XIST was one of the first lincRNAs to be characterized. It is directly involved in deactivation of one of the female X chromosomes during embryonic development. It has been described as having the ability to ”crumple an entire chromosome”. This is important because deactivation prevents lethal overexpression of genes found on the X chromosome.
RNA is important for getting polychrome complex to chromosome ncRNAs can activate downstream genes in Cis, opposite in trans; Xist does the same thing.