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Accumulation of large non-circular forms of the chromosome in recombination-defective mutants of Escherichia coli
BACKGROUND: Double-strand breakage of chromosomal DNA is obviously a serious threat to cells because various activities of the chromosome depend on its integrity. However, recent experiments suggest that such breakage may occur frequently during "normal" growth in various organisms – from...
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Formato: | Texto |
Lenguaje: | English |
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BioMed Central
2003
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC156651/ https://www.ncbi.nlm.nih.gov/pubmed/12718760 http://dx.doi.org/10.1186/1471-2199-4-5 |
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author | Handa, Naofumi Kobayashi, Ichizo |
author_facet | Handa, Naofumi Kobayashi, Ichizo |
author_sort | Handa, Naofumi |
collection | PubMed |
description | BACKGROUND: Double-strand breakage of chromosomal DNA is obviously a serious threat to cells because various activities of the chromosome depend on its integrity. However, recent experiments suggest that such breakage may occur frequently during "normal" growth in various organisms – from bacteria through vertebrates, possibly through arrest of a replication fork at some endogenous DNA damage. RESULTS: In order to learn how the recombination processes contribute to generation and processing of the breakage, large (> 2000 kb) linear forms of Escherichia coli chromosome were detected by pulsed-field gel electrophoresis in various recombination-defective mutants. The mutants were analyzed in a rich medium, in which the wild-type strain showed fewer of these huge broken chromosomes than in a synthetic medium, and the following results were obtained: (i) Several recB and recC null mutants (in an otherwise rec(+ )background) accumulated these huge linear forms, but several non-null recBCD mutants (recD, recC1001, recC1002, recC1003, recC1004, recC2145, recB2154, and recB2155) did not. (ii) In a recBC sbcA background, in which RecE-mediated recombination is active, recA, recJ, recQ, recE, recT, recF, recO, and recR mutations led to their accumulation. The recJ mutant accumulated many linear forms, but this effect was suppressed by a recQ mutation. (iii) The recA, recJ, recQ, recF and recR mutations led to their accumulation in a recBC sbcBC background. The recJ mutation showed the largest amount of these forms. (iv) No accumulation was detected in mutants affecting resolution of Holliday intermediates, recG, ruvAB and ruvC, in any of these backgrounds. CONCLUSION: These results are discussed in terms of stepwise processing of chromosomal double-strand breaks. |
format | Text |
id | pubmed-156651 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2003 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-1566512003-06-09 Accumulation of large non-circular forms of the chromosome in recombination-defective mutants of Escherichia coli Handa, Naofumi Kobayashi, Ichizo BMC Mol Biol Research Article BACKGROUND: Double-strand breakage of chromosomal DNA is obviously a serious threat to cells because various activities of the chromosome depend on its integrity. However, recent experiments suggest that such breakage may occur frequently during "normal" growth in various organisms – from bacteria through vertebrates, possibly through arrest of a replication fork at some endogenous DNA damage. RESULTS: In order to learn how the recombination processes contribute to generation and processing of the breakage, large (> 2000 kb) linear forms of Escherichia coli chromosome were detected by pulsed-field gel electrophoresis in various recombination-defective mutants. The mutants were analyzed in a rich medium, in which the wild-type strain showed fewer of these huge broken chromosomes than in a synthetic medium, and the following results were obtained: (i) Several recB and recC null mutants (in an otherwise rec(+ )background) accumulated these huge linear forms, but several non-null recBCD mutants (recD, recC1001, recC1002, recC1003, recC1004, recC2145, recB2154, and recB2155) did not. (ii) In a recBC sbcA background, in which RecE-mediated recombination is active, recA, recJ, recQ, recE, recT, recF, recO, and recR mutations led to their accumulation. The recJ mutant accumulated many linear forms, but this effect was suppressed by a recQ mutation. (iii) The recA, recJ, recQ, recF and recR mutations led to their accumulation in a recBC sbcBC background. The recJ mutation showed the largest amount of these forms. (iv) No accumulation was detected in mutants affecting resolution of Holliday intermediates, recG, ruvAB and ruvC, in any of these backgrounds. CONCLUSION: These results are discussed in terms of stepwise processing of chromosomal double-strand breaks. BioMed Central 2003-04-28 /pmc/articles/PMC156651/ /pubmed/12718760 http://dx.doi.org/10.1186/1471-2199-4-5 Text en Copyright © 2003 Handa and Kobayashi; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL. |
spellingShingle | Research Article Handa, Naofumi Kobayashi, Ichizo Accumulation of large non-circular forms of the chromosome in recombination-defective mutants of Escherichia coli |
title | Accumulation of large non-circular forms of the chromosome in recombination-defective mutants of Escherichia coli |
title_full | Accumulation of large non-circular forms of the chromosome in recombination-defective mutants of Escherichia coli |
title_fullStr | Accumulation of large non-circular forms of the chromosome in recombination-defective mutants of Escherichia coli |
title_full_unstemmed | Accumulation of large non-circular forms of the chromosome in recombination-defective mutants of Escherichia coli |
title_short | Accumulation of large non-circular forms of the chromosome in recombination-defective mutants of Escherichia coli |
title_sort | accumulation of large non-circular forms of the chromosome in recombination-defective mutants of escherichia coli |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC156651/ https://www.ncbi.nlm.nih.gov/pubmed/12718760 http://dx.doi.org/10.1186/1471-2199-4-5 |
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