XIST

Description

The XIST (X inactive specific transcript) is a ncRNA gene located on chromosome X.

Xist (X-inactive specific transcript) is a non-coding RNA transcribed from the X chromosome of placental mammals that acts as a major effector of the X-inactivation process. It is a component of the Xic – X-chromosome inactivation centre – along with two other RNA genes (Jpx and Ftx) and two protein genes (Tsx and Cnbp2). The Xist RNA, a large (17 kb in humans) transcript, is expressed on the inactive chromosome and not on the active one. It is processed in a similar way to mRNAs, through splicing and polyadenylation. However, it remains untranslated. It has been suggested that this RNA gene evolved at least partly from a protein-coding gene that became a pseudogene. The inactive X chromosome is coated with this transcript, which is essential for the inactivation. X chromosomes lacking Xist will not be inactivated, while duplication of the Xist gene on another chromosome causes inactivation of that chromosome. The human Xist gene was discovered by Andrea Ballabio through a cDNA library screening and then characterized in collaboration with Carolyn J. Brown and Hunt Willard.

== Function == X-inactivation is an early developmental process in mammalian females that transcriptionally silences one of the pair of X chromosomes, thus providing dosage equivalence between males and females (see dosage compensation).

XIST is also known as DXS1089, DXS399E, LINC00001, NCRNA00001, SXI1, swd66.

Associated Diseases

WES Whole Exome Sequencing

Clinical Exome Sequencing