A comparative analysis of 5-azacytidine and zebularine induced DNA demethylation using whole-genome bisulfite sequencing

The non-methylable cytosine analogs, 5-azacytidine and zebularine, are widely used to disrupt DNA methyltransferase activity and reduce genomic DNA methylation. In this study, whole-genome bisulfite sequencing is used to construct maps of DNA methylation with single base pair resolution in Arabidopsis thaliana seedlings treated with each demethylating agent. We find that 5-azacytidine and zebularine-treated seedlings have nearly indistinguishable patterns of DNA methylation genome-wide and that 5-azacytidine, despite being more unstable in aqueous solution, has a slightly greater demethylating effect at higher concentrations across the genome. Transcriptome analyses revealed a substantial number of up-regulated genes and transposable element genes, particularly CACTA-like elements, demonstrating that chemical demethylating agents have a disproportionately large effect on loci that are silenced by DNA methylation. Bisulfite-Seq and RNA-Seq