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2003
Romby P, Springer M
Bacterial translational control at atomic resolution Article de journal
Dans: Trends Genet, vol. 19, no. 3, p. 155-161, 2003, ISBN: 12615010, (0168-9525 Journal Article Review Review, Tutorial).
Résumé | Liens | BibTeX | Étiquettes: Bacterial *Gene Expression Regulation, Bacterial Models, Base Sequence Conserved Sequence Escherichia coli/*enzymology/*genetics *Gene Expression Regulation, Biological Models, Enzymologic Genes, Genetic, Messenger/genetics/*metabolism RNA, Molecular Molecular Mimicry Nucleic Acid Conformation Operator Regions (Genetics) RNA, Non-U.S. Gov't Threonine-tRNA Ligase/chemistry/*genetics/metabolism *Translation, ROMBY, Thr/*metabolism RNA-Binding Proteins/metabolism Support, Transfer, Unité ARN
@article{,
title = {Bacterial translational control at atomic resolution},
author = {P Romby and M Springer},
url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12615010},
isbn = {12615010},
year = {2003},
date = {2003-01-01},
journal = {Trends Genet},
volume = {19},
number = {3},
pages = {155-161},
abstract = {Translational regulation allows rapid adaptation of protein synthesis to environmental conditions. In prokaryotes, the synthesis of many RNA-binding proteins is regulated by a translational feedback mechanism involving a competition between their natural substrate and their binding site on mRNA, which are often thought to resemble each other. This article describes the case of threonyl-tRNA synthetase, which represses the translation of its own mRNA. Recent data provide the first opportunity to describe at the atomic level both the extent and the limit of mimicry between the way this enzyme recognizes tRNA(Thr) and its regulatory site in mRNA. The data also give some clues about how the binding of the synthetase to its mRNA inhibits translation.},
note = {0168-9525
Journal Article
Review
Review, Tutorial},
keywords = {Bacterial *Gene Expression Regulation, Bacterial Models, Base Sequence Conserved Sequence Escherichia coli/*enzymology/*genetics *Gene Expression Regulation, Biological Models, Enzymologic Genes, Genetic, Messenger/genetics/*metabolism RNA, Molecular Molecular Mimicry Nucleic Acid Conformation Operator Regions (Genetics) RNA, Non-U.S. Gov't Threonine-tRNA Ligase/chemistry/*genetics/metabolism *Translation, ROMBY, Thr/*metabolism RNA-Binding Proteins/metabolism Support, Transfer, Unité ARN},
pubstate = {published},
tppubtype = {article}
}
Translational regulation allows rapid adaptation of protein synthesis to environmental conditions. In prokaryotes, the synthesis of many RNA-binding proteins is regulated by a translational feedback mechanism involving a competition between their natural substrate and their binding site on mRNA, which are often thought to resemble each other. This article describes the case of threonyl-tRNA synthetase, which represses the translation of its own mRNA. Recent data provide the first opportunity to describe at the atomic level both the extent and the limit of mimicry between the way this enzyme recognizes tRNA(Thr) and its regulatory site in mRNA. The data also give some clues about how the binding of the synthetase to its mRNA inhibits translation.
1995
Brunel C, Romby P, Sacerdot C, de Smit M, Graffe M, Dondon J, van Duin J, Ehresmann B, Ehresmann C, Springer M
Stabilised secondary structure at a ribosomal binding site enhances translational repression in E. coli Article de journal
Dans: J Mol Biol, vol. 253, no. 2, p. 277-290, 1995, ISBN: 7563089, (0022-2836 Journal Article).
Résumé | Liens | BibTeX | Étiquettes: Bacterial *Gene Expression Regulation, Base Composition Base Sequence Binding Sites Comparative Study Enzyme Repression Escherichia coli/genetics/*metabolism Gene Expression Regulation, Enzymologic Homeostasis Kinetics Mathematics Models, Genetic *Translation, Genetic beta-Galactosidase/biosynthesis, Messenger/biosynthesis/*chemistry/*metabolism Recombinant Proteins/biosynthesis Ribosomes/*metabolism Support, Non-U.S. Gov't Temperature Threonine-tRNA Ligase/*biosynthesis Transcription, ROMBY, Site-Directed *Nucleic Acid Conformation RNA, Theoretical Molecular Sequence Data Mutagenesis, Unité ARN
@article{,
title = {Stabilised secondary structure at a ribosomal binding site enhances translational repression in E. coli},
author = {C Brunel and P Romby and C Sacerdot and M de Smit and M Graffe and J Dondon and J van Duin and B Ehresmann and C Ehresmann and M Springer},
url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=7563089},
isbn = {7563089},
year = {1995},
date = {1995-01-01},
journal = {J Mol Biol},
volume = {253},
number = {2},
pages = {277-290},
abstract = {The expression of the gene encoding Escherichia coli threonyl-tRNA synthetase is negatively autoregulated at the translational level. The negative feedback is due to the binding of the synthetase to an operator site on its own mRNA located upstream of the initiation codon. The present work describes the characterisation of operator mutants that have the rare property of enhancing repression. These mutations cause (1) a low basal level of expression, (2) a temperature-dependent expression, and (3) an increased capacity of the synthetase to repress its own expression at low temperature. Surprisingly, this enhancement of repression is not explained by an increase of affinity of the mutant operators for the enzyme but by the formation, at low temperature, of a few supplementary base-pairs between the ribosomal binding site and a normally single-stranded domain of the operator. Although this additional base-pairing only slightly inhibits ribosome binding in the absence of repressor, simple thermodynamic considerations indicate that this is sufficient to increase repression. This increase is explained by the competition between the ribosome and repressor for overlapping regions of the mRNA. When the ribosomal binding site is base-paired, the ribosome cannot bind while the repressor can, giving the repressor the advantage in the competition. Thus, the existence of an open versus base-paired equilibrium in a ribosomal binding site of a translational operator amplifies the magnitude of control. This molecular amplification device might be an essential component of translational control considering the low free repressor/ribosome ratio of the low affinity of translational repressors for their target operators.},
note = {0022-2836
Journal Article},
keywords = {Bacterial *Gene Expression Regulation, Base Composition Base Sequence Binding Sites Comparative Study Enzyme Repression Escherichia coli/genetics/*metabolism Gene Expression Regulation, Enzymologic Homeostasis Kinetics Mathematics Models, Genetic *Translation, Genetic beta-Galactosidase/biosynthesis, Messenger/biosynthesis/*chemistry/*metabolism Recombinant Proteins/biosynthesis Ribosomes/*metabolism Support, Non-U.S. Gov't Temperature Threonine-tRNA Ligase/*biosynthesis Transcription, ROMBY, Site-Directed *Nucleic Acid Conformation RNA, Theoretical Molecular Sequence Data Mutagenesis, Unité ARN},
pubstate = {published},
tppubtype = {article}
}
The expression of the gene encoding Escherichia coli threonyl-tRNA synthetase is negatively autoregulated at the translational level. The negative feedback is due to the binding of the synthetase to an operator site on its own mRNA located upstream of the initiation codon. The present work describes the characterisation of operator mutants that have the rare property of enhancing repression. These mutations cause (1) a low basal level of expression, (2) a temperature-dependent expression, and (3) an increased capacity of the synthetase to repress its own expression at low temperature. Surprisingly, this enhancement of repression is not explained by an increase of affinity of the mutant operators for the enzyme but by the formation, at low temperature, of a few supplementary base-pairs between the ribosomal binding site and a normally single-stranded domain of the operator. Although this additional base-pairing only slightly inhibits ribosome binding in the absence of repressor, simple thermodynamic considerations indicate that this is sufficient to increase repression. This increase is explained by the competition between the ribosome and repressor for overlapping regions of the mRNA. When the ribosomal binding site is base-paired, the ribosome cannot bind while the repressor can, giving the repressor the advantage in the competition. Thus, the existence of an open versus base-paired equilibrium in a ribosomal binding site of a translational operator amplifies the magnitude of control. This molecular amplification device might be an essential component of translational control considering the low free repressor/ribosome ratio of the low affinity of translational repressors for their target operators.
