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Expansions of CAG·CTG repeats in immortalized human astrocytes.

ARAN - Access to Research at NUI Galway

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dc.contributor.author Lahue, Robert S. en
dc.date.accessioned 2009-12-14T10:29:43Z en
dc.date.available 2009-12-14T10:29:43Z en
dc.date.issued 2007 en
dc.identifier.citation Claassen, D. A. & Lahue, R. S. (2007) Expansions of CAG·CTG repeats in immortalized human astrocytes. "Human Molecular Genetics Advance Access" 16(24) 3088-3096 (2007). en
dc.identifier.uri http://hdl.handle.net/10379/518 en
dc.description.abstract Expansions of trinucleotide repeats (TNRs) are the genetic cause for a number of neurodegenerative disorders. In some of these diseases, ongoing somatic expansions in the brain are thought to contribute to disease progression. Expansions can occur in both neurons and supporting glial cells, but little is known about molecular mechanisms of expansion in these cells, particularly glia. To help address this issue, a cultured human astrocyte cell line called SVG-A was tested for expansions of CAG¿CTG repeats present on a shuttle vector. A quantitative genetic selection showed that +4 to +15 repeat expansions occur readily for starting alleles of 25 repeats, thereby spanning the important boundary between short stable repeats and longer more unstable CAG¿CTG tracts. These expansions in glial cell culture, as in humans, were sequence and length-dependent, and were inhibited by the presence of a sequence interruption within the triplet repeat tract. These findings suggest that the mutations seen in cell culture reflect at least some of the in vivo expansions seen in glia. Mechanistically, it was found that the direction of DNA replication through the TNR influenced the frequency of expansions, suggesting that either replication or a replication-associated process, such as DNA repair, contributes to CAG¿CTG tract instability in SVG-A cells. This finding is consistent with the idea that replication-based mechanisms can be a source of TNR expansions in astrocytes, which, unlike neurons, retain proliferative capacity throughout life. en
dc.format application/pdf en
dc.language.iso en en
dc.publisher Oxford University Press en
dc.subject.lcsh Nervous system -- Degeneration en
dc.subject.lcsh Neuroglia en
dc.subject.lcsh Neurons en
dc.subject.lcsh Cell membranes en
dc.subject.lcsh Human cell culture en
dc.subject.lcsh Tissue culture en
dc.subject.lcsh DNA replication en
dc.subject.lcsh DNA repair en
dc.title Expansions of CAG·CTG repeats in immortalized human astrocytes. en
dc.type Article en
dc.local.publisherstatement This is a pre-copy-editing, author-produced PDF of an article accepted for publication in "Human Molecular Genetics Advance Access" following peer review. The definitive publisher-authenticated version Claassen, D. A. & Lahue, R. S. (2007) Expansions of CAG·CTG repeats in immortalized human astrocytes. "Human Molecular Genetics Advance Access" 16(24) 3088-3096 (2007) is available online at: http://hmg.oxfordjournals.org/cgi/content/abstract/16/24/3088. en
dc.description.peer-reviewed peer-reviewed en

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