Investigating the role of histone demethylation in the timing and epigenetic alterations of X chromosome inactivation in embryonic stem cells (360G-Wellcome-207267_Z_17_Z)

Epiblast cells within the inner cell mass of the blastocyst will differentiate to form the three germ layers during mammalian embryo development. Extracting these cells, known as embryonic stem cells, from mouse embryos has been a useful research tool as they are totipotent. This research works to understand gene-dosage compensation whereby one X chromosome (XC) is heterochromatically silenced in female embryonic cells and inactivated at blastocyst development. A series of epigenetic alterations through post-translational modifications to the XC’s histones are fundamental in this process. It has been established a reduction in acetylation occurs at histone level during inactivation and adding histone acetylase inhibitors can prevent XC silencing. However, timing is key as if the inhibitor is added too early or too late during differentiation it is ineffective. Other histone modifications, such as methylation, are as important as there is complex interaction between them. Using a range of biochemical techniques, including immunofluorescence microscopy, the extent of acetylation and methylation on the inactive XC at varying histone demethylase inhibitor concentrations will be measured. This research will work to define the inhibitor-sensitive time window of XC inactivation more clearly.