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. Author manuscript; available in PMC: 2023 Jan 6.
Published in final edited form as: Nature. 2022 Jul 6;607(7920):808–815. doi: 10.1038/s41586-022-04906-8

Figure 4: Recurrent mutations in the BCL6-iSE prevent BLIMP1 binding and transcriptional repression.

Figure 4:

a. Nucleotide sequence of WT and mutant probes encompassing the predicted BLIMP1 consensus binding site in the BCL6-iSE, used for EMSA. b. Top panel: EMSA of nuclear extracts from 293T cells overexpressing HA-BLIMP1 documents binding to the WT BCL6-iSE sequence (black arrow) and supershift by the HA antibody (red arrow); this is lost in 7 of 10 mutant probes tested. In the bottom panel, the same probes, used as cold competition oligos (50X and 100X), fail to compete with the labeled WT probe (one representative gel out of 3 that gave similar results). c. BLIMP1 ChIP-qPCR in control parental (M/WT) and corrected (WT/WT) clones from the HLY1 cell line (n=4 clones each; data pooled from 2 independent experiments; two-tailed unpaired t-test). d. BLIMP1 ChIP-qPCR in parental (M/WT) and corrected (WT/WT) clones from the LY18 cell line (n=4 clones each; data pooled from 2 independent experiments; one-way ANOVA with Bonferroni correction). Experiments were performed in basal conditions (NS) or upon CD40L stimulation, used to induce BLIMP1 expression.