Instability and chromatin structure of expanded trinucleotide repeats.
Trinucleotide repeat expansion underlies at least 17 neurological diseases. In affected individuals, the expanded locus is characterized by dramatic changes in chromatin structure and in repeat tract length. Interestingly, recent studies show that several chromatin modifiers, including a histone acetyltransferase, a DNA methyltransferase and the chromatin insulator CTCF can modulate repeat instability. Here, we propose that the unusual chromatin structure of expanded repeats directly impacts their instability. We discuss several potential models for how this might occur, including a role for DNA repair-dependent epigenetic reprogramming in increasing repeat instability, and the capacity of epigenetic marks to alter sense and antisense transcription, thereby affecting repeat instability.
Dion
Vincent
V
Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA. vincent.dion@fmi.ch
Wilson
John H
JH
D000818:Animals; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D002869:Chromosome Aberrations; D019175:DNA Methylation / Q000235:genetics / Q000502:physiology; D004260:DNA Repair / Q000235:genetics / Q000502:physiology; D047108:Embryonic Development / Q000235:genetics; D044127:Epigenesis, Genetic; D006801:Humans; D009422:Nervous System Diseases / Q000235:genetics; D019680:Trinucleotide Repeat Expansion
D002843:Chromatin