dependent transcription termination within the untranslated region of trpE. Anthranilate is a precursor of tryptophan, which is the product of trpE-encoded anthranilate synthase. Therefore, in trpE(fs) strains, growth on minimal glucose plates supplemented with anthranilate (100 μg/ml) reflects transcriptional polarity relief at the trp locus, and the same was scored after streaking the relevant strains on such medium

The trpE9777 is a frameshift (fs) mutationconfers Trp auxotrophy and also polarity on the downstream trpDCBA genes in the operon due to premature Rho-