Question

Regulatory proteins are the accessory proteins that interact with the RNA polymerase and affect its role in transcription. Which of the following statement is correct about regulatory proteins?

• A. They only increase expression
• B. They only decrease expression
• C. They interact with RNA polymerase but do not affect expression
• D. They can act both as activators and as repressors

Answer 1

The correct option is D They can act both as activators and as repressors

In a transcription unit of prokaryotes, the activity of RNA polymerase at a given promoter is regulated by interaction with accessory proteins called regulatory proteins which affect its ability to recognise start sites. These regulatory proteins can act both positively (activators) and negatively (repressors).