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Jodlbauer J, Rieder L, Glieder A, Wiltschi B. Bidirectional Promoter Libraries Enable the Balanced Co-expression of Two Target Genes in E. coli. Methods Mol Biol 2023; 2617:75-86. [PMID: 36656517 DOI: 10.1007/978-1-0716-2930-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In this chapter, we present a bidirectional promoter library toolbox to evaluate fast and efficiently the optimal conditions for the balanced co-expression of two target genes. As a proof-of-concept, we demonstrate the co-expression of CYP505x and the GroEL/ES complex, which resulted in noticeably elevated enzyme activity with one of the de-novo-designed promoters of the library. The new toolbox offers a straightforward one-pot cloning approach and is highly modular. As such, the method presented here should be of great interest to any gene co-expression study.
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Affiliation(s)
- Julia Jodlbauer
- acib - Austrian Centre of Industrial Biotechnology, Graz, Austria
| | - Lukas Rieder
- Institute of Molecular Biotechnology, Graz University of Technology, Graz, Austria
| | - Anton Glieder
- Institute of Molecular Biotechnology, Graz University of Technology, Graz, Austria
| | - Birgit Wiltschi
- acib - Austrian Centre of Industrial Biotechnology, Graz, Austria. .,Institute of Molecular Biotechnology, Graz University of Technology, Graz, Austria. .,Institute of Bioprocess Science and Engineering Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria.
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Yanofsky C. Advancing our knowledge in biochemistry, genetics, and microbiology through studies on tryptophan metabolism. Annu Rev Biochem 2002; 70:1-37. [PMID: 11395401 DOI: 10.1146/annurev.biochem.70.1.1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
I was fortunate to practice science during the last half of the previous century, when many basic biological and biochemical concepts could be experimentally addressed for the first time. My introduction to research involved isolating and identifying intermediates in the niacin biosynthetic pathway. These studies were followed by investigations focused on determining the properties of genes and enzymes essential to metabolism and examining how they were alterable by mutation. The most challenging problem I initially attacked was establishing the colinear relationship between gene and protein. Subsequent research emphasized identification and characterization of regulatory mechanisms that microorganisms use to control gene expression. An elaborate regulatory strategy, transcription attenuation, was discovered that is often based on selection between alternative RNA structures. Throughout my career I enjoyed the excitement of solving basic scientific problems. Most rewarding, however, was the feeling that I was helping young scientists experience the pleasure of performing creative research.
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Affiliation(s)
- C Yanofsky
- Department of Biological Sciences, Stanford University, Stanford, California 94305, USA.
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Affiliation(s)
- C Yanofsky
- Department of Biological Sciences, Stanford University, Stanford, California 94305, USA.
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Abe H, Abo T, Aiba H. Regulation of intrinsic terminator by translation in Escherichia coli: transcription termination at a distance downstream. Genes Cells 1999; 4:87-97. [PMID: 10320475 DOI: 10.1046/j.1365-2443.1999.00246.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Rho-independent terminators in Escherichia coli are DNA sequences of 30-50 bp consisting of a GC-rich dyad symmetry sequence followed by a run of T residues in the nontemplate strand. The transcription termination at the Rho-independent terminator occurs within the T-tract in vitro. It has been believed that the transcription termination at the Rho-independent terminator occurs within the T-tract in vivo, as established in vitro, and therefore the 3' ends of mRNAs are mostly generated as a direct result of transcription termination. However, how the transcription termination occurs and how the 3' ends of mRNAs are formed in living cells remains to be studied. RESULTS We developed a double terminator system in which a second Rho-independent terminator was placed downstream of the crp terminator. This system made it possible to detect transcripts that pass through the crp terminator by Northern blotting. We found that most of the crp transcripts extend beyond the crp terminator. The transcriptional read-through at the crp terminator was reduced when the translation of crp mRNA was interrupted. The level of the read-through transcript decreased with distance between the two terminators, suggesting that transcription termination occurs at multiple positions beyond the crp terminator. CONCLUSION We conclude that most RNA polymerase reads through the crp terminator in the natural situation and terminates transcription over a wide region downstream of the crp terminator, resulting in heterogeneous primary transcripts that are subsequently processed back to the terminator hairpin. We propose that ribosome translation to the crp stop codon causes read-through of the terminator. The regulatory effect of translation on Rho-independent termination may be a general phenomenon at other operons.
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Affiliation(s)
- H Abe
- Department of Molecular Biology, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan
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Roland KL, Liu CG, Turnbough CL. Role of the ribosome in suppressing transcriptional termination at the pyrBI attenuator of Escherichia coli K-12. Proc Natl Acad Sci U S A 1988; 85:7149-53. [PMID: 2459698 PMCID: PMC282141 DOI: 10.1073/pnas.85.19.7149] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Pyrimidine-mediated regulation of pyrBI operon expression in Escherichia coli K-12 occurs primarily by an attenuation control mechanism. Previous studies have suggested a model for attenuation control in which low intracellular levels of UTP cause close coupling of transcription and translation within the pyrBI leader region. This close coupling apparently prevents transcriptional termination at an attenuator (a rho-independent transcriptional terminator) located 23 base pairs before the pyrBI structural genes within an open reading frame for a 44-amino acid leader polypeptide. Presumably, a ribosome involved in the synthesis of the leader polypeptide disrupts or precludes the formation of the attenuator-encoded RNA hairpin, which is required for transcriptional termination. In this study, we examined the role of the ribosome in inhibiting transcriptional termination at the pyrBI attenuator. Using oligonucleotide-directed mutagenesis, we systematically introduced termination codons into the reading frame for the leader polypeptide to determine the distance a ribosome must translate to suppress transcriptional termination. These mutations were incorporated individually into a pyrB::lacZ gene fusion, which was then introduced into the E. coli chromosome. The resulting fusion strains were used to measure the effect of each mutation on pyrB::lacZ expression. The results show that a ribosome must translate to within 14-16 nucleotides of the attenuator-encoded RNA hairpin to inhibit transcriptional termination efficiently, which indicates a direct interaction between the ribosome and the termination hairpin sequence as proposed in the present model. Additional results indicate that factors not included in the present model for attenuation control contribute to the expression and regulation of the pyrBI operon.
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Affiliation(s)
- K L Roland
- Department of Microbiology, University of Alabama, Birmingham 35294
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Attenuation at nucleotide biosynthetic genes and amino acid biosynthetic operons of Escherichia coli. Trends Biochem Sci 1986. [DOI: 10.1016/0968-0004(86)90204-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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7
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Abstract
Here we report the identification of the Escherichia coli trp leader peptide synthesized in vivo. We identified the peptide in UV-irradiated maxicells by selective labeling with radioactive amino acids which are included in the predicted sequence of this peptide. Our results support the hypothesis that translation of the peptide-coding region of the leader RNA has a role in the mechanism of attenuation of biosynthetic operons in general and in the E. coli trp operon in particular.
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Translation activates the paused transcription complex and restores transcription of the trp operon leader region. Proc Natl Acad Sci U S A 1985; 82:4663-7. [PMID: 2991886 PMCID: PMC390446 DOI: 10.1073/pnas.82.14.4663] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
It has been proposed that RNA polymerase pausing in the leader region of the tryptophan (trp) operon of Escherichia coli is responsible for the synchronization of transcription and translation essential to attenuation control. In this report we use an in vitro coupled transcription/translation system to study the effect of trp leader peptide synthesis on RNA polymerase pausing in the trp leader region. Wild-type and translation-defective trp leader templates of E. coli and Serratia marcescens were employed, and pause RNA synthesis and paused complex release (activation) were quantified relative to synthesis of the terminated leader transcript. It was observed that pausing in the trp leader region was prolonged when translation of the leader transcript was reduced by mutations in the leader region or by addition of the translation inhibitor kasugamycin or chloramphenicol. Experiments with S-30 extracts from a mutant strain that is inefficient in translating the tryptophan codons in the leader transcript indicated that ribosome movement to these codons also releases the paused transcription complex. These findings indicate that the paused trp leader transcription complex resumes transcription when released by ribosome movement over the leader peptide coding region. This release would facilitate the coupling of transcription and translation essential to attenuation control.
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9
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Evidence for the transcript secondary structures predicted to regulate transcription attenuation in the trp operon. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(18)90823-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Abstract
The structural aspects of recognition by E. coli ribosomes of translational initiation regions on homologous messenger RNAs have been reviewed. Also discussed is the location of initiation region on mRNA, its confines, typical nucleotide sequences responsible for initiation signal, and the influence of RNA macrostructure on protein synthesis initiation. Most of the published DNA nucleotide sequences surrounding the start of various E. coli genes and those of its phages have been collected.
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11
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Nguyen TT, Postle K, Bertrand KP. Sequence homology between the tetracycline-resistance determinants of Tn10 and pBR322. Gene 1983; 25:83-92. [PMID: 6319234 DOI: 10.1016/0378-1119(83)90170-1] [Citation(s) in RCA: 105] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The Tn10 tetracycline resistance gene, tetA, encodes a tetracycline-inducible protein with an apparent Mr of 36 X 10(3). We have determined the nucleotide sequence of the Tn10 tetA gene. The extent of the tetA gene was determined by analysis of amino-terminal and carboxy-terminal deletion mutants. We conclude that a single Tn10 gene, the tetA gene, is sufficient to confer tetracycline resistance. The predicted Mr of the tetA protein is 43.2 X 10(3). The sequence homology between the Tn10 tetA gene and the pBR322 tetracycline resistance determinant (49% nucleotide homology, 44% amino acid homology) indicates that these phenotypically distinct tetracycline-resistance determinants must have evolved from a common ancestral sequence. The markedly hydrophobic character of the predicted amino acid sequences of the Tn10 tetA and pBR322 tet-coded proteins suggests that a substantial portion of these proteins may be embedded within the cytoplasmic membrane.
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12
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Olson ER, Flamm EL, Friedman DI. Analysis of nutR: a region of phage lambda required for antitermination of transcription. Cell 1982; 31:61-70. [PMID: 6218883 DOI: 10.1016/0092-8674(82)90405-6] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The N gene product of coliphage lambda acts with host factors (Nus) through sites (nut) to render subsequent downstream transcription resistant to a variety of termination signals. These sites, nutR and nutL, are downstream, respectively, from the early promoters PR and PL. Thus a complicated set of molecular interactions are likely to occur at the nut sites. We have selected mutations in the nutR region that reduce the effectiveness of pN in altering transcription initiating at the PR promoter. DNA sequence analysis of three independently selected mutations revealed, in each case, a deletion of a single base pair in the cro gene. Consideration of the effect of such mutations on the extension of translation of cro message into the adjacent downstream nut region led to the identification of a consensus sequence CGCTCT(T)TAA that appears to play a role in the recognition of a host factor, possibly the NusA protein.
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13
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Lawn RM, Adelman J, Bock SC, Franke AE, Houck CM, Najarian RC, Seeburg PH, Wion KL. The sequence of human serum albumin cDNA and its expression in E. coli. Nucleic Acids Res 1981; 9:6103-114. [PMID: 6171778 PMCID: PMC327587 DOI: 10.1093/nar/9.22.6103] [Citation(s) in RCA: 169] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
A recombinant plasmid has been constructed which contains the mature protein coding region of the human serum albumin (HSA) gene. Bacteria containing this plasmid synthesize HSA protein under control of the E. coli trp promoter-operator. The DNA sequence and predicted protein sequence of HSA were determined from the cDNA plasmid and are compared to existing data obtained from direct protein sequencing. The DNA sequence predicts a mature protein of 585 amino acids preceded by a 24 amino acid "prepro" peptide.
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Abstract
Bacterial operons concerned with the biosynthesis of amino acids are often controlled by a process of attenuation. The translation product of the initial segment of the transcript of each operon is a peptide rich in the amino acid that the particular operon controls. If the amino acid is in short supply translation is stalled at the relevant codons of the transcript long enough for the succeeding segment of the transcript to form secondary structures that allow the transcribing RNA polymerase molecule to proceed through a site that otherwise dictates termination of transcription. This site is the attenuator; the process is attenuation.
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Christie GE, Platt T. A functional hybrid ribosome binding site in tryptophan operon messenger RNA of Escherichia coli. J Mol Biol 1980; 143:335-41. [PMID: 6163864 DOI: 10.1016/0022-2836(80)90195-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Pannekoek H, Maat J, van den Berg E, Noordermeer I. Structure of a promotor on plasmid pMB9 derived from plasmid pSC101. Nucleic Acids Res 1980; 8:1535-50. [PMID: 6253940 PMCID: PMC324015 DOI: 10.1093/nar/8.7.1535] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The DNA sequence of a 354 basepair EcoRI-HindIII fragment of plasmid pMB9 which has originally been derived from plasmid pSC101 has been resolved. This fragment contains a promoter for transcription directed towards the EcoRI site. Escherichia coli RNA polymerase binds to a region within the EcoRI-HindIII fragment which contains the heptamer 5' TATGGTG (132-126) and the duodecamer 5' TGATGAACATCA (158-147). Based on commonalities with other promotors these DNA sequences probably function as, respectively, "binding site" and "recognition site". Furthermore, this fragment harbours a translation reading frame free of nonsense codons and at about 25 basepairs from the indicated heptamer a nucleotide sequence which meets with the requirements for initiation of translation. By heteroduplex mapping it was shown that the EcoRI-HindIII fragment has been derived from a region near or within the origin of replication of pSC101. The copynumber of plasmids containing the EcoRI-HindIII fragment is two-fold lower than that of plasmids lacking this fragment. This effect might be related to the original function of this fragment on plasmid pSC101.
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18
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Eisenberg SP, Yarus M, Soll L. The effect of an Escherichia coli regulatory mutation on transfer RNA structure. J Mol Biol 1979; 135:111-26. [PMID: 93644 DOI: 10.1016/0022-2836(79)90343-7] [Citation(s) in RCA: 86] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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19
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Kano Y, Imamoto F. Evidence for endonucleolytic cleavage at the 5'-proximal segment of the trp messenger RNA in Escherichia coli. MOLECULAR & GENERAL GENETICS : MGG 1979; 172:25-30. [PMID: 377022 DOI: 10.1007/bf00276211] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The 5'-proximal trp leader RNA segment (about 5S) decays at 2 to 3 times slower rates than the distal trp mRNA sequence. This has been demonstrated by employing the deletion mutants which lack a large portion of the structural genes but retain the promoter-proximal region of the trp operon. Relative stability of the leader RNA is not merely due to the presence of an untranslatable region in the segment; the internal untranslatable segment of trp mRNA downstream from the nonsense alteration site of a double mutant trpAD28.trpE9758 decays as fast as the normal trp mRNA sequence. These results suggest that the trp mRNA is endonucleolytically cleaved to yield the small 5'-proximal leader RNA segment before the distal mRNA decays and that the leader RNA sequence is not subject to usual mode of mRNA decay in the 5' to 3' direction.
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Neeleman L, van Vloten-Doting L. Determination of the number of ribosomal binding sites on the RNAs of eukaryotic viruses. Methods Enzymol 1979; 60:410-7. [PMID: 459911 DOI: 10.1016/s0076-6879(79)60039-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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21
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Abstract
The nucleotide sequence of the regulatory region of the trp operon of Serratia marcescens is presented. It contains a transcription termination control site in the transcribed leader region preceding the first structural gene of the operon as well as a regulated promoter/operator transcription initiation region. The structural organisation of the leader region differs substantially from that of Escherichia coli.
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22
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Calame K, Nakada D, Ihler G. Location of ribosome-binding sites on the tetracycline resistance transposon Tn10. J Bacteriol 1978; 135:668-74. [PMID: 681286 PMCID: PMC222428 DOI: 10.1128/jb.135.2.668-674.1978] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Eight ribosome-binding sites were located on the single-stranded Tn10 DNA loop which was formed after denaturation of lambda phage DNA containing the Tn10 transposon sequence. Ribosomes were bound only to the Tn10 loop contained on the R strand of lambda DNA but not to that on the L strand, suggesting that one of the two strands of Tn10 DNA is selectively transcribed. Six of the eight ribosome binding sites were located in one-half of the DNA loop. The maximum sizes of potential polypeptides were calculated for these genes to range between 9,500 and 84,000 daltons.
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Sommer H, Schmitz A, Schmeissner U, Miller JH, Wittmann HG. Genetic studies of the lac repressor. J Mol Biol 1978. [DOI: 10.1016/0022-2836(78)90090-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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24
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Lee F, Bertrand K, Bennett G, Yanofsky C. Comparison of the nucleotide sequences of the initial transcribed regions of the tryptophan operons of Escherichia coli and Salmonella typhimurium. J Mol Biol 1978; 121:193-217. [PMID: 351195 DOI: 10.1016/s0022-2836(78)80005-9] [Citation(s) in RCA: 82] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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25
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Bennett GN, Brown KD, Yanofsky C. Nucleotide sequence of the promoter--operator region of the tryptophan operon of Salmonella typhimurium. J Mol Biol 1978; 121:139-52. [PMID: 351192 DOI: 10.1016/s0022-2836(78)80002-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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26
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Miozzari GF, Yanofsky C. Translation of the leader region of the Escherichia coli tryptophan operon. J Bacteriol 1978; 133:1457-66. [PMID: 346574 PMCID: PMC222185 DOI: 10.1128/jb.133.3.1457-1466.1978] [Citation(s) in RCA: 118] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
When the trp operon of Escherichia coli contains either of two deletions that fuse the initial portion of the leader region to the distal segments of the trpE gene, novel fusion polypeptides are produced. The new polypeptides are synthesized efficiently both in vivo and in vitro, and their synthesis is subject to repression by trp repressor. Fingerprint analyses of tryptic and chymotryptic digests of the new polypeptides show that both contain trpE polypeptide sequences and, despite their different sizes, share the same N-terminal sequence. Our results suggest that synthesis of the new polypeptides is initiated at the AUG-centered ribosome-binding site in the leader region and proceeds in phase to the region coding for the C-terminal end of the trpE polypeptide.
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Steitz JA, Bryan RA. Two ribosome binding sites from the gene 0-3 messenger RNA of bacteriophages T7. J Mol Biol 1977; 114:527-43. [PMID: 915941 DOI: 10.1016/0022-2836(77)90176-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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29
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Bertrand K, Squires C, Yanofsky C. Transcription termination in vivo in the leader region of the tryptophan operon of Escherichia coli. J Mol Biol 1976; 103:319-37. [PMID: 781269 DOI: 10.1016/0022-2836(76)90315-6] [Citation(s) in RCA: 97] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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30
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Squires C, Lee F, Bertrand K, Squires CL, Bronson MJ, Yanofsky C. Nucleotide sequence of the 5' end of tryptophan messenger RNA of Escherichia coli. J Mol Biol 1976; 103:351-81. [PMID: 781271 DOI: 10.1016/0022-2836(76)90317-x] [Citation(s) in RCA: 100] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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31
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Morse DE, Morse AN. Dual-control of the tryptophan operon is mediated by both tryptophanyl-tRNA synthetase and the repressor. J Mol Biol 1976; 103:209-26. [PMID: 781267 DOI: 10.1016/0022-2836(76)90310-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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32
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Bertrand K, Yanofsky C. Regulation of transcription termination in the leader region of the tryptophan operon of Escherichia coli involves tryptophan or its metabolic product. J Mol Biol 1976; 103:339-49. [PMID: 781270 DOI: 10.1016/0022-2836(76)90316-8] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Lee F, Squires CL, Squires C, Yanofsky C. Termination of transcription in vitro in the Escherichia coli tryptophan operon leader region. J Mol Biol 1976; 103:383-93. [PMID: 781272 DOI: 10.1016/0022-2836(76)90318-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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34
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Bertrand K, Korn L, Lee F, Platt T, Squires CL, Squires C, Yanofsky C. New features of the regulation of the tryptophan operon. Science 1975; 189:22-6. [PMID: 1094538 DOI: 10.1126/science.1094538] [Citation(s) in RCA: 205] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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