Wir möchten Jonathan Cooper Lab am Fred Hutchinson Cancer Research Center für die Erlaubnis, ihre Kryostat verwenden danken. Diese Arbeit wurde vom NIH und der WM Keck Foundation unterstützt. BM ist ein Gordon und Betty Moore Fellow Life Science Research Foundation. Wir sind dankbar, dass Daniel Gottschling für die gemeinsame Nutzung seiner Befestigung Protokoll mit uns.

Ein. Befestigung Hefe Gemeinschaften <ol><li> Wachsen Hefe Gemeinden auf einem Membranfilter (zB Millipore MF Membranfilter; 2A). Dieses Protokoll entspricht einer typischen Gemeinschaft von weniger als 2x10 8 Zellen auf einer 6 mm-Durchmesser-Membranfilter. </li><li> Mit einem Stück Whatman 541 Filterpapier, um den Boden eines 1 cm Durchmesser und (2B) abzudecken. Diese Whatman Papier als Träger, um die Gemeinschaft in späteren Stadien übertragen werden. 1 ml 100% Methanol zum Brunnen, und lassen Sie das auch in -20 ° C für die Temperatur ins Gleichgewicht. </li><li> Legen flüssigem N 2 in einem Dewar. Frieren Gemeinde in flüssigem Stickstoff durch Eintauchen der Gemeinde für mindestens 15 sec in flüssigem N 2 mit einer Pinzette (Abbildung 2C). </li><li> Übertragen gefrorenen Gemeinschaft zum Wohl von -20 ° C Methanol (2D). Stellen Sie sicher, dass die Gemeinde gehalten wird horizontal, wenn Eintauchen in Methanol.Warten Sie 20 min. Der MF Membranfilter beginnt in Methanol zerfallen. </li><li> Transfergemeinschaft Verwendung des Trägers Whatman 541 Filterpapier aus dem Methanol auch zu einer kalten Petrischale bei -20 ° C für Methanol Verdampfung (2E) gehalten. Bei der Übertragung, halten die Gemeinschaft auf der Oberseite des Trägers Whatman-Filter und wegziehen zusätzliche Tropfen Methanol mit einem anderen Stück dickes Whatman-Papier, bevor sie in der kalten Petrischale. Dadurch wird sichergestellt, dass die Verdampfung Zeitablauf konsistent von Probe zu Probe. </li><li> Warten 4-6 Stunden für die Verdampfung, bis der Träger Whatman-Filter sieht trocken. Unzureichende Verdunstung hinterlässt restliches Methanol, das mit Schneiden stört. Over-Trocknung Ursachen Risse und Verformungen in den Gemeinden. </li><li> Nehmen Sie die Probe aus -20 ° C Gefrierschrank. Schneiden Sie Whatman 541 Filterpapier nicht unter das Gemeinschaftsrecht fallen. </li><li> Einen rechteckigen kubisches Aluminiumfolie Behälter, der groß genug ist, so dass die Probe wenigstens 2 mm ~ Marge von hat, istjede Seite (2F). Legen Sie die Gemeinde an der unteren Oberfläche der Aluminium-Folie Container; sofort decken die Probe mit Oktober um 3 bis 4 mm oberhalb Community Höhe. Wenn wichtige, kann die Ausrichtung der Probe in diesem Schritt in Bezug auf die Seiten des Behälters einstellbar ist. Warten Sie 10 min. </li><li> Legen Sie die Oktober-embedded Probe auf einer metallischen Platte auf Trockeneis zu frieren. Bewahren Sie die gefrorenen Gemeinden bei -20 ° C oder -80 ° C Gefrierschrank. </li></ol> 2. Schnitte Gefrorene Gemeinschaften für Fluoreszenz-Imaging <ol><li> Stellen Sie die Temperatur der Kammer Kryoschnitt bis -25 ° C und lassen die Proben in die Kammer, bis ihre Temperatur erreicht die Temperatur der Kammer. </li><li> Montieren Sie die Probe auf einer Kryo-mount nach dem Auftragen einen Rückgang von Oktober auf dem Berg. Oktober gleichmäßig ausgebreitet auf der Seite der Probe mit freiliegenden Whatman Filterpapier (Boden des Behälters) derart, dass die OCT Dicke 2-3 mm. Lassen Oktober freeze im Kryostatkammer bevor sectioning. Sicherstellung eines OCT-Marge von 2-3 mm an allen Seiten der Probe hilft, die Unversehrtheit der Abschnitte zu bewahren. </li><li> Die Seiten des Oktober Probenblock kann verwendet werden, um die Probe auszurichten. Wenn die Probe nicht mit Bezug auf die Klinge ausgerichtet ist, wird Schneidens von einer Ecke oder Seite der Probe beginnen. Anpassen der Halterung zu gewährleisten, dass die Klinge eine perfekt vertikal (oder horizontalen) Fläche des Probenblocks schneidet. </li><li> Typische Bereiche für Hefe-Gemeinden sind ~ 14 Mikrometer dicke. Nach Schneiden eines Abschnitts, mit einem Mikroskop-Objektträger bei Raumtemperatur gehalten, um den Abschnitt zu sammeln, durch langsames Anfahren der Folie in die Schnittfläche. Der Abschnitt wird schmelzen und Transfer zum Objektträger. Bis zu 18 Teile können auf einen Objektträger übertragen werden. </li><li> Bewahren Sie die Folien bei kalten Temperaturen, vorzugsweise -20 ° C, bevor Bildgebung. Signalverlust ist minimal, wenn für eine Woche bei 4 ° C gehalten wird Für maximale Fluoreszenzsignal wird Bildgebung bevorzugt unmittelbar nach Schneiden getan. </li></ol>

<ol>
	<li>Tolker-Nielsen, T., Molin, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatial+Organization+of+Microbial+Biofilm+Communities.">Spatial Organization of Microbial Biofilm Communities.</a> Microbial Ecology. 40 (2), 75-84 (2000).</li><li>Moller, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=+In+Situ+Gene+Expression+in+Mixed-Culture+Biofilms:+Evidence+of+Metabolic+Interactions+between+Community+Members."> In Situ Gene Expression in Mixed-Culture Biofilms: Evidence of Metabolic Interactions between Community Members.</a> Appl. Environ. Microbiol. 64 (2), 721-732 (1998).</li><li>Lepp, P. W., 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=Methanogenic+Archaea+and+human+periodontal+disease.">Methanogenic Archaea and human periodontal disease.</a> Proceedings of the National Academy of Sciences of the United States of America. 101 (16), 6176-6181 (2004).</li><li>V&#225;chov&#225;, L., 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=Architecture+of+developing+multicellular+yeast+colony:+spatio-temporal+expression+of+Ato1p+ammonium+exporter.">Architecture of developing multicellular yeast colony: spatio-temporal expression of Ato1p ammonium exporter.</a> Environmental Microbiology. 11 (7), 1866-1877 (2009).</li><li>Min&#225;rikov&#225;, L., 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=Differentiated+Gene+Expression+in+Cells+within+Yeast+Colonies.">Differentiated Gene Expression in Cells within Yeast Colonies.</a> Experimental Cell Research. 271 (2), 296-304 (2001).</li><li>Shou, W., 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=Synthetic+cooperation+in+engineered+yeast+populations.">Synthetic cooperation in engineered yeast populations.</a> Proc. Natl. Acad. Sci. U.S.A. 104, 1877-1882 (2007).</li><li>Momeni, B., 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=Cooperation+generates+a+unique+spatial+signature+in+microbial+communities.">Cooperation generates a unique spatial signature in microbial communities.</a> , (2012).</li><li>Kiernan, J., ed, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Histological and Histochemical Methods: Theory and Practice. , 4 (2008).</li><li>Piccirillo, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Rim101p/PacC+Pathway+and+Alkaline+pH+Regulate+Pattern+Formation+in+Yeast+Colonies.">The Rim101p/PacC Pathway and Alkaline pH Regulate Pattern Formation in Yeast Colonies.</a> Genetics. 184 (3), 707-716 (2010).</li></ol>

Keine Interessenskonflikte erklärt.

Das hier vorgestellte Verfahren bietet eine Möglichkeit, die innere Struktur des Hefe-Communities zu inspizieren. Das Methanol Fixierschritt macht die Hefekolonie starren 8 und bewahrt die Integrität der Kolonie, aber es verursacht auch Schrumpfung 8, sollte bei der Interpretation der Ergebnisse berücksichtigt werden. Wir in der Regel sehen rund 30% Schrumpfung in Höhe von Hefe-Kolonien im Vergleich zu Kolonien direkt in OCT ohne Befestigungsmaterial 9 eingebettet. <p class="jove...

<table border="1"><tbody><tr><td> Name des Reagenzes </td><td> Firma </td><td> Katalog-Nummer </td><td> Kommentare (optional) </td></tr><tr><td> 100% Methanol </td><td> JT Baker </td><td> 9070-01 </td><td></td></tr><tr><td> Tissue-Tek OCT Compound </td><td> Andwin Scientific </td><td> 4583 </td><td></td></tr><tr><td> Whatman Grade Nr. 541 Quantitative Filter Paper </td><td> Whatman </td><td> 1541-047 </td><td></td></tr><tr><td> Millipore-MF Membrane Filter </td><td> Millipore </td><td> HAWP04700 </td><td></td></tr><tr><td> Kryostat </td><td> Leica </td><td> CM 1510 S </td><td></td></tr></tbody></table>

cryosectioning yeast communities for examining fluorescence patterns

Mikroben leben typischerweise in den Gemeinden. Die räumliche Organisation von Zellen innerhalb einer Gemeinschaft wird angenommen, dass das Überleben und die Funktion der Reisenden 1 auswirken. Optische Schnitte Techniken, einschließlich konfokale und Zwei-Photonen-Mikroskopie, haben sich bewährt zur Beobachtung räumlichen Organisation von Bakterien und Archaeen Gemeinden 2,3. Eine Kombination von konfokale Bildgebung und physikalische Schnitte von Hefe-Kolonien hat interne Organisation von Zellen 4 enthüllt. Allerdings hat direkte optische Schnitte mittels konfokaler oder Zwei-Photonen-Mikroskopie war nur in der Lage, ein paar Zellschichten tief in Hefe-Kolonien zu erreichen. Diese Einschränkung ist aufgrund der starken Streuung des Lichts aus Hefezellen 4 wahrscheinlich. Hier präsentieren wir eine Methode zur Festsetzung und Kryoschneiden die räumliche Verteilung der fluoreszierenden Zellen in Saccharomyces cerevisiae Gemeinden zu basieren. Wir verwenden Methanol als Fixiermittelum die räumliche Verteilung der Zellen zu erhalten. Feste Gemeinden sind mit OCT-Verbindung, gefroren und kryogeschnitten in einem Kryostaten infiltriert. Fluoreszenz-Bildgebung der Abschnitte zeigt die interne Organisation der fluoreszierenden Zellen innerhalb der Gemeinschaft. Beispiele von Hefe Communities bestehend aus Stämmen exprimierenden rot und grün fluoreszierende Proteine ​​zeigen die Potentiale des Kryoschneiden Methode, um die räumliche Verteilung der fluoreszierenden Zellen sowie die der Genexpression innerhalb Hefekolonien 2,3 offenbaren. Obwohl unsere Fokussierung auf Saccharomyces cerevisiae Gemeinden gewesen ist, kann das gleiche Verfahren angewandt potentiell zu anderen mikrobiellen untersuchen.

Fluoreszenzbilder von vertikalen Querschnitten von Hefe Communities enthaltenden roten und grün-tagged wettbewerbsfähigen Populationen 6 sind in Abbildung 3 dargestellt. Diese Gemeinschaften bestehen aus zwei prototrophen Hefestämme und deren Wettbewerb für gemeinsam genutzte Ressourcen, einschließlich Raum, führt zu säulenartigen Strukturen 7, wie in ihrer vertikalen Querschnitten dargestellt. Auflösungen bis hinunter zu einer einzigen Zelle kann in Querschnitten gelöst w...

Watch this Scientific Journal Video about Cryosectioning Yeast Communities for Examining Fluorescence Patterns at JoVE.com

Cryosectioning Yeast Communities for Examining Fluorescence Patterns

Wir präsentieren ein Protokoll zum Einfrieren und Kryoschneiden Hefe Gemeinden internen Muster der fluoreszierenden Zellen zu beobachten. Die Methode beruht auf Methanol-Fixierung und OCT-Einbettung, um die räumliche Verteilung der Zellen ohne Inaktivierung fluoreszierende Proteine ​​innerhalb einer Gemeinschaft bewahren.

Kryoschneiden Hefe Gemeinschaften für die Prüfung Fluoreszenzmuster

Microbes typically live  in communities. The spatial organization  of cells within a community is believed to impact the survival and function of the  ...

cryosectioning-yeast-communities-for-examining-fluorescence-patterns

Research

JoVE Journal

Biology

8.8K Aufrufe.  Fred Hutchinson Cancer Research Center. Wir präsentieren ein Protokoll zum Einfrieren und Kryoschneiden Hefe Gemeinden internen Muster der fluoreszierenden Zellen zu beobachten. Die Methode beruht auf Methanol-Fixierung und OCT-Einbettung, um die räumliche Verteilung der Zellen ohne Inaktivierung fluoreszierende Proteine ​​innerhalb einer Gemeinschaft bewahren.

Serie: Cryosectioning Yeast Communities for Examining Fluorescence Patterns

Flash Freezing and Cryosectioning E12.5 Mouse Brain

Demonstrated in this video are the techniques for flash freezing and sectioning embryonic brain tissue from mouse. Useful tips for using the cryostat are given, including troubleshooting methods that can be used while cutting to ensure that the resultant tissues sections are free of cracks and other distortions.

Flash-Freezing und Kryoschneiden E12.5 Gehirn der Maus

Forschung

Biologie

Microbial Communities in Nature and Laboratory - Interview

Mikrobielle Gemeinschaften in Natur und Labor - Interview

Biology of Microbial Communities  - Interview

Biologie mikrobieller Gemeinschaften - Interview

A Microfluidic Device with Groove Patterns for Studying Cellular Behavior

We describe a microfluidic device with microgrooved patterns for studying cellular behavior. This microfluidic platform consists of a top fluidic channel and a bottom microgrooved substrate. To fabricate the microgrooved channels, a top poly(dimethylsiloxane) (PDMS) mold containing the impression of the microfluidic channels was aligned and bonded to a microgrooved substrate. Using this device, mouse fibroblast cells were immobilized and patterned within microgrooved substrates (25, 50, 75, and 100 &mu;m wide). To study apoptosis in a microfluidic device, media containing hydrogen peroxide, Annexin V, and propidium iodide was perfused into the fluidic channel for 2 hours. We found that cells exposed to the oxidative stress became apoptotic. These apoptotic cells were confirmed by Annexin V that bound to phosphatidylserine at the outer leaflet of the plasma membrane during the apoptosis process. Using this microfluidic device with microgrooved patterns, the apoptosis process was observed in real-time and analyzed by using an inverted microscope containing an incubation chamber (37&deg;C, 5% CO2). Therefore, this microfluidic device incorporated with microgrooved substrates could be useful for studying the cellular behavior and performing high-throughput drug screening.

We describe a protocol for the fabrication of microfluidic devices that can enable cell capture and culture. In this approach patterned microstructures such as grooves within microfluidic channels are used to create low shear stress regions within which cell can dock.

Einer mikrofluidischen Vorrichtung mit Groove Patterns für ein Studium Cellular Behavior

We describe a microfluidic device with microgrooved patterns for studying cellular behavior.  This microfluidic platform consists of a top fluidic channel ...

Time-lapse Imaging of Mitosis After siRNA Transfection

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and cellular content. Hallmark events of mitosis, such as chromosome movement, can be readily tracked on an individual cell basis using time-lapse fluorescence microscopy of mammalian cell lines expressing specific GFP-tagged proteins. In combination with RNAi-based depletion, this can be a powerful method for pinpointing the stage(s) of mitosis where defects occur after levels of a particular protein have been lowered. In this protocol, we present a basic method for assessing the effect of depleting a potential mitotic regulatory protein on the timing of mitosis. Cells are transfected with siRNA, placed in a stage-top incubation chamber, and imaged using an automated fluorescence microscope. We describe how to use software to set up a time-lapse experiment, how to process the image sequences to make either still-image montages or movies, and how to quantify and analyze the timing of mitotic stages using a cell-line expressing mCherry-tagged histone H2B. Finally, we discuss important considerations for designing a time-lapse experiment. This strategy is complementary to other approaches and offers the advantages of 1) sensitivity to changes in kinetics that might not be observed when looking at cells as a population and 2) analysis of mitosis without the need to synchronize the cell cycle using drug treatments. The visual information from such imaging experiments not only allows the sub-stages of mitosis to be assessed, but can also provide unexpected insight that would not be apparent from cell cycle analysis by FACS.

Here we describe a basic protocol to image and quantify the mitotic timing of live mammalian tissue culture cells after siRNA transfection.

Zeitraffer-Imaging der Mitose Nach siRNA-Transfektion

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and ...

Examining the Conformational Dynamics of Membrane Proteins in situ with Site-directed Fluorescence Labeling

Two electrode voltage clamp electrophysiology (TEVC) is a powerful tool to investigate the mechanism of ion transport1 for a wide variety of membrane proteins including ion channels2, ion pumps3, and transporters4. Recent developments have combined site-specific fluorophore labeling alongside TEVC to 
concurrently examine the conformational dynamics at specific residues and function of these proteins on the surface of single cells.
We will describe a method to study the conformational dynamics of membrane proteins by simultaneously monitoring fluorescence and current changes using voltage-clamp fluorometry. This approach can be used to examine the molecular motion of membrane proteins site-specifically following cysteine replacement and site-directed fluorophore labeling5,6. Furthermore, this method provides an approach to determine distance constraints between specific residues7,8. 
This is achieved by selectively attaching donor and acceptor fluorophores to two mutated cysteine residues of interest.
In brief, these experiments are performed following functional expression of the desired protein on the surface of Xenopus leavis oocytes. The large surface area of these oocytes enables facile functional measurements and a robust fluorescence signal5. It is also possible to readily change the extracellular conditions such as pH, ligand or cations/anions, which can provide further information on the mechanism of membrane proteins4. Finally, recent developments 
have also enabled the manipulation of select internal ions following co-expression with a second protein9.
Our protocol is described in multiple parts. First, cysteine scanning mutagenesis proceeded by fluorophore labeling is completed at residues located at the interface of the transmembrane and extracellular domains. Subsequent experiments are designed to identify residues which demonstrate large changes in fluorescence intensity (&lt;5%)3 upon a conformational change of the protein. Second, these changes in fluorescence intensity are compared to the kinetic parameters of 
the membrane protein in order to correlate the conformational dynamics to the function of the protein10. This enables a rigorous biophysical analysis of the molecular motion of the target protein. Lastly, two residues of the holoenzyme can be labeled with a donor and acceptor fluorophore in order to determine distance constraints using donor photodestruction methods. It is also possible to monitor the relative movement of protein subunits following labeling with a donor and acceptor fluorophore.

Examining the Conformational Dynamics of Membrane Proteins in situ with Site-directed Fluorescence Labeling

We will describe a method which measures the kinetics of ion transport of membrane proteins alongside site-specific analysis of conformational changes using fluorescence on single cells. This technique is adaptable to ion channels, transporters and ion pumps and can be utilized to determine distance constraints between protein subunits.

Die Untersuchung der Konformationsänderungen Dynamics von Membranproteinen In situ Mit Site-directed Fluoreszenzmarkierung

Two electrode voltage clamp electrophysiology (TEVC) is a powerful tool to investigate the mechanism of ion transport1 for a wide variety of membrane ...

A Fluorescence Microscopy Assay for Monitoring Mitophagy in the Yeast Saccharomyces cerevisiae

Autophagy is important for turnover of cellular components under a range of different conditions. It serves an essential homeostatic function as well as a quality control mechanism that can target and selectively degrade cellular material including organelles1-4. For example, damaged or redundant mitochondria (Fig. 1), not disposed of by autophagy, can represent a threat to cellular homeostasis and cell survival. In the yeast, Saccharomyces cerevisiae, nutrient deprivation (e.g., nitrogen starvation) or damage can promote selective turnover of mitochondria by autophagy in a process termed mitophagy 5-9.
We describe a simple fluorescence microscopy approach to assess autophagy. For clarity we restrict our description here to show how the approach can be used to monitor mitophagy in yeast cells. The assay makes use of a fluorescent reporter, Rosella, which is a dual-emission biosensor comprising a relatively pH-stable red fluorescent protein linked to a pH-sensitive green fluorescent protein. The operation of this reporter relies on differences in pH between the vacuole (pH ~ 5.0-5.5) and mitochondria (pH ~ 8.2) in living cells. Under growing conditions, wild type cells exhibit both red and green fluorescence distributed in a manner characteristic of the mitochondria. Fluorescence emission is not associated with the vacuole. When subjected to nitrogen starvation, a condition which induces mitophagy, in addition to red and green fluorescence labeling the mitochondria, cells exhibit the accumulation of red, but not green fluorescence, in the acidic vacuolar lumen representing the delivery of mitochondria to the vacuole. Scoring cells with red, but not green fluorescent vacuoles can be used as a measure of mitophagic activity in cells5,10-12.

A Fluorescence Microscopy Assay for Monitoring Mitophagy in the Yeast Saccharomyces cerevisiae

A robust approach to monitor the delivery of organelles to the acidic lumen of the yeast vacuole for degradation and recycling is described. The method relies on the specific labeling of target organelles with a genetically encoded dual-emission fluorescence pH-biosensor, and visualization of individual cells using fluorescence microscopy.

Eine Fluoreszenz-Mikroskopie Assay zur Überwachung Mitophagy in der Hefe Saccharomyces cerevisiae

Autophagy is important for turnover of cellular components under a range of different conditions. It serves an essential homeostatic function as well as a ...

Quantitative Live Cell Fluorescence-microscopy Analysis of Fission Yeast

Several microscopy techniques are available today that can detect a specific protein within the cell. During the last decade live cell imaging using fluorochromes like Green Fluorescent Protein (GFP) directly attached to the protein of interest has become increasingly popular 1. Using GFP and similar fluorochromes the subcellular localisations and movements of proteins can be detected in a fluorescent microscope. Moreover, also the subnuclear localisation of a certain region of a chromosome can be studied using this technique. GFP is fused to the Lac Repressor protein (LacR) and ectopically expressed in the cell where tandem repeats of the lacO sequence has been inserted into the region of interest on the chromosome2. The LacR-GFP will bind to the lacO repeats and that area of the genome will be visible as a green dot in the fluorescence microscope. Yeast is especially suited for this type of manipulation since homologous recombination is very efficient and thereby enables targeted integration of the lacO repeats and engineered fusion proteins with GFP 3. Here we describe a quantitative method for live cell analysis of fission yeast. Additional protocols for live cell analysis of fission yeast can be found, for example on how to make a movie of the meiotic chromosomal behaviour 4. In this particular experiment we focus on subnuclear organisation and how it is affected during gene induction. We have labelled a gene cluster, named Chr1, by the introduction of lacO binding sites in the vicinity of the genes. The gene cluster is enriched for genes that are induced early during nitrogen starvation of fission yeast 5. In the strain the nuclear membrane (NM) is labelled by the attachment of mCherry to the NM protein Cut11 giving rise to a red fluorescent signal. The Spindle Pole body (SPB) compound Sid4 is fused to Red Fluorescent Protein (Sid4-mRFP) 6. In vegetatively growing yeast cells the centromeres are always attached to the SPB that is embedded in the NM 7. The SPB is identified as a large round structure in the NM. By imaging before and 20 minutes after depletion of the nitrogen source we can determine the distance between the gene cluster (GFP) and the NM/SPB. The mean or median distances before and after nitrogen depletion are compared and we can thus quantify whether or not there is a shift in subcellular localisation of the gene cluster after nitrogen depletion.

The fission yeast, Schizosaccharomyces pombe, is a good model system to study basic cellular processes. Here we describe a method to perform quantitative live cell analysis of fission yeast. In this particular experiment we focus on organisation of the genome within the cell nucleus, but the method can also be used to study cytosolic factors.

Quantitative Live Cell Fluoreszenz-Mikroskopie Analyse von Fission Yeast

Several microscopy techniques are available today that can detect a specific protein within the cell. During the last decade live cell imaging using ...

Radioactive in situ Hybridization for Detecting Diverse Gene Expression Patterns in Tissue

Knowing the timing, level, cellular localization, and cell type that a gene is expressed in contributes to our understanding of the function of the gene. Each of these features can be accomplished with in situ hybridization to mRNAs within cells. Here we present a radioactive in situ hybridization method modified from Clayton et al. (1988)1 that has been working successfully in our lab for many years, especially for adult vertebrate brains2-5. The long complementary RNA (cRNA) probes to the target sequence allows for detection of low abundance transcripts6,7. Incorporation of radioactive nucleotides into the cRNA probes allows for further detection sensitivity of low abundance transcripts and quantitative analyses, either by light sensitive x-ray film or emulsion coated over the tissue. These detection methods provide a long-term record of target gene expression. Compared with non-radioactive probe methods, such as DIG-labeling, the radioactive probe hybridization method does not require multiple amplification steps using HRP-antibodies and/or TSA kit to detect low abundance transcripts. Therefore, this method provides a linear relation between signal intensity and targeted mRNA amounts for quantitative analysis. It allows processing 100-200 slides simultaneously. It works well for different developmental stages of embryos. Most developmental studies of gene expression use whole embryos and non-radioactive approaches8,9, in part because embryonic tissue is more fragile than adult tissue, with less cohesion between cells, making it difficult to see boundaries between cell populations with tissue sections. In contrast, our radioactive approach, due to the larger range of sensitivity, is able to obtain higher contrast in resolution of gene expression between tissue regions, making it easier to see boundaries between populations. Using this method, researchers could reveal the possible significance of a newly identified gene, and further predict the function of the gene of interest.

Radioactive in situ Hybridization for Detecting Diverse Gene Expression Patterns in Tissue

This protocol is successfully used to quantitatively detect levels and spatial patterns of mRNA expression in multiple tissue types across vertebrate species. The method can detect low abundance transcripts and allows processing of hundreds of slides simultaneously. We present this protocol using expression profiling of avian embryonic brain formation as an example.

Radioaktiv In-situ- Hybridisierung zum Nachweis Diverse Genexpressionsmuster in Tissue

Knowing the timing, level, cellular localization, and cell type that a gene is expressed in contributes to our understanding of the function of the gene. ...

Acquiring Fluorescence Time-lapse Movies of Budding Yeast and Analyzing Single-cell Dynamics using GRAFTS

Fluorescence time-lapse microscopy has become a powerful tool in the study of many biological processes at the single-cell level. In particular, movies depicting the temporal dependence of gene expression provide insight into the dynamics of its regulation; however, there are many technical challenges to obtaining and analyzing fluorescence movies of single cells. We describe here a simple protocol using a commercially available microfluidic culture device to generate such data, and a MATLAB-based, graphical user interface (GUI) -based software package to quantify the fluorescence images. The software segments and tracks cells, enables the user to visually curate errors in the data, and automatically assigns lineage and division times. The GUI further analyzes the time series to produce whole cell traces as well as their first and second time derivatives. While the software was designed for S. cerevisiae, its modularity and versatility should allow it to serve as a platform for studying other cell types with few modifications.

We present a simple protocol to obtain fluorescence microscopy movies of growing yeast cells, and a GUI-based software package to extract single-cell time series data. The analysis includes automated lineage and division time assignment integrated with visual inspection and manual curation of tracked data.

Acquiring Fluoreszenz Zeitraffer-Filme von Bäckerhefe und Analysieren von Einzel-Zell-Dynamics mit Transplantaten

Fluorescence time-lapse microscopy has become a powerful tool in the study of many biological processes at the single-cell level. In particular, movies ...