Chromatin Immunoprecipitation: Difference between revisions
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29. Make Elution Buffer for all IP tubes as well as all Input tubes (see Section C, step 7). | 29. Make Elution Buffer for all IP tubes as well as all Input tubes (see Section C, step 7). | ||
* For each tube, prepare 200 μL of elution buffer as follows: 10 μL 20% SDS, 20 μL 1 M NaHCO3 and 170 μL sterile, distilled water. | * For each tube, prepare 200 μL of elution buffer as follows: 10 μL 20% SDS, 20 μL 1 M NaHCO3 and 170 μL sterile, distilled water. | ||
* Alternatively, make a large volume to accommodate all tubes. For example, if there are 10 tubes mix together 105 μL 20% SDS, 210 μL 1M NaHCO3 and 1.785 mL sterile, distilled water. | |||
30. For Input tubes (see Section C, step 7), add 200 μL of Elution Buffer and set aside at room temperature until Section E. | |||
31. Add 100 μL of Elution Buffer to each tube containing the antibody/agarose complex. Mix by flicking tube gently. | |||
32. Incubate at room temperature for 15 minutes. | |||
33. Pellet agarose by brief centrifugation (3000-5000 x g for 1 minute) and collect supernatant into new microfuge tubes. | |||
34. Repeat steps 4-6 and combine eluates (total volume = 200 μL). | |||
=== Reverse Crosslinks of Protein/DNA Complexes to Free DNA=== | === Reverse Crosslinks of Protein/DNA Complexes to Free DNA=== | ||
36. To all tubes (IPs and Inputs) add 8 μL 5 M NaCl and incubate at 65°C for 4-5 hours or overnight to reverse the DNA – Protein crosslinks. After this step the sample can be stored at -20°C and the protocol continued the next day. | 36. To all tubes (IPs and Inputs) add 8 μL 5 M NaCl and incubate at 65°C for 4-5 hours or overnight to reverse the DNA – Protein crosslinks. After this step the sample can be stored at -20°C and the protocol continued the next day. | ||