Genetic characterization of forty ionizing radiation-sensitive strains of Deinococcus radiodurans: linkage information from transformation

Mattimore, V; Udupa, K S; Berne, G A; Battista, John R.

doi:10.1128/jb.177.18.5232-5237.1995

Cited by 44 publications

(27 citation statements)

References 19 publications

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“…IRS24 was isolated when colonies from mutagenized cultures of D. radiodurans strain 302 (uvrA1) were screened for sensitivity to 5,000 Gy of gamma radiation (29). Subsequent linkage analysis revealed that IRS24 carried a defect in a locus tentatively designated irrE (19). In Fig.…”

Section: Resultsmentioning

confidence: 99%

“…By characterizing a collection of DNA damage-sensitive strains isolated from mutagenized cultures of D. radiodurans, we were able to identify one such gene, DR0167. This gene's importance in the overall stress response of D. radiodurans was first identified in strain IRS24, a derivative of 302 (19,29). D. radiodurans strain 302 has a 144-bp deletion that removes the first 34 bp of the uvrA1 coding sequence and 110 bp of upstream sequence (25).…”

Section: Discussionmentioning

confidence: 99%

“…Strain 302 is approximately 50 times more mutable than the wild-type R1 strain following N-methyl-NЈ-nitro-N-nitrosoguanidine (MNNG) treatment, because it is incapable of carrying out nucleotide excision repair (19). This defect prevents effective repair of base damage caused by the alkylating agent.…”

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confidence: 99%

“…This defect prevents effective repair of base damage caused by the alkylating agent. These IRS strains were placed into 16 linkage groups designated irrA to irrP (19). Each linkage group is presumed to include mutations that adversely affect a single gene or operon necessary for ionizing radiation resistance.…”

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The IrrE Protein of Deinococcus radiodurans R1 Is a Novel Regulator of recA Expression

et al. 2002

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IRS24 is a DNA damage-sensitive strain of Deinococcus radiodurans strain 302 carrying a mutation in an uncharacterized locus designated irrE. Five overlapping cosmids capable of restoring ionizing radiation resistance to IRS24 were isolated from a genomic library. The ends of each cloned insert were sequenced, and these sequences were used to localize irrE to a 970-bp region on chromosome I of D. radiodurans R1. The irrE gene corresponds to coding sequence DR0167 in the R1 genome. The irrE gene encodes a 35,000-Da protein that has no similarity to any previously characterized peptide. The irrE locus of R1 was also inactivated by transposon mutagenesis, and this strain was sensitive to ionizing radiation, UV light, and mitomycin C. Preliminary findings indicate that IrrE is a novel regulatory protein that stimulates transcription of the recA gene following exposure to ionizing radiation.The bacterium Deinococcus radiodurans is known for its tolerance to many DNA-damaging agents, but it is its unusually high resistance to the lethal and mutagenic effects of ionizing radiation that distinguishes this species from other organisms (3,5,17,20,24). Exponential-phase cultures of D. radiodurans R1 survive exposure to gamma radiation at doses as high as 5,000 Gy without loss of viability or evidence of DNA damageinduced mutation (23). A 5,000-Gy dose of gamma radiation should introduce not less than 130 DNA double-strand breaks into each copy of the D. radiodurans R1 genome present within the irradiated cell (6), and direct measurements of ionizing radiation-induced DNA double-strand breaks indicate that D. radiodurans suffers this level of DNA damage (13, 18). The mechanisms responsible for the DNA damage resistance of this species remain unknown.As part of an effort to obtain a better understanding of the ionizing radiation resistance of D. radiodurans R1, this laboratory isolated 41 ionizing radiation-sensitive (IRS1 to -41) derivatives of D. radiodurans 302 (uvrA1) (29). Strain 302 is approximately 50 times more mutable than the wild-type R1 strain following N-methyl-

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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The IrrE Protein of Deinococcus radiodurans R1 Is a Novel Regulator of recA Expression

et al. 2002

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“…It has therefore been established that D. radiodurans possesses a DNA damage response mechanism. Additionally, analysis of DNAdamage-sensitive strains IRS24 (Mattimore et al, 1995) and KH840 (Kitayama & Matsuyama, 1975) identified a novel regulatory protein (DR0167; PprI protein, also called IrrE protein) that plays a role in regulating recA and pprA gene expression following c-irradiation (Earl et al, 2002;Hua et al, 2003;Ohba et al, 2005). Furthermore, in a previous study we identified the radiation-responsive minimal promoter of the pprA gene encoding the novel radiation-inducible protein PprA, which plays a critical role in radioresistance of D. radiodurans (Narumi et al, 2004;Ohba et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Down-regulation of radioresistance by LexA2 in Deinococcus radiodurans

et al. 2006

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The extremely radioresistant bacterium Deinococcus radiodurans contains two LexA homologues (LexA1 and LexA2) that are possible transcriptional regulators associated with the DNA damage response. In this study, resequencing revealed that there was an additional cytosine nucleotide (nucleotide position 612) in the D. radiodurans lexA2 gene. Purified LexA2 possessed proteolytic activity that could be stimulated by RecA. In an effort to gain an insight into the role of LexA2 in the radiation response mechanism, recA, lexA1 and lexA2 disruptant strains were generated and investigated. The intracellular level of RecA increased in lexA1 and lexA2 disruptant strains following γ-irradiation as in the wild-type strain. These results indicated that the two LexA homologues did not possess functional overlap regarding the induction of RecA. The lexA2 disruptant strains exhibited a much higher resistance to γ-rays than the wild-type strain. Furthermore, a luciferase assay showed that pprA promoter activation was enhanced in the lexA2 disruptant strain following γ-irradiation. The pprA gene encoding the novel radiation-inducible protein PprA plays a critical role in the radioresistance of D. radiodurans. The increase in radioresistance of the lexA2 disruptant strain is explained in part by the enhancement of pprA promoter activation.

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Deinococcus

Battista¹,

Rainey²

2015

Bergey's Manual of Systematics of Archaea and Bacteria

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Dei.no.coc' cus . Gr. adj. deinos strange or unusual; Gr. n. kokkos a grain or berry; M.L. masc. n. Deinococcus unusual coccus. “Deinococcus‐Thermus” / Deinococci / Deinococcales / Deinococcaceae / Deinococcus Deinococcus strains form either spherical cells 0.5–3.5 µm in diameter, or rods 0.6–1.2 µm wide × 1.5–4.0 µm long. Spherical cells form pairs or tetrads and appear larger than other cocci. Species are mesophilic or thermophilic , with optimum growth temperatures of 25–35°C or 45–50°C, respectively. With the exception of D. grandis , all species stain Gram‐positive. Nonmotile , without a differentiated resting stage. Aerobic, catalase is produced . Several distinct cell wall layers are visible by electron microscopy of sections and an outer membrane is included. The peptidoglycan is type A3β and contains l ‐ ornithine. Menaquinone 8 ( MK‐8 ) is the predominant respiratory quinone. The phospholipids do not include phosphatidylglycerol, diphosphatidylglycerol, or derivatives. Fatty acids are saturated or monounsaturated. Unbranched 15, 16, and 17 carbon acids predominate in mesophilic species, branched 16 and 17 carbon acids in thermophilic species. Chemoorganotrophic ; metabolism is respiratory. May be proteolytic. All natural isolates are ionizing‐radiation resistant . The habitat of the mesophilic species is not defined, thermophilic species are found in hot springs. The mol % G + C of the DNA is : 62–70. Type species : Deinococcus radiodurans Brooks and Murray 1981, 354.

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Genetic characterization of forty ionizing radiation-sensitive strains of Deinococcus radiodurans: linkage information from transformation

Cited by 44 publications

References 19 publications

The IrrE Protein of Deinococcus radiodurans R1 Is a Novel Regulator of recA Expression

The IrrE Protein of Deinococcus radiodurans R1 Is a Novel Regulator of recA Expression

Down-regulation of radioresistance by LexA2 in Deinococcus radiodurans

Deinococcus

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