A comprehensive analysis of AID's effects on the transcriptome and methylome of activated B cells

Beyond its well-characterized functions in antibody diversification, AID can catalyze off-target DNA damage and has been hypothesized to edit RNA and mediate DNA demethylation. To comprehensively examine AID's effects on the transcriptome and DNA methylome, we performed RNA-Seq and reduced-representation bisulfite sequencing (RRBS) on Aicda(−/−), wild-type and AID-overexpressing activated B cells. These analyses confirmed AID's known role in immunoglobulin isotype switching, while also demonstrating that it has little other effect on gene expression. Additionally, no evidence of AID-dependent mRNA or miRNA editing could be detected. Finally, RRBS data failed to support a role for AID in the regulation of DNA methylation. Thus, despite evidence of its additional activities in other systems, antibody diversification appears to be AID's sole physiological function in activated B cells.