Isolation of chromatin from egg extract and histone recovery (Shechter lab) and Tissue culture of Xenopus cell lines S3, XTC (Stukenberg lab): Difference between pages

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Protocol submitted by VGP from David Shechter lab protocols [http://www.xenbase.org/community/person.do?method=display&personId=1810&tabId=0]
Protocol submitted by VGP from Stukenberg lab protocols [http://www.xenbase.org/community/person.do?method=display&personId=1311&tabId=0]




Link to PDF: [http://www.shechterlab.org/wp-content/uploads/2009/07/Chromatin-Isolation-from-Egg-Extract.pdf]
link to protocol page [http://people.virginia.edu/~djb6t/LabWeb/frogs.htm]




PROTOCOL: Sperm Chromatin Isolation / Histone Preparation
Tissue Culture Care Instructions for Xenopus cell lines: S3, XTC
Media:  L-15 Medium (Leibovitz), Sigma-Aldrich product # L4386.  This comes in powder form, which we resuspend to a 66% solution (dissolve one 14.7g/L vial into 1.4L ddH2O and pH to 7.6).
 
New media must be filter sterilized into sterile bottles. We usually use Nalgene 500mL receiver bottles and  Store media at 4˚C. 
Before use with cells, you must add 10% FBS (fetal bovine serum),  1X Penn/Strep (antibiotic, comes as 100X stock), and 1X Sodium Pyruvate (also a 100X stock). 
Notes: Antibiotics are good for about 1 month, so if you’re using your media for longer than that, re-supplement it accordingly.
Getting started:


Recipes:
Keep everything sterile.  Don’t use non-autoclaved tips, coverslips, or pipets.  Make sure all dishes are sterile. 
Warm the media and trypsin (if using) to room temperature.  (I do this 30-60 minutes before I have hood time).
Make sure the UV light has been on in the hood you’re about to use.  Before use, turn off the UV and turn on the blower. Spray gloved hands with 70% EtOH.  Wipe down the surface of the hood with 70% EtOH.  Spray down and wipe all bottles, (basically anything going into the hood) with 70% EtOH.
Splitting/Passaging Cells:


ELB-CIB (Egg lysis buffer – Chromatin Isolation Buffer) - 1X Egg Lysis Buffer, containing .25M Sucrose 1mM Spermidine 1mM Spermine 0.5mM EDTA
Remove media. Wash cells with 3-5mL of sterile Dulbecco’s Phosphate Buffered Saline (PBS).  Remove PBS and add 2mL 1XTrypsin (red color) per 100mm plate.  Swirl around and tap plates a few times.  Let sit a few minutes.  Add appropriate amount of fresh complete media to new plates for the dilution you’ve chosen.  S3 cells grow slowly, so don’t split them too dilute if you need to use them that same week.
5mM DTT 0.1% Triton-X 100 1X Protease Inhibitor Cocktail (Roche) 10mM Sodium Butyrate 1X Phosphatase Inhibitor Cocktails I & II (Roche)
Growing cells on coverslips


ELB - 0.25M Sucrose 2.5mM MgCl2 50mM KCl 10mM Hepes-KOH pH 7.8 1mM DTT
Coverslips should be at the very least autoclaved or baked at 250˚C.  You can also HCl-wash and poly-lysine coat coverslips.  Cells are often happier on poly-lysine coated coverslips, so if you’re not happy with how the cells look, you may want to try these.  You can transfer coverslips to tissue culture dishes in two ways, either by tweezer (make sure it’s been cleaned well with EtOH, or by using the suction on a sterile Pasteur pipette (of course if your coverslips are in solution, this won’t work).  Rinse coverslips a few times in PBS, and then add an appropriate volume of fresh media to them.  Then, split your cells as normal, adding a sufficient density of cells to each well. I’d advise splitting them pretty densely so that you can use them the next day if possible. Lab lore indicates that the cells are more mitotic if you use them the next day.
Finishing up


 
Remove all your materials from the hood. Make sure you’ve turned off the aspirator, thrown away all pipettes, and plugged back in the pipetaid (if necessary). Wipe down the hood with 70% EtOH. Shut the hood, and turn on the UV light.
Procedures/Steps:
 
1. Incubate sperm in egg extract (LSS, HSS, NPE, etc), use 10-100 μl/reaction, and 2000- 10,000 sperm/ μl. Flash freeze at time points or continue with unfrozen extract. For large-scale histone preparation: use 1-2ml of LSS extract and 10,000 sperm/ μl.
 
2. Add 900 μl of 1X ELB-CIB (ice-cold); mix thoroughly and incubate on ice for 10 minutes. Underlayer carefully with 200 μl of ELB-CIB containing 0.6M sucrose.
 
3. Spin in swinging bucket rotor at 4000g for 5-10 minutes at 4C. (In eppendorf, 6000RPM). There should be a visible white pellet at the bottom of the tube.
 
4. Carefully remove supernatant with pipet and respin briefly. Aspirate remaining supernatant with pipet.
 
5. Wash pellet 1X with 1ml ELB-CIB. (For histone prep, include 0.3M NaCl). Completely aspirate supernatant with pipet.
 
6. For gel analysis: Resuspend pellet in 1X Laemmli loading buffer. The DNA can get viscous when hot; cool before loading on SDS-PAGE gel.
 
7. For histone prep: Extract pellet in 0.4N H2SO4 for 2 hours or overnight. Precipitate extracted proteins in supernatant with 25% cold TCA for 30 minutes on ice, spin down and wash pellet with 100% cold acetone. Dissolve pellet in appropriate volume of water.

Revision as of 15:01, 11 November 2011

Protocol submitted by VGP from Stukenberg lab protocols [1]


link to protocol page [2]


Tissue Culture Care Instructions for Xenopus cell lines: S3, XTC

Media: L-15 Medium (Leibovitz), Sigma-Aldrich product # L4386. This comes in powder form, which we resuspend to a 66% solution (dissolve one 14.7g/L vial into 1.4L ddH2O and pH to 7.6).

New media must be filter sterilized into sterile bottles. We usually use Nalgene 500mL receiver bottles and Store media at 4˚C. Before use with cells, you must add 10% FBS (fetal bovine serum), 1X Penn/Strep (antibiotic, comes as 100X stock), and 1X Sodium Pyruvate (also a 100X stock). Notes: Antibiotics are good for about 1 month, so if you’re using your media for longer than that, re-supplement it accordingly.

Getting started:

Keep everything sterile. Don’t use non-autoclaved tips, coverslips, or pipets. Make sure all dishes are sterile. Warm the media and trypsin (if using) to room temperature. (I do this 30-60 minutes before I have hood time). Make sure the UV light has been on in the hood you’re about to use. Before use, turn off the UV and turn on the blower. Spray gloved hands with 70% EtOH. Wipe down the surface of the hood with 70% EtOH. Spray down and wipe all bottles, (basically anything going into the hood) with 70% EtOH.

Splitting/Passaging Cells:

Remove media. Wash cells with 3-5mL of sterile Dulbecco’s Phosphate Buffered Saline (PBS). Remove PBS and add 2mL 1XTrypsin (red color) per 100mm plate. Swirl around and tap plates a few times. Let sit a few minutes. Add appropriate amount of fresh complete media to new plates for the dilution you’ve chosen. S3 cells grow slowly, so don’t split them too dilute if you need to use them that same week.

Growing cells on coverslips

Coverslips should be at the very least autoclaved or baked at 250˚C. You can also HCl-wash and poly-lysine coat coverslips. Cells are often happier on poly-lysine coated coverslips, so if you’re not happy with how the cells look, you may want to try these. You can transfer coverslips to tissue culture dishes in two ways, either by tweezer (make sure it’s been cleaned well with EtOH, or by using the suction on a sterile Pasteur pipette (of course if your coverslips are in solution, this won’t work). Rinse coverslips a few times in PBS, and then add an appropriate volume of fresh media to them. Then, split your cells as normal, adding a sufficient density of cells to each well. I’d advise splitting them pretty densely so that you can use them the next day if possible. Lab lore indicates that the cells are more mitotic if you use them the next day.

Finishing up

Remove all your materials from the hood. Make sure you’ve turned off the aspirator, thrown away all pipettes, and plugged back in the pipetaid (if necessary). Wipe down the hood with 70% EtOH. Shut the hood, and turn on the UV light.