Abstract
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Molecular and General Genetics MGG |
| Vol/bind | 201 |
| Udgave nummer | 2 |
| Sider (fra-til) | 247-251 |
| ISSN | 0026-8925 |
| Status | Udgivet - 1985 |
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I: Molecular and General Genetics MGG, Bind 201, Nr. 2, 1985, s. 247-251.
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
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TY - JOUR
T1 - Role of translation in the UTP-modulated attenuation at the pyrBI operon of Escherichia coli
AU - Clemmesen, Kåre
AU - Bonekamp, Fons
AU - Karlström, Olle
AU - Jensen, Kaj Frank
PY - 1985
Y1 - 1985
N2 - A 273 bp DNA fragment containing the attenuator of the pyrBI operon was inserted into a synthetic cloning site early in the lacZ gene on a plasmid. By this operation the first few codons of lacZ were joined through a linker to the last 39 codons of the open reading frame for the putative pyrB leader peptide. In addition a gene fusion encoding a hybrid protein with -galactosidase activity was formed between the pyrB start and the rest of lacZ. This gene fusion is expressed from the lac promoter and the transcript is subject to facultative termination at the pyrBI attenuator. Different variants of the lacZ start were used that either contained a stop codon or directed the translation toward the attenuator in any of the alternative reading frames. The following results were obtained.No significant read-through of transcription over the pyrB attenuator was seen when the leader translation ended 49 nucleotide residues, or more, upstream of the attenuator symmetry, but a UTP-modulated attenuation was established if the leader translation was allowed to proceed across the attenuator as for the putative leader peptide or in a frame-shifted version. The regulation, however, was not as great as for the native pyrB gene. This is probably because the substitution of the normal start of the leader peptide by the start of lacZ alters the coupling between transcription and translation and thereby the attenuation frequency. It cannot, however, be ruled out that the pyrBI operon is regulated at the promoters in addition to the control by attenuation.
AB - A 273 bp DNA fragment containing the attenuator of the pyrBI operon was inserted into a synthetic cloning site early in the lacZ gene on a plasmid. By this operation the first few codons of lacZ were joined through a linker to the last 39 codons of the open reading frame for the putative pyrB leader peptide. In addition a gene fusion encoding a hybrid protein with -galactosidase activity was formed between the pyrB start and the rest of lacZ. This gene fusion is expressed from the lac promoter and the transcript is subject to facultative termination at the pyrBI attenuator. Different variants of the lacZ start were used that either contained a stop codon or directed the translation toward the attenuator in any of the alternative reading frames. The following results were obtained.No significant read-through of transcription over the pyrB attenuator was seen when the leader translation ended 49 nucleotide residues, or more, upstream of the attenuator symmetry, but a UTP-modulated attenuation was established if the leader translation was allowed to proceed across the attenuator as for the putative leader peptide or in a frame-shifted version. The regulation, however, was not as great as for the native pyrB gene. This is probably because the substitution of the normal start of the leader peptide by the start of lacZ alters the coupling between transcription and translation and thereby the attenuation frequency. It cannot, however, be ruled out that the pyrBI operon is regulated at the promoters in addition to the control by attenuation.
M3 - Journal article
SN - 0026-8925
VL - 201
SP - 247
EP - 251
JO - Molecular and General Genetics MGG
JF - Molecular and General Genetics MGG
IS - 2
ER -