Name: a fast air-dry dropping chromosome preparation method suitable for fish in plants
Uploaded: 2015-12-16T14:00:00.000+00:00
Duration: 9 min 8 s
Description: Watch this Scientific Journal Video about A Fast Air-dry Dropping Chromosome Preparation Method Suitable for FISH in Plants at JoVE.com

We gratefully thank the DFG for financial support (HO 1779/21-1) as well as Katrin Kumke and Dr. Veit Schubert (IPK, Gatersleben) for technical advice.

1. Chromosomenpräparation <ol><li> Keimung der Samen und die Fixierung des Wurzelspitzen <ol><li> Keimen 10-20 Gerstensamen auf zwei Lagen von feuchtem Filterpapier in einer Petrischale unter dunklen Bedingungen 2 Tage bei 22-24 ° C. Abgeschnitten kräftige Wurzeln mit der Länge von 1-2 cm vom Samen unter Verwendung einer Rasierklinge. </li><li> Bereiten Sie eiskaltes Wasser, indem ein 500 ml-Glasflasche mit kaltem Leitungswasser in zerstoßenes Eis-Wasser. Lüften Sie den eiskalten Wasser und tauchen Sie den Wurzelspitzen 20 Stunden, um die Frequenz des Metaphase-Zellen zu erhöhen. </li><li> Bringen Wurzeln aus dem Wasser, um 50 ml Ethanol: Essigsäure (3: 1) Fixierungsmittel, um sie bei Raumtemperatur für 2 Tage zu beheben. Speicher Wurzeln in eine frisch hergestellte Ethanol: Essigsäure (3: 1) Fixiermittel bei 4 ° C bis zur Verwendung bis zu einem Jahr. </li></ol></li><li> Waschen und Enzymbehandlung <ol><li> 5 min zweimal mit einem 50 ml Becherglas waschen 10-20 Wurzeln mit 30 ml eiskaltem Leitungswasser. Verwenden Binokular. Übertragen Wurzeln nacheinander in30 ml 0,01 M Citratpuffer (0,01 M Citronensäure + 0,01 M Natriumcitrat, pH 4,8) unter Verwendung einer Pinzette und wäscht zweimal durch Schütteln des Becherglas für 5 min. Platzieren Wurzeln auf Filterpapier, um die Flüssigkeit vollständig zu entfernen und Trenn unerwünschte nicht Meristemgewebe mit einer Rasierklinge. </li><li> Inkubieren bis 20 Wurzelspitzen in 1 ml Enzymgemisch bei 37 ° C für ca. 50 min, das Pflanzengewebe erweichen (Tabelle 1) in einem Uhrglas. Enzymmischung enthält 0,7% Cellulase R10, 0,7% Cellulase, 1% Pectolyase und 1% Cytohelicase in 0,01 M Citratpuffer verdünnt. Speichern das Enzymgemisch bei -20 ° C und bis zu fünf Mal wiederverwendet. </li><li> Entfernen Sie das Enzym durch Pipettieren und waschen Sie die Wurzelspitzen auf Eis mit 5 ml 0,01 M Citratpuffer zweimal, um das restliche Enzym zu ersetzen. </li></ol></li><li> Root Mazeration <ol><li> Wash Wurzelspitzen mit 1 ml 96% igem Ethanol zweimal vorsichtig auf die gleiche Uhrglas. Ethanol mit frisch zubereiteten Fixierungsmittel (25% Ethanol 75% Essigsäure) zu ersetzen. Verwenden Sie 10-15ul Fixiermittel pro Wurzelspitze. </li><li> Übertragungswurzelspitzen zusammen mit dem Fixierungsmittel in ein 2-ml-Röhrchen und zerfallen Wurzelmeristemen mit Seziernadel oder Pinzette. Tippen Sie auf das Rohr 20 mal zu resuspendieren Zellen, um eine Zellsuspension zu erhalten. Bewahren Sie die Zellsuspension bei -20 ° C bis zu zwei Monate. </li></ol></li><li> Dropping der Zellsuspension <ol><li> Man gibt 2-3 Schichten von mit Wasser getränkten Papiertuch auf einer heißen Platte bei 50 ° C. Tauchen Objektträger in eiskaltem Leitungswasser in den Kühlschrank für 30 Minuten. Ort und gleitet auf dem feuchten Papiertuch. </li><li> Pipette 7-10 ul der Zellsuspension und legen Sie sie in einem Abstand von 20 cm auf die gekühlten Schieber auf der Heizplatte gelegt. Je 10 &amp; mgr; l Essigsäure-Ethanol-Gemisch auf der gleichen Stelle wie Zellsuspension auf der Folie und halten Sie den Schieber auf der heißen Platte für weitere 2 min. Setzen Sie den Schieber auf der heißen Platte ohne die Feuchttuch und lassen Sie es für 1 min trocknen. </li></ol></li><li> Qualitätskontrolle und storage von Dias <ol><li> Überprüfen Sie Dias mit einem Phasenkontrastmikroskop, um die Qualität des Chromosoms Ausbreitung zu kontrollieren. Verwenden Sie Folien entweder am selben Tag oder Wert auf in 96% Ethanol bei -20 ° C eingetaucht in eine Coplin-Gefäß. </li></ol></li><li> Eine Vorbehandlung der Folien vor FISH; Alle Schritte werden bei Raumtemperatur durchgeführt <ol><li> Die Objektträger in eine Coplin-Gefäß mit 50 ml 2 × SSC (20x SSC enthält 3 M NaCl und 300 mM Trinatriumcitrat) für 5 min. Mit einer Pinzette, Transferfolien in einen Coplin-Gefäß mit 50 ml 45% Essigsäure für 3-10 min. </li><li> Objektträger in eine Coplin-Gefäß mit 50 ml 2 × SSC für 10 Minuten. Objektträger in eine Coplin-Gefäß mit 50 ml 4% Formaldehyd (in 2x SSC) und tauchen Folien für 10 Minuten, um Chromosomen zu beheben. </li><li> Entfernen Formaldehyd durch Spülen der Objektträger 3 mal pro 4 min, in einer Glasküvette mit 50 ml 2 × SSC. Dehydratisieren Folien in einer Coplin-Gefäß für 2 min in der Reihe von 70%, 90% und 100% Ethanol um und trocken gleitet in einem vertikalenPosition. </li></ol></li></ol> 2. Fluoreszenz in situ Hybridisierung (FISH) <ol><li> Für jede Folie, bereiten eine Hybridisierungslösung von 20 ul insgesamt mit 10 ul deionisiertem Formamid, 5 &amp; mgr; l 4x Hybridisierungspuffer (200 ul Puffer enthält 80 ul 20x SSC, 8 ul 1 M Tris-HCl pH 8,0, 1,6 ul 0,5 M EDTA, 11,2 &amp; mgr; l 10 ug / ul Lachssperma und 99,2 ul DNase-freies Wasser), 3 &amp; mgr; l der Sonde und 2 ul DNase-freiem Wasser. </li><li> In 20 ul Hybridisierungslösung pro Folie und Deckel mit einem 24 x 32 mm Deckglas und die Festnahme des Deckglas mit Gummi-Zement. Denaturieren Folien mit Sonden gleichzeitig bei 80 ° C für 2 Minuten auf einer heißen Platte. </li><li> Objektträger in eine feuchte Kammer und inkubieren Objektträger bei 37 ° CO / N Vermeidung von Licht. Entfernen Sie Deckgläser durch Spülen der Objektträger in eine Coplin-Gefäß mit 2x SSC. Die Objektträger in eine Glasküvette mit 55-60 ° C 2 × SSC und Inkubation für 20 min. </li><li> Legen Sie die Folien an SSC in einer Coplin-Gefäß für 2 min bei RT 2x. Dehydratisieren Folien in einer Coplin-Gefäß für 2 min in der Reihe von 70%, 90% und 100% Ethanol auf. </li><li> Der Luft trocknen die Folien und Gegenfärbung mit 1 ug / ml 4 &#39;, 6-Diamidino-2-Phenylindolin (DAPI) in Antibleich Eindeckmedium, vermeiden Sie intensives Licht. </li></ol> 3. Die mikroskopische Analyse und Speicherung <ol><li> Analysieren Sie die Folien mit einem Epifluoreszenz-Mikroskop. Die Auswahl der Filter hängt von der Fluorochrom für die Sondenmarkierung eingesetzt. Falls erforderlich, speichern gleitet bei 4 ° C bei schlechten Lichtverhältnissen bis zu einem Jahr. </li></ol>

<ol>
	<li>Geber, G., Schweizer, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytochemical+heterochromatin+differentiation+in+Sinapis+alba+(Cruciferae)+using+a+simple+air-drying+technique+for+producing+chromosome+spreads.">Cytochemical heterochromatin differentiation in Sinapis alba (Cruciferae) using a simple air-drying technique for producing chromosome spreads.</a> Pl Syst Evol. 158 (2-4), 97-106 (1988).</li><li>Andras, S. C., 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=A+drop-spreading+technique+to+produce+cytoplasm-free+mitotic+preparations+from+plants+with+small+chromosomes.">A drop-spreading technique to produce cytoplasm-free mitotic preparations from plants with small chromosomes.</a> Chromosome Res. 7 (8), 641-647 (1999).</li><li>Rothfels, K. H., Siminovitch, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+air-drying+technique+for+flattening+chromosomes+in+mammalian+cells+grown+in+vitro.">An air-drying technique for flattening chromosomes in mammalian cells grown in vitro.</a> Stain Technology. 33 (2), 73-77 (1958).</li><li>Martin, R., Busch, W., Herrmann, R. G., Wanner, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+preparation+of+plant+chromosomes+for+high-resolution+scanning+electron+microscopy.">Efficient preparation of plant chromosomes for high-resolution scanning electron microscopy.</a> Chromosome Res. 2 (5), 411-415 (1994).</li><li>Kato, A., Albert, P. S., Vega, J. M., Birchler, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensitive+fluorescence+in+situ+hybridization+signal+detection+in+maize+using+directly+labeled+probes+produced+by+high+concentration+DNA+polymerase+nick+translation.">Sensitive fluorescence in situ hybridization signal detection in maize using directly labeled probes produced by high concentration DNA polymerase nick translation.</a> Biotech. Histochem. 81 (2-3), 71-78 (2006).</li><li>Kirov, I., Divashuk, M., Van Laere, K., Soloviev, A., Khrustaleva, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+easy+'SteamDrop'+method+for+high+quality+plant+chromosome+preparation.">An easy 'SteamDrop' method for high quality plant chromosome preparation.</a> Mol. Cytogenet. 7, 21 (2014).</li><li>Spurbeck, J. L., Zinsmeister, A. R., Meyer, K. J., Jalal, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamics+of+chromosome+spreading.">Dynamics of chromosome spreading.</a> Am J Med Genet. 61 (4), 387-393 (1996).</li><li>Ma, 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=Synteny+between+Brachypodium+distachyon+and+Hordeum+vulgare+as+revealed+by+FISH.">Synteny between Brachypodium distachyon and Hordeum vulgare as revealed by FISH.</a> Chromosome Res. 18 (7), 841-850 (2010).</li><li>Kato, A., Lamb, J. C., Birchler, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chromosome+painting+using+repetitive+DNA+sequences+as+probes+for+somatic+chromosome+identification+in+maize.">Chromosome painting using repetitive DNA sequences as probes for somatic chromosome identification in maize.</a> Proc. Natl. Acad. Sci. U S A. 101 (37), 13554-13559 (2004).</li><li>Pan, W. H., Houben, A., Schlegel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+effective+cell+synchronization+in+plant-roots+by+hydroxyurea+and+amiprophos-methyl+or+colchicine.">Highly effective cell synchronization in plant-roots by hydroxyurea and amiprophos-methyl or colchicine.</a> Genome. 36 (2), 387-390 (1993).</li><li>Kim, J. 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=Integrated+karyotyping+of+sorghum+by+in+situ+hybridization+of+landed+BACs.">Integrated karyotyping of sorghum by in situ hybridization of landed BACs.</a> Genome. 45 (2), 402-412 (2002).</li><li>Lapitan, N. L. V., Brown, S. E., Kennard, W., Stephens, J. L., Knudson, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FISH+physical+mapping+with+barley+BAC+clones.">FISH physical mapping with barley BAC clones.</a> Plant J. 11 (1), 149-156 (1997).</li><li>Aliyeva-Schnorr, 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=Cytogenetic+mapping+with+centromeric+BAC+contigs+shows+that+this+recombination-poor+region+comprises+more+than+half+of+barley+chromosome+3H.">Cytogenetic mapping with centromeric BAC contigs shows that this recombination-poor region comprises more than half of barley chromosome 3H.</a> Plant J. 84, 385-394 (2015).</li></ol>

The authors have nothing to disclose.

Das Chromosom Vorbereitung Experiment wurde unter Verwendung von jungen Wurzeln von Getreide zu der Familie der Gräser (Poaceae) gehören, durchgeführt. Alle untersuchten Arten haben 14 relativ lange mitotischen Metaphase-Chromosomen (11-15 &amp; mgr; m) in der diploiden Genom-Set und gehören zu großen Genom-Arten (5,1-7,9 GBP). Länge der gekeimten Wurzeln nicht mehr als 2 cm, maximal Meristemgewebe erhalten. Synchronisation von sich teilenden Zellen wurde durch eine 20 Stunden lang Eis...

Fluoreszenz in situ Hybridisierung (FISH) ist ein effektives Werkzeug für die physische Zuordnung von Ein- und hohe Kopien Sequenzen an der chromosomalen Ebene. Voraussetzung ist die Herstellung von qualitativ hochwertigen Chromosomenspreads. Es gibt keine allgemeine Chromosomen Vorschrift, die gleichermaßen für die Tier- und Pflanzenzellen wären. Herstellung von Pflanzenchromosomen ist besonders herausfordernd aufgrund der starren Zellwand und Zellplasma verschiedener Konsistenz innerhalb verschiedener Arten. Einer der vorteilhaften Verfahren zur Herstellung von Pflanzenchromosomen ist eine sogenannte Drop-Technik auch als Drop Spreiztechnik und lufttrocknenden Technik 1,2 bekannt. Diese Methode wurde erstmals 1958 von Rothfels und Siminovitch für die in vitro gezüchtet Säugerzellen 3 eingeführt. Später Martin et al. 4 und Kato et al. 5 geeignet ist diese Methode für die Pflanzen. In jüngerer Zeit ist ein Verfahren namens &#39;&amp; SteamDrop# 39; entwickelt, das Wasserdampf zur Herstellung von nicht überlappenden Chromosomen 6 verwendet. Zwar wurde der positive Einfluss der hohen Luftfeuchtigkeit früheren 7 beobachtet, &#39;SteamDrop&#39; liefert eine gesteuerte Workflow von hochwertigen Chromosomenpräparate 6. Die Dampfbehandlung bewirkt Dehnung der Chromosomen wahrscheinlich zu einigen Änderungen der chromosomalen Proteinen verbunden. Die Qualität der resultierenden Metaphasespreitungen ist sehr hoch, obwohl der Halte ausreichende Anzahl von kompletten Metaphasespreitungen zur anschließenden FISH Experimente erfordert technisches Know-how. Hier präsentieren wir ein Protokoll für die Herstellung von Getreide mitotischen Chromosomen für die FISH Nachweis einzelner und hohe Kopier Sonden 5,8. Dieses Verfahren ist eine verbesserte Variante des von Kato 9 unter einer relativen Luftfeuchtigkeit von 50% bis 55% durchgeführt (Abbildung 1) beschriebenen lufttrockenen Tropfverfahren. Dieses Protokoll eine reduzierte Anzahl umfasstder Waschschritte machen seine Anwendung einfach, effizient und reproduzierbar. Unter Verwendung dieses Protokolls erlangten hochwertigen Chromosomenspreads und FISH-Ergebnisse für Hordeum vulgäre, H. bulbosum, H. marinum, H. murinum, H. pubiflorum und Secale cereale.

<table><tbody><tr><td>Hot Plate</td><td>MEDAX GmbH</td><td>12603</td><td></td></tr><tr><td>Cellulase R10</td><td>Duchefa</td><td>C8001</td><td></td></tr><tr><td>Cellulase&amp;nbsp;</td><td>CalBioChem</td><td>219466</td><td></td></tr><tr><td>Pectolyase</td><td>Sigma</td><td>P3026</td><td></td></tr><tr><td>Cytohelicase</td><td>Sigma</td><td>C8274</td><td></td></tr><tr><td>Texas Red-12-dUTP</td><td>Invitrogen</td><td>C3176</td><td>direct fluorochrome&amp;nbsp;</td></tr><tr><td>Fluor488-5-dUTP</td><td>Invitrogen</td><td>C11397</td><td>direct fluorochrome&amp;nbsp;</td></tr><tr><td>Fluorecsence microscope</td><td>Olympus BX61</td><td>BX61</td><td></td></tr><tr><td>CCD camera</td><td>Orca ER, Hamamatsu</td><td>C10600</td><td></td></tr><tr><td>4&amp;rsquo;,6-diamidino-2-phenylindole (DAPI)&amp;nbsp;</td><td>Vector Laboratories</td><td>H-1200</td><td>fluorecsent dye</td></tr></tbody></table>

a fast air-dry dropping chromosome preparation method suitable for fish in plants

Herstellung von Chromosom-Spreads ist eine Voraussetzung für die erfolgreiche Durchführung von Fluoreszenz-in situ-Hybridisierung (FISH). Herstellung von hochwertigen Pflanzenchromosom Spreads ist eine Herausforderung durch die starre Zellwand. Eine der anerkannten Methoden zur Herstellung von Pflanzenchromosomen ist eine so genannte Drop Zubereitung, die auch Drop Verstreuen oder lufttrocknende Technik bekannt. Hier präsentieren wir ein Protokoll für die schnelle Herstellung von mitotischen Chromosomen-Spreads für die FISH Nachweis einzelner und hohe Kopier DNA-Sonden. Dieses Verfahren ist eine verbesserte Variante des lufttrockenen Tropfenverfahren unter einer relativen Luftfeuchtigkeit von 50% bis 55% durchgeführt. Dieses Protokoll besteht aus einer verringerten Anzahl von Waschschritten machte die Anwendung einfach, effizient und reproduzierbar. Offensichtliche Vorteile dieses Ansatzes sind gut verbreitet, unbeschädigt und zahlreiche Metaphasechromosomen als eine perfekte Voraussetzung für eine erfolgreiche FISH-Analyse dient. Mit diesem Protokoll hochwertigen chrom wir erhaltenOsome Spreads und reproduzierbare FISH-Ergebnisse für Hordeum vulgäre, H. bulbosum, H. marinum, H. murinum, H. pubiflorum und Secale cereale.

Objektträger mit den mitotischen Metaphase-Spreads wurden mit dem oben beschriebenen schnellen Luft trocknen Tropf Chromosom Herstellungsverfahren hergestellt (Suppl. 1). FISH-Analyse wurde unter Verwendung von beiden, sich wiederholende und Einzelkopie-Sequenzen durchgeführt. Bilder wurden durch ein Epifluoreszenz-Mikroskop mit einem Satz von Filtern ermöglicht Anregung entsprechender Fluorophore erhalten und durch eine hochempfindliche CCD monochrome Kamera eingefangen. Für die Bildaufnahme verwen...

Watch this Scientific Journal Video about A Fast Air-dry Dropping Chromosome Preparation Method Suitable for FISH in Plants at JoVE.com

A Fast Air-dry Dropping Chromosome Preparation Method Suitable for FISH in Plants

A protocol is described for the preparation of high-quality mitotic plant chromosome spreads by a fast air-dry dropping method suitable for the FISH detection of single and high copy DNA probes.

Eine schnelle Klima trockenen Dropping Chromosom Herstellungsverfahren Geeignet für FISH in Pflanzen

Preparation of chromosome spreads is a prerequisite for the successful performance of fluorescence in situ hybridization (FISH). Preparation of high ...

a-fast-air-dry-dropping-chromosome-preparation-method-suitable-for

Universidad de Cartagena UDEC

Research

JoVE Journal

Biology

13.2K Aufrufe.  Leibniz Institute of Plant Genetics and Crop Plant Research (IPK). A protocol is described for the preparation of high-quality mitotic plant chromosome spreads by a fast air-dry dropping method suitable for the FISH detection of single and high copy DNA probes.

Serie: A Fast Air-dry Dropping Chromosome Preparation Method Suitable for FISH in Plants

Profiling DNA Replication Timing Using Zebrafish as an In Vivo Model System

DNA replication timing is an important cellular characteristic, exhibiting significant relationships with chromatin structure, transcription, and DNA mutation rates. Changes in replication timing occur during development and in cancer, but the role replication timing plays in development and disease is not known. Zebrafish were recently established as an in vivo model system to study replication timing. Here is detailed the protocols for using the zebrafish to determine DNA replication timing. After sorting cells from embryos and adult zebrafish, high-resolution genome-wide DNA replication timing patterns can be constructed by determining changes in DNA copy number through analysis of next generation sequencing data. The zebrafish model system allows for evaluation of the replication timing changes that occur in vivo throughout development, and can also be used to assess changes in individual cell types, disease models, or mutant lines. These methods will enable studies investigating the mechanisms and determinants of replication timing establishment and maintenance during development, the role replication timing plays in mutations and tumorigenesis, and the effects of perturbing replication timing on development and disease.

Profiling DNA Replication Timing Using Zebrafish as an In Vivo Model System

Zebrafish were recently used as an in vivo model system to study DNA replication timing during development. Here is detailed the protocols for using zebrafish embryos to profile replication timing. This protocol can be easily adapted to study replication timing in mutants, individual cell types, disease models, and other species.

DNA-Replikation Timing mit Zebrafisch als ein In Vivo Modell-System-Profiling

DNA replication timing is an important cellular characteristic, exhibiting significant relationships with chromatin structure, transcription, and DNA ...

Forschung

Genetik

Ploidy Manipulation of Zebrafish Embryos with Heat Shock 2 Treatment

Manipulation of ploidy allows for useful transformations, such as diploids to tetraploids, or haploids to diploids. In the zebrafish Danio rerio, specifically the generation of homozygous gynogenetic diploids is useful in genetic analysis because it allows the direct production of homozygotes from a single heterozygous mother. This article describes a modified protocol for ploidy duplication based on a heat pulse during the first cell cycle, Heat Shock 2 (HS2). Through inhibition of centriole duplication, this method results in a precise cell division stall during the second cell cycle. The precise one-cycle division stall, coupled to unaffected DNA duplication, results in whole genome duplication. Protocols associated with this method include egg and sperm collection, UV treatment of sperm, in vitro fertilization and heat pulse to cause a one-cell cycle division delay and ploidy duplication. A modified version of this protocol could be applied to induce ploidy changes in other animal species.

A modified protocol for ploidy manipulation uses a heat shock to induce a one-cycle stall in cytokinesis in the early embryo. This protocol is demonstrated in the zebrafish but may be applicable to other species.

Ploidy Manipulation von Zebrafischembryonen mit Heat Shock 2 Behandlung

Manipulation of ploidy allows for useful transformations, such as diploids to tetraploids, or haploids to diploids. In the zebrafish Danio rerio, ...

Entwicklungsbiologie

Fluorescent in situ Hybridization on Mitotic Chromosomes of Mosquitoes

Fluorescent in situ hybridization (FISH) is a technique routinely used by many laboratories to determine the chromosomal position of DNA and RNA probes. One important application of this method is the development of high-quality physical maps useful for improving the genome assemblies for various organisms. The natural banding pattern of polytene and mitotic chromosomes provides guidance for the precise ordering and orientation of the genomic supercontigs. Among the three mosquito genera, namely Anopheles, Aedes, and Culex, a well-established chromosome-based mapping technique has been developed only for Anopheles, whose members possess readable polytene chromosomes 1. As a result of genome mapping efforts, 88% of the An. gambiae genome has been placed to precise chromosome positions 2,3 . Two other mosquito genera, Aedes and Culex, have poorly polytenized chromosomes because of significant overrepresentation of transposable elements in their genomes 4, 5, 6. Only 31 and 9% of the genomic supercontings have been assigned without order or orientation to chromosomes of Ae. aegypti 7 and Cx. quinquefasciatus 8, respectively. Mitotic chromosome preparation for these two species had previously been limited to brain ganglia and cell lines. However, chromosome slides prepared from the brain ganglia of mosquitoes usually contain low numbers of metaphase plates 9. Also, although a FISH technique has been developed for mitotic chromosomes from a cell line of Ae. aegypti 10, the accumulation of multiple chromosomal rearrangements in cell line chromosomes 11 makes them useless for genome mapping. Here we describe a simple, robust technique for obtaining high-quality mitotic chromosome preparations from imaginal discs (IDs) of 4th instar larvae which can be used for all three genera of mosquitoes. A standard FISH protocol 12 is optimized for using BAC clones of genomic DNA as a probe on mitotic chromosomes of Ae. aegypti and Cx. quinquefasciatus, and for utilizing an intergenic spacer (IGS) region of ribosomal DNA (rDNA) as a probe on An. gambiae chromosomes. In addition to physical mapping, the developed technique can be applied to population cytogenetics and chromosome taxonomy/systematics of mosquitoes and other insect groups.

Fluorescent in situ Hybridization on Mitotic Chromosomes of Mosquitoes

Among the three mosquito genera, namely Anopheles, Aedes, and Culex, physical genome mapping techniques were established only for Anopheles, whose members possess readable polytene chromosomes. For the genera of Aedes and Culex, however, cytogenetic mapping remains challenging because of the poor quality of polytene chromosomes. Here we present a universal protocol for obtaining high-quality preparations of mitotic chromosomes and an optimized FISH protocol for all three genera of mosquitoes.

Fluoreszierend<em&gt; In situ</em&gt; Hybridisierung auf mitotischen Chromosomen der Moskitos

Fluorescent in situ hybridization (FISH) is a technique routinely used by many laboratories to determine the chromosomal position of DNA and RNA probes. ...

Immunologie und Infektion

Preparation of Meiotic Chromosome Spreads from Zebrafish Spermatocytes

Meiosis is the key cellular process required to create haploid gametes for sexual reproduction. Model organisms have been instrumental in understanding the chromosome events that take place during meiotic prophase, including the pairing, synapsis, and recombination events that ensure proper chromosome segregation. While the mouse has been an important model for understanding the molecular mechanisms underlying these processes, not all meiotic events in this system are analogous to human meiosis. We recently demonstrated the exciting potential of the zebrafish as a model of human spermatogenesis. Here we describe, in detail, our methods to visualize meiotic chromosomes and associated proteins in chromosome spread preparations. These preparations have the advantage of allowing high resolution analysis of chromosome structures. First, we describe the procedure for dissecting testes from adult zebrafish, followed by cell dissociation, lysis, and spreading of the chromosomes. Next, we describe the procedure for detecting the localization of meiotic chromosome proteins, by immunofluorescence detection, and nucleic acid sequences, by fluorescence in situ hybridization (FISH). These techniques comprise a useful set of tools for the cytological analysis of meiotic chromatin architecture in the zebrafish system. Researchers in the zebrafish community should be able to quickly master these techniques and incorporate them into their standard analyses of reproductive function.

Nuclear surface spreads are an indispensable tool for studying chromosome events during meiosis. Here we demonstrate a method to prepare and visualize meiotic chromosomes during prophase I from zebrafish spermatocytes.

Zubereitung von meiotischen Chromosomenaufstrichen aus Zebrafisch Spermatozyten

Meiosis is the key cellular process required to create haploid gametes for sexual reproduction. Model organisms have been instrumental in understanding ...

Co-expression of Multiple Chimeric Fluorescent Fusion Proteins in an Efficient Way in Plants

Information about the spatiotemporal subcellular localization(s) of a protein is critical to understand its physiological functions in cells. Fluorescent proteins and generation of fluorescent fusion proteins have been wildly used as an effective tool to directly visualize the protein localization and dynamics in cells. It is especially useful to compare them with well-known organelle markers after co-expression with the protein of interest. Nevertheless, classical approaches for protein co-expression in plants usually involve multiple independent expression plasmids, and therefore have drawbacks that include low co-expression efficiency, expression-level variation, and high time expenditure in genetic crossing and screening. In this study, we describe a robust and novel method for co-expression of multiple chimeric fluorescent proteins in plants. It overcomes the limitations of the conventional methods by using a single expression vector that is composed of multiple semi-independent expressing cassettes. Each protein expression cassette contains its own functional protein expression elements, and therefore it can be flexibly adjusted to meet diverse expression demand. Also, it is easy and convenient to perform the assembly and manipulation of DNA fragments in the expression plasmid by using an optimized one-step reaction without additional digestion and ligation steps. Furthermore, it is fully compatible with current fluorescent protein derived bio-imaging technologies and applications, such as FRET and BiFC. As a validation of the method, we employed this new system to co-express fluorescently fused vacuolar sorting receptor and secretory carrier membrane proteins. The results show that their perspective subcellular localizations are the same as in previous studies by both transient expression and genetic transformation in plants.

We have developed a novel method for co-expressing multiple chimeric fluorescent fusion proteins in plants to overcome the difficulties of conventional methods. It takes advantage of using a single expression plasmid that contains multiple functionally independent protein expressing cassettes to achieve protein co-expression.

Co Ausdruck von mehreren Chimären fluoreszierende Fusionsproteinen in effizienter Weise in Pflanzen

Information about the spatiotemporal subcellular localization(s) of a protein is critical to understand its physiological functions in cells. Fluorescent ...

Chemie

2D and 3D Chromosome Painting in Malaria Mosquitoes

Fluorescent in situ hybridization (FISH) of whole arm chromosome probes is a robust technique for mapping genomic regions of interest, detecting chromosomal rearrangements, and studying three-dimensional (3D) organization of chromosomes in the cell nucleus. The advent of laser capture microdissection (LCM) and whole genome amplification (WGA) allows obtaining large quantities of DNA from single cells. The increased sensitivity of WGA kits prompted us to develop chromosome paints and to use them for exploring chromosome organization and evolution in non-model organisms. Here, we present a simple method for isolating and amplifying the euchromatic segments of single polytene chromosome arms from ovarian nurse cells of the African malaria mosquito Anopheles gambiae. This procedure provides an efficient platform for obtaining chromosome paints, while reducing the overall risk of introducing foreign DNA to the sample. The use of WGA allows for several rounds of re-amplification, resulting in high quantities of DNA that can be utilized for multiple experiments, including 2D and 3D FISH. We demonstrated that the developed chromosome paints can be successfully used to establish the correspondence between euchromatic portions of polytene and mitotic chromosome arms in An. gambiae. Overall, the union of LCM and single-chromosome WGA provides an efficient tool for creating significant amounts of target DNA for future cytogenetic and genomic studies.

Chromosome painting is a useful method for studying organization of the cell nucleus and evolution of the karyotype. Here, we demonstrate an approach to isolate and amplify specific regions of interest from single polytene chromosomes that are subsequently used for two- and three-dimensional fluorescent in situ hybridization (FISH).

2D und 3D Chromosom Malerei in Malaria-Mücken

Fluorescent in situ hybridization (FISH) of whole arm chromosome probes is a robust technique for mapping genomic regions of interest, detecting ...

A High-Throughput Method For Zebrafish Sperm Cryopreservation and In Vitro Fertilization

This is a method for zebrafish sperm cryopreservation that is an adaptation of the Harvey method (Harvey et al., 1982).  We have introduced two changes to the original protocol that both streamline the procedure and increase sample uniformity.  First, we normalize all sperm volumes using freezing media that does not contain the cryoprotectant. Second, cryopreserved sperm are stored in cryovials instead of capillary tubes.  The rates of sperm freezing and thawing (&delta;&deg;C/time) are probably the two most critical variables to control in this procedure.  For this reason, do not substitute different tubes for those specified.  Working in teams of 2 it is possible to freeze the sperm of 100 males per team in ~2 hrs.  Sperm cryopreserved using this protocol has an average of 25% fertility (measured as the number of viable embryos generated in an in vitro fertilization divided by the total number of eggs fertilized) and this percent fertility is stable over many years.

A High-Throughput Method For Zebrafish Sperm Cryopreservation and In Vitro Fertilization

This is a high-throughput sperm cryopreservation protocol for zebrafish. Sperm cryopreserved using this protocol has an average of 25% fertility in subsequent vitro fertilization and is stable over many years.

Ein High-Throughput-Methode für Zebrabärblinge Sperma Kryokonservierung und In Vitro Fertilisation

This is a method for zebrafish sperm cryopreservation that is an adaptation of the Harvey method (Harvey et al., 1982).  We have introduced two changes to ...

Biologie

Making Gynogenetic Diploid Zebrafish by Early Pressure

Heterozygosity in diploid eukaryotes often makes genetic studies cumbersome. Methods that produce viable homozygous diploid offspring directly from heterozygous females allow F1 mutagenized females to be screened directly for deleterious mutations in an accelerated forward genetic screen. Streisinger et al.1,2 described methods for making gynogenetic (homozygous) diploid zebrafish by activating zebrafish eggs with ultraviolet light-inactivated sperm and preventing either the second meiotic or the first zygotic cell division using physical treatments (heat or pressure) that deploymerize microtubules. The "early pressure" (EP) method blocks the meiosis II, which occurs shortly after fertilization. The EP method produces a high percentage of viable embryos that can develop to fertile adults of either sex. The method generates embryos that are homozygous at all loci except those that were separated from their centromere by recombination during meiosis I. Homozygous mutations are detected in EP clutches at between 50% for centromeric loci and less than 1% for telomeric loci. This method is reproduced verbatim from the Zebrafish Book3.

This is a method for generating gynogenetic diploid zebrafish embryos (embryos whose only genetic contribution comes from the mother) by blocking the second meiotic division immediately after fertilization with ultraviolet light-inactivated sperm. EP embryos are not fully homozygous due to recombination during the first meiotic division, however they are homozygous at all loci that have not been separated from their centromere by recombination.

Machen Gynogenetic Diploid Zebrafisch von Anfang Druck

Heterozygosity in diploid eukaryotes often makes genetic studies cumbersome. Methods that produce viable homozygous diploid offspring directly from ...

Slide Preparation Method to Preserve Three-dimensional Chromatin Architecture of Testicular Germ Cells

During testicular germ cell differentiation, the structure of nuclear chromatin dynamically changes. The following describes a method designed to preserve the three-dimensional chromatin arrangement of testicular germ cells found in mice; this method has been termed as the three-dimensional (3D) slide method. In this method, testicular tubules are directly treated with a permeabilization step that removes cytoplasmic material, followed by a fixation step that fixes nuclear materials. Tubules are then dissociated, the cell suspension is cytospun, and cells adhere to slides. This method improves sensitivity towards detection of subnuclear structures and is applicable for immunofluorescence, DNA, and RNA fluorescence in situ hybridization (FISH) and the combination of these detection methods. As an example of a possible application of the 3D slide method, a Cot-1 RNA FISH is shown to detect nascent RNAs. The 3D slide method will facilitate the detailed examination of spatial relationships between chromatin structure, DNA, and RNA during testicular germ cell differentiation.

The material here describes a method developed to preserve the three-dimensional chromatin structure of testicular germ cells. This has been termed the three-dimensional (3D) slide method. This method improves sensitivity for detection of subnuclear structures and is applicable for immunofluorescence, DNA, and RNA fluorescence in situ hybridization (FISH).

Folienvorbereitungsmethode zur Erhaltung der dreidimensionalen Chromatinarchitektur von Hodenkeimzellen

During testicular germ cell differentiation, the structure of nuclear chromatin dynamically changes. The following describes a method designed to preserve ...

Silencing the Spark: CRISPR/Cas9 Genome Editing in Weakly Electric Fish

Electroreception and electrogenesis have changed in the evolutionary history of vertebrates. There is a striking degree of convergence in these independently derived phenotypes, which share a common genetic architecture. This is perhaps best exemplified by the numerous convergent features of gymnotiforms and mormyrids, two species-rich teleost clades that produce and detect weak electric fields and are called weakly electric fish. In the 50 years since the discovery that weakly electric fish use electricity to sense their surroundings and communicate, a growing community of scientists has gained tremendous insights into evolution of development, systems and circuits neuroscience, cellular physiology, ecology, evolutionary biology, and behavior. More recently, there has been a proliferation of genomic resources for electric fish. Use of these resources has already facilitated important insights with regards to the connection between genotype and phenotype in these species. A major obstacle to integrating genomics data with phenotypic data of weakly electric fish is a present lack of functional genomics tools. We report here a full protocol for performing CRISPR/Cas9 mutagenesis that utilizes endogenous DNA repair mechanisms in weakly electric fish. We demonstrate that this protocol is equally effective in both the mormyrid species Brienomyrus brachyistius and the gymnotiform Brachyhypopomus gauderio by using CRISPR/Cas9 to target indels and point mutations in the first exon of the sodium channel gene scn4aa. Using this protocol, embryos from both species were obtained and genotyped to confirm that the predicted mutations in the first exon of the sodium channel scn4aa were present. The knock-out success phenotype was confirmed with recordings showing reduced electric organ discharge amplitudes when compared to uninjected size-matched controls.

Here, a protocol is presented to produce and rear CRISPR/Cas9 genome knockout electric fish. Outlined in detail are the required molecular biology, breeding, and husbandry requirements for both a gymnotiform and a mormyrid, and injection techniques to produce Cas9-induced indel F0 larvae.

Eine schnelle Klima trockenen Dropping Chromosom Herstellungsverfahren Geeignet für FISH in Pflanzen

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