Trans-acting RNA inhibits tRNA suppressor activity in vivo

Abstract

We constructed two aptamers, each of which contains a 7-nt-long loop complementary to the anticodon loop of a suppressor tRNA. One of these aptamers can form a stable bimolecular complex with the suppressor tRNA in vitro and protects the 7 nt in the suppressor's anticodon loop from RNase S1. An Escherichia coli strain, carrying an amber mutation in the lac Z gene, produces b-galactosidase only if the suppressor is present; the aptamer's coexpression in the cell inhibits the activity of the suppressor tRNA. Moreover, in E. coli extract, the aptamer partially inhibits the read-through of the stop codon on the part of the suppressor tRNA. These results point to a novel strategy that need not be limited to the suppressor tRNA. By constructing appropriate inducible aptamers, it may well be possible to effectively control translation in vivo.

Rational Design of Aptamer-Tagged tRNAs

“…Alternatively, some of the endogenous tRNAs or tRNA-aaRS pairs might be replaceable with allo-tRNAs or orthogonal pairs composed of allo-tRNAs [ 60 , 63 , 64 , 65 ]. For reprogramming the genetic code, the allo-tRNA sequestration system may be useful for use in vivo and in vitro [ 66 ] and for the purification and elimination of allo-tRNA molecules from tRNA mixtures [ 66 , 67 , 68 , 69 ]. Application of the allo-tRNA chassis may not be limited to E. coli but may possibly need further optimization, especially for their use in archaea and eukaryotes due to the difference in the manner of tRNA Ser recognition by SerRS [ 70 , 71 ].…”