E+ codes for a certain enzyme

Question: In a plant the gene e+ codes for a certain enzyme. The gene r+ codes for a regulatory protein that binds to the regulatory region of gene e+ in order for transcription to occur. A recessive mutation is obtained in each of the genes, r and e, respectively. A dihybrid e+/e; r+/r is allowed to self. In the progeny what will be the proportion of individuals with enzyme? (Suppose lack of enzyme is not lethal and that the genes are on different chromosomes.)