Transcriptional profiles of knockouts of m6A writer and readers in Germinal Center B cells

We performed RNA-seq (MARS-seq) on germinal center (GC) light zone and dark zone B cells sorted to purity from freshly dissociated mouse popliteal lymph nodes immunized with NP-KLH for 7 to 14 days. Germinal center B cell subsets were gated as follows: Dump (CD8, CD4, F4/80, Gr-1)- B220+ CD38- GL-7+ FAS+. Dark zone GC cells were in addition CD86lo, CXCR4hi; LZ cells were in addition CD86hi, CXCR4lo. Three different mouse models were used: AID-cre Mettl3-flox, AID-cre Ythdf2-flox, Igf2bp3-knockout. We used these data to derive differentially expressed genes between B cell subsets of control and knockout genotypes. We also performed m6A-IP on ex vivo activated wild type B cells and determined the m6A targets in B cells. These studies revealed that the GC response depends on m6A RNA methylation and the functions of specific methyl-readers Ythdf2 and Igf2bp3. mRNA profiles of GC B cells deficient in m6A-machinery enzymes Mettl3, Ythdf2 and Igf2bp3. m6A target profile of ex vivo activated wild type B cells.