Agradecemos Kerry Bloom (Universidade da Carolina do Norte), Kyung Lee (NCI), Steven Markus (Colorado State University), e Elmar Schiebel (Universität Heidelberg) para a partilha de vários plasmídeos FP-TUB1. Somos gratos a Melissa Gardner (University of Minnesota) para nós treinando no método de preparação câmara de slide. Este trabalho foi apoiado pelo National Institutes of Health (NIH) conceder R01GM112893-01A1 (a JKM) e T32GM008730 (a CE).

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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coordinating+mitosis+with+cell+polarity:+Molecular+motors+at+the+cell+cortex.">Coordinating mitosis with cell polarity: Molecular motors at the cell cortex.</a> Semin Cell Dev Biol. 21 (3), 283-289 (2010).</li><li>Gartz Hanson, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+alpha-tubulin+mutation+disrupts+neural+development+and+tubulin+proteostasis.">Novel alpha-tubulin mutation disrupts neural development and tubulin proteostasis.</a> Dev Biol. 409 (2), 406-419 (2016).</li><li>Fees, C. P., Aiken, J., O'Toole, E. T., Giddings, T. H. J., Moore, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+negatively+charged+carboxy-terminal+tail+of+beta-tubulin+promotes+proper+chromosome+segregation.">The negatively charged carboxy-terminal tail of beta-tubulin promotes proper chromosome segregation.</a> Mol Biol Cell. 27 (11), 1786-1796 (2016).</li><li>Song, S., Lee, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+function+of+Saccharomyces+cerevisiae+CDC5+in+cytokinesis.">A novel function of Saccharomyces cerevisiae CDC5 in cytokinesis.</a> J Cell Biol. 152 (3), 451-469 (2001).</li><li>Knop, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epitope+tagging+of+yeast+genes+using+a+PCR-based+strategy:+more+tags+and+improved+practical+routines.">Epitope tagging of yeast genes using a PCR-based strategy: more tags and improved practical routines.</a> Yeast. 15 (10B), 963-972 (1999).</li><li>Kosco, K. 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=Control+of+microtubule+dynamics+by+Stu2p+is+essential+for+spindle+orientation+and+metaphase+chromosome+alignment+in+yeast.">Control of microtubule dynamics by Stu2p is essential for spindle orientation and metaphase chromosome alignment in yeast.</a> Mol Biol Cell. 12 (9), 2870-2880 (2001).</li><li>Toso, R. J., Jordan, M. A., Farrell, K. W., Matsumoto, B., Wilson, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetic+stabilization+of+microtubule+dynamic+instability+in+vitro+by+vinblastine.">Kinetic stabilization of microtubule dynamic instability in vitro by vinblastine.</a> Biochemistry. 32 (5), 1285-1293 (1993).</li><li>Aiken, J., Sept, D., Costanzo, M., Boone, C., Cooper, J. A., Moore, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-wide+analysis+reveals+novel+and+discrete+functions+for+tubulin+carboxy-terminal+tails.">Genome-wide analysis reveals novel and discrete functions for tubulin carboxy-terminal tails.</a> Curr Biol. 24 (12), 1295-1303 (2014).</li><li>Straight, A. F., Marshall, W. F., Sedat, J. W., Murray, A. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitosis+in+living+budding+yeast:+anaphase+A+but+no+metaphase+plate.">Mitosis in living budding yeast: anaphase A but no metaphase plate.</a> Science. 277 (5325), 574-578 (1997).</li><li>Khmelinskii, A., Lawrence, C., Roostalu, J., Schiebel, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cdc14-regulated+midzone+assembly+controls+anaphase+B.">Cdc14-regulated midzone assembly controls anaphase B.</a> J Cell Biol. 177 (6), 981-993 (2007).</li><li>Markus, S. M., Omer, S., Baranowski, K., Lee, W. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+Plasmids+for+Fluorescent+Protein+Tagging+of+Microtubules+in+Saccharomyces+cerevisiae.">Improved Plasmids for Fluorescent Protein Tagging of Microtubules in Saccharomyces cerevisiae.</a> Traffic. 16 (7), 773-786 (2015).</li></ol>

Os autores declaram que não têm interesses financeiros concorrentes.

O modelo de levedura de germinação oferece grandes vantagens para a recolha de medições de alta resolução de dinâmica dos microtúbulos num cenário in vivo, incluindo a capacidade de imagem microtúbulos individuais ao longo do tempo e a capacidade de manipular tubulinas e reguladores de microtúbulos, utilizando as ferramentas de genética de leveduras. As câmaras de Concanavalina A-revestimento proporciona um número de vantagens sobre os dispositivos anteriormente descri...

Os microtúbulos são polímeros feitos do citoesqueleto de subunidades de proteína αβ-tubulina e são utilizados numa grande variedade de contextos celulares, incluindo o transporte intracelular, a divisão celular, a morfogénese e a motilidade. Para construir redes de microtúbulos para essas funções diversas, as células devem cuidadosamente regulam onde e quando forma microtúbulos. Esta regulação é conseguida por controlo das reacções que quer montar subunidades αβ-tubulina em microtúbulos ou polímeros microtúbulos desmontar em subunidades livres; isso é conhecido como dinâmica dos microtúbulos. Um objectivo principal do campo de microtúbulos é elucidar os mecanismos moleculares que regulam a dinâmica dos microtúbulos, incluindo estudos das subunidades αβ-tubulina e reguladores extrínsecos que se ligam a tubulina e / ou aos microtulos. Uma abordagem experimental bem estabelecido é a reconstituir este sistema in vitro utilizando a proteína αβ-tubulina purificada, muitas vezes em COMbinação com reguladores extrínsecos purificadas. Embora esta seja uma abordagem útil, é claro que a dinâmica dos microtúbulos em sistemas reconstituídos difere fortemente da observada em células vivas. Por exemplo, os microtúbulos crescem mais rapidamente e encolher mais lenta in vivo que in vitro. Estas diferenças podem ser atribuídas à disponibilidade de reguladores extrínsecos conhecidos 1, bem como a factores ainda indefinido em células. Portanto, é crítico para determinar as actividades dos reguladores de microtúbulos e mutantes que perturbam dinâmica num contexto celular nativo. Embora os modelos metazoários provaram ser os sistemas vigentes para investigar a função dos microtúbulos e organização de ordem superior, várias preocupações práticas limitar severamente a utilidade destes modelos para a medição precisa da dinâmica dos microtúbulos. Primeiro, o elevado número de microtúbulos, variando de dezenas de milhares por célula, torna difícil a confiançarastrear microtúbulos individuais ao longo do tempo. Muitos estudos de responder a este desafio por imagiologia de proteínas que se localizam selectivamente para as extremidades dos microtúbulos, tais como as proteínas da família de ligao final (EB). No entanto, estas proteínas são conhecidos para localizar apenas às extremidades de crescimento de microtúbulos em metazoários 2. Portanto, a utilidade destas proteínas é limitado para medir directamente as taxas de crescimento, ao passo que apenas indirectamente medindo outros aspectos da dinâmica, tal como a frequência de catástrofe. Em segundo lugar, apesar dos avanços na tecnologia de edição genoma, a criação de células que expressam de forma estável tubulina marcado por fluorescência ou a introdução de mutações de manipular selectivamente tubulina ou reguladores de microtúbulos permanece um desafio significativo. Além disso, a presença de diversos isotipos de tubulina em metazoários confunde o estudo de como os genes da tubulina mutações impacto individuais. O sistema de levedura de germinação oferece várias vantagens importantes para a medição em microtubu vivole dinâmica. Levedura tem uma rede de microtúbulos simplificada que permite a visualização de microtúbulos individuais. Em levedura, os microtúbulos emanam de organizar centros conhecidos como fusos corpos pólo (SPBs), que são incorporados no envelope nuclear 3. Os SPBs servir como suportes para pequenos complexos y-tubulina que nucleada microtúbulos 4, 5. SPBs núcleos duas classes de microtúbulos, os microtúbulos do fuso e microtúbulos astrais. Projecto microtúbulos do fuso para o nucleoplasma e são importantes para a fixação de cromossomas através de microtúbulos cinetocoro e para a estabilização do fuso através de sobreposição de microtúbulos interpolares 6. Em contraste, os microtúbulos astrais projecto para o exterior para o citosol e são relativamente raros em comparação com a densa rede de microtúbulos de fuso. Durante a mitose, as células pré-anafase têm apenas 1-2 microtúbulos astrais que emanam a partir de qualquer SPB; estes existir como imicrotúbulos ndividual e não como feixes 7. O papel de microtúbulos astrais durante a mitose é mover o núcleo e o eixo em junção entre a mãe e bud compartimentos, conhecidos como o pescoço broto. Este movimento envolve vias bem definidas que geram força sobre microtúbulos astrais, que puxam o núcleo e para a fuso e, eventualmente, para o botão 8 pescoço. Outra vantagem do sistema de levedura é a utilidade da sua genética, que podem ser utilizados para investigar os reguladores de microtúbulos e subunidades de tubulina com precisão sem paralelo. A levedura também possuir um repertório simplificado de isotipos de tubulina: um único β-tubulina gene (TUB2) e dois genes alfa-tubulina (TUB1 e tub3). As mutações podem ser facilmente introduzidos nestes genes e, assim, estudado em uma população de tubulina homogénea 9, 10. Há uma série de amplamenteconstrues disponíveis para microtúbulos de rotulagem, e estes podem ser alvo para a integração cromossómica em loci para a expressão estável (ver a discussão). O objectivo global do presente método é a imagem individuais microtúbulos em células de levedura vivendo em quatro dimensões (X, Y, Z, e t) para medições de alta resolução de dinâmica dos microtúbulos. Os métodos para a integração de construções para a expressão constitutiva de baixo nível de tubulina marcado com fluorescência em células de levedura são descritos. Antes da imagiologia, as células vivas são montados em câmaras inclinadas revestidos com a lectina Concanavalina A para estabilizar as células para imagiologia de longo prazo. Os parâmetros óptimos para a aquisição de imagem, bem como um fluxo de trabalho para a análise de dados, também são descritos.

<table><tbody><tr><td>DOB (dropout bases)</td><td>Sunrise science&amp;nbsp;</td><td>1650</td><td></td></tr><tr><td>CSM-Leu</td><td>Sunrise science&amp;nbsp;</td><td>1005</td><td></td></tr><tr><td>Agar</td><td>Ameresco</td><td>N833</td><td></td></tr><tr><td>100 mm polystyrene plates</td><td>Fisher Scientific</td><td>FB0875713</td><td></td></tr><tr><td>ssDNA (Samon Sperm)&amp;nbsp; in sterile DiH&lt;sub&gt;2&lt;/sub&gt;O</td><td>Sigma-Aldrich&amp;nbsp;</td><td>&amp;nbsp;D7656</td><td>resuspend at 10 mg/mL in DiH2O. Store aliquots at -20 &amp;ordm;C</td></tr><tr><td>Synthetic Complete Media&amp;nbsp;</td><td>Sunrise science&amp;nbsp;</td><td>1459-100</td><td></td></tr><tr><td>Concanavalin A</td><td>Sigma-Aldrich&amp;nbsp;</td><td>L7647</td><td>resuspend at 2 mg/mL in DiH2O. Store aliquots at -20 &amp;ordm;C</td></tr><tr><td>Microscope slides</td><td>Fisher Scientific</td><td>12-544-1</td><td></td></tr><tr><td>Microscope Coverslips</td><td>Fisher Scientific</td><td>12-541-B</td><td></td></tr><tr><td>Parafilm</td><td>Fisher Scientific</td><td>13-374-12</td><td>paraffin film</td></tr><tr><td>VALAP (Equal parts of Vaseline, lanolin and paraffin)</td><td></td><td></td><td>melt at 75 &amp;ordm;C before use</td></tr><tr><td>forceps&amp;nbsp;</td><td>Fisher Scientific</td><td>16-100-106</td><td></td></tr><tr><td>Poyethylene glycol (PEG) 3350</td><td>Sigma-Aldrich&amp;nbsp;</td><td>202444</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Microscope&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Ti E inverted Perfect Focus microscope</td><td>Nikon Instruments</td><td>MEA53100</td><td></td></tr><tr><td>1.45 NA 100X CFI Plan Apo objective</td><td>Nikon Instruments</td><td>MRD01905</td><td></td></tr><tr><td>Piezo electric stage&amp;nbsp;</td><td>Physik Instrumente</td><td>P-736</td><td></td></tr><tr><td>Spinning disk scanner</td><td>Yokogawa</td><td>CSU10</td><td></td></tr><tr><td>Laser combiner module</td><td>Agilent Technologies</td><td>MCL400B</td><td></td></tr><tr><td>EMCCD camera</td><td>Andor Technology</td><td>iXon Ultra 897&amp;nbsp;</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Software&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>NIS Elements software</td><td>Nikon Instruments</td><td>MQS31100</td><td></td></tr><tr><td>Microsoft Excel software</td><td>Microsoft</td><td></td><td></td></tr><tr><td>MATLAB software</td><td>MathWorks, Inc</td><td></td><td></td></tr><tr><td>ImageJ64</td><td>NIH</td><td></td><td>Rasband, W.S., ImageJ, U. S. National Institutes of Health, Bethesda, Maryland, USA, http://imagej.nih.gov/ij/, 1997-2016.</td></tr><tr><td>Bio-Formats Importer plug-in</td><td>Open Microscopy Environment</td><td></td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Plasmids&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>pUC19-LEU2::GFP-TUB1</td><td></td><td>pSK1050</td><td>reference: Song, S. and Lee, K. S. A novel function of Saccharomyces cerevisiae CDC5 in cytokinesis. J Cell Biol. 152 (3), 451-469 (2001)</td></tr></tbody></table>

high-resolution imaging and analysis of individual astral microtubule dynamics in budding yeast

microtúbulos dinâmicos são fundamentais para muitos processos celulares, e medições precisas de dinâmica dos microtúbulos pode fornecer insights sobre como as células regulam esses processos e como genética mutações regulação impacto. A quantificação da dinâmica dos microtúbulos em modelos metazoários tem um número de desafios associados, incluindo uma densidade elevada de microtúbulos e limitações em manipulações genéticas. Em contraste, o modelo de levedura de brotamento oferece vantagens que superam esses desafios. Este protocolo descreve um método para medir a dinâmica dos microtúbulos individuais em células de levedura viva. As células que expressam a tubulina fluorescente etiquetado são aderidas às câmaras de deslizamento montados, permitindo a aquisição de imagem em tempo desfasado estável. Um guia detalhado para a alta velocidade, a aquisição de imagem de quatro dimensões também é fornecido, assim como um protocolo para quantificar as propriedades dinâmicas de microtúbulos em pilhas de imagens confocais. Este método, em combinação com levedura genética convencionais, provIdes uma abordagem que é singularmente adequado para quantitativamente avaliar os efeitos reguladores de microtúbulos ou mutações que alteram a actividade de subunidades de tubulina.

Medição dinâmica dos microtúbulos em células de levedura viva fornece uma ferramenta atraente para avaliar a forma como as mutações em genes que codificam para reguladores de microtúbulos tubulina ou subunidades de polimerização impacto e taxas de despolimerização, bem como a frequência de transição entre estes estados. A Figura 1 apresenta uma série de tempo da dinâmica dos microtúbulos astrais em uma célula de tipo selvagem e um mutante de células c...

Watch this Scientific Journal Video about High-resolution Imaging and Analysis of Individual Astral Microtubule Dynamics in Budding Yeast at JoVE.com

High-resolution Imaging and Analysis of Individual Astral Microtubule Dynamics in Budding Yeast

Budding levedura é um modelo vantajoso para o estudo da dinâmica dos microtúbulos in vivo, devido às suas poderosas da genética e a simplicidade do seu citoesqueleto de microtúbulos. O protocolo a seguir descreve como transformar e cultura de células de levedura, adquirir imagens de microscopia confocal, e quantitativamente analisar a dinâmica dos microtúbulos em células de levedura viva.

Imagens de alta resolução e Análise de individuais Astral microtúbulos Dynamics em brotamento Yeast

Dynamic microtubules are fundamental to many cellular processes, and accurate measurements of microtubule dynamics can provide insight into how cells ...

high-resolution-imaging-analysis-individual-astral-microtubule

Research

JoVE Journal

Biology

9.3K visualizações.  University of Colorado School of Medicine.  Budding levedura é um modelo vantajoso para o estudo da dinâmica dos microtúbulos in vivo, devido às suas poderosas da genética e a simplicidade do seu citoesqueleto de microtúbulos. O protocolo a seguir descreve como transformar e cultura de células de levedura, adquirir imagens de microscopia confocal, e quantitativamente analisar a dinâmica dos microtúbulos em células de levedura viva. 

Vídeo: High-resolution Imaging and Analysis of Individual Astral Microtubule Dynamics in Budding Yeast

Analysis of the Development of a Morphological Phenotype as a Function of Protein Concentration in Budding Yeast

Gene deletion and protein overexpression are common methods for studying functions of proteins. In this article, we describe a protocol for analysis of phenotype development as a function of protein concentration at population and single-cell levels in Saccharomyces cerevisiae. Although this protocol is based on the overexpression of a protein, it can easily be adapted for morphological phenotypes dependent on suppression of protein expression. Our lab is interested in studying the signaling properties of the endocytic adaptor protein epsin. To that purpose we used a dominant negative approach in which we over-expressed the conserved Epsin N-Terminal Homology (ENTH) domain in order to interfere with the functions of endogenous epsin-2 (Ent2 or YLR206W). We observed that overexpression of the ENTH domain of Ent2 (ENTH2) in wild type cells led to a cell division defect that is dependent on the mislocalization of a family of scaffolding proteins, septins.

Gene deletion and protein overexpression are common methods for studying functions of proteins. In this article, we describe a protocol for analysis of phenotype development as a function of protein concentration at population and single-cell levels in Saccharomyces cerevisiae.

Análise do desenvolvimento de um fenótipo morfológico como uma função da concentração de proteínas em levedura de brotamento

Gene deletion and protein overexpression are common methods for studying functions of proteins. In this article, we describe a protocol for analysis of ...

Biologia

Simultaneous Visualization of the Dynamics of Crosslinked and Single Microtubules In Vitro by TIRF Microscopy

Microtubules are polymers of &#945;&#946;-tubulin heterodimers that organize into distinct structures in cells. Microtubule-based architectures and networks often contain subsets of microtubule arrays that differ in their dynamic properties. For example, in dividing cells, stable bundles of crosslinked microtubules coexist in close proximity to dynamic non-crosslinked microtubules. TIRF-microscopy-based in vitro reconstitution studies enable the simultaneous visualization of the dynamics of these different microtubule arrays. In this assay, an imaging chamber is assembled with surface-immobilized microtubules, which are either present as single filaments or organized into crosslinked&#160;bundles. Introduction of tubulin, nucleotides, and protein regulators allows direct visualization of associated proteins and of dynamic properties of single and crosslinked microtubules. Furthermore, changes that occur as dynamic single microtubules organize into bundles can be monitored in real-time. The method described here allows for a systematic evaluation of the activity and localization of individual proteins, as well as synergistic effects of protein regulators on two different microtubule subsets under identical experimental conditions, thereby providing mechanistic insights that are inaccessible by other methods.

Simultaneous Visualization of the Dynamics of Crosslinked and Single Microtubules In Vitro by TIRF Microscopy

Here, a TIRF microscopy-based in vitro reconstitution assay is presented to simultaneously quantify and compare the dynamics of two microtubule populations. A method is described to simultaneously view the collective activity of multiple microtubule-associated proteins on crosslinked microtubule bundles and single microtubules.

Visualização Simultânea da Dinâmica dos Microtúbulos Cruzados e Únicos In Vitro pela Microscopia TIRF

Microtubules are polymers of &#945;&#946;-tubulin heterodimers that organize into distinct structures in cells. Microtubule-based architectures and ...

Bioquímica

Microscopy of Fission Yeast Sexual Lifecycle

The fission yeast Schizosaccharomyces pombe has been an invaluable model system in studying the regulation of the mitotic cell cycle progression, the mechanics of cell division and cell polarity. Furthermore, classical experiments on its sexual reproduction have yielded results pivotal to current understanding of DNA recombination and meiosis. More recent analysis of fission yeast mating has raised interesting questions on extrinsic stimuli response mechanisms, polarized cell growth and cell-cell fusion. To study these topics in detail we have developed a simple protocol for microscopy of the entire sexual lifecycle. The method described here is easily adjusted to study specific mating stages. Briefly, after being grown to exponential phase in a nitrogen-rich medium, cell cultures are shifted to a nitrogen-deprived medium for periods of time suited to the stage of the sexual lifecycle that will be explored. Cells are then mounted on custom, easily built agarose pad chambers for imaging. This approach allows cells to be monitored from the onset of mating to the final formation of spores.

We provide a reproducible basic method for the long-term microscopy of the fission yeast sexual lifecycle. With minor adjustments described, the presented protocol allows research focus on different steps of the reproductive process.

Microscopia do ciclo de vida sexual por fissão de levedura

The fission yeast Schizosaccharomyces pombe has been an invaluable model system in studying the regulation of the mitotic cell cycle progression, the ...

High-resolution Time-lapse Imaging and Automated Analysis of Microtubule Dynamics in Living Human Umbilical Vein Endothelial Cells

The physiological process by which new vasculature forms from existing vasculature requires specific signaling events that trigger morphological changes within individual endothelial cells (ECs). These processes are critical for homeostatic maintenance such as wound healing, and are also crucial in promoting tumor growth and metastasis. EC morphology is defined by the organization of the cytoskeleton, a tightly regulated system of actin and microtubule (MT) dynamics that is known to control EC branching, polarity and directional migration, essential components of angiogenesis. To study MT dynamics, we used high-resolution fluorescence microscopy coupled with computational image analysis of fluorescently-labeled MT plus-ends to investigate MT growth dynamics and the regulation of EC branching morphology and directional migration. Time-lapse imaging of living Human Umbilical Vein Endothelial Cells (HUVECs) was performed following transfection with fluorescently-labeled MT End Binding protein 3 (EB3) and Mitotic Centromere Associated Kinesin (MCAK)-specific cDNA constructs to evaluate effects on MT dynamics. PlusTipTracker software was used to track EB3-labeled MT plus ends in order to measure MT growth speeds and MT growth lifetimes in time-lapse images. This methodology allows for the study of MT dynamics and the identification of how localized regulation of MT dynamics within sub-cellular regions contributes to the angiogenic processes of EC branching and migration.

Protocols for Human Umbilical Vein Endothelial Cell (HUVEC) culture, transient transfection of fluorescently-labeled markers of microtubule growth, live-cell imaging and automated analysis of interphase microtubule growth dynamics are detailed.

De alta resolução de imagem Time-lapse e análise automatizada de microtúbulos Dynamics em Viver umbilical humano Células Endoteliais da Veia

The physiological process by which new vasculature forms from existing vasculature requires specific signaling events that trigger morphological changes ...

Reconstitution of Basic Mitotic Spindles in Spherical Emulsion Droplets

Mitotic spindle assembly, positioning and orientation depend on the combined forces generated by microtubule dynamics, microtubule motor proteins and cross-linkers. Growing microtubules can generate pushing forces, while depolymerizing microtubules can convert the energy from microtubule shrinkage into pulling forces, when attached, for example, to cortical dynein or chromosomes. In addition, motor proteins and diffusible cross-linkers within the spindle contribute to spindle architecture by connecting and sliding anti-parallel microtubules. In vivo, it has proven difficult to unravel the relative contribution of individual players to the overall balance of forces. Here we present the methods that we recently developed in our efforts to reconstitute basic mitotic spindles bottom-up in vitro. Using microfluidic techniques, centrosomes and tubulin are encapsulated in water-in-oil emulsion droplets, leading to the formation of geometrically confined (double) microtubule asters. By additionally introducing cortically anchored dynein, plus-end directed microtubule motors and diffusible cross-linkers, this system is used to reconstitute spindle-like structures. The methods presented here provide a starting point for reconstitution of more complete mitotic spindles, allowing for a detailed study of the contribution of each individual component, and for obtaining an integrated quantitative view of the force-balance within the mitotic spindle.

The assembly and positioning of the mitotic spindle depend on the combined forces generated by microtubule dynamics, motor proteins and cross-linkers. Here we present our recently developed methods in which the geometrical confinement of spherical emulsion droplets is used for the bottom-up reconstitution of basic mitotic spindles.

Reconstituição do Basic mitótico Fusos no esféricas Emulsão Gotas

Mitotic spindle assembly, positioning and orientation depend on the combined forces generated by microtubule dynamics, microtubule motor proteins and ...

Spatiotemporal Analysis of Cytokinetic Events in Fission Yeast

Cytokinesis, the final step in cell division is critical for maintaining genome integrity. Proper cytokinesis is important for cell differentiation and development. Cytokinesis involves a series of events that are well coordinated in time and space. Cytokinesis involves the formation of an actomyosin ring at the division site, followed by ring constriction, membrane furrow formation and extra cellular matrix remodeling. The fission yeast, Schizosaccharomyces pombe (S.&#160;pombe)&#160;is a well-studied model system that has revealed with substantial clarity the initial events in cytokinesis. However, we do not understand clearly how different cytokinetic events are coordinated spatiotemporally. To determine this, one needs to analyze the different cytokinetic events in great details in both time and in space. Here we describe a microscopy approach to examine different cytokinetic events in live cells. With this approach it is possible to time different cytokinetic events and determine the time of recruitment of different proteins during cytokinesis. In addition, we describe protocols to compare protein localization, and distribution at the site of cell division. This is a basic protocol to study cytokinesis in fission yeast and can also be used for other yeasts and fungal systems.

The fission yeast, Schizosaccharomyces pombe&#160;is an excellent model system to study cytokinesis, the final stage in cell division. Here we describe a microscopy approach to analyze different cytokinetic events in live fission yeast cells.

Análise espacial e temporal da Cytokinetic Eventos na levedura de fissão

Cytokinesis, the final step in cell division is critical for maintaining genome integrity. Proper cytokinesis is important for cell differentiation and ...

4D Microscopy of Yeast

The goal of this protocol is to characterize how membrane compartments form and transform in live cells of budding yeast. Many intracellular compartments in yeast are dynamic, and a full understanding of their properties requires time-lapse imaging. Multi-color 4D confocal fluorescence microscopy is a powerful method for tracking the behavior and composition of an intracellular compartment on a time scale of 5-15 min. Rigorous analysis of compartment dynamics requires the capture of thousands of optical sections. To achieve this aim, photobleaching and phototoxicity are minimized by scanning rapidly at very low laser power, and the pixel dimensions and Z-step intervals are set to the largest values that are compatible with sampling the image at full resolution. The resulting 4D data sets are noisy but can be smoothed by deconvolution. Even with high quality data, the analysis phase is challenging because intracellular structures are often numerous, heterogeneous, and mobile. To meet this need, custom ImageJ plugins were written to array 4D data on a computer screen, identify structures of interest, edit the data to isolate individual structures, quantify the fluorescence time courses, and make movies of the projected Z-stacks. 4D movies are particularly useful for distinguishing stable compartments from transient compartments that turn over by maturation. Such movies can also be used to characterize events such as compartment fusion, and to test the effects of specific mutations or other perturbations.

This protocol describes the analysis of fluorescently labeled intracellular compartments in budding yeast using multi-color 4D (time-lapse 3D) confocal microscopy. The imaging parameters are chosen to capture adequate signals while limiting photodamage. Custom ImageJ plugins allow labeled structures to be tracked and quantitatively analyzed.

4D microscopia de levedura

The goal of this protocol is to characterize how membrane compartments form and transform in live cells of budding yeast. Many intracellular compartments ...

Examination of Mitotic and Meiotic Fission Yeast Nuclear Dynamics by Fluorescence Live-cell Microscopy

Live-cell imaging is a microscopy technique used to examine cell and protein dynamics in living cells. This imaging method is not toxic, generally does not interfere with cell physiology, and requires minimal experimental handling. The low levels of technical interference enable researchers to study cells across multiple cycles of mitosis and to observe meiosis from beginning to end. Using fluorescent tags such as Green Fluorescent Protein (GFP) and Red Fluorescent Protein (RFP), researchers can analyze different factors whose functions are important for processes like transcription, DNA replication, cohesion, and segregation. Coupled with data analysis using Fiji (a free, optimized ImageJ version), live-cell imaging offers various ways of assessing protein movement, localization, stability, and timing, as well as nuclear dynamics and chromosome segregation. However, as is the case with other microscopy methods, live-cell imaging is limited by the intrinsic properties of light, which put a limit to the resolution power at high magnifications, and is also sensitive to photobleaching or phototoxicity at high wavelength frequencies. However, with some care, investigators can bypass these physical limitations by carefully choosing the right conditions, strains, and fluorescent markers to allow for the appropriate visualization of mitotic and meiotic events.

Here, we present live-cell imaging which is a non-toxic microscopy method that allows researchers to study protein behavior and nuclear dynamics in living fission yeast cells during mitosis and meiosis.

Examinação da dinâmica nuclear do fermento mitotic e Meiotic da fissão pela microscopia viva-pilha da fluorescência

Live-cell imaging is a microscopy technique used to examine cell and protein dynamics in living cells. This imaging method is not toxic, generally does ...

Measurement of Microtubule Dynamics by Spinning Disk Microscopy in Monopolar Mitotic Spindles

We describe a modification of an established method to determine microtubule dynamics in living cells. The protocol is based on the expression of a genetically encoded marker for the positive ends of microtubules (EB3 labelled with tdTomato fluorescent protein) and high-speed, high-resolution, live-cell imaging using spinning disk confocal microscopy. Cell cycle synchronization and increased density of microtubules are achieved by inhibiting centrosomal separation in mitotic cells, and analysis of growth is performed using open-source U-Track software. The use of a bright and red-shifted fluorescent protein, in combination with the lower laser power and reduced exposure time required for spinning disk microscopy reduce phototoxicity and the probability of light-induced artifacts. This allows for imaging a larger number of cells in the same preparation while maintaining the cells in a growth medium under standard culture conditions. Because the analysis is performed in a supervised automatic fashion, the results are statistically robust and reproducible.

Here we present a robust and detailed method of microtubule dynamics analysis in cells synchronized in prometaphase using live-cell spinning disk confocal microscopy and MATLAB-based image processing.

Medição da dinâmica do microtúbulo girando microscopia do disco em fusos mitocticos monopolares

We describe a modification of an established method to determine microtubule dynamics in living cells. The protocol is based on the expression of a ...

Super-Resolution Live Cell Imaging of Subcellular Structures

There has long been a crucial tradeoff between spatial and temporal resolution in imaging. Imaging beyond the diffraction limit of light has traditionally been restricted to be used only on fixed samples or live cells outside of tissue labeled with strong fluorescent signal. Current super-resolution live cell imaging techniques require the use of special fluorescence probes, high illumination, multiple image acquisitions with post-acquisition processing, or often a combination of these processes. These prerequisites significantly limit the biological samples and contexts that this technique can be applied to.
Here we describe a method to perform super-resolution (~140 nm XY-resolution) time-lapse fluorescence live cell imaging in situ. This technique is also compatible with low fluorescent intensity, for example, EGFP or mCherry endogenously tagged at lowly expressed genes. As a proof-of-principle, we have used this method to visualize multiple subcellular structures in the Drosophila testis. During tissue preparation, both the cellular structure and tissue morphology are maintained within the dissected testis. Here, we use this technique to image microtubule dynamics, the interactions between microtubules and the nuclear membrane, as well as the attachment of microtubules to centromeres.
This technique requires special procedures in sample preparation, sample mounting and immobilizing of specimens. Additionally, the specimens must be maintained for several hours after dissection without compromising cellular function and activity. While we have optimized the conditions for live super-resolution imaging specifically in Drosophila male germline stem cells (GSCs) and progenitor germ cells in dissected testis tissue, this technique is broadly applicable to a variety of different cell types. The ability to observe cells under their physiological conditions without sacrificing either spatial or temporal resolution will serve as an invaluable tool to researchers seeking to address crucial questions in cell biology.

Presented here is a protocol for super-resolution live-cell imaging in intact tissue. We have standardized the conditions for imaging a highly sensitive adult stem cell population in its native tissue environment. This technique involves balancing temporal and spatial resolution to allow for the direct observation of biological phenomena in live tissue.

Imagem celular ao vivo super-resolução de estruturas subcelulares

There has long been a crucial tradeoff between spatial and temporal resolution in imaging. Imaging beyond the diffraction limit of light has traditionally ...