Mutations in bacterial promoters may increase or decrease the rate of gene transcription. Promoter mutations that increase transcription are termed up-promoter mutations, and those that decrease transcription are termed down-promoter mutations. As shown in Figure 12.5, the sequence of the -10 region of the promoter for the lac operon is TATGTT. Would you expect the following mutations to be up-promoter or down-promoter mutations?
A. TATGTT to TATATT
B. TATGTT to TTTGTT
C. TATGTT to TATGAT