Expression of ________ Would Inhibit X-Inactivation

Question

Expression of ________ would inhibit X-inactivation.
A) Xic
B) Xist
C) Tsix
D) All of the answers are correct
E) None of the answers are correct

Accepted Answer

Tsix is a non-coding RNA gene located upstream of Xist on the X chromosome. When Tsix is expressed, it inhibits the expression of Xist, which is necessary for X-inactivation to occur. Therefore, the expression of Tsix would inhibit X-inactivation. Xic (X-inactivation center) is a region on the X chromosome that contains regulatory genes, including Tsix and Xist. Xist, on the other hand, is a long non-coding RNA gene that is essential for X-inactivation to occur. Therefore, the expression of Xist is necessary for X-inactivation, not inhibition of it. Therefore, A and B are incorrect. Finally, D is incorrect because Xic and Xist do not inhibit X-inactivation.