Tag Archives: X chromosome inactivation

Researchers use CRISPR to show that the short splicing isoform of Xist RNA is sufficient to induce X-chromosome inactivation

lncRNA

Alternative splicing of mRNA precursors results in multiple protein variants from a single gene and is critical for diverse cellular processes and development. Xist encodes a long noncoding RNA which is a central player to induce X-chromosome inactivation in female mammals and has two major splicing variants: long and short isoforms of Xist RNA. Although a differentiation-specific and a female-specific ...

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Female immune cells use lncRNA to keep their second X chromosome shut off

lncRNA

Autoimmune diseases tend to strike women more than men and having multiple X chromosomes could be the main reason why. While a process called X chromosome inactivation serves to balance out gene dosage between males and females, some genes on the “inactive X” chromosome in immune cells can sometimes escape this process, giving women an extra dose of immunity-related gene ...

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The initiation of imprinted X-chromosome inactivation absolutely requires Xist

lncrna

The long noncoding RNA Xist is expressed from only the paternal X chromosome in mouse preimplantation female embryos and mediates transcriptional silencing of that chromosome. In females, absence of Xist leads to postimplantation lethality. Here, through single-cell RNA sequencing of early preimplantation mouse embryos, PSL Research University scientists found that the initiation of imprinted X-chromosome inactivation absolutely requires Xist. Lack ...

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X-inactivation: xist RNA uses chromosome contacts to coat the X

The mechanisms by which Xist RNA associates with the X chromosome to mediate alterations in chromatin structure remain mysterious. Recent genome-wide Xist RNA distribution studies suggest that this long noncoding RNA uses 3-dimensional chromosome contacts to move to its sites of action. In organisms with XY sex chromosomes, chromatin modifications are directed to the X chromosomes (X) to equalize X-linked ...

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Jpx RNA Activates Xist by Evicting CTCF

In mammals, dosage compensation between XX and XY individuals occurs through X chromosome inactivation (XCI). The noncoding Xist RNA is expressed and initiates XCI only when more than one X chromosome is present. Current models invoke a dependency on the X-to-autosome ratio (X:A), but molecular factors remain poorly defined. Here, researchers at the Howard Hughes Medical Institute demonstrate that molecular ...

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Advances in understanding chromosome silencing by the long non-coding RNA Xist

In female mammals, one of the two X chromosomes becomes genetically silenced to compensate for dosage imbalance of X-linked genes between XX females and XY males. X chromosome inactivation (X-inactivation) is a classical model for epigenetic gene regulation in mammals and has been studied for half a century. In the last two decades, efforts have been focused on the X ...

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X-Inactivation, Imprinting, and Long Noncoding RNAs in Health and Disease

x chomosome inactivation

X chromosome inactivation and genomic imprinting are classic epigenetic processes that cause disease when not appropriately regulated in mammals. Whereas X chromosome inactivation evolved to solve the problem of gene dosage, the purpose of genomic imprinting remains controversial. Nevertheless, the two phenomena are united by allelic control of large gene clusters, such that only one copy of a gene is ...

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