Mammalian embryogenesis comprises two independent instances of global DNA demethylation that each coincide with an increase in developmental potential: firstly during the development of the inner cell mass from the gametes, and secondly during the development of primordial germ cells. Although some of these changes in DNA methylation are correlated with gene expression, it is not yet understood why this epigenetic reprogramming is so extensive. Recent research has revealed that multiple different examples of global demethylation are orchestrated by regulation of UHRF1, which recruits the maintenance methyltransferase DNMT1 to newly replicated DNA. This project set out to elucidate the mechanism(s) by which UHRF1 protein is regulated during epigenetic reprogramming. Further dissection of the regulation of DNA methylation machinery in naïve pluripotency highlights that proteasomal degradation of UHRF1 driven specifically by ERK inhibition is the principal cause of global demethylation in these conditions. Mass spectrometry analysis of post-translational UHRF1 phosphorylations as well as stability analysis of UHRF1 fragments highlight regions of the protein that may be implicated in this degradation. Analysis of signal sequences and post-translational UHRF1 phosphorylations in oocytic UHRF1, followed by microinjection of germinal vesicle oocytes with mutant Uhrf1 mRNAs, was used to investigate regulation of intracellular UHRF1 localisation. Continued elucidation of the mechanisms of UHRF1 regulation during global DNA demethylation will allow us to assess the importance of this process to the acquisition of pluripotency during cellular reprogramming in vitro and mammalian embryonic development in vivo.