DNA supercoiling in Escherichia coli: topA mutations can be suppressed by DNA amplifications involving the tolC locus
Dorman, C. J. ; Lynch, A. S. ; Bhriain, N. Ni ; Higgins, C. F.
Oxford, UK : Blackwell Publishing Ltd
Published 1989
Oxford, UK : Blackwell Publishing Ltd
Published 1989
| ISSN: |
1365-2958
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|---|---|
| Source: |
Blackwell Publishing Journal Backfiles 1879-2005
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| Topics: |
Biology
Medicine
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| Notes: |
The level of DNA supercoiling is crucial for many cellular processes, Including gene expression, and is determined, primarily, by the opposing actions of two enzymes: topoisomerase I and DNA gyrase. Escherichia coli strains lacking topoisomerase I (topA mutants) normally fail to grow in the absence of compensatory mutations which are presumed to relax DNA. We have found that, in media of low osmolarity, topA mutants are viable in the absence of any compensatory mutation, consistent with the view that decreased extracellular osmolarity causes a relaxation of cellular DNA. At higher osmolarity most compensatory mutations, as expected, are in the gyrA and gyrB genes. The only other locus at which compensatory mutations arise, designated toc, is shown to involve the amplification of a region of chromosomal DNA which includes the tolC gene. However, amplification of tolC alone is insufficient to explain the phenotypes of toc mutants. tolC insertion mutations alter the distribution of plasmid topoisomers in vivo. This effect is probably indirect, possibly a result of altered membrane structure and an alteration in the cell's osmotic barrier. As tolC is a highly pleiotropic locus, affecting the expression of many genes, it is possible that some of the TolC phenotypes are a direct result of this topological change. The possible relationship between toe and tolC mutations, and the means by which tolC mutations might affect DNA supercoiling, are discussed.
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| Type of Medium: |
Electronic Resource
|
| URL: |
| _version_ | 1798290416003448832 |
|---|---|
| autor | Dorman, C. J. Lynch, A. S. Bhriain, N. Ni Higgins, C. F. |
| autorsonst | Higgins, C. F. |
| book_url | http://dx.doi.org/10.1111/j.1365-2958.1989.tb00199.x |
| datenlieferant | nat_lic_papers |
| hauptsatz | hsatz_simple |
| identnr | NLZ241779987 |
| insertion_date | 2012-04-27 |
| issn | 1365-2958 |
| journal_name | Molecular microbiology |
| materialart | 1 |
| notes | The level of DNA supercoiling is crucial for many cellular processes, Including gene expression, and is determined, primarily, by the opposing actions of two enzymes: topoisomerase I and DNA gyrase. Escherichia coli strains lacking topoisomerase I (topA mutants) normally fail to grow in the absence of compensatory mutations which are presumed to relax DNA. We have found that, in media of low osmolarity, topA mutants are viable in the absence of any compensatory mutation, consistent with the view that decreased extracellular osmolarity causes a relaxation of cellular DNA. At higher osmolarity most compensatory mutations, as expected, are in the gyrA and gyrB genes. The only other locus at which compensatory mutations arise, designated toc, is shown to involve the amplification of a region of chromosomal DNA which includes the tolC gene. However, amplification of tolC alone is insufficient to explain the phenotypes of toc mutants. tolC insertion mutations alter the distribution of plasmid topoisomers in vivo. This effect is probably indirect, possibly a result of altered membrane structure and an alteration in the cell's osmotic barrier. As tolC is a highly pleiotropic locus, affecting the expression of many genes, it is possible that some of the TolC phenotypes are a direct result of this topological change. The possible relationship between toe and tolC mutations, and the means by which tolC mutations might affect DNA supercoiling, are discussed. |
| package_name | Blackwell Publishing |
| publikationsjahr_anzeige | 1989 |
| publikationsjahr_facette | 1989 |
| publikationsjahr_intervall | 8014:1985-1989 |
| publikationsjahr_sort | 1989 |
| publikationsort | Oxford, UK |
| publisher | Blackwell Publishing Ltd |
| reference | 3 (1989), S. 0 |
| search_space | articles |
| shingle_author_1 | Dorman, C. J. Lynch, A. S. Bhriain, N. Ni Higgins, C. F. |
| shingle_author_2 | Dorman, C. J. Lynch, A. S. Bhriain, N. Ni Higgins, C. F. |
| shingle_author_3 | Dorman, C. J. Lynch, A. S. Bhriain, N. Ni Higgins, C. F. |
| shingle_author_4 | Dorman, C. J. Lynch, A. S. Bhriain, N. Ni Higgins, C. F. |
| shingle_catch_all_1 | Dorman, C. J. Lynch, A. S. Bhriain, N. Ni Higgins, C. F. DNA supercoiling in Escherichia coli: topA mutations can be suppressed by DNA amplifications involving the tolC locus Blackwell Publishing Ltd The level of DNA supercoiling is crucial for many cellular processes, Including gene expression, and is determined, primarily, by the opposing actions of two enzymes: topoisomerase I and DNA gyrase. Escherichia coli strains lacking topoisomerase I (topA mutants) normally fail to grow in the absence of compensatory mutations which are presumed to relax DNA. We have found that, in media of low osmolarity, topA mutants are viable in the absence of any compensatory mutation, consistent with the view that decreased extracellular osmolarity causes a relaxation of cellular DNA. At higher osmolarity most compensatory mutations, as expected, are in the gyrA and gyrB genes. The only other locus at which compensatory mutations arise, designated toc, is shown to involve the amplification of a region of chromosomal DNA which includes the tolC gene. However, amplification of tolC alone is insufficient to explain the phenotypes of toc mutants. tolC insertion mutations alter the distribution of plasmid topoisomers in vivo. This effect is probably indirect, possibly a result of altered membrane structure and an alteration in the cell's osmotic barrier. As tolC is a highly pleiotropic locus, affecting the expression of many genes, it is possible that some of the TolC phenotypes are a direct result of this topological change. The possible relationship between toe and tolC mutations, and the means by which tolC mutations might affect DNA supercoiling, are discussed. 1365-2958 13652958 |
| shingle_catch_all_2 | Dorman, C. J. Lynch, A. S. Bhriain, N. Ni Higgins, C. F. DNA supercoiling in Escherichia coli: topA mutations can be suppressed by DNA amplifications involving the tolC locus Blackwell Publishing Ltd The level of DNA supercoiling is crucial for many cellular processes, Including gene expression, and is determined, primarily, by the opposing actions of two enzymes: topoisomerase I and DNA gyrase. Escherichia coli strains lacking topoisomerase I (topA mutants) normally fail to grow in the absence of compensatory mutations which are presumed to relax DNA. We have found that, in media of low osmolarity, topA mutants are viable in the absence of any compensatory mutation, consistent with the view that decreased extracellular osmolarity causes a relaxation of cellular DNA. At higher osmolarity most compensatory mutations, as expected, are in the gyrA and gyrB genes. The only other locus at which compensatory mutations arise, designated toc, is shown to involve the amplification of a region of chromosomal DNA which includes the tolC gene. However, amplification of tolC alone is insufficient to explain the phenotypes of toc mutants. tolC insertion mutations alter the distribution of plasmid topoisomers in vivo. This effect is probably indirect, possibly a result of altered membrane structure and an alteration in the cell's osmotic barrier. As tolC is a highly pleiotropic locus, affecting the expression of many genes, it is possible that some of the TolC phenotypes are a direct result of this topological change. The possible relationship between toe and tolC mutations, and the means by which tolC mutations might affect DNA supercoiling, are discussed. 1365-2958 13652958 |
| shingle_catch_all_3 | Dorman, C. J. Lynch, A. S. Bhriain, N. Ni Higgins, C. F. DNA supercoiling in Escherichia coli: topA mutations can be suppressed by DNA amplifications involving the tolC locus Blackwell Publishing Ltd The level of DNA supercoiling is crucial for many cellular processes, Including gene expression, and is determined, primarily, by the opposing actions of two enzymes: topoisomerase I and DNA gyrase. Escherichia coli strains lacking topoisomerase I (topA mutants) normally fail to grow in the absence of compensatory mutations which are presumed to relax DNA. We have found that, in media of low osmolarity, topA mutants are viable in the absence of any compensatory mutation, consistent with the view that decreased extracellular osmolarity causes a relaxation of cellular DNA. At higher osmolarity most compensatory mutations, as expected, are in the gyrA and gyrB genes. The only other locus at which compensatory mutations arise, designated toc, is shown to involve the amplification of a region of chromosomal DNA which includes the tolC gene. However, amplification of tolC alone is insufficient to explain the phenotypes of toc mutants. tolC insertion mutations alter the distribution of plasmid topoisomers in vivo. This effect is probably indirect, possibly a result of altered membrane structure and an alteration in the cell's osmotic barrier. As tolC is a highly pleiotropic locus, affecting the expression of many genes, it is possible that some of the TolC phenotypes are a direct result of this topological change. The possible relationship between toe and tolC mutations, and the means by which tolC mutations might affect DNA supercoiling, are discussed. 1365-2958 13652958 |
| shingle_catch_all_4 | Dorman, C. J. Lynch, A. S. Bhriain, N. Ni Higgins, C. F. DNA supercoiling in Escherichia coli: topA mutations can be suppressed by DNA amplifications involving the tolC locus Blackwell Publishing Ltd The level of DNA supercoiling is crucial for many cellular processes, Including gene expression, and is determined, primarily, by the opposing actions of two enzymes: topoisomerase I and DNA gyrase. Escherichia coli strains lacking topoisomerase I (topA mutants) normally fail to grow in the absence of compensatory mutations which are presumed to relax DNA. We have found that, in media of low osmolarity, topA mutants are viable in the absence of any compensatory mutation, consistent with the view that decreased extracellular osmolarity causes a relaxation of cellular DNA. At higher osmolarity most compensatory mutations, as expected, are in the gyrA and gyrB genes. The only other locus at which compensatory mutations arise, designated toc, is shown to involve the amplification of a region of chromosomal DNA which includes the tolC gene. However, amplification of tolC alone is insufficient to explain the phenotypes of toc mutants. tolC insertion mutations alter the distribution of plasmid topoisomers in vivo. This effect is probably indirect, possibly a result of altered membrane structure and an alteration in the cell's osmotic barrier. As tolC is a highly pleiotropic locus, affecting the expression of many genes, it is possible that some of the TolC phenotypes are a direct result of this topological change. The possible relationship between toe and tolC mutations, and the means by which tolC mutations might affect DNA supercoiling, are discussed. 1365-2958 13652958 |
| shingle_title_1 | DNA supercoiling in Escherichia coli: topA mutations can be suppressed by DNA amplifications involving the tolC locus |
| shingle_title_2 | DNA supercoiling in Escherichia coli: topA mutations can be suppressed by DNA amplifications involving the tolC locus |
| shingle_title_3 | DNA supercoiling in Escherichia coli: topA mutations can be suppressed by DNA amplifications involving the tolC locus |
| shingle_title_4 | DNA supercoiling in Escherichia coli: topA mutations can be suppressed by DNA amplifications involving the tolC locus |
| sigel_instance_filter | dkfz geomar wilbert ipn albert |
| source_archive | Blackwell Publishing Journal Backfiles 1879-2005 |
| timestamp | 2024-05-06T08:16:23.097Z |
| titel | DNA supercoiling in Escherichia coli: topA mutations can be suppressed by DNA amplifications involving the tolC locus |
| titel_suche | DNA supercoiling in Escherichia coli: topA mutations can be suppressed by DNA amplifications involving the tolC locus |
| topic | W WW-YZ |
| uid | nat_lic_papers_NLZ241779987 |