Quantification of proline to serine mistranslation in a Saccharomyces cerevisiae strain expressing an inducible tRNA variant

ABSTRACT: Altering the genetic code for applications in synthetic biology and genetic code expansion involves engineered tRNAs that incorporate amino acids that differ from what is defined by the “standard” genetic code. Since these engineered tRNA variants can be lethal due to proteotoxic stress, regulating their expression is necessary to achieve high levels of the resulting novel proteins. Mechanisms to positively regulate transcription with exogenous activator proteins like those often used to regulate RNA polymerase II (RNAP II) transcribed genes are not applicable to tRNAs as their expression by RNA polymerase III requires elements internal to the tRNA. Here, we show that tRNA expression is repressed by overlapping transcription from an adjacent RNAP II promoter. Regulating the expression of the RNAP II promoter allows inverse regulation of the tRNA. Placing either Gal4 or TetR-VP16 activated promoters downstream of a mistranslating tRNA serine variant that mis-incorporates serine at proline codons in Saccharomyces cerevisiae allows mistranslation at a level not otherwise possible because of the toxicity of the unregulated tRNA. Using mass spectrometry, we determine th frequency of mistranslation in both the induced and repressed conditions of the galactose inducible and tetracycline inducible systems.

INSTRUMENT(S): Orbitrap Exploris 480

ORGANISM(S): Saccharomyces Cerevisiae (baker's Yeast)

SUBMITTER: Matthew Berg  

LAB HEAD: Judit Villen

PROVIDER: PXD028496 | Pride | 2021-11-03

REPOSITORIES: Pride