نتایج جستجو برای: trinucleotide expansion
تعداد نتایج: 142243 فیلتر نتایج به سال:
DNA must constantly be repaired to maintain genome stability. Although it is clear that DNA repair reactions depend on cell type and developmental stage, we know surprisingly little about the mechanisms that underlie this tissue specificity. This is due, in part, to the lack of adequate study systems. This review discusses recent progress toward understanding the mechanism leading to varying ra...
Stabilizing effects of interruptions on trinucleotide repeat expansions in Saccharomyces cerevisiae.
In most trinucleotide repeat (TNR) diseases, the primary factor determining the likelihood of expansions is the length of the TNR. In some diseases, however, stable alleles contain one to three base pair substitutions that interrupt the TNR tract. The unexpected stability of these alleles compared to the frequent expansions of perfect TNRs suggested that interruptions somehow block expansions a...
DNA methylation of CpG dinucleotides is essential for mammalian development, X inactivation, genomic imprinting, and may also be involved in immobilization of transposons and the control of tissue-specific gene expression (Bird & Wolffe, 1999). The common theme in each of these processes is gene silencing. Therefore, gene silencing is a major biological consequence of DNA methylation. As such, ...
We investigated a CAG trinucleotide repeat expansion in the ATXN2 gene in amyotrophic lateral sclerosis (ALS). Two new case-control studies, a British dataset of 1474 ALS cases and 567 controls, and a Dutch dataset of 1328 ALS cases and 691 controls were analyzed. In addition, to increase power, we systematically searched PubMed for case-control studies published after 1 August 2010 that invest...
Trinucleotide repeat expansions are the genetic cause of numerous human diseases, including fragile X mental retardation, Huntington disease, and myotonic dystrophy type 1. Disease severity and age of onset are critically linked to expansion size. Previous mouse models of repeat instability have not recreated large intergenerational expansions ("big jumps"), observed when the repeat is transmit...
Expansion of (AGC)n repeats has been associated with genetic disorders called triplet-repeat diseases such as Huntington's disease (HD), myotonic muscular dystrophy (DM) and Kennedy's disease. To gain insight into the abnormal behavior of these repeats, we studied their structural properties in supercoiled DNA. Chemical probing revealed that, under physiological salt and pH conditions, Zn2+ or ...
Eleven human loci, responsible for nine diseases, exhibit an unprecedented form of mutation: the expansion of trinucleotide repeats. Normally polymorphic CGG/CCG or CAG/CTG repeats (means of approximately 20 triplets) are found enlarged to either 2-3 or 10-1000 times normal lengths. The smaller expansions are found within genes coding for polyglutamine and are associated with neurodegenerative ...
Friedreich ataxia is usually caused by an expansion of a GAA trinucleotide repeat in intron 1 of the FRDA gene. Occasionally, a fully expanded allele has been found to arise from a premutation of 100 or less triplet repeats. We have examined the sperm DNA of a premutation carrier. This man's leucocyte DNA showed one normal allele and one allele of approximately 100 repeats. His sperm showed an ...
Expansions of (CTG)·(CAG) repeated DNAs are the mutagenic cause of 14 neurological diseases, likely arising through the formation and processing of slipped-strand DNAs. These transient intermediates of repeat length mutations are formed by out-of-register mispairing of repeat units on complementary strands. The three-way slipped-DNA junction, at which the excess repeats slip out from the duplex...
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