Single-cell RNA-Seq of different B cell populations from WT and B-Fip200 ^−/− mice, related to Fig. 6. (A) UMAP of 13 B cell clusters and phenotypic identities in merged WT and Fip200^−/− groups in Fig. 6 A. (B and C) Feature plot of the B cells in A showing relative expression of signature genes labeled on top (B) and antibody-derived tag (ADT) antibody expression (C). Color scale represents centered natural log transformation across cells. (D) Distribution of immunoglobulin subclass mapped in the plasma population (Fig. 6 C) UMAP representation. The color scale represents centered natural log transformation across cells. (E) Plot of nucleotide mutation counts in the heavy chain variable region of different plasma clusters. Feature plot of cells for their CITE-Seq/ADT antibody expression. (F) NP-specific IgG1, IgG2b, IgG2c titers and IgA antibody level were detected by ELISA at day 56 in WT (n = 7) or B-Fip200^−/− (n = 8) mice after 30 μg NP₂₉-KLH with Imject Alum immunization. Plots show values for individual mice (symbols) and means (bars). Significant P values were determined by an unpaired t test. Top: ***P = 0.0003; bottom: **P = 0.0093, ***P = 0.0003.