We thank Zhaohua Irene Tang in the W. M. Keck Science Department for the use of her epifluorescence microscope and the Werren lab for donating Nasonia for dissections. This work was supported in part by an NIH-NRSA fellowship (5F32GM105317-02) to AML.

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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=Sequence+finishing+and+mapping+of+Drosophila+melanogaster+heterochromatin.">Sequence finishing and mapping of Drosophila melanogaster heterochromatin.</a> Science. 316 (58331), 1625-1628 (2007).</li><li>Treangen, T. J., Salzberg, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Repetitive+DNA+and+next-generation+sequencing:+computational+challenges+and+solutions.">Repetitive DNA and next-generation sequencing: computational challenges and solutions.</a> Nature Reviews Genetics. 13 (1), 36-46 (2012).</li><li>He, 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=Mapping+the+pericentric+heterochromatin+by+comparative+genomic+hybridization+analysis+and+chromosome+deletions+in+Drosophila+melanogaster.">Mapping the pericentric heterochromatin by comparative genomic hybridization analysis and chromosome deletions in Drosophila melanogaster.</a> Genome Research. 22 (12), 2507-2519 (2012).</li><li>Pimpinelli, S., Bonaccorsi, S., Fanti, L., Gatti, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+in+situ+hybridization+(FISH)+of+mitotic+chromosomes+from+Drosophila+larval+brain.">Fluorescent in situ hybridization (FISH) of mitotic chromosomes from Drosophila larval brain.</a> Cold Spring Harbor Protocols. 2010 (3), (2010).</li><li>Larracuente, A. M., Noor, M. A., Clark, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Translocation+of+Y-linked+genes+to+the+dot+chromosome+in+Drosophila+pseudoobscura.">Translocation of Y-linked genes to the dot chromosome in Drosophila pseudoobscura.</a> Molecular Biology and Evolution. 27 (7), 1612-1620 (2010).</li><li>Ferree, P. M., Barbash, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Species-specific+heterochromatin+prevents+mitotic+chromosome+segregation+to+cause+hybrid+lethality+in+Drosophila.">Species-specific heterochromatin prevents mitotic chromosome segregation to cause hybrid lethality in Drosophila.</a> PLoS Biology. 7 (10), e1000234 (2009).</li><li>Williams, B. C., Karr, T. L., Montgomery, J. M., Goldberg, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Drosophila+l(1)zw10+gene+product,+required+for+accurate+mitotic+chromosome+segregation,+is+redistributed+at+anaphase+onset.">The Drosophila l(1)zw10 gene product, required for accurate mitotic chromosome segregation, is redistributed at anaphase onset.</a> The Journal of Cell Biology. 118 (4), 759-773 (1992).</li><li>Gatti, M., Bonaccorsi, S., Pimpinelli, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Looking+at+Drosophila+Mitotic+Chromosomes.">Looking at Drosophila Mitotic Chromosomes.</a> Methods in Cell Biology. 44, 371-391 (1994).</li><li>Werren, J. H., Stouthamer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PSR+(paternal+sex+ratio)+chromosomes:+the+ultimate+selfish+genetic+elements.">PSR (paternal sex ratio) chromosomes: the ultimate selfish genetic elements.</a> Genetica. 117 (1), 85-101 (2003).</li></ol>

The authors declare that they have no competing financial or any other conflict of interest.

كثيرا ما يستخدم الحمض النووي ISH لرسم خريطة تسلسل محددة لالكروموسومات. وصفناها طريقة بسيطة لDNA ISH الأمثل لعدد نسخ عالية، متواليات heterochromatic. بدلا من استخدام يغسل في حل الفورماميد، الذي هو شرط في غيرها من البروتوكولات ISH DNA الموجودة، ونحن نضع شرائح محمولة على الأنسجة مباش...

DNA الموقع التهجين (DNA ISH) في هو طريقة تستخدم عادة لتسلسل رسم الخرائط للمناطق كروموسوم محددة. يمكن أن تتولد تحقيقات لمناطق نسخة واحدة داخل كروماتين حقيقي من خلال حفنة من النهج، بما نيك الترجمة أو نهاية توسيم منتجات DNA طويلة 1،2 وإدراج deoxygenin (DIG) النيوكليوتيدات -attached والاعتراف بها من خلال مجموعة متنوعة واسعة من الأجسام المضادة مترافق مجموعة 1-3. تصور تسلسل الكروماتين الحقيقي في قلة أو واحد في عدد النسخ يتطلب استخدام إما واحدة، تحقيقات واسعة للنشاط معين عالية أو مزيج من عدة تحقيقات أصغر التي تعزز إشارة جماعي. في المقابل، تسلسل المتكررة للغاية وجدت في المغاير، مثل السلطات الوطنية المعينة الأقمار الصناعية، هي أهداف أسهل لDNA ISH لأنها موجودة بشكل طبيعي عن عشرات الآلاف من يكرر تتجمع في مناطق كروموسوم واحد يعرف باسم الكتل. العناصر القابلة للنقل أيضا يمكن أن يكونوجدت في أرقام نسخة عالية في مواضع متميزة الكروموسومات 2. في هذه الحالات، يمكن أن تحقيقات واحدة مع النشاط النوعي المنخفض التدريسية بشكل فعال تسلسل heterochromatic بسبب التهجين بهم في مواقع متعددة. تحقيقات للتسلسل المتكررة يمكن توليفها [أليغنوكليوتيد تجاريا قصيرة باسم (30-50 بي بي) ومترافق كيميائيا مع أي من مجموعات متعددة الفلورسنت مختلفة. رسم تسلسل المتكررة داخل المغاير باستخدام تقنيات الجينوم التسلسل من الصعب نظرا للتحديات التي واجهتها في بناء السقالات داخل كتل الفضائية المتكررة للغاية 4-6،7. حاليا، ISH تقف باعتبارها السبيل الأكثر فعالية لرسم هذه المتتاليات على مستوى كروموسوم الفرعية. هذه الاستراتيجية مهمة لرسم خرائط أعداد كبيرة من تسلسل المتكررة التي يتم كشفت عنه دراسات الجينوم وTranscriptome على التسلسل الجارية. سيتم GRE كفاءة وسهولة رسم الخرائط تسلسل المتكررة على الكروموسومات محمولة على الشرائحتعزيز atly بأي بروتوكول مبسطة لDNA ISH. على سبيل المثال، والبروتوكولات القائمة لDNA ISH تنطوي يغسل متعددة من الأنسجة تهجين في حل الفورماميد 2،8، مما يضيف إلى حد كبير في الوقت المطلوب لمتواليات رسم الخرائط وأيضا إنتاج كميات كبيرة من النفايات الكيميائية لهذا كاشف مكلفة. نحن هنا تصف طريقة DNA ISH المنقحة التي تلتف على الحاجة لغسيل الفورماميد وتستخدم المعدات المختبرية الأساسية والكواشف. وهذه الطريقة صممت في الأصل لرسم خرائط السريع لتسلسل الحمض النووي المتكررة للغاية في المناطق heterochromatic من neuroblasts اليرقات ذبابة الفاكهة باستخدام oligos تصنيعه تجاريا التي يتم مترافق مع الأصباغ مضان. ومع ذلك، يعمل هذا الأسلوب أيضا لرسم خرائط تسلسل المتكررة باستخدام مجسات أكبر توليفها من خلال وسائل أخرى 9،10 وعبر عدة أنواع الأنسجة وكروموسوم مختلفة. بالإضافة إلى ذلك، وهذه الطريقة يمكن أن تستخدم لرسم خريطة تسلسل الكروماتين الحقيقي باستخدام أطول أو multipجنيه، تحقيقات قصيرة ضمن تسلسل الكروماتين الحقيقي من الاهتمام.

<table><tbody><tr><td>Poly-L-lysine coated slides (regular slides also can be used)</td><td>Sigma Aldrich</td><td></td><td></td></tr><tr><td>Ultrafine tweezers (5 gauge)</td><td>Dumont</td><td></td><td></td></tr><tr><td>22 x 22 mm cover slips</td><td>Fisher</td><td></td><td>Sigmacote-treated by immersion for 15 sec, blotting dry, and wiping away all traces of Sigmacote so that cover slip is clear</td></tr><tr><td>Sigmacote</td><td>Sigma</td><td></td><td></td></tr><tr><td>Filter paper</td><td></td><td></td><td>75 - 150 mm</td></tr><tr><td>Paraffin wax paper</td><td></td><td></td><td></td></tr><tr><td>Heat block with thermometer</td><td></td><td></td><td></td></tr><tr><td>Dry incubator</td><td></td><td></td><td></td></tr><tr><td>Razor blades</td><td></td><td></td><td></td></tr><tr><td>Humidity chamber</td><td></td><td></td><td>empty pipette tip box or Tupperware, lined with moistened paper towels or Kimwipes</td></tr><tr><td>Coplin jars</td><td></td><td></td><td>with slide grooves</td></tr><tr><td>Aluminum foil</td><td></td><td></td><td></td></tr><tr><td>Pasteur pipettes</td><td></td><td></td><td></td></tr><tr><td>1.5 ml microfuge tubes</td><td></td><td></td><td></td></tr><tr><td>Nail polish</td><td></td><td></td><td>clear or colored</td></tr><tr><td>P20 micropipette and plastic tips</td><td></td><td></td><td></td></tr><tr><td>Paperclips</td><td></td><td></td><td>20 - 25 standard metal paperclips linked to form a chain</td></tr><tr><td colspan="4">Reagents</td></tr><tr><td>16% EM grade paraformaldehyde</td><td>Electron Microscopy Reagents</td><td></td><td></td></tr><tr><td>Acetic acid</td><td>Sigma</td><td></td><td></td></tr><tr><td>Liquid nitrogen</td><td></td><td></td><td></td></tr><tr><td>100% Ethanol, chemical grade</td><td></td><td></td><td></td></tr><tr><td colspan="4">Commercially synthesized, fluorescently labeled oligos</td></tr><tr><td>Long biotinylated probe</td><td>Invitrogen; Alternative steps 2.7.1-2.7.3</td><td></td><td>&lt;em&gt;e.g.,&lt;/em&gt; nick translated and biotinylated with BioNick from Invitrogen</td></tr><tr><td>Rhodamine-Avidin</td><td>Roche; Alternative steps 2.7.1-2.7.3</td><td></td><td>for detection of long biotinylated probe</td></tr><tr><td>Hybridization buffer</td><td>Recipe above</td><td></td><td></td></tr><tr><td>4x SSCT</td><td>Recipe above</td><td></td><td>saline-sodium citrate + Tween</td></tr><tr><td>0.1x SSC</td><td>Recipe above</td><td></td><td>saline-sodium citrate</td></tr><tr><td>Blocking solution</td><td>Recipe above</td><td></td><td></td></tr><tr><td>SBT</td><td>Recipe above</td><td></td><td>SSC, bovine serum albumin, Tween</td></tr><tr><td>1x PBT</td><td>Recipe above</td><td></td><td>phosphate-buffered saline + Tween</td></tr><tr><td>1x PBS</td><td></td><td></td><td>phosphate-buffered saline</td></tr><tr><td>Hypotonic solution</td><td></td><td></td><td>0.5% sodium citrate in H&lt;sub&gt;2&lt;/sub&gt;O</td></tr><tr><td>Formamide</td><td>Sigma Aldrich</td><td></td><td></td></tr><tr><td>Vectashield mounting medium with DAPI</td><td>Vector laboratories</td><td></td><td></td></tr></tbody></table>

simple method for fluorescence dna in situ hybridization to squashed chromosomes

DNA الموقع التهجين (DNA ISH) في هو طريقة تستخدم عادة لتسلسل رسم الخرائط للمناطق كروموسوم محددة. هذا النهج غير فعالة بشكل خاص في رسم الخرائط تسلسل المتكررة للغاية لمناطق heterochromatic، حيث تواجه المناهج الحسابية التحديات باهظة. نحن هنا وصف بروتوكول مبسط للDNA ISH أن تلتف يغسل الفورماميد التي هي الخطوات القياسية في غيرها من البروتوكولات ISH DNA. هو الأمثل لدينا بروتوكول لالتهجين مع واحدة تحقيقات DNA حبلا القصيرة التي تحمل الأصباغ الفلورية، والتي احتفال بفعالية تسلسل الحمض النووي المتكررة داخل المناطق الكروموسومات heterochromatic عبر عدد من مختلف أنواع الأنسجة الحشرات. ومع ذلك، يجوز تمديد التطبيقات لاستخدام مع تحقيقات أكبر والتصور من متواليات نسخة واحدة (غير متكرر) DNA. ونحن لشرح هذه الطريقة عن طريق تعيين عدة سلاسل متكررة مختلفة لسحق الكروموسومات من الخلايا العصبية الدروسوفيلاميلانوجاستر وNasoniavitripennis الخلايا المنوية. وتبين لنا أنماط التهجين على حد سواء، تحقيقات صغيرة توليفها تجاريا وتحقيق أكبر للمقارنة. يستخدم هذا الإجراء وازم المختبرات بسيطة والكواشف، ويعتبر مثاليا للمحققين الذين لديهم خبرة قليلة مع أداء DNA ISH.

لشرح هذا الأسلوب، نحن تهجين مجموعة من oligos صغيرة توليفها تجاريا التي تم تعديلها كيميائيا مع تقارن الفلورسنت (الشكل 2) والتحقيق يعد المعقدة البيروكسيديز (التي تتم من خلال الترجمة نيك لمنتج PCR، الشكل 2B)، إلى الكروموسومات من عدة أنسجة مختلفة أنواع (انظر ...

Watch this Scientific Journal Video about Simple Method for Fluorescence DNA In Situ Hybridization to Squashed Chromosomes at JoVE.com

Simple Method for Fluorescence DNA In Situ Hybridization to Squashed Chromosomes

Here, we present a simple method for performing fluorescence DNA in situ hybridization (DNA ISH) to visualize repetitive heterochromatic sequences on slide-mounted chromosomes. The method requires minimal reagents and it is versatile for use with short or long probes, different tissues, and detection with fluorescence or non-fluorescence-based signals.

طريقة بسيطة لDNA الإسفار<em&gt; في الموقع</em&gt; التهجين لسحق الكروموسومات

DNA in situ hybridization (DNA ISH) is a commonly used method for mapping sequences to specific chromosome regions. This approach is particularly ...

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Universidad de Cartagena UDEC

Research

JoVE Journal

Biology

Simple Method for Fluorescence DNA In Situ Hybridization to Squashed Chromosomes

18.0K Views.  University of Rochester. Here, we present a simple method for performing fluorescence DNA in situ hybridization (DNA ISH) to visualize repetitive heterochromatic sequences on slide-mounted chromosomes. The method requires minimal reagents and it is versatile for use with short or long probes, different tissues, and detection with fluorescence or non-fluorescence-based signals.

Video: Simple Method for Fluorescence DNA In Situ Hybridization to Squashed Chromosomes

Single Molecule Fluorescence In Situ Hybridization (smFISH) Analysis in Budding Yeast Vegetative Growth and Meiosis

Single molecule fluorescence in situ hybridization (smFISH) is a powerful technique to study gene expression in single cells due to its ability to detect and count individual RNA molecules. Complementary to deep sequencing-based methods, smFISH provides information about the cell-to-cell variation in transcript abundance and the subcellular localization of a given RNA. Recently, we have used smFISH to study the expression of the gene&#160;NDC80&#160;during meiosis in budding yeast, in which two transcript isoforms exist and the short transcript isoform has its entire sequence shared with the long isoform. To confidently identify each transcript isoform, we optimized known smFISH protocols and obtained high consistency and quality of smFISH data for the samples acquired during budding yeast meiosis. Here, we describe this optimized protocol, the criteria that we use to determine whether high quality of smFISH data is obtained, and some tips for implementing this protocol in&#160;other yeast strains and growth conditions.

Single Molecule Fluorescence In Situ Hybridization smFISH Analysis in Budding Yeast Vegetative Growth and Meiosis

This single molecule fluorescence in situ hybridization protocol is optimized to quantify the number of RNA molecules in budding yeast during vegetative growth and meiosis.

التهجين في الموقع Fluorescence جزيء واحد (سمفيش) التحليل في مهدها الخميرة النمو الخضري والانقسام الاختزالي

Single molecule fluorescence in situ hybridization (smFISH) is a powerful technique to study gene expression in single cells due to its ability to detect ...

Genetics

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.

فلوري<em&gt; في الموقع</em&gt; التهجين على الكروموسومات الميتوزى من البعوض

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

Immunology and Infection

Preparation of Drosophila Polytene Chromosome Squashes for Antibody Labeling

Drosophila has long been a favorite model system for studying the relationship between chromatin structure and gene regulation due to the cytological advantages provided by the giant salivary gland polytene chromosomes of third instar larvae.  In this tissue the chromosomes undergo many rounds of replication in the absence of cell division giving rise to approximately 1000 copies.  The DNA remains aligned after each replicative cycle resulting in greatly enlarged chromosomes that provide a unique opportunity to correlate chromatin morphology with the localization of specific proteins.  Consequently, there has been a high level of interest in defining the epigenetic modifications present at different genes and at different stages of the transcription process. An important tool for such studies is the labeling of polytene chromosomes with antibodies to the enzyme, transcription factor, or histone modification of interest. This video protocol illustrates the squash technique used in the Johansen laboratory to prepare Drosophila polytene chromosomes for antibody labeling.

This video protocol illustrates the squash technique used in the Johansen laboratory to prepare Drosophila polytene chromosomes for antibody labeling.

إعداد يسحق ذبابة الفاكهة كروموسوم كثور الخيوط الصبغية للجسم وصفها

Drosophila has long been a favorite model system for studying the relationship between chromatin structure and gene regulation due to the cytological ...

Fluorescent Calcium Imaging and Subsequent In Situ Hybridization for Neuronal Precursor Characterization in Xenopus laevis

Spontaneous intracellular calcium activity can be observed in a variety of cell types and is proposed to play critical roles in a variety of physiological processes. In particular, appropriate regulation of calcium activity patterns during embryogenesis is necessary for many aspects of vertebrate neural development, including proper neural tube closure, synaptogenesis, and neurotransmitter phenotype specification. While the observation that calcium activity patterns can differ in both frequency and amplitude suggests a compelling mechanism by which these fluxes might transmit encoded signals to downstream effectors and regulate gene expression, existing population-level approaches have lacked the precision necessary to further explore this possibility. Furthermore, these approaches limit studies of the role of cell-cell interactions by precluding the ability to assay the state of neuronal determination in the absence of cell-cell contact. Therefore, we have established an experimental workflow that pairs time-lapse calcium imaging of dissociated neuronal explants with a fluorescence in situ hybridization assay, allowing the unambiguous correlation of calcium activity pattern with molecular phenotype on a single-cell level. We were successfully able to use this approach to distinguish and characterize specific calcium activity patterns associated with differentiating neural cells and neural progenitor cells, respectively; beyond this, however, the experimental framework described in this article could be readily adapted to investigate correlations between any time-series activity profile and expression of a gene or genes of interest.

Fluorescent Calcium Imaging and Subsequent In Situ Hybridization for Neuronal Precursor Characterization in Xenopus laevis

We present a two-part protocol that combines fluorescent calcium imaging with in situ hybridization, allowing the experimenter to correlate patterns of calcium activity with gene expression profiles on a single-cell level.

تصوير الكالسيوم الفلوري والتهجين في الموقع اللاحق لتوصيف السلائف العصبية في زينوبوس laevis

Spontaneous intracellular calcium activity can be observed in a variety of cell types and is proposed to play critical roles in a variety of physiological ...

Developmental Biology

High-throughput Physical Mapping of Chromosomes using Automated in situ Hybridization

Projects to obtain whole-genome sequences for 10,000 vertebrate species1 and for 5,000 insect and related arthropod species2 are expected to take place over the next 5 years. For example, the sequencing of the genomes for 15 malaria mosquitospecies is currently being done using an Illumina platform3,4. This Anopheles species cluster includes both vectors and non-vectors of malaria. When the genome assemblies become available, researchers will have the unique opportunity to perform comparative analysis for inferring evolutionary changes relevant to vector ability. However, it has proven difficult to use next-generation sequencing reads to generate high-quality de novo genome assemblies5. Moreover, the existing genome assemblies for Anopheles gambiae, although obtained using the Sanger method, are gapped or fragmented4,6.
Success of comparative genomic analyses will be limited if researchers deal with numerous sequencing contigs, rather than with chromosome-based genome assemblies. Fragmented, unmapped sequences create problems for genomic analyses because: (i) unidentified gaps cause incorrect or incomplete annotation of genomic sequences; (ii) unmapped sequences lead to confusion between paralogous genes and genes from different haplotypes; and (iii) the lack of chromosome assignment and orientation of the sequencing contigs does not allow for reconstructing rearrangement phylogeny and studying chromosome evolution. Developing high-resolution physical maps for species with newly sequenced genomes is a timely and cost-effective investment that will facilitate genome annotation, evolutionary analysis, and re-sequencing of individual genomes from natural populations7,8.
Here, we present innovative approaches to chromosome preparation, fluorescent in situ hybridization (FISH), and imaging that facilitate rapid development of physical maps. Using An. gambiae as an example, we demonstrate that the development of physical chromosome maps can potentially improve genome assemblies and, thus, the quality of genomic analyses. First, we use a high-pressure method to prepare polytene chromosome spreads. This method, originally developed for Drosophila9, allows the user to visualize more details on chromosomes than the regular squashing technique10. Second, a fully automated, front-end system for FISH is used for high-throughput physical genome mapping. The automated slide staining system runs multiple assays simultaneously and dramatically reduces hands-on time11. Third, an automatic fluorescent imaging system, which includes a motorized slide stage, automatically scans and photographs labeled chromosomes after FISH12. This system is especially useful for identifying and visualizing multiple chromosomal plates on the same slide. In addition, the scanning process captures a more uniform FISH result. Overall, the automated high-throughput physical mapping protocol is more efficient than a standard manual protocol.

High-throughput Physical Mapping of Chromosomes using Automated in situ Hybridization

Genome assemblies based on massively parallel DNA sequencing technologies are usually highly fragmented. The development of physical chromosome maps can potentially improve genome assemblies. Here, we demonstrate innovative approaches to chromosome preparation, fluorescent in situ hybridization, and imaging that significantly increase throughput of the physical map development.

الإنتاجية العالية لرسم الخرائط المادية للالكروموسومات باستخدام الآلي<em&gt; في الموقع</em&gt; التهجين

Projects to obtain whole-genome sequences for 10,000 vertebrate species1 and for 5,000 insect and related arthropod species2 are expected to take place ...

Chromosome Replicating Timing Combined with Fluorescent In situ Hybridization

Mammalian DNA replication initiates at multiple sites along chromosomes at different times during S phase, following a temporal replication program. The specification of replication timing is thought to be a dynamic process regulated by tissue-specific and developmental cues that are responsive to epigenetic modifications. However, the mechanisms regulating where and when DNA replication initiates along chromosomes remains poorly understood. Homologous chromosomes usually replicate synchronously, however there are notable exceptions to this rule. For example, in female mammalian cells one of the two X chromosomes becomes late replicating through a process known as X inactivation1. Along with this delay in replication timing, estimated to be 2-3 hr, the majority of genes become transcriptionally silenced on one X chromosome. In addition, a discrete cis-acting locus, known as the X inactivation center, regulates this X inactivation process, including the induction of delayed replication timing on the entire inactive X chromosome. In addition, certain chromosome rearrangements found in cancer cells and in cells exposed to ionizing radiation display a significant delay in replication timing of &gt;3 hours that affects the entire chromosome2,3. Recent work from our lab indicates that disruption of discrete cis-acting autosomal loci result in an extremely late replicating phenotype that affects the entire chromosome4. Additional 'chromosome engineering' studies indicate that certain chromosome rearrangements affecting many different chromosomes result in this abnormal replication-timing phenotype, suggesting that all mammalian chromosomes contain discrete cis-acting loci that control proper replication timing of individual chromosomes5.
Here, we present a method for the quantitative analysis of chromosome replication timing combined with fluorescent in situ hybridization. This method allows for a direct comparison of replication timing between homologous chromosomes within the same cell, and was adapted from6. In addition, this method allows for the unambiguous identification of chromosomal rearrangements that correlate with changes in replication timing that affect the entire chromosome. This method has advantages over recently developed high throughput micro-array or sequencing protocols that cannot distinguish between homologous alleles present on rearranged and un-rearranged chromosomes. In addition, because the method described here evaluates single cells, it can detect changes in chromosome replication timing on chromosomal rearrangements that are present in only a fraction of the cells in a population.

Chromosome Replicating Timing Combined with Fluorescent In situ Hybridization

A quantitative method for the analysis of chromosome replication timing is described. The method utilizes BrdU incorporation in combination with fluorescent in situ hybridization (FISH) to assess replication timing of mammalian chromosomes. This technique allows for the direct comparison of rearranged and un-rearranged chromosomes within the same cell.

التوقيت كروموسوم النسخ المتماثل جنبا إلى جنب مع نيون<em&gt; في الموقع</em&gt; التهجين

Mammalian DNA replication initiates at multiple sites along chromosomes at different times during S phase, following a temporal replication program. The ...

Combined Immunofluorescence and DNA FISH on 3D-preserved Interphase Nuclei to Study Changes in 3D Nuclear Organization

Fluorescent in situ hybridization using DNA probes on 3-dimensionally preserved nuclei followed by 3D confocal microscopy (3D DNA FISH) represents the most direct way to visualize the location of gene loci, chromosomal sub-regions or entire territories in individual cells. This type of analysis provides insight into the global architecture of the nucleus as well as the behavior of specific genomic loci and regions within the nuclear space. Immunofluorescence, on the other hand, permits the detection of nuclear proteins (modified histones, histone variants and modifiers, transcription machinery and factors, nuclear sub-compartments, etc). The major challenge in combining immunofluorescence and 3D DNA FISH is, on the one hand to preserve the epitope detected by the antibody as well as the 3D architecture of the nucleus, and on the other hand, to allow the penetration of the DNA probe to detect gene loci or chromosome territories 1-5. Here we provide a protocol that combines visualization of chromatin modifications with genomic loci in 3D preserved nuclei.

Here we describe a protocol for simultaneous detection of histone modifications by immunofluorescence and DNA sequences by DNA FISH followed by 3D microscopy and analyses (3D immuno-DNA FISH).

الجمع بين المناعي وFISH DNA على الحفاظ على النواة 3D-الطور البيني لدراسة التغيرات في منظمة النووية 3D

Fluorescent in situ hybridization using DNA probes  on 3-dimensionally preserved nuclei followed by 3D confocal microscopy (3D DNA  FISH) represents the ...

Robust 3D DNA FISH Using Directly Labeled Probes

3D DNA FISH has become a major tool for analyzing three-dimensional organization of the nucleus, and several variations of the technique have been published. In this article we describe a protocol which has been optimized for robustness, reproducibility, and ease of use. Brightly fluorescent directly labeled probes are generated by nick-translation with amino-allyldUTP followed by chemical coupling of the dye. 3D DNA FISH is performed using a freeze-thaw step for cell permeabilization and a heating step for simultaneous denaturation of probe and nuclear DNA. The protocol is applicable to a range of cell types and a variety of probes (BACs, plasmids, fosmids, or Whole Chromosome Paints) and allows for high-throughput automated imaging. With this method we routinely investigate nuclear localization of up to three chromosomal regions.

We describe a robust and versatile protocol for analyzing nuclear architecture by 3D DNA FISH using directly labeled fluorescent probes.

قوية FISH DNA 3D استخدام مجسات إعتبر مباشرة

3D DNA FISH has become a major tool for  analyzing three-dimensional organization of the nucleus, and several variations  of the technique have been ...

Fluorescence In Situ Hybridization on DNA Halo Preparations to Reveal Whole Chromosomes, Telomeres and Gene Loci

The genome is associated with several structures inside cell nuclei, in order to regulate its activity and anchor it in specific locations. These structures are collectively known as the nucleoskeleton and include the nuclear lamina, the nucleoli, and nuclear bodies. Although many variants of fluorescence in situ hybridization (FISH) exist to study the genome and its organization, these are often limited by resolution and provide insufficient information on the genome&#39;s association with nuclear structures. The DNA halo method uses high salt concentrations and nonionic detergents to generate DNA loops that remain anchored to structures within nuclei through attachment regions within the genome. Here, soluble nuclear proteins, such as histones, lipids, and DNA not tightly bound to the nuclear matrix, are extracted. This leads to the formation of a halo of unattached DNA surrounding a residual nucleus which itself contains DNA closely associated with internal nuclear structures and extraction-resistant proteins. These extended DNA strands enable increased resolution and can facilitate physical mapping. In combination with FISH, this method has the added advantage of studying genomic interactions with all the structures that the genome is anchored by. This technique, termed HALO-FISH, is highly versatile whereby DNA halos can be coupled with nucleic acid probes to reveal gene loci, whole chromosomes, alpha satellite, telomeres and even RNA. This technique provides an insight into nuclear organization and function in normal&#160;cells and in disease progression such as with cancer.

Combining DNA halo preparations with fluorescence in situ hybridization enables high-resolution analysis of genomic interactions with the nucleoskeleton. Attached genome leads to hybridized fluorescent signals located within the residual extracted nuclei, whereas non-attached genome is in the halo of DNA surrounding the residual nuclei.

التهجين الفلوري في الموقع على مستحضرات هالة الحمض النووي للكشف عن الكروموسومات الكاملة والتيلوميرات ومواقع الجينات

The genome is associated with several structures inside cell nuclei, in order to regulate its activity and anchor it in specific locations. These ...

HCR-DNA FISH: A Fluorescence In Situ Hybridization Technique to Detect Viral DNA in Infected Cells

Source: Wei Liu&#160;et al., <a href="https://jove.unicartagenaproxy.elogim.com/v/58950"> Merkel Cell Polyomavirus Infection and Detection</a>, J. Vis. Exp. (2019).
In this video, the cells infected with MCPyV virions were subjected to in situ hybridization chain reaction to detect MCPyV specific genomes. Further, the DNA-HCR technique was combined with FISH to visualize the MCPyV DNA in infected human skin cells.

أسماك HCR-DNA: تقنية تهجين مضان في الموقع للكشف عن الحمض النووي الفيروسي في الخلايا المصابة

Source: Wei Liu&#160;et al.,  Merkel Cell Polyomavirus Infection and Detection, J. Vis. Exp. (2019).
In this video, the cells infected with MCPyV virions ...

طريقة بسيطة لDNA الإسفار

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