Investigating the causal role of DNA methylation in transcriptional regulation

DNA methylation of CpG sites (5mC) is an essential epigenetic mark that has been associated with regulation of gene expression, alternative splicing, and alternative promoter usage. However, evidence for these proposed functions of 5mC has mainly relied on correlative approaches due to the lack of molecular tools to modify 5mC specifically in the genome. This thesis developed and applied 5mC editing tools to broadly assess whether 5mC plays a causal role in regulation of transcriptional processes including alternative splicing, gene repression, and alternative promoter usage.