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CEG1 DEPLETION REVEALS MECHANISMS GOVERNING DEGRADATION OF NON-CAPPED RNAs

ABSTRACT: All eukaryotic mRNAs contain a 7-methylguanosine (m7G) cap which serves as a platform that recruits proteins to support essential biological functions such as mRNA processing, nuclear export and cap-dependent translation. Although the caping is one of the first steps of transcription and uncapped mRNA is not functional, the fate and turnover of uncapped transcripts have not been studied extensively. Here, we employed fast nuclear depletion of the capping enzymes in yeast Saccharomyces cerevisiae to uncover the turnover of transcripts that failed to be capped. We found that the degradation of non-capped mRNA is mainly performed by Xrn1, the exonuclease which is predominantly localized in the cytoplasm, and the fate of such transcripts is determined principally by the abundance of their synthesis. Nuclear depletion of the capping enzymes increased the levels of poorly expressed mRNAs and non-coding RNAs and did not affect the distribution of RNA Polymerase II on chromatin. Overall, our data indicate that mRNAs that failed to be capped are not directed to any specific quality-control pathway and are stochastically degraded.

ORGANISM(S): Saccharomyces cerevisiae

PROVIDER: GSE213942 | GEO | 2022/09/25

REPOSITORIES: GEO

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