2003/12/15 by Ikuhiro Okamoto, Arie P. Otte, C. David Allis +2 · 5 citations
Biochemistry, Genetics and Molecular Biology · #Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities #Epigenetics and DNA Methylation #Genetics and Neurodevelopmental Disorders
paper · doi:10.1126/science.1092727
openalex publication_date 2003/12/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23
The initiation of X-chromosome inactivation is thought to be tightly correlated with early differentiation events during mouse development. Here, we show that although initially active, the paternal X chromosome undergoes imprinted inactivation from the cleavage stages, well before cellular differentiation. A reversal of the inactive state, with a loss of epigenetic marks such as histone modifications and polycomb proteins, subsequently occurs in cells of the inner cell mass (ICM), which give rise to the embryo-proper in which random X inactivation is known to occur. This reveals the remarkable plasticity of the X-inactivation process during preimplantation development and underlines the importance of the ICM in global reprogramming of epigenetic marks in the early embryo.