Originally published in Science Express on 15 January 2009
Science 20 February 2009:
Vol. 323. no. 5917, pp. 1060 - 1063
A Genetic Defect Caused by a Triplet Repeat Expansion in Arabidopsis thaliana
Sridevi Sureshkumar,1,2* Marco Todesco,1* Korbinian Schneeberger,1 Ramya Harilal,1 Sureshkumar Balasubramanian,1,2 Detlef Weigel1
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.
1 Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany.
2 School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia.
* These authors contributed equally to the work.
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