Question

A transcriptional repressor that controls the transcription of gene A is not normally active unless bound by an effector molecule X. In a certain cell, the domain of the repressor that binds X is mutated. With all other factors being the same, what effect do you predict on the transcription of gene A?

Answer 1

Answer:

Increase in transcription

Explanation:

Transcription is the process of forming RNA from DNA. It can be controlled by many factors like a repressor. Repressor can bind to the operator region of the promoter and hinder the movement of RNA Polymerase enzyme, halting the process.

Here, it is given that the repressor needs to first bind to an effector molecule X. Once it binds to X, it is activated and then it can bind to operator of gene A to inhibit its transcription. If the X binding domain on repressor is mutated it wont be able to bind to X. Thus it wont get activated and wont be able to attach to operator region to inhibit transcription. Hence, transcription process will keep going on uncontrolled.