Question

1. adhE mRNA encodes alcohol dehydrogenase.
   1. Describe in word the regulation of adhE mRNA by RNase III. [Hints: The ribosome-binding site (RBS)]
   2. Do you expect the rnc mutants that lack RNase III to increase, decrease or cause no change to the translation of the adhE mRNA? Why?

Answer 1

a.) RNase III is known for activation of adhE gene expression by stem-loop structure cleavage. adhE mRNA is responsible for production of ethanol dehydrogenase. RNase III mediated removal of stem-loop structure is essential for translation of the adhE message as this structure obstructs its ribosome binding site.The regulation of the dehydrogenase by RNase III is very tightly controlled and anaerobic growth is nearly impossible when RNase III is absent.

b.) The rnc mutants that lack RNase III is expected to decrease the translation of the adhE mRNA because RNase III is essential for translation of the adhE message as it removes a stem-loop structure that obstructs its ribosome binding site.