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Updated: Jul 3, 2026
A Semi-Quantitative Drug Affinity Responsive Target Stability (DARTS) assay for studying Rapamycin/mTOR interaction
Published on: August 27, 2019
An approach to analyse the specific impact of rapamycin on mRNA-ribosome association
Raphael Genolet1, Tanguy Araud, Laetitia Maillard
1Department of Microbiology and Molecular Medicine, University of Geneva Medical School (CMU), 1 rue Michel Servet, CH-1211 Geneva, Switzerland. Raphael.Genolet@medecine.unige.ch
Background:
Recent work, using both cell culture model systems and tumour derived cell lines, suggests that the differential recruitment into polysomes of mRNA populations may be sufficient to initiate and maintain tumour formation. Consequently, a major effort is underway to use high density microarray profiles to establish molecular fingerprints for cells exposed to defined drug regimes. The aim of these pharmacogenomic approaches is to provide new information on how drugs can impact on the translational read-out within a defined cellular background.
Methods:
We describe an approach that permits the analysis of de-novo mRNA-ribosome association in-vivo during short drug exposures. It combines hypertonic shock, polysome fractionation and high-throughput analysis to provide a molecular phenotype of translationally responsive transcripts. Compared to previous translational profiling studies, the procedure offers increased specificity due to the elimination of the drugs secondary effects (e.g. on the transcriptional read-out). For this pilot "proof-of-principle" assay we selected the drug rapamycin because of its extensively studied impact on translation initiation.
Results:
High throughput analysis on both the light and heavy polysomal fractions has identified mRNAs whose re-recruitment onto free ribosomes responded to short exposure to the drug rapamycin. The results of the microarray have been confirmed using real-time RT-PCR. The selective down-regulation of TOP transcripts is also consistent with previous translational profiling studies using this drug.
Conclusion:
The technical advance outlined in this manuscript offers the possibility of new insights into mRNA features that impact on translation initiation and provides a molecular fingerprint for transcript-ribosome association in any cell type and in the presence of a range of drugs of interest. Such molecular phenotypes defined pre-clinically may ultimately impact on the evaluation of a particular drug in a living cell.
Insights
Researchers developed a new method to analyze how drugs affect mRNA and ribosome interactions in cells. This technique identifies specific mRNA changes in response to drugs like rapamycin, aiding in drug evaluation.
Area of Science:
- Molecular Biology
- Pharmacogenomics
- Cancer Research
Background:
- Tumor formation may be driven by differential mRNA recruitment into polysomes.
- Pharmacogenomic approaches aim to create molecular fingerprints of drug effects on translation.
- Understanding drug impact on translational read-out is crucial.
Purpose of the Study:
- To develop a method for analyzing de-novo mRNA-ribosome association in vivo during drug exposure.
- To identify translationally responsive transcripts using a novel approach.
- To provide a molecular phenotype of drug-induced translational changes.
Main Methods:
- Combined hypertonic shock, polysome fractionation, and high-throughput analysis.
- Analyzed de-novo mRNA-ribosome association in vivo.
- Used rapamycin as a model drug due to its known effect on translation initiation.
Main Results:
- Identified mRNAs that re-recruited onto free ribosomes after short rapamycin exposure.
- Confirmed microarray results using real-time RT-PCR.
- Observed selective down-regulation of TOP transcripts, consistent with prior studies.
Conclusions:
- The new technique offers insights into mRNA features affecting translation initiation.
- Provides a molecular fingerprint for transcript-ribosome association across cell types and drugs.
- Pre-clinical molecular phenotypes may influence drug evaluation in living cells.
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