Document Detail


Linkage distortion following conjugational transfer of sbcC+ to recBC sbcBC strains of Escherichia coli.
MedLine Citation:
PMID:  1885546     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Conjugational recombination in Escherichia coli depends normally on RecBCD enzyme, a multifunctional nuclease and DNA helicase produced by the recB, recC, and recD genes. However, recombination can proceed efficiently without RecBCD in recB or recC strains carrying additional mutations in both the sbcB and sbcC genes. Recombination in these strains, sometimes referred to as the RecF pathway, requires gene products that are not essential in the RecBCD-dependent process predominating in the wild type. It has also been reported to produce a different spectrum of recombinant genotypes in crosses with Hfr donors. However, the sbcC+ gene was unknowingly transferred to the recipient strain in some of these crosses, and this may have affected the outcome. This possibility was examined by conducting parallel crosses with Hfr donors that were either wild type or mutant for sbcC. Transfer of sbcC+ from an Hfr donor is shown to alter the frequency of recombinant genotypes recovered. There is a severe reduction in progeny that inherit donor markers linked to the sbcC+ allele and an increase in the incidence of multiple exchanges. Colonies of mixed genotype for one or more of the unselected proximal markers are also much more prevalent. Since the yield of recombinants is lower than normal, these changes are attributed to the reduced viability of recombinants that inherit sbcC+ from the Hfr donor. When the Hfr donor used is also mutant for sbcC, the yield of recombinants is greater and the frequencies of the different genotypes recovered are similar to those obtained in crosses with a rec+ sbc+ recipient, in which transfer of sbcC+ has no apparent effect. Earlier studies are re-examined in light of these findings. It is concluded that, while recombination in recBC sbcBC strains involves different enzymes, the underlying molecular mechanism is essentially the same as that in the wild type.
Authors:
R G Lloyd
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of bacteriology     Volume:  173     ISSN:  0021-9193     ISO Abbreviation:  J. Bacteriol.     Publication Date:  1991 Sep 
Date Detail:
Created Date:  1991-10-09     Completed Date:  1991-10-09     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2985120R     Medline TA:  J Bacteriol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  5694-8     Citation Subset:  IM    
Affiliation:
Department of Genetics, University of Nottingham, Queens Medical Centre, United Kingdom.
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MeSH Terms
Descriptor/Qualifier:
Chromosomes, Bacterial / ultrastructure
Conjugation, Genetic*
Escherichia coli / genetics*
Escherichia coli Proteins*
Exodeoxyribonuclease V
Exodeoxyribonucleases / physiology
Genes, Bacterial
Linkage (Genetics)
Recombination, Genetic*
Grant Support
ID/Acronym/Agency:
//Wellcome Trust
Chemical
Reg. No./Substance:
0/Escherichia coli Proteins; EC 3.1.-/Exodeoxyribonucleases; EC 3.1.11.5/Exodeoxyribonuclease V; EC 3.1.11.5/exodeoxyribonuclease V, E coli
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