Trans-acting RNA inhibits tRNA suppressor activity in vivo.
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 beta-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.
Attardi
Domenica Gandini
DG
Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche, Monterotondo Scalo, RM, Italy.
Tocchini-Valentini
Glauco P
GP
D000926:Anticodon / Q000235:genetics; D001483:Base Sequence; D018388:Codon, Terminator / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D007763:Lac Operon; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010443:Peptide Chain Termination, Translational; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012343:RNA, Transfer / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013489:Suppression, Genetic; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics
D000926:Anticodon; D018388:Codon, Terminator; D012329:RNA, Bacterial; D012343:RNA, Transfer; D001616:beta-Galactosidase