title: A genetic defect caused by a triplet repeat expansion in Arabidopsis thaliana.
abstract: Variation in the length of simple DNA triplet repeats has been linked to phenotypic variability in microbes and to several human disorders. Population-level forces driving triplet repeat contraction and expansion in multicellular organisms are, however, not well understood. We have identified a triplet repeat-associated genetic defect in an Arabidopsis thaliana variety collected from the wild. The Bur-0 strain carries a dramatically expanded TTC/GAA repeat in the intron of the ISOPROPYL MALATE ISOMERASE LARGE SUB UNIT1 (IIL1; At4g13430) gene. The repeat expansion causes an environment-dependent reduction in IIL1 activity and severely impairs growth of this strain, whereas contraction of the expanded repeat can reverse the detrimental phenotype. The Bur-0 IIL1 defect thus presents a genetically tractable model for triplet repeat expansions and their variability in natural populations.
authors.affiliation: Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany.
authors.forename: Sridevi
authors.initials: S
authors.lastname: Sureshkumar
authors.forename: Marco
authors.initials: M
authors.lastname: Todesco
authors.forename: Korbinian
authors.initials: K
authors.lastname: Schneeberger
authors.forename: Ramya
authors.initials: R
authors.lastname: Harilal
authors.forename: Sureshkumar
authors.initials: S
authors.lastname: Balasubramanian
authors.forename: Detlef
authors.initials: D
authors.lastname: Weigel
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D017343:Genes, Plant; D014644:Genetic Variation; D007438:Introns; D007535:Isomerases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D018515:Plant Leaves / Q000254:growth & development; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D013696:Temperature; D019680:Trinucleotide Repeat Expansion; D018911:Trinucleotide Repeats
chemical_list: D029681:Arabidopsis Proteins; D018749:RNA, Plant; C032241:isopropylmalate isomerase; D007535:Isomerases