Solved by a verified expert:You have isolated two different mutants (reg1 and reg2) causing constitutive expression of the emu operon (constitutive expression of emu1 and emu2). One mutant contains a defect in a DNA binding site, and the other has a loss-of-function defect in the gene encoding a protein that binds to the site. Is the DNA binding protein a positive or negative regulator of expression?