Figure 9.
Applications. (A) Biological containment. An active containment system using a toxin-antitoxin gene is shown. Bacteria survive only in the presence of the Uaa because the antitoxin gene has a TAG insertion and is expressed in a Uaa-dependent manner. (B) Live attenuated-virus vaccine. The virus is propagated only in a cell-line expressing UaaRS/tRNACUA in the presence of the Uaa but is not propagated in natural host cells. (C) High-yield and zero-leakage expression system. In the usual transcriptional controlling system, a small amount of mRNA is produced even in the OFF-state, resulting in a leakage (production) of protein. A combination with translation control using a Uaa translational switch can completely suppress the translation of the mRNA in the OFF-state.