Question

What is the function of Xist?

1) It coats one of the X-chromosomes
2) It leads to epigenetic modification
3) It condenses and silences gene expression from the chromosome
4) All of the above

Answer 1

Xist RNA is essential for X-chromosome inactivation in females, leading to coating, epigenetic modifications, and gene expression silencing of one X chromosome to form a Barr body.

Step-by-step explanation:

Function of Xist

The function of Xist (X-inactive specific transcript) encompasses several processes related to the regulation of one of the two X chromosomes in female mammals. The Xist RNA plays a crucial role in initiating X-chromosome inactivation (XCI) during embryonic development. Xist's functions involve coating one of the X-chromosomes, leading to epigenetic modifications such as methylation of DNA and hypo-acetylation of histones, and ultimately causing the condensation and silencing of gene expression on the chromosome. This compaction of chromatin into a densely packed structure forms what is known as a Barr body, rendering the chromosome largely transcriptionally inactive. Therefore, the correct answer for the function of Xist is All of the above.