Name: purification of viral dna for the identification of associated viral and cellular proteins
Uploaded: 2017-08-31T15:00:00.000+00:00
Duration: 8 min 26 s
Description: Watch this Scientific Journal Video about Purification of Viral DNA for the Identification of Associated Viral and Cellular Proteins at JoVE.com

אנו להכיר חנה פוקס לעזרה בהכנת כתב היד הזה. עבודה זו נתמכה על ידי NIH הענק R01AI030612.

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	<li>Knipe, D. M., Howley, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Fields virology. , (2013).</li><li>Engel, E. A., Song, R., Koyuncu, O. O., Enquist, L. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigating+the+biology+of+alpha+herpesviruses+with+MS-based+proteomics.">Investigating the biology of alpha herpesviruses with MS-based proteomics.</a> Proteomics. 15, 1943-1956 (2015).</li><li>Wagner, L. M., DeLuca, N. 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R., 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=During+lytic+infection+herpes+simplex+virus+type+1+is+associated+with+histones+bearing+modifications+that+correlate+with+active+transcription.">During lytic infection herpes simplex virus type 1 is associated with histones bearing modifications that correlate with active transcription.</a> J Virol. 78, 10178-10186 (2004).</li><li>Oh, J., Fraser, N. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+association+of+the+herpes+simplex+virus+genome+with+histone+proteins+during+a+lytic+infection.">Temporal association of the herpes simplex virus genome with histone proteins during a lytic infection.</a> J Virol. 82, 3530-3537 (2008).</li><li>Catez, F., 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=HSV-1+genome+subnuclear+positioning+and+associations+with+host-cell+PML-NBs+and+centromeres+regulate+LAT+locus+transcription+during+latency+in+neurons.">HSV-1 genome subnuclear positioning and associations with host-cell PML-NBs and centromeres regulate LAT locus transcription during latency in neurons.</a> PLoS Pathog. 8, e1002852 (2012).</li><li>Everett, R. D., Murray, J., Orr, A., Preston, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Herpes+simplex+virus+type+1+genomes+are+associated+with+ND10+nuclear+substructures+in+quiescently+infected+human+fibroblasts.">Herpes simplex virus type 1 genomes are associated with ND10 nuclear substructures in quiescently infected human fibroblasts.</a> J Virol. 81, 10991-11004 (2007).</li><li>Tang, Q., 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=Determination+of+minimum+herpes+simplex+virus+type+1+components+necessary+to+localize+transcriptionally+active+DNA+to+ND10.">Determination of minimum herpes simplex virus type 1 components necessary to localize transcriptionally active DNA to ND10.</a> J Virol. 77, 5821-5828 (2003).</li><li>Ishov, A. M., Maul, G. 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B., Cortez, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monitoring+the+spatiotemporal+dynamics+of+proteins+at+replication+forks+and+in+assembled+chromatin+using+isolation+of+proteins+on+nascent+DNA.">Monitoring the spatiotemporal dynamics of proteins at replication forks and in assembled chromatin using isolation of proteins on nascent DNA.</a> Nat Protoc. 7, 594-605 (2012).</li><li>Leung, K. H., Abou El Hassan, M., Bremner, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+rapid+and+efficient+method+to+purify+proteins+at+replication+forks+under+native+conditions.">A rapid and efficient method to purify proteins at replication forks under native conditions.</a> BioTechniques. 55, 204-206 (2013).</li><li>Hobbs, W. E., DeLuca, N. 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פרוטוקול זה כולל מספר שלבים אשר, אם לא עקבו בזהירות, עלולה לגרום התשואה חלבון מופחתת באופן משמעותי או זיהום עם תאי ה-DNA. . זה קריטי כי נייח תאים משמשים לניסויים כל כדי להבטיח כי DNA הסלולר לא מתויג, מטוהרים זה יכול להיות מאושרות על ידי העדר polymerases DNA הסלולר במדגם חלבון כי HSV-1 לא לנצל את הסלולר DNA פ...

וירוסים יש קיבולת מוגבלת כדי לבצע פונקציות חיוניות, ולכן תלויות בגורמים המארח כדי להקל על היבטים קריטיים זיהום כולל ביטוי גנים ויראליים, שכפול, תיקון, רקומבינציה תחבורה. הפעילות של גורמים אלה מארח הם לעיתים קרובות בתוספת לשווק מקודד חלבונים. בנוסף, וירוסים עליך להימנע וזיהוי הפרעות על-ידי תגובות הסלולר זיהום ויראלי. לכן, וירוס מחשב מארח אינטראקציות להכתיב את התוצאה של זיהום. חשיבות עליונה היא ההבנה כמה וירוסים לשנות את הסביבה הסלולר, במטרה להתאים את מכונות הסלולר כדי להקל על התהליכים ויראלי. עניין מיוחד הוא זיהוי גורמים ותהליכים אשר פועלים על הגנום הנגיפי במהלך מחזור זיהומיות.
וירוס הרפס סימפלקס סוג 1 (HSV-1) הוא שכפול תקועים וירוס DNA מדביק חלק ניכר של האוכלוסייה האנושית. בתוך שעה הראשונה של זיהום, הגנום הנגיפי נכנס לגרעין, איפה מדורגת מסודרת של ביטוי גנים ויראליים מתפתח בתיאום עם שכפול נגיפי DNA (vDNA)1. בגרעין, הגנום הם כפופים לכללים epigenetic, לעבור רקומבינציה ותיקון, ארוזים לתוך capsids, כך virions הראשון רומא מיוצרים תוך פחות מ-6 שעות. הערכה מקיפה של גנום ויראלי הקשורים חלבונים לאורך כל הקורס של זיהום תניח את הקרקע כדי לחקור את הפרטים מולקולרית של תהליכים פועלים על הגנום הנגיפי, יספק תובנות אילו גורמים נגיפיים וסלולריות מעורבים בשלבים שונים של זיהום.
שיטות קודמות לחקירה של המארח גורמים מעורבים זיהום ויראלי לכלול טיהור זיקה של חלבונים נגיפיים לניתוח של החלבונים הקשורים2,3,4,5 , 6 , 7 , 8 , 9. מבחני אלה סייעו לצורך הזיהוי של הגורמים המעורבים הסלולר מארח תגובות אנטי ויראליים, כמו גם השינוי כרומטין ויראלי, ביטוי גנים, ותיקון דנ א. עם זאת, קשה לאמת אם האינטראקציות תלויים השיוך vDNA ולאחר פרוטאומיקס רק לספק תובנות האינטראקציות המתרחשות כפונקציה של גורם ויראלי ספציפי. Immunoprecipitation כרומטין (ChIP) נעשה שימוש כדי לזהות איפה לאגד חלבונים נגיפיים וסלולריות ספציפיים הגנום הנגיפי10,11,12,13,14 , 15 ופלורסנט היברידיזציה (דגים) בשילוב עם immunocytochemistry אפשרה את הפריט החזותי של גורמים הסלולר colocalize עם vDNA16,17,18, 19 , 20. מבחני אלה מאפשרים יכולות ניתוח. עם זאת, מגבלות כוללים את הצורך של נוגדנים ספציפיים מאוד רגישות מוגבלת, הצורך הקודם תובנה וירוס מחשב מארח אינטראקציות. לכן פיתחנו שיטת עבודה המבוססת על iPOND (בידוד של חלבונים על ה-DNA nascent)21 , aniPOND (iPOND יליד מואצת)22 כדי לתייג באופן סלקטיבי ולטהר vDNA מן נגוע תאים לצורך זיהוי מוטים אפידמיולוגיה חלבונים הקשורים באמצעות ספקטרומטר מסה. iPOND היה אינסטרומנטלי החקירה של דינמיקה מזלג שכפול הסלולר.
לטיהור סלקטיבי של הגנום הנגיפי של תאים נגועים, שכפול vDNA נקראת עם ethynyl ששינה נוקלאוזידים, 5-ethynyl-2´-deoxyuridine (אדו) או 5-ethynyl-2´-deoxycytidine (EdC) (איור 1), ואחריו קוולנטיות ההטיה כדי ביוטין אזיד באמצעות לחץ על כימיה כדי להקל על צעד בודד טיהור של הגנום הנגיפי וחלבונים הקשורים על חרוזים מצופים streptavidin (איור 2B). חשוב לציין, זיהומים מבוצעות בתאי נייח, אשר לא עוסקים הסלולר שכפול ה-DNA כדי לאפשר תיוג ספציפית של vDNA. יתר על כן, זיהום HSV-1 גורם מחזור מעצר התא, ומעכב הסלולר DNA שכפול23,24. הוירוס יכול להיות prelabeled לפני זיהום לניתוח של חלבונים הקשורים נכנסות הגנום הנגיפי (איור 1 א') או תווית במהלך שכפול ה-DNA על הניתוח של חלבונים הקשורים לאחרונה מסונתז vDNA (איור 1B) 25. יתר על כן, ניתוח צ'ייס הדופק יכול לשמש כדי לחקור את הטבע של חלבונים הקשורים שכפול ויראלי מזלגות (איור 1C)26. בנוסף, vDNA ethynyl-השתנה יכול מצומדת covalently כדי fluorophore לחקירה המרחבי של חלבון דינמיקה (2A איור , איור 3). הדמיה מאפשר פריט חזותי ישיר של vDNA היא גישה ללא תשלום עבור האימות של אינטראקציות חלבון vDNA, ניתן להתאים לאתר הגנום הנגיפי במהלך זיהום. אנו צופים כי הגישות האלה יכול להיות עוד יותר שונה ללמוד בכל היבט של זיהום herpesviral, לרבות השהיית הפעלה מחדש, וכדי ללמוד וירוסים אחרים, ה-DNA. יתר על כן, תיוג עם 5-ethynyl uridine (EU) עלולה לאפשר לניתוח של הגנום נגיפי RNA.

<table><tbody><tr><td>MRC-5 cells</td><td>ATCC</td><td>CCL-171</td><td></td></tr><tr><td>Fetal Bovine Serum (FBS)</td><td>Gibco</td><td>26140-179</td><td></td></tr><tr><td>Dulbecco&#039;s Modified Eagle Medium (DMEM)</td><td>Gibco</td><td>12800-082</td><td>Substituted with 10% FBS, 2 mM L-glutamine, 12 mM&amp;nbsp; (for growth in flasks) or 30 mM (for growth in dishes) sodium-bicarbinate</td></tr><tr><td>600 cm&lt;sup&gt;2&lt;/sup&gt; tissue culture dish</td><td>Thermo Fisher Scientific</td><td>166508</td><td></td></tr><tr><td>Tris Buffered Saline (TBS), pH 7.4</td><td></td><td></td><td>137 mM NaCl, 5 mM KCl, 491 mM MgCl, 680 mM CaCl, 25.1 mM Tricine</td></tr><tr><td>HSV-1 stock</td><td></td><td></td><td>Stocks with titers greater than 1x10&lt;sup&gt;9&lt;/sup&gt; PFU/mL work best</td></tr><tr><td>Sephadex G-25&amp;nbsp; column (PD-10 Desalting Column)</td><td>GE Healthcare</td><td>17085101</td><td></td></tr><tr><td>Dimethyl sulfoxide (DMSO)</td><td>Fisher Scientific</td><td>D128-1</td><td></td></tr><tr><td>5&amp;acute;-Ethynyl-2&amp;acute;-deoxycytidine (EdC)</td><td>Sigma-Aldrich</td><td>T511307</td><td>Dissolve in DMSO to prepare 40 mM stock, aliquot, and store at -20 &amp;deg;C&amp;nbsp;</td></tr><tr><td>2&amp;acute;-deoxycytidine (deoxyC)</td><td>Sigma-Aldrich</td><td>D3897</td><td>Dissolve in water to prepare 40 mM stock, aliquot, and store at -20 &amp;deg;C&amp;nbsp;</td></tr><tr><td>Nuclear Extraction Buffer (NEB)</td><td></td><td></td><td>Prepare fresh (20 mM Hepes pH 7.2, 50 mM NaCl, 3 mM MgCl&lt;sub&gt;2&lt;/sub&gt;, 300 mM Sucrose, 0.5% Igepal)</td></tr><tr><td>Cell scraper</td><td>Bellco glass</td><td>7731-22000</td><td>Autoclave before use</td></tr><tr><td>Trypan blue solution</td><td>Sigma-Aldrich</td><td>T8154</td><td></td></tr><tr><td>PBS, pH 7.2 (10x)</td><td></td><td></td><td>1.37 M NaCl, 27 mM KCl, 100 mM Na&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt;, 18 mM KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt; (dilute to 1x in sterile water before use)</td></tr><tr><td>Copper (II) sulfate pentahydrate (CuSO4-5H2O)</td><td>Fisher Scientific</td><td>C489</td><td>Prepare 100 mM stock and store at 4 &amp;deg;C for up to 1 month</td></tr><tr><td>(+) Sodium L-ascorbate</td><td>Sigma-Aldrich</td><td>A4034</td><td>Freshly prepare 100 mM stock and store on ice until use</td></tr><tr><td>Biotin azide</td><td>Invitrogen</td><td>B10184</td><td>Prepare 10 mM stock in DMSO, aliquot, and store at -20 &amp;deg;C for up to 1 year&amp;nbsp;</td></tr><tr><td>Click Reaction Mix</td><td></td><td></td><td>Prepare immediately before use by adding reagents in the indicated order (10 mL: 8.8 mL 1x PBS, 200 mL 100 mM CuSO&lt;sub&gt;4&lt;/sub&gt;, 25mL 10 mM Biotin Azide, 1 mL 100 mM sodium ascorbate)&amp;nbsp;&amp;nbsp;</td></tr><tr><td>Complete Protease Inhibitor Cocktail</td><td>Roche</td><td>11697498001</td><td>Dissolve in 1 mL water to prepare 50x stock, can store at 4 &amp;deg;C for up to 1 week, or directly add 1 pill to 50 mL buffer</td></tr><tr><td>Freezing buffer</td><td></td><td></td><td>Prepare fresh (7 mL 100% glycerol, 3 mL NEB, 200 &amp;mu;L 50x protease inhibitor)</td></tr><tr><td>Buffer B1</td><td></td><td></td><td>Prepare fresh (25 mM NaCl, 2 mM EDTA, 50 mM Tris-HCl pH 8, 1% Igepal, 1x protease inhibitor)</td></tr><tr><td>Buffer B2</td><td></td><td></td><td>Prepare fresh (150 mM NaCl, 2 mM EDTA, 50 mM Tris-HCl pH 8, 0.5% Igepal, 1x protease inhibitor)</td></tr><tr><td>Buffer B3</td><td></td><td></td><td>Prepare fresh (150 mM NaCl, 2 mM EDTA, 50 mM Tris-HCl pH 8, 1x protease inhibitor)</td></tr><tr><td>Vibra Cell Ultra Sonic Processer equipped with a 3 mm microtip probe</td><td>Sonics</td><td>VCX 130</td><td></td></tr><tr><td>Cell strainer</td><td>Falcon</td><td>352360</td><td></td></tr><tr><td>Dynabeads MyOne Streptavidin T1</td><td>Life Technologies</td><td>65601</td><td></td></tr><tr><td>DynaMag-2 Magnet</td><td>Life Technologies</td><td>12321D</td><td></td></tr><tr><td>Mini-Tube Rotator</td><td>Fisher Scientific</td><td>260750F</td><td></td></tr><tr><td>2x Laemmli sample buffer</td><td></td><td></td><td>Mix 400 mg of SDS, 2 mL 100% glycerol, 1.25 mL of 1 M Tris (pH 6.8), and 10 mg of bromophenol blue in 8 mL water. Store at 4&amp;nbsp; &amp;deg;C for up to 6 months. Before use add 1 M DTT to a final concentration of 200 mM.</td></tr><tr><td>Cap locks for 1.5 mL tube</td><td>Fisher Scientific</td><td>NC9679153</td><td></td></tr><tr><td>Standard western blotting reagents</td><td></td><td></td><td></td></tr><tr><td>NOVEX Colloidal Blue Staining Kit</td><td>Invitrogen</td><td>LC6025</td><td></td></tr><tr><td>12-well tissue culture dish</td><td>Corning</td><td>3513</td><td></td></tr><tr><td>Coverslips</td><td>Fisher Scientific</td><td>12-545-100</td><td>Autoclave before use</td></tr><tr><td>Microscope slides</td><td>Fisher Scientific</td><td>12-552-5</td><td></td></tr><tr><td>16% paraformaldehyde</td><td>Electron Microscopy Sciences</td><td>15710</td><td>Dilute to 3.7% in 1x PBS before use</td></tr><tr><td>Bovine serum albumin (BSA)</td><td>Fisher Scientific</td><td>BP1605</td><td>Prepare 3% in 1x PBS</td></tr><tr><td>Permeabilization buffer (0.5% Triton-X 100)</td><td>Sigma-Aldrich</td><td>T8787</td><td>Prepare 0.5% Triton-X 100 in 1x PBS</td></tr><tr><td>Click reaction cocktail - Click-iT EdU Alexa Fluor 488 Imaging Kit</td><td>Molecular Probes</td><td>C10337</td><td>Prepare according to manufactorer&#039;s protocol</td></tr><tr><td>Hoechst 33342</td><td>Life Technologies</td><td>H1399</td><td>Prepare 10 mg/mL in water, can store at 4 &amp;deg;C for up to 1 year</td></tr><tr><td>Mouse anti-ICP8 primary antibody</td><td>Abcam</td><td>ab20194</td><td>Use a 1:200 dilution in 1x PBS</td></tr><tr><td>Mouse anti-UL42 primary antibody (2H4)</td><td>Abcam</td><td>ab19311</td><td>Use a 1:200 dilution in 1x PBS</td></tr><tr><td>Goat anti-mouse 594-conjugated secondary antibody</td><td>Life Technologies</td><td>a11005</td><td>Use a 1:500 dilution in 1x PBS</td></tr><tr><td>Immu-mount</td><td>Thermo Fisher Scientific</td><td>9990402</td><td></td></tr><tr><td>2x SDS-bicarb solution</td><td></td><td></td><td>2% SDS, 200 mM NaHCO3</td></tr><tr><td>Phenol:chloroform:isoamyl alcohol</td><td></td><td></td><td>Mix 25:24:1 at least 1 day before use, store at 4 &amp;deg;C in the dark</td></tr><tr><td>chloroform:isoamyl alcohol</td><td></td><td></td><td>Mix 24:1 at least 1 day before use, store at room temperature in the dark</td></tr><tr><td>10x Tris EDTA (TE), pH 8.0</td><td></td><td></td><td>100 mM Tris, 10 mM EDTA (dilute to 1x before use)</td></tr><tr><td>Qiaquick PCR purification kit</td><td>Qiagen</td><td>28104</td><td></td></tr><tr><td>3 M sodium acetate pH 5.2</td><td></td><td></td><td></td></tr><tr><td>Qubit 2.0 Fluorometer</td><td>Invitrogen</td><td>Q32866</td><td></td></tr><tr><td>Qubit dsDNA HS Assay Kit</td><td>Invitrogen</td><td>Q32851</td><td></td></tr><tr><td>Qubit assay tubes</td><td>Invitrogen</td><td>Q32856</td><td></td></tr><tr><td>Fluorescence microscope equipped with imaging software</td><td></td><td></td><td></td></tr><tr><td>Microcentrifuge for 1.5 mL tubes</td><td></td><td></td><td></td></tr><tr><td>Tabletop centrifuge for 15 and 50 mL tubes</td><td></td><td></td><td></td></tr><tr><td>Cell culture incubator</td><td></td><td></td><td></td></tr><tr><td>Biosafety cabinet</td><td></td><td></td><td></td></tr><tr><td>Heat blocks</td><td></td><td></td><td>65 &amp;deg;C and 95 &amp;deg;C</td></tr></tbody></table>

purification of viral dna for the identification of associated viral and cellular proteins

המטרה של פרוטוקול זה הוא לבודד את וירוס הרפס סימפלקס סוג 1 (HSV-1) ה-DNA של תאים נגועים לצורך הזיהוי הקשורים ויראלי החלבונים על ידי מסה ספקטרומטר. למרות חלבונים המקיימים אינטראקציה עם הגנום הנגיפי משחק תפקידים עיקריים בקביעת התוצאה של זיהום, ניתוח מקיף של גנום ויראלי הקשורים חלבונים לא היה אפשרי בעבר. כאן נדגים שיטה המאפשרת את טיהור ישירה של HSV-1 הגנום של תאים נגועים. שכפול ה-DNA הנגיפי מסומן באופן סלקטיבי עם נוקלאוטידים ששונה מכילים קבוצה פונקציונלית של אלקין. דנ א שכותרתו אז במיוחד ובלתי הפיך מתויג באמצעות החזקה קוולנטיות של ביוטין אזיד דרך נחושת (I)-מזורז אזיד-אלקין cycloaddition או לחץ על התגובה. מתויג ביוטין DNA מטוהר על חרוזים מצופים streptavidin, חלבונים הקשורים eluted, המזוהה באמצעות ספקטרומטר מסה. שיטה זו מאפשרת מיקוד סלקטיבי ובידוד של מזלגות שכפול HSV-1 או כל הגנום של סביבות ביולוגיות מורכבות. יתר על כן, עיבוד של גישה זו יאפשר החקירה של היבטים שונים של זיהום herpesviral, כמו גם הבחינה של הגנום של וירוסים אחרים, ה-DNA.

השימוש לחץ כימיה לטיהור של ה-DNA של תאים בוצעה לראשונה על ידי שיטת iPOND21. מטרת iPOND היא לטהר מזלגות שכפול הסלולר לצורך זיהוי חלבונים הקשורים. אנחנו הסתגלו טכניקה זו ללמוד אינטראקציות חלבון vDNA במיוחד במהלך זיהום. מניפולציה של הגישה לתייג הגנום הנגיפי עם EdC (<strong class=...

Watch this Scientific Journal Video about Purification of Viral DNA for the Identification of Associated Viral and Cellular Proteins at JoVE.com

Purification of Viral DNA for the Identification of Associated Viral and Cellular Proteins

המטרה של פרוטוקול זה היא במיוחד לתייג באופן סלקטיבי לבודד את ה-DNA הנגיפי של תאים נגועים על האפיון של גנום ויראלי הקשורים חלבונים.

טיהור של ה-DNA הנגיפי לצורך זיהוי חלבונים הקשורים ויראלי וסלולריות

The goal of this protocol is to isolate herpes simplex virus type 1 (HSV-1) DNA from infected cells for the identification of associated viral and ...

purification-viral-dna-for-identification-associated-viral-cellular

Research

JoVE Journal

Immunology and Infection

13.4K Views.  University of Pittsburgh School of Medicine. המטרה של פרוטוקול זה היא במיוחד לתייג באופן סלקטיבי לבודד את ה-DNA הנגיפי של תאים נגועים על האפיון של גנום ויראלי הקשורים חלבונים.

Video: Purification of Viral DNA for the Identification of Associated Viral and Cellular Proteins

Preparation of Viral DNA from Nucleocapsids

Viruses are obligate cellular parasites, and thus the study of their DNA requires isolating viral material away from host cell contaminants and DNA. Several downstream applications require large quantities of pure viral DNA, which is provided by this protocol. These applications include viral genome sequencing, where the removal of host DNA is crucial to optimize data output for viral sequences, and the production of new viral recombinant strains, where co-transfection of purified plasmid and linear viral DNA facilitates recombination.1,2,3 
This procedure utilizes a combination of extractions and density-based centrifugation to isolate purified linear herpesvirus nucleocapsid DNA from infected cells.4,5 The initial purification steps aim to isolate purified viral capsids, which contain and protect the viral DNA during the extractions and centrifugation steps that remove cellular proteins and DNA. Lysis of nucleocapsids then releases viral DNA, and two final phenol-chloroform steps remove remaining proteins. The final DNA captured from solution is highly concentrated and pure, with an average OD260/280 of 1.90. Depending on the quantity of infected cells used, yields of viral DNA range from 150-800 &mu;g or more. The purity of this DNA makes it stable during long-term storage at 4C. This DNA is thus ideally suited for high-throughput sequencing, high fidelity PCR reactions, and transfections. 
Prior to beginning the protocol, it is important to know the average number of cells per dish (e.g. an average of 8 x 106 PK-15 cells in a confluent 15 cm dish), and the titer of the viral stock to be used (e.g. 1 x 108 plaque-forming units per ml). These are necessary to calculate the appropriate multiplicity of infection (MOI) for the protocol.6 For instance, to infect one 15 cm dish of PK-15 cells with the above viral stock, at an MOI of 5, you would use 400 &mu;l of viral stock and dilute it with 3.6 ml of medium (total inoculation volume of 4 ml for one 15 cm plate).
Multiple viral DNA preparations can be prepared at the same time. The number of simultaneous preparations is limited only by the number of tubes held by the ultracentrifuge rotor (one per virus; see step 3.9 below). Here we describe the procedure as though being done for one virus.

We describe the process of isolating high purity herpesvirus nucleocapsid DNA from infected cells. The final DNA captured from solution is of high concentration and purity, making it ideally suited for high-throughput sequencing, high fidelity PCR reactions, and transfections to produce new viral recombinants.

ההכנה של ה-DNA ויראלי של Nucleocapsids

Viruses are obligate cellular parasites, and thus the study of their DNA requires isolating viral material away from host cell contaminants and DNA. ...

Isolation and Genome Analysis of Single Virions using 'Single Virus Genomics'

Whole genome amplification and sequencing of single microbial cells enables genomic characterization without the need of cultivation 1-3. Viruses, which are ubiquitous and the most numerous entities on our planet 4 and important in all environments 5, have yet to be revealed via similar approaches. Here we describe an approach for isolating and characterizing the genomes of single virions called 'Single Virus Genomics' (SVG). SVG utilizes flow cytometry to isolate individual viruses and whole genome amplification to obtain high molecular weight genomic DNA (gDNA) that can be used in subsequent sequencing reactions.

Single Virus Genomics (SVG) is a method to isolate and amplify the genomes of single virons. Viral suspensions of a mixed assemblage are sorted using flow cytometry onto a microscope slide with discrete wells containing agarose, thereby capturing the virion and reducing genome shearing during downstream processing. Whole genome amplification is achieved using multiple displacement amplification (MDA) resulting in genomic material that is suitable for sequencing.

בידוד ואנליזה של הגנום virions יחיד באמצעות &#39;נומיקס וירוס אחד &quot;

Whole genome amplification and sequencing of single microbial cells enables genomic characterization without the need of cultivation 1-3. Viruses, which ...

Affinity Purification of Influenza Virus Ribonucleoprotein Complexes from the Chromatin of Infected Cells

Like all negative-strand RNA viruses, the genome of influenza viruses is packaged in the form of viral ribonucleoprotein complexes (vRNP), in which the single-stranded genome is encapsidated by the nucleoprotein (NP), and associated with the trimeric polymerase complex consisting of the PA, PB1, and PB2 subunits. However, in contrast to most RNA viruses, influenza viruses perform viral RNA synthesis in the nuclei of infected cells. Interestingly, viral mRNA synthesis uses cellular pre-mRNAs as primers, and it has been proposed that this process takes place on chromatin1. Interactions between the viral polymerase and the host RNA polymerase II, as well as between NP and host nucleosomes have also been characterized1,2.
Recently, the generation of recombinant influenza viruses encoding a One-Strep-Tag genetically fused to the C-terminus of the PB2 subunit of the viral polymerase (rWSN-PB2-Strep3) has been described. These recombinant viruses allow the purification of PB2-containing complexes, including vRNPs, from infected cells. To obtain purified vRNPs, cell cultures are infected, and vRNPs are affinity purified from lysates derived from these cells. However, the lysis procedures used to date have been based on one-step detergent lysis, which, despite the presence of a general nuclease, often extract chromatin-bound material only inefficiently. 
Our preliminary work suggested that a large portion of nuclear vRNPs were not extracted during traditional cell lysis, and therefore could not be affinity purified. To increase this extraction efficiency, and to separate chromatin-bound from non-chromatin-bound nuclear vRNPs, we adapted a step-wise subcellular extraction protocol to influenza virus-infected cells. Briefly, this procedure first separates the nuclei from the cell and then extracts soluble nuclear proteins (here termed the "nucleoplasmic" fraction). The remaining insoluble nuclear material is then digested with Benzonase, an unspecific DNA/RNA nuclease, followed by two salt extraction steps: first using 150 mM NaCl (termed "ch150"), then 500 mM NaCl ("ch500") (Fig. 1). These salt extraction steps were chosen based on our observation that 500 mM NaCl was sufficient to solubilize over 85% of nuclear vRNPs yet still allow binding of tagged vRNPs to the affinity matrix.
After subcellular fractionation of infected cells, it is possible to affinity purify PB2-tagged vRNPs from each individual fraction and analyze their protein and RNA components using Western Blot and primer extension, respectively. Recently, we utilized this method to discover that vRNP export complexes form during late points after infection on the chromatin fraction extracted with 500 mM NaCl (ch500)3.

Influenza viruses replicate their RNA genome in association with host-cell chromatin. Here, we present a method to purify intact viral ribonucleoprotein complexes from the chromatin of infected cells. Purified viral complexes can be analyzed by both Western blot and primer extension of protein and RNA content, respectively.

זיקה טיהור של נגיף השפעת תסביכים Ribonucleoprotein של הכרומטין של תאים נגועים

Like all negative-strand RNA viruses, the genome of influenza viruses is packaged in the form of viral ribonucleoprotein complexes (vRNP), in which the ...

Purification and Visualization of Influenza A Viral Ribonucleoprotein Complexes

The influenza A viral genome consists of eight negative-sense, single stranded RNA molecules, individually packed with multiple copies of the influenza A nucleoprotein (NP) into viral ribonulceoprotein particles (vRNPs). The influenza vRNPs are enclosed within the viral envelope. During cell entry, however, these vRNP complexes are released into the cytoplasm, where they gain access to the host nuclear transport machinery. In order to study the nuclear import of influenza vRNPs and the replication of the influenza genome, it is useful to work with isolated vRNPs so that other components of the virus do not interfere with these processes. Here, we describe a procedure to purify these vRNPs from the influenza A virus. The procedure starts with the disruption of the influenza A virion with detergents in order to release the vRNP complexes from the enveloped virion. The vRNPs are then separated from the other components of the influenza A virion on a 33-70% discontinuous glycerol gradient by velocity sedimentation. The fractions obtained from the glycerol gradient are then analyzed on via SDS-PAGE after staining with Coomassie blue. The peak fractions containing NP are then pooled together and concentrated by centrifugation. After concentration, the integrity of the vRNPs is verified by visualization of the vRNPs by transmission electron microscopy after negative staining. The glycerol gradient purification is a modification of that from Kemler et al. (1994)1, and the negative staining has been performed by Wu et al. (2007).2

The genome of the influenza A virus consists of eight separate complexes of RNA and proteins, termed viral ribonucleoprotein complexes (vRNPs). This paper describes the glycerol gradient purification and transmission electron microscopy visualization of influenza A vRNPs.

טיהור ויזואליזציה של שפעת מכלולים Ribonucleoprotein ויראלי

The influenza A viral genome consists of eight negative-sense, single stranded RNA molecules, individually packed with multiple copies of the influenza A ...

Biology

Isolation of Viral Replication Compartment-enriched Sub-nuclear Fractions from Adenovirus-infected Normal Human Cells

During infection of human cells by adenovirus (Ad), the host cell nucleus is dramatically reorganized, leading to formation of nuclear microenvironments through the recruitment of viral and cellular proteins to sites occupied by the viral genome. These sites, called replication compartments (RC), can be considered viral-induced nuclear domains where the viral genome is localized and viral and cellular proteins that participate in replication, transcription and post-transcriptional processing are recruited. Moreover, cellular proteins involved in the antiviral response, such as tumor suppressor proteins, DNA damage response (DDR) components and innate immune response factors are also co-opted to RC. Although RC seem to play a crucial role to promote an efficient and productive replication cycle, a detailed analysis of their composition and associated activities has not been made. To facilitate the study of adenoviral RC and potentially those from other DNA viruses that replicate in the cell nucleus, we adapted a simple procedure based on velocity gradients to isolate Ad RC and established a cell-free system amenable to conduct morphological, functional and compositional studies of these virus-induced subnuclear structures, as well as to study their impact on host-cell interactions.

We provide a novel strategy to isolate viral replication compartments (RC) from adenovirus (Ad)-infected human cells. This approach represents a cell-free system that can help to elucidate the molecular mechanisms regulating viral genome replication and expression as well as regulation of viral-host interactions established at the RC.

בידוד של שברים תת-גרעיניים מועשרים-תא ויראלי שכפול מתאים נורמלים אדם נגוע Adenovirus

During infection of human cells by adenovirus (Ad), the host cell nucleus is dramatically reorganized, leading to formation of nuclear microenvironments ...

Combining Analysis of DNA in a Crude Virion Extraction with the Analysis of RNA from Infected Leaves to Discover New Virus Genomes

This metagenome approach is used to identify plant viruses with circular DNA genomes and their transcripts. Often plant DNA viruses that occur in low titers in their host or cannot be mechanically inoculated to another host are difficult to propagate to achieve a greater titer of infectious material. Infected leaves are ground in a mild buffer with optimal pH and ionic composition recommended for purifying most bacilliform Para retroviruses. Urea is used to break up inclusion bodies that trap virions and to dissolve cellular components. Differential centrifugation provides further separation of virions from plant contaminants. Then proteinase K treatment removes the capsids. Then the viral DNA is concentrated and used for next-generation sequencing (NGS). The NGS data are used to assemble contigs which are submitted to NCBI-BLASTn to identify a subset of virus sequences in the generated dataset. In a parallel pipeline, RNA is isolated from infected leaves using a standard column-based RNA extraction method. Then ribosome depletion is carried out to enrich for a subset of mRNA and virus transcripts. Assembled sequences derived from RNA sequencing (RNA-seq) were submitted to NCBI-BLASTn to identify a subset of virus sequences in this dataset. In our study, we identified two related full-length badnavirus genomes in the two datasets. This method is preferred to another common approach which extracts the aggregate population of small RNA sequences to reconstitute plant virus genomic sequences. This latter metagenomic pipeline recovers virus related sequences that are retro-transcribing elements inserted into the plant genome. This is coupled to biochemical or molecular assays to further discern the actively infectious agents. The approach documented in this study, recovers sequences representative of replicating viruses that likely indicate active virus infection.

Here we present a new approach to identify plant viruses with double-strand DNA genomes. We use standard methods to extract DNA and RNA from infected leaves and carry out next-generation sequencing. Bioinformatic tools assemble sequences into contigs, identify contigs representing virus genomes and assign genomes to taxonomic groups.

שילוב ניתוח של דנ א ב מיצוי Virion גולמי עם הניתוח של RNA של עלים נגועים לגלות הגנום וירוס חדש

This metagenome approach is used to identify plant viruses with circular DNA genomes and their transcripts. Often plant DNA viruses that occur in low ...

Detection of Low Copy Number Integrated Viral DNA Formed by In Vitro Hepatitis B Infection

Hepatitis B Virus (HBV) is a common blood-borne pathogen causing liver cancer and liver cirrhosis resulting from chronic infection. The virus generally replicates through an episomal DNA intermediate; however, integration of HBV DNA fragments into the host genome has been observed, even though this form is not necessary for viral replication. The exact purpose, timing, and mechanism(s) by which HBV DNA integration occurs is not yet clear, but recent data show that it occurs very early after infection. Here, the in vitro generation and detection of HBV DNA integrations are described in detail. Our protocol specifically amplifies single copies of virus-cell DNA integrations and allows both absolute quantification and single-base pair resolution of the junction sequence. This technique has been applied to various HBV-susceptible cell types (including primary human hepatocytes), to various HBV mutants, and in conjunction with various drug exposures. We foresee this technique becoming a key assay to determine the underlying molecular mechanisms of this clinically relevant phenomenon.

Detection of Low Copy Number Integrated Viral DNA Formed by In Vitro Hepatitis B Infection

We describe here the in vitro generation of HBV DNA via a Hepatitis B virus infection system and the highly sensitive detection of its (1&#8211;2 copies) integration using inverse nested PCR.

זיהוי של עותק נמוך מספר משולב ה-DNA הנגיפי נוצר על ידי במבחנה הפטיטיס B זיהום

Hepatitis B Virus (HBV) is a common blood-borne pathogen causing liver cancer and liver cirrhosis resulting from chronic infection. The virus generally ...

Identification of Protein Interacting Partners Using Tandem Affinity Purification

A critical and often limiting step in understanding the function of host and viral proteins is the identification of interacting cellular or viral protein partners. There are many approaches that allow the identification of interacting partners, including the yeast two hybrid system, as well as pull down assays using recombinant proteins and immunoprecipitation of endogenous proteins followed by mass spectrometry identification1. Recent studies have highlighted the utility of double-affinity tag mediated purification, coupled with two specific elution steps in the identification of interacting proteins. This approach, termed Tandem Affinity Purification (TAP), was initially used in yeast2,3 but more recently has been adapted to use in mammalian cells4-8.
As proof-of-concept we have established a tandem affinity purification (TAP) method using the well-characterized eukaryotic translation initiation factor eIF4E9,10.The cellular translation factor eIF4E is a critical component of the cellular eIF4F complex involved in cap-dependent translation initiation10. The TAP tag used in the current study is composed of two Protein G units and a streptavidin binding peptide separated by a Tobacco Etch Virus (TEV) protease cleavage sequence. The TAP tag used in the current study is composed of two Protein G units and a streptavidin binding peptide separated by a Tobacco Etch Virus (TEV) protease cleavage sequence8. To forgo the need for the generation of clonal cell lines, we developed a rapid system that relies on the expression of the TAP-tagged bait protein from an episomally maintained plasmid based on pMEP4 (Invitrogen). Expression of tagged murine eIF4E from this plasmid was controlled using the cadmium chloride inducible metallothionein promoter.
Lysis of the expressing cells and subsequent affinity purification via binding to rabbit IgG agarose, TEV protease cleavage, binding to streptavidin linked agarose and subsequent biotin elution identified numerous proteins apparently specific to the eIF4E pull-down (when compared to control cell lines expressing the TAP tag alone). The identities of the proteins were obtained by excision of the bands from 1D SDS-PAGE and subsequent tandem mass spectrometry. The identified components included the known eIF4E binding proteins eIF4G and 4EBP-1. In addition, other components of the eIF4F complex, of which eIF4E is a component were identified, namely eIF4A and Poly-A binding protein. The ability to identify not only known direct binding partners as well as secondary interacting proteins, further highlights the utility of this approach in the characterization of proteins of unknown function.

Tandem affinity purification is a robust approach for the identification of protein binding partners. As proof of concept, this methodology was applied to the well-characterized translation initiation factor eIF4E to co-precipitate the host cell factors involved in translation initiation. This method is easily adapted to any cellular or viral protein.

זיהוי שותפים חלבון אינטראקציה באמצעות טיהור טנדם זיקה

A critical and often limiting step in understanding the function of host and viral proteins is the identification of interacting cellular or viral protein ...

<meta charset="utf8"></head><body>ניתוח של SARS-CoV-2 באמצעות טכנולוגיית דיווח כפול ומולטיפלקס

Profiling of Surface Protein Epitopes on Viral Particles by Multiplex Dual-Reporter Strategy

Membrane proteins on enveloped viruses play an important role in many biological functions involving virus attachment to target cell receptors, fusion of viral particles to host cells, host-virus interactions, and disease pathogenesis. Furthermore, viral membrane proteins on virus particles and presented on host cell surfaces have proven to be excellent targets for antivirals and vaccines. Here, we describe a protocol to investigate surface proteins on intact severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) particles using the dual-reporter flow cytometric system. The assay exploits multiplex technology to obtain a triple detection of viral particles by three independent affinity reactions. Magnetic beads conjugated to recombinant human angiotensin-converting enzyme-2 (ACE2) were used to capture viral particles from the supernatant of cells infected with SARS-CoV-2. Then, two detection reagents labeled with R-phycoerythrin (PE) or Brilliant Violet 421 (BV421) were applied simultaneously. As a proof-of-concept, antibody fragments targeting different epitopes of the SARS-CoV-2 surface protein Spike (S1) were used. The detection of viral particles by three independent affinity reactions provides strong specificity and confirms the capture of intact virus particles. Dose-dependency curves of SARS-CoV-2 infected cell supernatant were generated with replicate coefficient variances (mean/SD) &#706;14%. Good assay performance in both channels confirmed that two virus surface target protein epitopes are detectable in parallel. The protocol described here could be applied for (i) high-multiplex, high-throughput profiling of surface proteins expressed on enveloped viruses; ii) detection of active intact viral particles; and (iii) assessment of specificity and affinity of antibodies and antiviral drugs for surface epitopes of viral antigens.The application can be potentially extended to any type of extracellular vesicles and bioparticles, exposing surface antigens in body fluids or other liquid matrices.

<meta charset="utf8"></head><body>מחבר זרקור: קידום אסטרטגיות אנטי-ויראליות באמצעות טכניקות חדשניות של לכידת חיסונים וספקטרומטריית מסות

Here, we describe a newly developed multiplex fluorescent immunoassay that uses a dual-reporter flow cytometric system to concurrently detect two unique spike protein epitopes on intact severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral particles that had been captured by angiotensin-converting enzyme-2-coupled magnetic microspheres.

יצירת פרופיל של אפיטופים של חלבון פני השטח על חלקיקים נגיפיים על ידי אסטרטגיית Multiplex Dual-Reporter

Membrane proteins on enveloped viruses play an important role in many biological functions involving virus attachment to target cell receptors, fusion of ...

טיהור של ה-DNA הנגיפי לצורך זיהוי חלבונים הקשורים ויראלי וסלולריות

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ההכנה של ה-DNA ויראלי של Nucleocapsids

בידוד ואנליזה של הגנום virions יחיד באמצעות 'נומיקס וירוס אחד "

זיקה טיהור של נגיף השפעת תסביכים Ribonucleoprotein של הכרומטין של תאים נגועים

טיהור ויזואליזציה של שפעת מכלולים Ribonucleoprotein ויראלי

בידוד של שברים תת-גרעיניים מועשרים-תא ויראלי שכפול מתאים נורמלים אדם נגוע Adenovirus

שילוב ניתוח של דנ א ב מיצוי Virion גולמי עם הניתוח של RNA של עלים נגועים לגלות הגנום וירוס חדש

זיהוי של עותק נמוך מספר משולב ה-DNA הנגיפי נוצר על ידי במבחנה הפטיטיס B זיהום

זיהוי שותפים חלבון אינטראקציה באמצעות טיהור טנדם זיקה

יצירת פרופיל של אפיטופים של חלבון פני השטח על חלקיקים נגיפיים על ידי אסטרטגיית Multiplex Dual-Reporter

יצירת פרופיל של אפיטופים של חלבון פני השטח על חלקיקים נגיפיים על ידי אסטרטגיית Multiplex Dual-Reporter