1. XIST dampens X chromosome activity in a SPEN-dependent manner during early human development.
- Author
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Alfeghaly C, Castel G, Cazottes E, Moscatelli M, Moinard E, Casanova M, Boni J, Mahadik K, Lammers J, Freour T, Chauviere L, Piqueras C, Boers R, Boers J, Gribnau J, David L, Ouimette JF, and Rougeulle C
- Subjects
- Humans, Female, Human Embryonic Stem Cells metabolism, Gene Expression Regulation, Developmental, Embryonic Development genetics, Chromatin metabolism, Dosage Compensation, Genetic, Genes, X-Linked, RNA, Long Noncoding genetics, RNA, Long Noncoding metabolism, X Chromosome Inactivation, Chromosomes, Human, X genetics, Chromosomes, Human, X metabolism
- Abstract
XIST (X-inactive specific transcript) long noncoding RNA (lncRNA) is responsible for X chromosome inactivation (XCI) in placental mammals, yet it accumulates on both X chromosomes in human female preimplantation embryos without triggering X chromosome silencing. The XACT (X-active coating transcript) lncRNA coaccumulates with XIST on active X chromosomes and may antagonize XIST function. Here, we used human embryonic stem cells in a naive state of pluripotency to assess the function of XIST and XACT in shaping the X chromosome chromatin and transcriptional landscapes during preimplantation development. We show that XIST triggers the deposition of polycomb-mediated repressive histone modifications and dampens the transcription of most X-linked genes in a SPEN-dependent manner, while XACT deficiency does not significantly affect XIST activity or X-linked gene expression. Our study demonstrates that XIST is functional before XCI, confirms the existence of a transient process of X chromosome dosage compensation and reveals that XCI and dampening rely on the same set of factors., (© 2024. The Author(s).)
- Published
- 2024
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