Figure 3.

Translational regulation by leader regions. Core biosynthetic pathways can contain mRNA leader regions that sample charged tRNA pools to control gene expression. Left panel, when charged cognate tRNA levels are high, rapid translation of the leader peptide leads to the formation of a terminator stem-loop. This stem-loop leads to transcription termination. Middle panel, when the levels of charged tRNA are low, ribosome pausing leads to the formation of a mutually exclusive antiterminator loop that facilitates transcription of the downstream gene. Right panel, in the event of mistranslation, mischarged tRNA can lead to premature termination of transcription when cognate amino acid levels are low.