Rho-dependent transcription termination in the tyrT operon of Escherichia coli

Madden, Kathleen A.; Landy, Arthur

doi:10.1016/0378-1119(89)90167-4

Cited by 6 publications

(3 citation statements)

References 22 publications

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“…The major transcription termination site of tyrT is present within the second repeat (8), but primary transcripts beyond this site are identified (7). However, the presence of either repeat results in a termination efficiency of 88% in an appropriate reporter system (9).…”

Section: Introductionmentioning

confidence: 99%

A novel RNA product of thetyrToperon ofEscherichia Coli

Bösl

Kersten

1991

Nucl Acids Res

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The tyrT operon of E. coli and several other tRNA operons of E. coli show striking structural features: they contain repeated sequence units including a 19bp motif resembling the 3' end of the corresponding mature tRNA. A novel RNA, encoded by the repeated sequence of the tyrT operon, was identified. The RNA, characterized by primer extension and Nuclease-S1 analysis, contained 171 nucleotides and terminated with the 19bp motif of the CCA-end of tRNA(1Tyr). The RNA, designated as rtT RNA, is probably released from the primary transcript of tyrT during tRNA processing, it includes the coding capacity for the arginine rich peptide Tpr. Predictions of secondary folding resulted a rather stable RNA structure with a free energy of -44.3kcal/mol. A weak ribosome binding site was found, preceding the second possible AUG initiator codon for Tpr. The comparison of rtT RNA with putative transcripts from the repeated sequences associated with related tRNA genes showed common features with respect to primary structure, arrangement and secondary folding. In E. coli cultures the lag-phase during growth, caused by transient glycine or by isoleucine limitation, was found to be overcome or markedly shortened in the presence of rtT RNA. These and previously reported results suggest a modulatory effect of rtT RNA on stringent response.

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Section: Introductionmentioning

confidence: 99%

A novel RNA product of thetyrToperon ofEscherichia Coli

Bösl

Kersten

1991

Nucl Acids Res

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“…On the other hand, the potential 'auxiliary sequence' CAAUCAA, observed at some Rho sites (see later), is also found at the tyrT operon terminator (Küpper et al, 1978). Madden & Landy (1989) showed that progressive removal of the region preceding the tRNA Tyr terminator progressively reduces Rho-dependent Gene IV of bacteriophage f1. A peculiar type of terminator lies at the end of gene IV of the E. coli bacteriophage f1.…”

Section: Constitutive Rho-dependent Terminatorsmentioning

confidence: 99%

Rho-dependent terminators and transcription termination

2006

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Rho-dependent transcription terminators participate in sophisticated genetic regulatory mechanisms, in both bacteria and phages; they occur in regulatory regions preceding the coding sequences of genes and within coding sequences, as well as at the end of transcriptional units, to prevent readthrough transcription. Most Rho-dependent terminators have been found in enteric bacteria, but they also occur in Gram-positive bacteria and may be widespread among bacteria. Rho-dependent termination requires both cis-acting elements, on the mRNA, and trans-acting factors. The only cis-acting element common to Rho-dependent terminators is richness in rC residues. Additional sequence elements have been observed at different Rho termination sites. These 'auxiliary elements' may assist in the termination process; they differ among terminators, their occurrence possibly depending on the function and sequence context of the terminator. Specific nucleotides required for termination have also been identified at Rho sites. Rho is the main factor required for termination; it is a ring-shaped hexameric protein with ATPase and helicase activities. NusG, NusA and NusB are additional factors participating in the termination process. Rho-dependent termination occurs by binding of Rho to ribosome-free mRNA, C-rich sites being good candidates for binding. Rho's ATPase is activated by Rho-mRNA binding, and provides the energy for Rho translocation along the mRNA; translocation requires sliding of the message into the central hole of the hexamer. When a polymerase pause site is encountered, the actual termination occurs, and the transcript is released by Rho's helicase activity. Many aspects of this process are still being studied. The isolation of mutants suppressing termination, site-directed mutagenesis of cis-acting elements in Rho-dependent termination, and biochemistry, are and will be contributing to unravelling the still undefined aspects of the Rho termination machinery. Analysis of the more sophisticated regulatory mechanisms relying on Rho-dependent termination may be crucial in identifying new essential elements for termination.

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“…The ability to sequence genes and their adjacent control elements has also contribu ted greatly to our understanding of the mechanisms which regulate gene expression, and cloning vectors have been designed specifically to study the characteristics of control elements such as promoters (Williams et al, 1981;Farinha and Kropinski, 1989;Robbins et al, 1989), translation initiation signals (Schauder and McCarthy, 1989), transcription terminators (Kupsch, 1989;Madden and Landy, 1989;Peabody et al, 1989) and other modulator binding sites (Aiba et al, 1989, Kim et al, 1989.…”

Section: Research and Developmentmentioning

confidence: 99%

Recombinant plasmids

Hussey¹

1992

Safety in Industrial Microbiology and Biotechnology

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Rho-dependent transcription termination in the tyrT operon of Escherichia coli

Cited by 6 publications

References 22 publications

A novel RNA product of thetyrToperon ofEscherichia Coli

A novel RNA product of thetyrToperon ofEscherichia Coli

Rho-dependent terminators and transcription termination

Recombinant plasmids

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