RNA-seq:Total RNA was isolated using QIAGEN RNAeasy plus mini kit from FACS sorted FoB or ABC cells ATAC-seq: The nuclei of sorted DKO ABC or DKO Follicular B cells were prepared by incubation of cells with nuclear preparation buffer (0.30 M sucrose, 10 mM Tris, pH 7.5, 60 mM KCl, 15 mM NaCl, 5 mM MgCl2, 0.1 mM EGTA, 0.1% NP40, 0.15 mM spermine, 0.5 mM spermidine and 2 mM 6AA) RNA-seq: Sequence-compatible libraries were prepared using Seq v3 Ultra Low Input RNA Kit (Clontech) followed by Nextera library preparation at the Weil Cornell Epigenomics core. Quality of all RNA and library preparations were evaluated with BioAnalyser 2100 (Agilent) ATAC-seq: Sequencing libraries were constructed as discribed in PMID: 26083756 :Buenrostro JD, Wu B, Litzenburger UM, Ruff D, Gonzales ML, Snyder MP, Chang HY, Greenleaf WJ. Single-cell chromatin accessibility reveals principles of regulatory variation. Nature. 2015 Jul 23;523(7561):486-90. doi: 10.1038/nature14590. Epub 2015 Jun 17. PubMed PMID: 26083756; PubMed Central PMCID: PMC4685948.