Basic Information
Transcripts
Summary
In mammals, dosage compensation of genes on the X chromosome occurs by X inactivation, which is regulated in cis by the X-inactivation center (XIC) and expression of the XIST non-coding RNA. This gene expresses a non-coding antisense transcript across the 3' end of the XIST locus, and is coexpressed with XIST only from the inactive X chromosome. The mouse ortholog of this locus is required for imprinted X inactivation in extraembryonic tissues and silences Xist through modification of the chromatin structure in the Xist promoter region. In contrast, imprinted X inactivation does not occur in human extraembryonic tissues and transcripts from this locus do not repress XIST expression or affect random X chromosome inactivation in embryonic cells. This transcript is thought to be unspliced and extend over more than 30 kb, but its exact nature has not been determined. [provided by RefSeq, Jul 2008]
Forensic Context
A study in human body fluids and organ tissues demonstrated that the TSIX is a non-translated RNA gene transcribed antisense to XIST, which acts as a negative regulator of XIST and is expressed from both X-chromosomes prior to X-inactivation but is repressed once inactivation is established [van den Berge et al. DOI:10.1016/j.fsigen.2016.10.018]. The TSIX is a long non-coding RNA that functions in X inactivation centre regulation by targeting CTCF [Mattick et al. DOI:10.1038/s41580-022-00566-8].