Breaking the balance: The initial steps of X chromosome inactivation

Female placental mammals randomly inactivate one X chromosome to compensate for gene dosage imbalances between females (XX) and males (XY). This process is known as X Chromosome Inactivation (XCI) and has numerous implications for health and disease. At the molecular level, XCI is regulated through a complex interplay of factors and regulatory mechanisms that ensure that a single X chromosome remains active per diploid genome early during embryonic development. Although significant progress has been made in understanding the molecular mechanisms underlying XCI, essential questions remain unanswered. This thesis aims to further clarify the initial steps of XCI and explore novel factors that potentially act in XCI, using genetically modified female mouse Embryonic Stem Cells combined with multiple omics and microscopy techniques.