Question: Which is the transcript responsible for X-chromosome inactivation?

Context:
Xist, a gene responsible for X chromosome inactivation (XCI)
X inactivation-specific transcript (XIST) is a long ncRNA that mediates X chromosome inactivation
the X inactive specific transcript (Xist) gene, which is known now to represent the master switch locus regulating X inactivation
IST, a long non-coding RNA, plays an important role in triggering X chromosome inactivation in eutherians
X inactive-specific transcript (XIST) gene in humans
Xist (X-inactive specific transcript) is a major effector of the X-inactivation process
efforts have been focused on the X inactive-specific transcript (Xist) locus, discovered to be the master regulator of X-inactivation
X-inactivation specific transcript (Xist) RNA
transcriptional silencing of one of the female X-chromosomes is a finely regulated process that requires accumulation in cis of the long non-coding RNA X-inactive-specific transcript (Xist)
the X-inactivated-specific transcript (Xist) gene, whose gene product consists of RNA which coats and thereby inactivates one of the X chromosomes
the X inactivation center (Xic). Xic contains many of the regulatory elements for the mutual interplay of X-inactive specific transcript (Xist
chromosome inactivation (XCI) in female mammals depends on the noncoding RNA X inactivation specific transcript (Xist)
 One of the striking features that characterize the Xic landscape is the abundance of loci transcribing non-coding RNAs (ncRNAs), including Xist, the master regulator of the inactivation process
The process is mediated by the non-coding RNA X inactive specific transcript (Xist) that binds in cis and propagates along the inactive X chromosome elect, triggering chromosome-wide silencing
the X chromosome of paternal origin (Xp) is silenced during early embryogenesis owing to imprinted expression of the regulatory RNA, Xist (X-inactive specific transcript)
X-inactive-specific transcript (Xist) gene 
expression of the non-coding X-inactive specific transcript (Xist) RNA and depends on specific cellular contexts, in which essential silencing factors are expressed
Xist (X-inactive specific transcript) and Tsix gene pair, which is pivotal in X-inactivation.
In eutherian mammals X inactivation is regulated by the X-inactive specific transcript (Xist), a cis-acting non-coding RNA that triggers silencing of the chromosome from which it is transcribed
 inactivation in female mammals involves transcriptional silencing of an entire chromosome in response to a cis-acting noncoding RNA, the X inactive-specific transcript (Xist)
chromosome inactivation (XCI) depends on a noncoding sense-antisense transcript pair, Xist
 The key regulatory molecule that triggers silencing is the Xist transcrip
chromosome inactivation begins when a novel chromosomal RNA (cRNA) from the imprinted mouse Xist or human XIST locus coats or "paints" one X chromosome in cis and initiates a cascade of chromosome remodeling events
X-inactive-specific transcript (Xist) locus is a cis-acting switch that regulates X chromosome inactivation in mammals
 In X chromosome inactivation (XCI), unfavorable XCI ratios promote X-linked disease penetrance in females. During XCI, one X is randomly silenced by Xist
 imprinted mouse Xist (X-inactive specific transcript) gene is involved in the initiation of X-chromosome inactivation
initiation of X-chromosome inactivation are critically dependent on the expression of the X-inactive specific transcript (Xist)
X chromosome inactivation requires the presence, in cis, of the X inactivation center (XIC). The Xist gene, which lies within the XIC region in both human and mouse
inactive-specific transcript (Xist
 X inactive-specific transcript (Xist) is thought to be essential for the initiation of X chromosome inactivation and dosage compensation during female embryo development
deletions of the X inactivation center (XIC/Xic) and/or the X inactive specific transcript (XIST/Xist) gene result in failure of cis X-inactivation
Xist (X inactive specific transcript) gene plays an essential role in X chromosome inactivation.
expression of the Xist (X inactive specific transcript) gene correlates with X inactivation 
XIST (X inactive specific transcript) gene 
one of the two X chromosomes in somatic cells of the female becomes inactivated through a process that is thought to depend on a unique initiator region, the X-chromosome inactivation center (Xic). The recently characterized Xist sequence (X-inactive-specific transcript) is thought to be a possible candidate for Xic
human XIST gene, a candidate for a role in X chromosome inactivation,

Answer: The long non- coding RNA Xist (X inactive specific transcript)
Exact answer: Xist