Sample Collection
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Harvest cells: For one immunoprecipitation reaction the use of 10^6 - 10^7 mammalian cells (approx. one 10 cm dish) is recommended. To harvest adherent cells, aspirate growth medium, add 1 ml ice-cold PBS to cells and scrape cells from dish. Transfer cells to a pre-cooled tube, spin at 500 g for 3 min at +4°C and discard supernatant. Wash cell pellet twice with ice-cold PBS, gently resuspending the cells.
Lyse cells
- 1. Resuspend cell pellet in 200 μL ice-cold lysis buffer by pipetting or using a syringe.
note: Supplement lysis buffer with protease inhibitors and 1 mM PMSF (not included). optional for nuclear/chromatin proteins: Use RIPA buffer supplemented with 1 mg/mL DNase, 2.5 mM MgCl2, protease inhibitors and 1 mM PMSF (not included). - 2. Place the tube on ice for 30 min with extensively pipetting every 10 min.
- 3. Centrifuge cell lysate at 20.000x g for 10 min at +4°C. Transfer lysate to a pre-cooled tube. Add 300 μl dilution buffer to lysate. Discard pellet.
note: At this point cell lysate may be put at -80°C for long-term storage. optional: Add 1 mM PMSF and protease inhibitors (not included) to dilution buffer
We recommend that during incubation with the beads the final concentration of detergents does not exceed 0.2% to avoid unspecific binding to the matrix. If required, use more dilution buffer to dilute the supernatant accordingly.
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