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Genome-wide Surveillance of Transcription Errors in Eukaryotic Organisms
Published on: September 13, 2018
Transcription destabilizes triplet repeats.
Yunfu Lin1, Leroy Hubert, John H Wilson
1Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Molecular Carcinogenesis
|November 1, 2008
Summary
Triplet repeat expansion causes human diseases. Transcription, not just DNA replication, drives repeat instability, particularly in neurons, involving DNA repair and other cellular processes.
Area of Science:
- Genetics
- Molecular Biology
- Human Diseases
Background:
- Triplet repeat expansion is the molecular basis for numerous human diseases.
- Studies across various model systems reveal insights into repeat instability mechanisms.
- Age-dependent repeat instability in somatic tissues, especially neurons, suggests replication-independent pathways.
Purpose of the Study:
- To investigate the role of transcription in mediating triplet repeat instability.
- To explore how DNA repair pathways modulate transcription-induced repeat instability.
- To understand the complex interplay of factors contributing to repeat instability in human diseases.
Main Methods:
- Comparative studies in bacteria, yeast, flies, mammalian cells, and mice.
- Genetic analyses to identify factors influencing repeat instability.
- Investigating the involvement of DNA repair proteins like mismatch repair (MMR) and transcription-coupled nucleotide excision repair (TC-NER).
Main Results:
- Transcription plays a critical role in triplet repeat instability, especially in non-dividing cells like neurons.
- DNA repair proteins modulate transcription-induced repeat instability.
- Transcription likely facilitates the formation of secondary DNA structures that trigger repair, altering repeat length.
Conclusions:
- Triplet repeat instability mechanisms are complex and involve an interplay of transcription, DNA repair, chromatin remodeling, and supercoiling.
- Transcription is a significant contributor to repeat instability in human diseases, particularly in terminally differentiated cells.
- Further research is needed to fully elucidate the intricate molecular processes driving repeat instability.
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