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Repression of the human dihydrofolate reductase gene by a non-coding interfering transcript.
Igor Martianov1, Aroul Ramadass, Ana Serra Barros
1Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
Nature
|January 24, 2007
Summary
A non-coding RNA from a minor promoter represses the major dihydrofolate reductase promoter in quiescent cells. This RNA-guided epigenetic mechanism involves direct interaction with transcription factors, ensuring gene expression regulation.
Area of Science:
- Molecular Biology
- Epigenetics
- Gene Regulation
Background:
- Alternative promoters are common in gene expression but their regulatory mechanisms are poorly understood.
- Selective regulation of alternative promoters varies significantly between genes.
Purpose of the Study:
- To elucidate the mechanism of transcriptional repression of the major dihydrofolate reductase promoter in quiescent cells.
- To investigate the role of a non-coding transcript from an upstream minor promoter in gene regulation.
Main Methods:
- Inducible and reconstituted transcription assays.
- RNA bandshifts, RNA interference (RNAi), chromatin immunoprecipitation (ChIP), and RNA immunoprecipitation (RIP).
- In vivo and in vitro experimental approaches.
Main Results:
- A non-coding transcript from the minor promoter mediates repression of the major dihydrofolate reductase promoter.
- Repression involves direct RNA interaction with the major promoter and general transcription factor IIB.
- Formation of a stable RNA-promoter complex leads to dissociation of the preinitiation complex.
Conclusions:
- The regulatory non-coding transcript plays a critical role in epigenetic, promoter-specific transcriptional repression.
- This mechanism highlights a novel pathway for controlling gene expression via non-coding RNAs.
- Findings contribute to understanding the complex regulation of alternative promoters.
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