Fig. 4: METTL1 regulates m7G tRNA modification in B cells. | Nature Communications

Fig. 4: METTL1 regulates m7G tRNA modification in B cells.

From: Aberrant METTL1-mediated tRNA m7G modification alters B-cell responses in systemic autoimmunity in humans and mice

Fig. 4

a Northwestern blot showing m7G modification in B cells from WT and cKO mice. Representative bands are shown. b Experimental scheme of TRAC-seq for calculating cleavage scores. c List of m7G-modified tRNAs identified by TRAC-seq in spleen B cells from WT and cKO mice. d The motif sequence “AGGTC” at the m7G site was identified by TRAC-seq in B cells. e Representative image showing the different cleavage scores at the motif sequence. f Quantitative comparison of cleavage scores between B cells from WT and cKO mice (n = 1 mouse for each group). The upper whisker is the maxima, and the lower whisker is the minima. The upper and lower bounds of the box are the 75th percentile and 25th percentile, respectively. The center of the box is the median. g, h Expression profile of the 22 m7G-modified tRNAs based on TRAC-seq. The relative expression of each tRNA type was calculated from the combined expression of all tRNA genes belonging to the same tRNA type. The expression of the indicated tRNA type was then normalized by its overall average level in both groups and transformed by log2 (n = 1 mouse for each group). The upper whisker is the maxima, and the lower whisker is the minima. The upper and lower bounds of the box are the 75th percentile and 25th percentile, respectively. The center of the box is the median. i–k METTL1-IP tRNA experiments. i Western blots showing METTL1 overexpression in 293 T cells. Representative bands were shown. j Scatter plot displaying METTL1-IP tRNAs recognized by the tRNA library-seq. k Venn diagram displaying overlap of METTL1-RIP tRNA-seq and TRAC-seq data. l, m A puromycin intake assay was performed via flow cytometry, and representative histograms of B cells from WT (n = 5 biological independent samples) and cKO (n = 4 biological independent samples) mice are shown. The data are presented as the mean ± SEM. A two-tailed Mann–Whitney test was used in f, h, and a two-tailed unpaired Student’s t test was used in m. Source data are provided as a Source Data file.

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