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X-chromosome inactivation

Sunday 8 May 2005

In mammals, dosage compensation is achieved by transcriptional silencing of one of the two female X chromosomes.

X inactivation is dynamically regulated in development.

The non-coding Xist RNA localizes to the inactive X, initiates gene repression in the early embryo, and later stabilizes the inactive state. Different functions of Xist are observed depending on which epigenetic regulatory pathways are active in a given cell.

Because Xist has evolved recently, with the origin of placental mammals, the underlying pathways are also important in regulating developmental control genes.

References

- Wutz A. Xist function: bridging chromatin and stem cells. Trends Genet. 2007 Sep;23(9):457-64. PMID: 17681633

- Sado T, Ferguson-Smith AC. Imprinted X inactivation and reprogramming in the preimplantation mouse embryo. Hum Mol Genet. 2005 Apr 15;14 Spec No 1:R59-64. PMID: 15809274

- Reik W, Lewis A. Co-evolution of X-chromosome inactivation and imprinting in mammals. Nat Rev Genet. 2005 May;6(5):403-10. PMID: 15818385

- Huynh KD, Lee JT. X-chromosome inactivation: a hypothesis linking ontogeny and phylogeny. Nat Rev Genet. 2005 May;6(5):410-8. PMID: 15818384