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Functional hammerhead ribozymes naturally encoded in the genome of Arabidopsis thaliana.

Przybilski, Rita and Gräf, Stefan and Lescoute, Aurélie and Nellen, Wolfgang and Westhof, Eric and Steger, Gerhard and Hammann, Christian (2005):
Functional hammerhead ribozymes naturally encoded in the genome of Arabidopsis thaliana.
In: The Plant cell, pp. 1877-85, 17, (7), ISSN 1040-4651, [Article]

Abstract

The hammerhead ribozyme (HHRz) is an autocatalytic RNA motif found in subviral plant pathogens and transcripts of repetitive DNA sequences in animals. Here, we report the discovery and characterization of unique HHRzs encoded in a plant genome. Two novel sequences were identified on chromosome IV of Arabidopsis thaliana in a database search, which took into account recently defined structural requirements. The HHRzs are expressed in several tissues and coexist in vivo as both cleaved and noncleaved species. In vitro, both sequences cleave efficiently at physiological Mg(2+) concentrations, indicative of functional loop-loop interactions. Kinetic analysis of loop nucleotide variants was used to determine a three-dimensional model of these tertiary interactions. Based on these results, on the lack of infectivity of hammerhead-carrying viroids in Arabidopsis, and on extensive sequence comparisons, we propose that the ribozyme sequences did not invade this plant by horizontal transfer but have evolved independently to perform a specific, yet unidentified, biological function.

Item Type: Article
Erschienen: 2005
Creators: Przybilski, Rita and Gräf, Stefan and Lescoute, Aurélie and Nellen, Wolfgang and Westhof, Eric and Steger, Gerhard and Hammann, Christian
Title: Functional hammerhead ribozymes naturally encoded in the genome of Arabidopsis thaliana.
Language: English
Abstract:

The hammerhead ribozyme (HHRz) is an autocatalytic RNA motif found in subviral plant pathogens and transcripts of repetitive DNA sequences in animals. Here, we report the discovery and characterization of unique HHRzs encoded in a plant genome. Two novel sequences were identified on chromosome IV of Arabidopsis thaliana in a database search, which took into account recently defined structural requirements. The HHRzs are expressed in several tissues and coexist in vivo as both cleaved and noncleaved species. In vitro, both sequences cleave efficiently at physiological Mg(2+) concentrations, indicative of functional loop-loop interactions. Kinetic analysis of loop nucleotide variants was used to determine a three-dimensional model of these tertiary interactions. Based on these results, on the lack of infectivity of hammerhead-carrying viroids in Arabidopsis, and on extensive sequence comparisons, we propose that the ribozyme sequences did not invade this plant by horizontal transfer but have evolved independently to perform a specific, yet unidentified, biological function.

Journal or Publication Title: The Plant cell
Volume: 17
Number: 7
Divisions: 10 Department of Biology
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10 Department of Biology > Ribogenetics
Date Deposited: 29 Jul 2010 12:25
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