Imaging RNA polymerase III transcription using a photostable RNA–fluorophore complex
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Open Access
- 25 September 2017
- journal article
- research article
- Published by Springer Nature in Nature Chemical Biology
- Vol. 13 (11), 1187-1194
- https://doi.org/10.1038/nchembio.2477
Abstract
A highly photostable RNA mimic of red fluorescent protein, Corn, was designed and used to image RNA polymerase III transcription. Quantitative imaging of Corn-tagged transcripts revealed transcription dynamics in live cells following mTOR inhibition. Quantitative measurement of transcription rates in live cells is important for revealing mechanisms of transcriptional regulation. This is particularly challenging when measuring the activity of RNA polymerase III (Pol III), which transcribes growth-promoting small RNAs. To address this issue, we developed Corn, a genetically encoded fluorescent RNA reporter suitable for quantifying RNA transcription in cells. Corn binds and induces fluorescence of 3,5-difluoro-4-hydroxybenzylidene-imidazolinone-2-oxime, which resembles the fluorophore found in red fluorescent protein (RFP). Notably, Corn shows high photostability, enabling quantitative fluorescence imaging of mTOR-dependent Pol III transcription. We found that, unlike actinomycin D, mTOR inhibitors resulted in heterogeneous transcription suppression in individual cells. Quantitative imaging of Corn-tagged Pol III transcript levels revealed distinct Pol III transcription 'trajectories' elicited by mTOR inhibition. Together, these studies provide an approach for quantitative measurement of Pol III transcription by direct imaging of Pol III transcripts containing a photostable RNA–fluorophore complex.Keywords
This publication has 40 references indexed in Scilit:
- A superfolding Spinach2 reveals the dynamic nature of trinucleotide repeat–containing RNANature Methods, 2013
- Regulation of pol III transcription by nutrient and stress signaling pathwaysBiochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms, 2012
- RNA Mimics of Green Fluorescent ProteinScience, 2011
- mTOR associates with TFIIIC, is found at tRNA and 5S rRNA genes, and targets their repressor Maf1Proceedings of the National Academy of Sciences, 2010
- Requirement of the mTOR Kinase for the Regulation of Maf1 Phosphorylation and Control of RNA Polymerase III-dependent Transcription in Cancer CellsJournal of Biological Chemistry, 2010
- RNA polymerase III transcription and cancerOncogene, 2004
- The mitogen-activated protein (MAP) kinase ERK induces tRNA synthesis by phosphorylating TFIIIBThe EMBO Journal, 2003
- Generation of Destabilized Green Fluorescent Protein as a Transcription ReporterJournal of Biological Chemistry, 1998
- Mitotic Regulation of a TATA-Binding-Protein-Containing ComplexMolecular and Cellular Biology, 1995
- Specificity of RNA maturation pathways: RNAs transcribed by RNA polymerase III are not substrates for splicing or polyadenylation.Molecular and Cellular Biology, 1987