| Abstract Detail
Mechanisms of Gene Regulation Wachter, Andreas [1], Tunc-Ozdemir, Meral [2], Grove, Beth C. [3], Green, Pamela J. [4], Shintani, David K. [2], Breaker, Ronald R. [5]. Riboswitch mediated gene control in plants. Riboswitches are gene control elements typically located in the 5´ untranslated region (UTR) of messenger RNAs that sense cellular metabolite concentrations to regulate gene expression in bacteria. So far eleven distinct classes of riboswitches have been characterized that specifically bind compounds including coenzymes, amino acids, and nucleotide bases. The most widespread riboswitch class is responsive to thiamine pyrophosphate (TPP), and is known to be present in the mRNAs of thiamine metabolic genes from some eukaryotes. We have determined that this RNA element is widely distributed in plant species from mosses to higher flowering plants. In plants, the TPP riboswitch usually is located in the 3´ UTR of the thiamine biosynthetic gene THIC, and is also present in the THI4 gene in the moss Physcomitrella patens. The genomic organization of the 3´ region of THIC genes is conserved among different plant species, and the production of two THIC transcript types with varying 3´ UTRs is always observed. In Arabidopsis thaliana, thiamine application results in down regulation of total THIC transcript amount. We show that TPP riboswitch function is responsible for the formation of transcripts with different 3´ UTRs and is responsible for the feedback control of THIC expression that results when thiamine concentrations are elevated. Furthermore, our data demonstrate that 3´ UTR length influences transcript stability and thereby governs the level of gene expression. Our findings reveal a mechanism for riboswitch function in higher eukaryotes that involves metabolite-dependent gene control by differential 3´ terminus processing of RNA transcripts. Log in to add this item to your schedule
1 - Yale University, Department of Molecular, Cellular and Developmental Biology, 266 Whitney Avenue, New Haven, Ct, 06511, United States 2 - University of Nevada, Department of Biochemistry and Molecular Biology 3 - Yale University, Department of Molecular, Cellular and Developmental Biology 4 - University of Delaware, Department of Plant and Soil Sciences & Delaware Biotechnology Institute 5 - Yale University, Department of Molecular, Cellular and Developmental Biology & Department of Molecular Biophysics and Biochemistry
Keywords: riboswitch aptamer thiamine 3´ terminus processing.
Presentation Type: ASPB Minisymposium Session: M17 Location: Waldorf Room/Hilton Date: Monday, July 9th, 2007 Time: 11:05 AM Number: M17002 Abstract ID:678 |