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A SCA7 CAG/CTG repeat expansion is stable in Drosophila melanogaster despite modulation of genomic context and gene dosage
- Source :
- Gene. 347:35-41
- Publication Year :
- 2005
- Publisher :
- Elsevier BV, 2005.
-
Abstract
- CAG and CTG repeat expansions are the cause of at least a dozen inherited neurological disorders. In these so-called "dynamic mutation" diseases, the expanded repeats display dramatic genetic instability, changing in size when transmitted through the germline and within somatic tissues. As the molecular basis of the repeat instability process remains poorly understood, modeling of repeat instability in model organisms has provided some insights into potentially involved factors, implicating especially replication and repair pathways. Studies in mice have also shown that the genomic context of the repeat sequence is required for CAG/CTG repeat instability in the case of spinocerebellar ataxia type 7 (SCA7), one of the most unstable of all CAG/CTG repeat disease loci. While most studies of repeat instability have taken a candidate gene approach, unbiased screens for factors involved in trinucleotide repeat instability have been lacking. We therefore attempted to use Drosophila melanogaster to model expanded CAG repeat instability by creating transgenic flies carrying trinucleotide repeat expansions, deriving flies with SCA7 CAG90 repeats in cDNA and genomic context. We found that SCA7 CAG90 repeats are stable in Drosophila, regardless of context. To screen for genes whose reduced function might destabilize expanded CAG repeat tracts in Drosophila, we crossed the SCA7 CAG90 repeat flies with various deficiency stocks, including lines lacking genes encoding the orthologues of flap endonuclease-1, PCNA, and MutS. In all cases, perfect repeat stability was preserved, suggesting that Drosophila may not be a suitable system for determining the molecular basis of SCA7 CAG repeat instability.
- Subjects :
- congenital, hereditary, and neonatal diseases and abnormalities
Candidate gene
Flap Endonucleases
Quantitative Trait Loci
Gene Dosage
Nerve Tissue Proteins
Context (language use)
Biology
Gene dosage
Genomic Instability
Animals, Genetically Modified
Proliferating Cell Nuclear Antigen
Genetics
medicine
Animals
Drosophila Proteins
Gene
Spinocerebellar Degenerations
Ataxin-7
Genome
DNA
General Medicine
medicine.disease
biology.organism_classification
Disease Models, Animal
DNA Repair Enzymes
Drosophila melanogaster
Dynamic mutation
Spinocerebellar ataxia
Trinucleotide Repeat Expansion
Trinucleotide repeat expansion
Subjects
Details
- ISSN :
- 03781119
- Volume :
- 347
- Database :
- OpenAIRE
- Journal :
- Gene
- Accession number :
- edsair.doi.dedup.....fcca34e1159f81af8ad4763b9fc88e3d