ChIP: Difference between revisions
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==Notes== | ==Notes== | ||
# | # This protocol will likely fail the first time you try it. Your LM-PCR product will contain no DNA. Don't loose heart. Try, try again. (Hard to pin down exactly what goes wrong between sonication and LM-PCR, but it seems that the blunting step is very sensitive. Most people get it to work by trying two or three times.) ~ [[User:Cconboy|cmc]] 16:25, 21 August 2006 (EDT) | ||
==References== | ==References== |
Revision as of 13:25, 21 August 2006
This protocol is in development.~ cmc 15:03, 21 August 2006 (EDT)
Overview
Replace this sentence with a brief description of the protocol and its goal.
Materials
11% Formaldehyde Solution
per 50 ml: (Final concentration)
- 14.9 ml of 37% Formaldehyde (11%)
- 1 ml of 5M NaCl (0.1M)
- 100 µl of 0.5 M EDTA, pH 8 (1 mM)
- 50 µl of 0.5 M EGTA, pH 8 (0.5 mM)
- 2.5 ml of 1M Hepes, pH 8 (50 mM)
2.5 M glycine (187.5 g/L)
- Dissolve glycine in water with constant stirring
- Don’t adjust pH
BSA/PBS Solution
per 100 mL:
- 10 mL of 10x PBS
- 500 mg of BSA
- 90 mL of H20
(good for at least a week)
Lysis Buffer 1 (LB1)
per 100 ml: (final concentration)
- 5 ml of 1M Hepes-KOH, pH 7.5 (50 mM)
- 2.8 ml of 5M NaCl (140 mM)
- 0.2 ml of 0.5M EDTA (1 mM)
- 10 ml of glycerol (10%)
- 5 ml of 10% NP-40 (0.5%)
- 0.25 ml of Triton X-100 (0.25%)
Lysis Buffer 2 (LB2)
per 100 ml: (final concentration)
- 4 ml of 5M NaCl (200 mM)
- 0.2 ml of 0.5M EDTA (1 mM)
- 0.1 ml of 0.5M EGTA (0.5 mM)
- 1.0 ml of 1M Tris pH 7.5 (10 mM)
Lysis Buffer 3 (LB3)
per 100 ml: (final concentration)
- 0.2 ml of 0.5M EDTA (1 mM)
- 0.1 ml of 0.5M EGTA (0.5 mM)
- 1.0 ml of 1M Tris-HCl, pH7.5 (10 mM)
- 2 mL of 5M NaCl (100 mM)
- 1 mL of 10% Na-Deoxycholate (0.1%)
- 500 mg of N-lauroyl sarcosine (0.5%)
Wash buffer (RIPA buffer)
per 100ml: (final concentration)
- 5ml of 1M Hepes, pH 7.6 (50 mM)
- 200µL of 0.5M EDTA (1 mM)
- 7 ml of 10% DOC (Na deoxycholate) (0.7%)
- 10 ml of 10% NP-40 (IPGEL) (1%)
- 10 ml of 5M LiCl or 2.12g powder (0.5 M)
Elution buffer
- 50mM Tris pH8
- 1mM EDTA
- 1% SDS
Procedure
I. Cell cross-linking
- Use 5x107 – 1x108 cells (70-80% confluency for adhesion cells of 8-12 15 cm2 plates or 175 cm2 flasks) for each ChIP reaction.
- Adherent cells:
- Add 1/10 volume of fresh 11% formaldehyde solution to plates.
- Swirl plates briefly and let them sit at RT for 10 min.
- Add 1/20 volume of 2.5 M glycine to plates to quench formaldehyde.
- Rinse cells twice with 5 ml 1X PBS. Harvest cells using silicon scraper.
- Spin cells at 4k for 10’ at 4°C.
- Transfer cells to 15ml conical tubes and spin 4k 10’ at 4°C.
- Flash freeze cells in liquid nitrogen and store pellets at –80 °C.
- Suspension cells:
- Add 1/10 volume of fresh 11% formaldehyde solution to flasks.
- Swirl flasks briefly and let them sit at RT for 20 min.
- Add 1/20 volume of 2.5 M glycine to flasks to quench formaldehyde.
- Spin cells at 2500rpm for 10’ at 4°C.
- Rinse cells with 100ml 1x PBS and spin cells at 2500rpm for 10’ at 4°C.
- Rinse cells with 10ml 1x PBS and transfer to 15ml conical tubes and spin 4k 10’ at 4°C.
- Flash freeze cells in liquid nitrogen and store pellets at –80 °C.
II. Preblock and binding of antibody to magnetic beads
- Keep beads on ice for all steps
- wash 100 µL Dynal magnetic beads (per reaction) in 1 ml fresh BSA/PBS
- collect the beads with magnet wash beads in 1.5 ml BSA/PBS 2 times, collect the beads with the magnet.
- Add 6-10 µg of Ab + 250µL of PBS/BSA.
- incubate 4 hr to O.N. on a rotating platform at 4∞C.
- wash beads 3 times in 1.5 ml PBS/BSA.
- Resuspend in 100µL PBS/BSA.
III. Cell Sonication
IV. Chromatin Immunoprecipitation
- Add 100 µL Ab prebound Dynal magnetic beads from step III.
- Rock 4∞C 6 hrs to O/N.
V. Washing, eluting, and reverse cross-linking
VI. RNase, Proteinase K
Notes
- This protocol will likely fail the first time you try it. Your LM-PCR product will contain no DNA. Don't loose heart. Try, try again. (Hard to pin down exactly what goes wrong between sonication and LM-PCR, but it seems that the blunting step is very sensitive. Most people get it to work by trying two or three times.) ~ cmc 16:25, 21 August 2006 (EDT)