Loss of rac locus DNA in merozygotes of Escherichia coli K12

Evans, R P; Seeley, Neil R.; Kuempel, Peter L.

doi:10.1007/bf00397223

Cited by 28 publications

(17 citation statements)

References 25 publications

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“…recE mutations reduce elevated levels of conjugational and plasmid recombination and UV and mitomycin C resistance produced by sbcA mutations in a recB recC genetic background (8,10,11,14,19,26,31,32). This supports the hypothesis that exoVIII plays a role in the processes of recombination and repair in recB recC sbcA mutants (3).The relationship of sbcA to recE has previously been investigated by Southern blot analysis of restriction endonuclease-digested chromosomal DNA (23,24 (5,9,13,15,23,29,35). The Southern blot analysis also revealed that mutations called sbcA differ; point mutations and one large deletion were found.…”

supporting

confidence: 76%

“…The relationship of sbcA to recE has previously been investigated by Southern blot analysis of restriction endonuclease-digested chromosomal DNA (23,24 (5,9,13,15,23,29,35). The Southern blot analysis also revealed that mutations called sbcA differ; point mutations and one large deletion were found.…”

mentioning

confidence: 99%

“…Both recE and sbcA genetically map to within the Rac prophage (between 29.6 and 30.2 min) on the E. coli chromosome (5,9,13,15,23,29,35). The Southern blot analysis also revealed that mutations called sbcA differ; point mutations and one large deletion were found.…”

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confidence: 99%

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Analysis of the recE locus of Escherichia coli K-12 by use of polyclonal antibodies to exonuclease VIII

1988

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Exonuclease VIII (exoVIII) of Escherichia coli has been purified from a strain carrying a plasmid-encoded recE gene by using a new procedure. This procedure yielded 30 times more protein per gram of cells, and the protein had a twofold higher specific activity than the enzyme purified by the previously published procedure (J. W. Joseph and R. Kolodner, J. Biol. Chem. 258:10411-10417, 1983). The sequence of the 12 N-terminal amino acids was also obtained and found to correspond to one of the open reading frames predicted from the nucleic acid sequence of the recE region of Rac (C. Chu, A. Templin, and A. J. Clark, manuscript in preparation). Polyclonal antibodies directed against purified exoVIII were also prepared. Cell-free extracts prepared from strains containing a wide range of chromosomal-or plasmid-encoded point, insertion, and deletion mutations which result in expression of exoVIII were examined by Western blot (immunoblot) analysis. This analysis showed that two point sbcA mutations (sbcA5 and sbcA23) and the sbc insertion mutations led to the synthesis of the 140-kilodalton (kDa) polypeptide of wild-type exoVIII. Plasmid-encoded partial deletion mutations of recE reduced the size of the cross-reacting protein(s) in direct proportion to the size of the deletion, even though exonuclease activity was still present. The analysis suggests that 39 kDa of the 140-kDa exoVIII subunit is all that is essential for exonuclease activity. One of the truncated but functional exonucleases (the pRAC3 exonuclease) has been purified and confirmed to be a 41-kDa polypeptide. The first 18 amino acids from the N terminus of the 41-kDa pRAC3 exonuclease were sequenced and found to correspond to one of the translational start signals predicted from the nucleotide sequence of racC (Chu et al., in preparation).sbcA mutations suppress the conjugation-mediated recombination deficiency, UV sensitivity, and mitomycin C sensitivity of Escherichia coli strains containing recB or recC mutations or both (3). In addition, an sbcA mutation in a recB recC mutant background stimulates the recombination of circular monomer and dimer and linear dimer plasmid substrates 20-to 100-fold and increases the efficiency of recombination-mediated transformation of linear dimer plasmids at least 100-fold (10,19,26,31).One additional phenotype associated with the presence of an sbcA mutation is the presence of an ATP-independent DNase, exonuclease VIII (exoVIII;3,25). ExoVIII is a highly processive 5'-to-3' exonuclease with a subunit molecular weight of 140,000 (21, 25). The enzyme preferentially degrades double-stranded linear DNA and has no activity on single-stranded DNA or double-stranded circular DNA in a supercoiled, nicked, or gapped configuration (21). ExoVIII is functionally similar to A exonuclease (6,21,22,25,27), and can substitute for the X red functions (12). The structural gene for exoVIII has been termed recE (25). recE mutations reduce elevated levels of conjugational and plasmid recombination and UV and mitomycin C resistance produ...

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confidence: 76%

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Analysis of the recE locus of Escherichia coli K-12 by use of polyclonal antibodies to exonuclease VIII

1988

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“…The CP4 elements are not closely related to the prophages at the same location in the other strains. c. Phage l was cured from the sequenced version of E. coli K-12 (Blattner et al ., 1997); Eut [also called CPZ-55 (Rudd, 1999) and 'CP-unnamed' (Hayashi et al ., 2001b)] is missing from some extant K-12 laboratory strains (Kofoid et al ., 1999); Rac and e14 are also excisable (Evans et al ., 1979;Brody et al ., 1985). d. CP-22 is a provisional name for a region not formally identified as a prophage by Perna et al .…”

Section: Types Of Prophages and Related Entitiesmentioning

confidence: 99%

“…Rac was the first defective prophage to be discovered in E. coli K-12 (Low, 1973;Kaiser and Murray, 1979). In this strain, it was shown that, although no Rac virions were ever produced upon induction, (i) parts of Rac can be picked up by the phage l chromosome through homologous recombination (Zissler et al, 1971;Kaiser and Murray, 1979); (ii) the Rac prophage can be excised upon induction (Evans et al, 1979;Brikun et al, 1994); (iii) Rac is lethal to the host if expression of its genes is induced, and this lethality results from an inhibitor of host cell division that is homologous to the Fig. 4.…”

Section: The Rac Prophagesmentioning

confidence: 99%

Prophages and bacterial genomics: what have we learned so far?

Casjens

2003

Molecular Microbiology

785

815

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EpigraphThere is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact. Mark Twain 1883 Life on the Mississippi SummaryBacterial genome nucleotide sequences are being completed at a rapid and increasing rate. Integrated virus genomes (prophages) are common in such genomes. Fifty-one of the 82 such genomes published to date carry prophages, and these contain 230 recognizable putative prophages. Prophages can constitute as much as 10-20% of a bacterium's genome and are major contributors to differences between individuals within species. Many of these prophages appear to be defective and are in a state of mutational decay. Prophages, including defective ones, can contribute important biological properties to their bacterial hosts. Therefore, if we are to comprehend bacterial genomes fully, it is essential that we are able to recognize accurately and understand their prophages from nucleotide sequence analysis. Analysis of the evolution of prophages can shed light on the evolution of both bacteriophages and their hosts. Comparison of the Rac prophages in the sequenced genomes of three Escherichia coli strains and the Pnm prophages in two Neisseria meningitidis strains suggests that some prophages can lie in residence for very long times, perhaps millions of years, and that recombination events have occurred between related prophages that reside at different locations in a bacterium's genome. In addition, many genes in defective prophages remain functional, so a significant portion of the temperate bacteriophage gene pool resides in prophages.Prophage biology

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Rac- E. coli K12 strains carry a preferential attachment site for λrev

Díaz

Kaiser

1981

Molec. Gen. Genet.

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Lambda rev is a hybrid lambdoid phage formed by recombination between lambda and a defective lambdoid prophage (Rac) present in most E. coli K12 derivatives. We show here that three independently derived Rac-E. coli K12 strains are specifically deleted for the entire Rac prophage consistent with loss of Rac by excisive recombination between hybrid attachment sites that flank the prophage (c.f. excision of a lambda prophage). lambda rev, in which int and PP' of lambda have been replaced by integrative recombination genes and an attachment site derived from Rac (Gottesman et al. 1974), integrates site-specifically and in the correct orientation at the preferential attachment site generated by Rac excision.

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Loss of rac locus DNA in merozygotes of Escherichia coli K12

Cited by 28 publications

References 25 publications

Analysis of the recE locus of Escherichia coli K-12 by use of polyclonal antibodies to exonuclease VIII

Analysis of the recE locus of Escherichia coli K-12 by use of polyclonal antibodies to exonuclease VIII

Prophages and bacterial genomics: what have we learned so far?

Rac- E. coli K12 strains carry a preferential attachment site for λrev

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