Identity elements in tRNA-mediated transcription antitermination: implication of tRNA D- and T-arms in mRNA recognition.
tRNA-mediated transcription antitermination has been shown to control the expression of several amino acid biosynthesis operons and aminoacyl-tRNA-synthetase-encoding genes in Gram-positive bacteria. A model originally put forward by Grundy & Henkin describes the conserved structural features of the leader sequences of these operons and genes. Two sequences of 3 and 4 nt, respectively, take a central position in this model and are thought to be responsible for the binding of the system-specific uncharged tRNA, an interaction which would stabilize the antiterminator conformation of the leader. Here a further evolution of this model is presented based on an analysis of trp regulation in Lactococcus lactis in which a function is assigned to hitherto unexplained conserved structures in the leader sequence. It is postulated that the mRNA-tRNA interaction involves various parts of the tRNA in addition to the anticodon and the acceptor in the original model and that these additional interactions contribute to the recognition of a specific tRNA, and hence to the specificity and efficacy of the regulatory response.
van de Guchte
Maarten
M
Laboratoire de Génétique Microbienne, Institut National de la Recherche Agronomique, 78352Jouy-en-Josas Cedex, France1.
Ehrlich
S Dusko
SD
Laboratoire de Génétique Microbienne, Institut National de la Recherche Agronomique, 78352Jouy-en-Josas Cedex, France1.
Chopin
Alain
A
Laboratoire de Génétique Microbienne, Institut National de la Recherche Agronomique, 78352Jouy-en-Josas Cedex, France1.
D020121:5' Untranslated Regions; D001483:Base Sequence; D017124:Conserved Sequence; D015964:Gene Expression Regulation, Bacterial; D013294:Lactococcus lactis / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics*; D012364:RNA, Transfer, Trp / Q000235:genetics*; D013379:Substrate Specificity; D013728:Terminator Regions, Genetic
D020121:5' Untranslated Regions; D012333:RNA, Messenger; D012364:RNA, Transfer, Trp