Profiling the epigenome at home

Steven Henikoff; Jorja G. Henikoff

• Resuspend the bead/nuclei pellet in 50 µL tagmentation solution while vortexing and invert by rotation to allow the solution to dislodge most or all of the beads as in Section 5. • After a quick spin (<500 x g), incubate at 37ºC for 1 hr in a PCR cycler with heated lid. • Place tubes on a magnet stand, and withdraw the liquid with the pipettor set to 5 µL less than the volume to be removed, followed by a quick spin. • Place the tubes on a magnet stand and remove any remaining liquid using a 20 µL pipette tip, then resuspend the beads in 50 µL TAPS wash and invert by rotation to mix. • Place tubes on a magnet stand, and withdraw the liquid with the pipettor set to 5 µL less than the volume to be removed, followed by a quick spin. • Place the tubes on a magnet stand and remove any remaining liquid using a 20 µL pipette tip, and proceed immediately to the next step. • Resuspend the beads in 5 µL 0.1% SDS Release solution using a fresh 20 µL pipette tip to dispense while wetting the sides of the tubes to recover the fraction of beads sticking to the sides. Tip: Twirling the tube back and forth rapidly between thumb and finger will effectively wet the sides of the tube, followed by a quick spin to bring most of the beads to the bottom. • Incubate at 58 ºC for 1 hr in a PCR cycler with heated lid to reverse the crosslinks and release pA-Tn5 from the tagmented DNA.