</td><td>L8-80M</td><td></td></tr><tr><td>Ultracentrifuge rotor</td><td>Beckman</td><td>SW 50.1</td><td></td></tr><tr><td>Vectashield (anti-fade mounting medium)</td><td>Vector</td><td>H-1000</td><td></td></tr></tbody></table>

a cell-free assay using xenopus laevis embryo extracts to study mechanisms of nuclear size regulation

والسؤال الأساسي في بيولوجيا الخلية هو كيف يتم تنظيم أحجام الخلية وعضية. منذ فترة طويلة كان من المسلم به أن حجم النواة جداول عموما مع حجم الخلية، لا سيما خلال مرحلة التطور الجنيني عندما تحدث تخفيضات كبيرة في كل خلية والأحجام النووية. آليات تنظيم حجم النووي غير معروفة إلى حد كبير ويمكن أن تكون ذات صلة السرطان حيث حجم النووي غيرت معلمة التشخيص والنذير الرئيسية. المجراة النهج لتحديد المنظمين حجم النووية تعقيدا بسبب الطبيعة الأساسية والمعقدة من وظيفة النووية. النهج المتبع في المختبر الموصوفة هنا لدراسة مراقبة حجم النووية يستفيد من التخفيضات طبيعية في حجم النووي التي تحدث أثناء تطور المورق القيطم. أولا، يتم تجميع نوى في اكس. المورق استخراج البيض. ثم، يتم عزل هذه النوى ومعلق في السيتوبلازم من الأجنة مرحلة متأخرة. بعد 30 - فترة الحضانة 90 دقيقة، مساحة النووييقلل من 20-60٪، وتوفير الفحص المفيد تحديد مكونات هيولية الموجودة في الأجنة المرحلة المتأخرة التي تساهم في تنموي حجم النووي التحجيم. والميزة الرئيسية لهذا النهج هو مرفق النسبي الذي مقتطفات البيض والجنين يمكن التلاعب بها كيميائيا، مما يسمح للتعرف على البروتينات والأنشطة الجديدة التي تنظم حجم النووي. كما هو الحال مع أي في نهج المختبر، التحقق من النتائج في نظام في الجسم الحي هو المهم، وMicroinjection من X. الأجنة المورق مناسبة بشكل خاص لهذه الدراسات.

جمعية نوى في استخراج البيض الخطوات الأولى من هذا البروتوكول هي لإعداد اكس. المورق استخراج البيض (بروتوكول 1) ونوى الحيوانات المنوية demembranated (بروتوكول 2). ثم يتم استخدام هذه الكواشف ...

Watch this Scientific Journal Video about A Cell-Free Assay Using Xenopus laevis Embryo Extracts to Study Mechanisms of Nuclear Size Regulation at JoVE.com

A Cell-Free Assay Using Xenopus laevis Embryo Extracts to Study Mechanisms of Nuclear Size Regulation

Mechanisms of cellular and intra-cellular scaling remain elusive. The use of Xenopus embryo extracts has become increasingly common to elucidate mechanisms of organelle size regulation. This method describes embryo extract preparation and a novel nuclear scaling assay through which mechanisms of nuclear size regulation can be identified.

فحص خلية مجاني عن طريق<em&gt; القيطم المورق</em&gt; الأجنة مقتطفات لدراسة آليات الحجم رقابة النووية

A fundamental question in cell biology is how cell and organelle sizes are regulated. It has long been recognized that the size of the nucleus generally ...

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A Cell-Free Assay Using Xenopus laevis Embryo Extracts to Study Mechanisms of Nuclear Size Regulation

8.3K Views.  University of Wyoming. Mechanisms of cellular and intra-cellular scaling remain elusive. The use of Xenopus embryo extracts has become increasingly common to elucidate mechanisms of organelle size regulation. This method describes embryo extract preparation and a novel nuclear scaling assay through which mechanisms of nuclear size regulation can be identified.

Video: A Cell-Free Assay Using Xenopus laevis Embryo Extracts to Study Mechanisms of Nuclear Size Regulation

Manipulation and In Vitro Maturation of Xenopus laevis Oocytes, Followed by Intracytoplasmic Sperm Injection, to Study Embryonic Development

Amphibian eggs have been widely used to study embryonic development. Early embryonic development is driven by maternally stored factors accumulated during oogenesis. In order to study roles of such maternal factors in early embryonic development, it is desirable to manipulate their functions from the very beginning of embryonic development. Conventional ways of gene interference are achieved by injection of antisense oligonucleotides (oligos) or mRNA into fertilized eggs, enabling under- or over-expression of specific proteins, respectively. However, these methods normally require more than several hours until protein expression is affected, and, hence, the interference of gene functions is not effective during early embryonic stages. Here, we introduce an experimental system in which expression levels of maternal proteins can be altered before fertilization. Xenopus laevis oocytes obtained from ovaries are defolliculated by incubating with enzymes. Antisense oligos or mRNAs are injected into defolliculated oocytes at the germinal vesicle (GV) stage. These oocytes are in vitro matured to eggs at the metaphase II (MII) stage, followed by intracytoplasmic sperm injection (ICSI). By this way, up to 10% of ICSI embryos can reach the swimming tadpole stage, thus allowing functional tests of specific gene knockdown or overexpression. This approach can be a useful way to study roles of maternally stored factors in early embryonic development.

Manipulation and In Vitro Maturation of Xenopus laevis Oocytes, Followed by Intracytoplasmic Sperm Injection, to Study Embryonic Development

We describe methods of manipulating Xenopus laevis immature oocytes, in vitro maturation of oocytes to eggs, and intracytoplasmic sperm injection. This protocol allows degradation of some maternal proteins and overexpression of genes of interest at fertilization, and hence is valuable to study roles of specific factors in early embryonic development.

التلاعب و<em&gt; في المختبر</em&gt; نضوج<em&gt; القيطم المورق</em&gt; البويضات، تلاه سهم داخل الهيولى حقن الحيوانات المنوية، لدراسة التطور الجنيني

Amphibian eggs have been widely used to study embryonic development. Early embryonic development is driven by maternally stored factors accumulated during ...

Developmental Biology

Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients

This protocol describes a method to visualise ligands distributed across a field of cells. The ease of expressing exogenous proteins, together with the large size of their cells in early embryos, make Xenopus laevis a useful model for visualising GFP-tagged ligands. Synthetic mRNAs are efficiently translated after injection into early stage Xenopus embryos, and injections can be targeted to a single cell. When combined with a lineage tracer such as membrane tethered RFP, the injected cell (and its descendants) that are producing the overexpressed protein can easily be followed. This protocol describes a method for the production of fluorescently tagged Wnt and Shh ligands from injected mRNA. The methods involve the micro dissection of ectodermal explants (animal caps) and the analysis of ligand diffusion in multiple samples. By using confocal imaging, information about ligand secretion and diffusion over a field of cells can be obtained. Statistical analyses of confocal images provide quantitative data on the shape of ligand gradients. These methods may be useful to researchers who want to test the effects of factors that may regulate the shape of morphogen gradients.

Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients

The manuscript here provides a simple set of methods for analysing the secretion and diffusion of fluorescently tagged ligands in Xenopus. This provides a context for testing the ability of other proteins to modify ligand distribution and allowing experiments that may give insight into mechanisms regulating morphogen gradients.

باستخدام تحليل متحد البؤر من<em&gt; القيطم المورق</em&gt; بالتحقيق المغيرون من WNT وShh على محدثة التخلق التدرجات

This protocol describes a method to visualise ligands distributed across a field of cells. The ease of expressing exogenous proteins, together with the ...

Reconstitution of Cell-cycle Oscillations in Microemulsions of Cell-free Xenopus Egg Extracts

Real-time measurement of oscillations at the single-cell level is important to uncover the mechanisms of biological clocks. Although bulk extracts prepared from Xenopus laevis eggs have been powerful in dissecting biochemical networks underlying the cell-cycle progression, their ensemble average measurement typically leads to a damped oscillation, despite each individual oscillator being sustained. This is due to the difficulty of perfect synchronization among individual oscillators in noisy biological systems. To retrieve the single-cell dynamics of the oscillator, we developed a droplet-based artificial cell system that can reconstitute mitotic cycles in cell-like compartments encapsulating cycling cytoplasmic extracts of Xenopus laevis eggs. These simple cytoplasmic-only cells exhibit sustained oscillations for over 30 cycles. To build more complicated cells with nuclei, we added demembranated sperm chromatin to trigger nuclei self-assembly in the system. We observed a periodic progression of chromosome condensation/decondensation and nuclei envelop breakdown/reformation, like in real cells. This indicates that the mitotic oscillator functions faithfully to drive multiple downstream mitotic events. We simultaneously tracked the dynamics of the mitotic oscillator and downstream processes in individual droplets using multi-channel time-lapse fluorescence microscopy. The artificial cell-cycle system provides a high-throughput framework for quantitative manipulation and analysis of mitotic oscillations with single-cell resolution, which likely provides important insights into the regulatory machinery and functions of the clock.

Reconstitution of Cell-cycle Oscillations in Microemulsions of Cell-free Xenopus Egg Extracts

We present a method for the generation of in vitro self-sustained mitotic oscillations at the single-cell level by encapsulating egg extracts of Xenopus laevis in water-in-oil microemulsions.

إعادة تشكيل ذبذبات دورة الخلية في ميكرومولسيونس مستخرجات البيض خالية من الخلية النمو

Real-time measurement of oscillations at the single-cell level is important to uncover the mechanisms of biological clocks. Although bulk extracts ...

Biochemistry

Preparation and Fractionation of Xenopus laevis Egg Extracts

Crude and fractionated Xenopus egg extracts can be used to provide ingredients for reconstituting cellular processes for morphological and biochemical analysis. Egg lysis and differential centrifugation are used to prepare the crude extract which in turn in used to prepare fractionated extracts and light membrane preparations.

Crude and fractionated Xenopus egg extracts can be used to provide ingredients for reconstituting cellular processes for morphological and biochemical analysis. Egg lysis and differential centrifugation are used to prepare the crude extract which in turn in used to prepare fractionated extracts and light membrane preparations.

إعداد والتقطير من البيض مقتطفات القيطم المورق

Crude and fractionated Xenopus egg extracts can be used to provide ingredients for reconstituting cellular processes for morphological and biochemical ...

In Vitro Nuclear Assembly Using Fractionated Xenopus Egg Extracts

Nuclear membrane assembly is an essential step in the cell division cycle; this process can be replicated in the test tube by combining Xenopus sperm chromatin, cytosol, and light membrane fractions. Complete nuclei are formed, including nuclear membranes with pore complexes, and these reconstituted nuclei are capable of normal nuclear processes.

Nuclear membrane assembly is an essential step in the cell division cycle; this process can be replicated in the test tube by combining Xenopus sperm chromatin, cytosol, and light membrane fractions. Complete nuclei are formed, including nuclear membranes with pore complexes, and these reconstituted nuclei are capable of normal nuclear processes.

في المختبر عن طريق الجمعية النووية مجزأ مقتطفات البيض القيطم

Nuclear membrane assembly is an essential step in the cell division cycle; this process can be replicated in the test tube by combining Xenopus sperm ...

Live-cell Imaging and Quantitative Analysis of Embryonic Epithelial Cells in Xenopus laevis

Embryonic epithelial cells serve as an ideal model to study morphogenesis where multi-cellular tissues undergo changes in their geometry, such as changes in cell surface area and cell height, and where cells undergo mitosis and migrate. Furthermore, epithelial cells can also regulate morphogenetic movements in adjacent tissues1. A traditional method to study epithelial cells and tissues involve chemical fixation and histological methods to determine cell morphology or localization of particular proteins of interest. These approaches continue to be useful and provide "snapshots" of cell shapes and tissue architecture, however, much remains to be understood about how cells acquire specific shapes, how various proteins move or localize to specific positions, and what paths cells follow toward their final differentiated fate. High resolution live imaging complements traditional methods and also allows more direct investigation into the dynamic cellular processes involved in the formation, maintenance, and morphogenesis of multicellular epithelial sheets. Here we demonstrate experimental methods from the isolation of animal cap tissues from Xenopus laevis embryos to confocal imaging of epithelial cells and simple measurement approaches that together can augment molecular and cellular studies of epithelial morphogenesis.

Live-cell Imaging and Quantitative Analysis of Embryonic Epithelial Cells in Xenopus laevis

Xenopus embryonic epithelia are an ideal model system to study cell behaviors such as polarity development and shape change during epithelial morphogenesis. Traditional histology of fixed samples is increasingly being complemented by live-cell confocal imaging. Here we demonstrate methods to isolate frog tissues and visualize live epithelial cells and their cytoskeleton using live-cell confocal microscopy.

تعيش خلية التصوير والتحليل الكمي من الخلايا الظهارية في الجنينية القيطم المورق</em

Embryonic epithelial cells serve as an ideal model to study morphogenesis where multi-cellular tissues undergo changes in their geometry, such as changes ...

Production of Transgenic Xenopus laevis by Restriction Enzyme Mediated Integration and Nuclear Transplantation

Stable integration of cloned gene products into the Xenopus genome is necessary to control the time and place of expression, to express genes at later stages of embryonic development, and to define how enhancers and promoters regulate gene expression within the embryo. The protocol demonstrated here can be used to efficiently produce transgenic Xenopus laevis embryos. This transgenesis approach involves three parts: 1. Sperm nuclei are isolated from adult X. laevis testis by treatment with lysolecithin, which permeabilizes the sperm plasma membrane. 2. Egg extract is prepared by low speed centrifugation, addition of calcium to cause the extract to progress to interphase of the cell cycle, and a high-speed centrifugation to isolate interphase cytosol. 3. Nuclear transplantation: the nuclei and extract are combined with the linearized plasmid DNA to be introduced as the transgene and a small amount of restriction enzyme. During a short reaction, egg extract partially decondenses the sperm chromatin and the restriction enzyme generates chromosomal breaks that promote recombination of the transgene into the genome. The treated sperm nuclei are then transplanted into unfertilized eggs. Integration of the transgene usually occurs prior to the first embryonic cleavage such that the resulting embryos are not chimeric. These embryos can be analyzed without any need to breed to the next generation, allowing for efficient and rapid generation of transgenic embryos for analyses of promoter and gene function. Adult X. laevis resulting from this procedure also propagate the transgene through the germline and can be used to generate lines of transgenic animals for multiple purposes.

Production of Transgenic Xenopus laevis by Restriction Enzyme Mediated Integration and Nuclear Transplantation

This video protocol demonstrates a method for generating transgenic Xenopus laevis by introduction of transgenes into sperm nuclei followed by nuclear transplantation into unfertilized eggs.

إنتاج المعدلة وراثيا القيطم المورق عن طريق تقييد أنزيم التكامل وساطة وزرع النووية

Stable integration of cloned gene products into the Xenopus genome is necessary to control the time and place of expression, to express genes at later ...

Production of Xenopus tropicalis Egg Extracts to Identify Microtubule-associated RNAs

Many organisms localize mRNAs to specific subcellular destinations to spatially and temporally control gene expression. Recent studies have demonstrated that the majority of the transcriptome is localized to a nonrandom position in cells and embryos. One approach to identify localized mRNAs is to biochemically purify a cellular structure of interest and to identify all associated transcripts. Using recently developed high-throughput sequencing technologies it is now straightforward to identify all RNAs associated with a subcellular structure. To facilitate transcript identification it is necessary to work with an organism with a fully sequenced genome. One attractive system for the biochemical purification of subcellular structures are egg extracts produced from the frog Xenopus laevis. However, X. laevis currently does not have a fully sequenced genome, which hampers transcript identification. In this article we describe a method to produce egg extracts from a related frog, X. tropicalis, that has a fully sequenced genome. We provide details for microtubule polymerization, purification and transcript isolation. While this article describes a specific method for identification of microtubule-associated transcripts, we believe that it will be easily applied to other subcellular structures and will provide a powerful method for identification of localized RNAs.

Production of Xenopus tropicalis Egg Extracts to Identify Microtubule-associated RNAs

We describe the collection of unfertilized Xenopus tropicalis eggs and production of a meiosis II-arrested egg extract. This egg extract can be used to purify microtubules and microtubule-associated RNAs.

إنتاج<em&gt; القيطم مداري</em&gt; البيض مقتطفات من التعرف على الرنا أنيبيب المرتبطة بها

Many  organisms localize mRNAs to specific subcellular destinations to spatially and  temporally control gene expression. Recent studies have demonstrated ...

Reconstitution Of &#946;-catenin Degradation In Xenopus Egg Extract

Xenopus laevis egg extract is a well-characterized, robust system for studying the biochemistry of diverse cellular processes. Xenopus egg extract has been used to study protein turnover in many cellular contexts, including the cell cycle and signal transduction pathways1-3. Herein, a method is described for isolating Xenopus egg extract that has been optimized to promote the degradation of the critical Wnt pathway component, &beta;-catenin. Two different methods are described to assess &beta;-catenin protein degradation in Xenopus egg extract. One method is visually informative ([35S]-radiolabeled proteins), while the other is more readily scaled for high-throughput assays (firefly luciferase-tagged fusion proteins). The techniques described can be used to, but are not limited to, assess &beta;-catenin protein turnover and identify molecular components contributing to its turnover. Additionally, the ability to purify large volumes of homogenous Xenopus egg extract combined with the quantitative and facile readout of luciferase-tagged proteins allows this system to be easily adapted for high-throughput screening for modulators of &beta;-catenin degradation.

Reconstitution Of &#946;-catenin Degradation In Xenopus Egg Extract

A method is described for analyzing protein degradation using radiolabeled and luciferase-fusion proteins in Xenopus egg extract and its adaptation for high-throughput screening for small molecule modulators of protein degradation.

إعادة تشكيل β-catenin تدهور في<em&gt; القيطم</em&gt; مستخلصات البيض

Xenopus laevis egg extract is a well-characterized, robust system for studying the biochemistry of diverse cellular processes. Xenopus egg extract has ...

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

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

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

خلية الفحص مجاني لدراسة لونين Decondensation في نهاية الانقسام

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

فحص خلية مجاني عن طريق

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التلاعب و

باستخدام تحليل متحد البؤر من

إعادة تشكيل ذبذبات دورة الخلية في ميكرومولسيونس مستخرجات البيض خالية من الخلية النمو

إعداد والتقطير من البيض مقتطفات القيطم المورق

في المختبر عن طريق الجمعية النووية مجزأ مقتطفات البيض القيطم

تعيش خلية التصوير والتحليل الكمي من الخلايا الظهارية في الجنينية القيطم المورق

إنتاج المعدلة وراثيا القيطم المورق عن طريق تقييد أنزيم التكامل وساطة وزرع النووية

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إعادة تشكيل β-catenin تدهور في

خلية الفحص مجاني لدراسة لونين Decondensation في نهاية الانقسام