Fig. 7: METTL1 regulates mitochondrial ETC activity through BCR signaling.

a METTL1 and WDR4 expression in B cells from Mettl1-cKI mice or WT mice was measured via western blotting. Representative bands are shown. b, c Representative flow cytometry plots for p-SYK stimulated with anti-mouse IgM. The data are summarized in c (n = 4 biological independent samples). d The expression of p-PI3K, p-AKT, and p-BTK in B cells was measured by western blotting. Representative bands are shown. e Transmission electronic microscopy images showing the mitochondria of WT B cells, cKI B cells, and cKI B cells treated with R406. Representative images are shown. f The expression level of the ETC in WT B cells, cKI B cells, or cKI B cells treated with the SYK inhibitor R406 was measured by qPCR (n = 4 biological independent samples). g The expression of SDHB and NDUFA12 in WT B cells, cKI B cells, or cKI B cells treated with the SYK inhibitor R406 was measured via western blotting. Representative bands are shown. h Experimental scheme of NP-OVA immunization. i Frequencies of B cells in the spleens of WT or cKI mice (n = 6 biological independent samples). j, k Representative flow cytometry plots, and frequencies of GC B cells in WT and cKI mice (n = 6 biological independent samples). l–o OVA⁺ B cells (l, m) and OVA⁺ GC B cells (n, o) in WT and cKI mice were measured via flow cytometry (n = 6 biological independent samples). p, q Representative ELISpot wells and summary data for anti-NP25- and anti-NP2-specific B cells in the splenocytes of WT and cKI mice (n = 4 biological independent samples). r ELISA for anti-NP25 and anti-NP2 IgG antibodies in the sera of WT and cKI mice (n = 4 biological independent samples). The data are presented as the mean ± SEM. A two-tailed unpaired Student’s t test was used in c, i, k, m, o, q, r. Source data are provided as a Source Data file.