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Updated: May 15, 2026

An In Vitro Assay to Detect tRNA-Isopentenyl Transferase Activity
Published on: October 8, 2018
Mammalian Trit1 is a tRNA([Ser]Sec)-isopentenyl transferase required for full selenoprotein expression
Noelia Fradejas1, Bradley A Carlson, Eddy Rijntjes
1Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany.
Abstract:
Selenoproteins are proteins carrying the rare amino acid Sec (selenocysteine). Full expression of selenoproteins requires modification of tRNA([Ser]Sec), including N(6)-isopentenylation of base A(37). We show that Trit1 is a dimethylallyl:tRNA([Ser]Sec) transferase. Knockdown of Trit1 reduces expression of selenoproteins. Incubation of in vitro transcribed tRNA[Ser]Sec with recombinant Trit1 transfers [(14)C]dimethylallyl pyrophosphate to tRNA([Ser]Sec). 37A>G tRNA([Ser]Sec) is resistant to isopentenylation by Trit1.
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