A genetic defect caused by a triplet repeat expansion in Arabidopsis thaliana.
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.
Sureshkumar
Sridevi
S
Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany.
Todesco
Marco
M
Schneeberger
Korbinian
K
Harilal
Ramya
R
Balasubramanian
Sureshkumar
S
Weigel
Detlef
D
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
D029681:Arabidopsis Proteins; D018749:RNA, Plant; C032241:isopropylmalate isomerase; D007535:Isomerases