Question

You know that the argB gene is regulated, but you do not know if the regulatory protein is an activator or a repressor. You find a mutant strain of this bacterium where the gene encoding the regulatory protein has been deleted, so no regulatory protein is expressed. This strain produces the argB protein in the presence of arginine. Which of the following statements is correct?
A)The expression of the argB gene is regulated by a repressor
B) The expression of the argB gene is regulated by an activator
C) The expression of the argB gene is regulated by either an activator or a repressor