GSE118902
ATACseq in T. brucei wild-type and histone variant deletion cell lines.
3x107 cells were harvested and washed in 30 ml cold 1x TDB. The pellet was resuspended in 300 µl permeabilization buffer with protease inhibitors, 3 µl of 4 mM digitonin was added and incubated for 5 minutes at RT. The cells were pelleted, resuspended in 600 µl isotonic buffer with protease inhibitors and split in two samples, containing 1x107 and 2x107 cells, respectively. The transposition reaction was performed by adding 50 µl of transposition mix to the pellet (25 µl TD (2x reaction buffer from Nextera kit), 25 µl TDE1 (Tn5 transposase from Nextera kit), 22.5 µl nuclease-free water) and incubation for 30 minutes at 37 °C. For the gDNA control, 200 ng of gDNA was treated in the same manner. The DNA samples were purified using Qiagen MinElute PCR Purification Kit and eluted in 10 µl EB (10 mM Tris-HCl, pH 8). The transposed DNA fragments were amplified using the NEBNext® High-Fidelity 2X PCR Master Mix (M0541) supplied with 2.5 µl of 25 µM barcoded primers and amplification for 13 cycles. The libraries were purified using AMPure XP beads (Beckman Coulter) following the manufacturer's instructions. The library fragment sizes between 150 and 1000 bp were purified from a 6% polyacrylamide gel. Paired-end 76 bp sequencing was carried out using the Illumina NextSeq system with a mid-output NextSeq 500/550 kit according to the manufacturer's instructions. Overall design: ATACseq in T. brucei wild-type, H3.V-/-, H4.V-/- and H3.V-/- H4V-/- cells. Each performed in duplicates with 10 and 20 million cells, respectively. A gDNA control was included to check for biases in accessiblity.