Triplet repeat reduces expression of GREENWORMS at high temperatures

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Fraser Moss
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Triplet repeat reduces expression of GREENWORMS at high temperatures

Originally published in Science Express on 15 January 2009
Science 20 February 2009:
Vol. 323. no. 5917, pp. 1060 - 1063
DOI: 10.1126/science.1164014


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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Ivan Delgado
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This article reminds me of a

This article reminds me of a Science article that came out in 2005 (Microsatellite Instability Generates Diversity in Brain and Sociobehavioral Traits, Hammock and Young, Science 308 (5728): 1630-1634, that described how the length of a DNA microsatellite correlated with the behavior of the prairie vole. 
Basically the size of the DNA region 5' of the vasopressin 1a receptor (avpr1a) determined the expression level of the avpr1a gene as well as the the behavior of the vole towards its partner (prairie voles mate for life). The size of the microsatellite only varied in the males (the females had the same genotype; ie. no change in the size of their microsatellite). If the microsatellite was longer in the male, they huddled more; if it was shorter, they huddled less. In other words, if the microsatellite was longer, he stayed around (looked after the babies, stayed closer to his mate, etc); if it was shorter he was not as good as a father/partner.