<i>Deinococcus radiodurans</i>: What Belongs to the Survival Kit?

Blasius, Melanie; Sommer, Suzanne; Hübscher, Ulrich

doi:10.1080/10409230802122274

Cited by 212 publications

(144 citation statements)

References 175 publications

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“…Although there is still a lack of in vivo evidence linking the HU protein of D. radiodurans to radiation resistance, the unique preferential binding of the N terminus to four-way DNA junctions coupled to an effective DNA repair system during recombination events in D. radiodurans are highly suggestive of the role of the Nterminus HU protein in radiation survival (Ghosh & Grove, 2006;Blasius et al, 2008). Chromatin organization and radiation survival in G. obscuriglobus have been linked to an effective DNA repair mechanism (Lieber et al, 2009).…”

Section: Possible Role In Dna Repair?mentioning

confidence: 99%

Making heads or tails of the HU proteins in the planctomycete Gemmata obscuriglobus

2011

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Gemmata obscuriglobus has a highly condensed nucleoid which is implicated in its resistance to radiation. However, the mechanisms by which such compaction is achieved, and the proteins responsible, are still unknown. Here we have examined the genome of G. obscuriglobus for the presence of proteins homologous to those that have been associated with nucleoid condensation. We found two different proteins homologous to the bacterial nucleoid-associated protein HU, one with an N-terminal and one with a C-terminal extension relative to the amino acid sequence of the HU found in Escherichia coli. Sequence analysis revealed that one of these HU homologues represents a novel type with a high number of prolines in its C-terminal extension, whereas the other one has motifs similar to the N terminus of the HU homologue from the radio-resistant bacterium Deinococcus radiodurans. The occurrence of two such HU homologue proteins with these two different terminal extensions in one organism appears to be unique among the Bacteria. INTRODUCTIONArchitectural chromosomal proteins are best known for their role in the compaction of DNA in a cell. The compaction of the nucleoid is an important cellular process in all living cells, and is achieved via a combination or the single mode of action of bending, wrapping and bridging DNA. The architectural proteins are apparently functionally conserved but share neither sequence nor structural similarity (Luijsterburg et al., 2008). In eukaryotes, a massive reduction in volume of the genome is achieved predominantly via the action of having the DNA wrapped around histone complexes at specific regions called histone-fold domains (Luger et al., 1997). In bacteria, several proteins work in tandem to condense the bacterial nucleoid (Azam & Ishihama, 1999;Luijsterburg et al., 2006;Dillon & Dorman, 2010). Some of these proteins, such as the HU protein and histone-like nucleoid structuring protein (HN-S), have histone-like characteristics such as a similar amino acid composition and the ability to condense DNA into a densely packed nucleoid structure upon overexpression of the protein (Rouvière-Yaniv & Gros, 1975; Rouvière-Yaniv et al., 1979; Spurio et al., 1992).Members of the phylum Planctomycetes within the domain Bacteria have many uncommon features, both structural and molecular. All planctomycetes examined display a compartmentalized cell plan as well as a much more condensed nucleoid compared with most other bacteria, and in the case of Gemmata obscuriglobus, the nucleoid is further bounded within a double-membrane envelope (Fuerst & Webb, 1991;Lindsay et al., 2001;Fuerst, 2005). A recent study of G. obscuriglobus has revealed resistance to UV radiation 40 times greater than that of Escherichia coli, and this increased tolerance is proposed to be associated with a highly effective DNA repair mechanism at least partly due to the condensed chromatin structure in this species (Lieber et al., 2009). However, the identity and mechanism of the proteins responsible for the condensation of the nucle...

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Section: Possible Role In Dna Repair?mentioning

confidence: 99%

Making heads or tails of the HU proteins in the planctomycete Gemmata obscuriglobus

2011

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“…The bacterium Deinococcus radiodurans and other members of the Deinococcaceae are famous for their extraordinary tolerance towards high doses of gamma and UV radiation or long periods of desiccation. This extreme tolerance is linked to the ability of these bacteria to accurately repair massive DNA damage, including hundreds of doublestrand DNA breaks and thousands of other lesions (Cox and Battista, 2005;Blasius et al, 2008). It has been proposed that DNA repair in Deinococcus could be facilitated by a high intracellular Mn/Fe ratio that prevents oxidation of proteins (Daly et al, 2007) and by a highly condensed nucleoid that may restrict diffusion of DNA fragments generated by irradiation (Zimmerman and Battista, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…The genomes of D. radiodurans and Deinococcus geothermalis contain homologues of most Escherichia coli DNA repair genes (Makarova et al, 2001;2007), and several of these contribute to various extents to gamma and/or UV radiation tolerance (Blasius et al, 2008). The recombinational repair protein RecA is absolutely required for extreme radiation tolerance in D. radiodurans (Gutman et al, 1994;Bonacossa de Almeida et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Mutagenic lesion bypass and two functionally different RecA proteins in Deinococcus deserti

Dulermo

Fochesato

Blanchard

et al. 2009

Molecular Microbiology

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SummaryRecA is essential for extreme radiation tolerance in Deinococcus radiodurans. Interestingly, Sahara bacterium Deinococcus deserti has three recA genes (recAC, recAP1, recAP3) that code for two different RecA proteins (RecAC, RecAP). Moreover, and in contrast to other sequenced Deinococcus species, D. deserti possesses homologues of translesion synthesis (TLS) DNA polymerases, including ImuY and DnaE2. Together with a lexA homologue, imuY and dnaE2 form a gene cluster similar to a widespread RecA/LexA-controlled mutagenesis cassette. After having developed genetic tools, we have constructed mutant strains to characterize these recA and TLS polymerase genes in D. deserti. Both RecAC and RecAP are functional and allow D. deserti to survive, and thus repair massive DNA damage, after exposure to high doses of radiation. D. deserti is mutable by UV, which requires ImuY, DnaE2 and RecAC, but not RecAP. RecAC, but not RecAP, facilitates induced expression of imuY and dnaE2 following UV exposure. We propose that the extra recAP1 and recAP3 genes may provide higher levels of RecA protein for efficient error-free repair of DNA damage, without further increasing error-prone lesion bypass by ImuY and DnaE2, whereas limited TLS may contribute to adaptation to harsh conditions by generating genetic variability.

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“…Deinococcus radiodurans R1 is characterized by its extraordinary tolerance to radiation, desiccation and other DNA-damaging agents (Battista, 2000;Makarova et al, 2001;Blasius et al 2008). A DNA double-strand break produced by these abiotic agents is repaired in two phases.…”

Section: Introductionmentioning

confidence: 99%

DNA polymerase X from Deinococcus radiodurans implicated in bacterial tolerance to DNA damage is characterized as a short patch base excision repair polymerase

Khairnar

Misra

2009

Microbiology

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The Deinococcus radiodurans R1 genome encodes an X-family DNA repair polymerase homologous to eukaryotic DNA polymerase b. The recombinant deinococcal polymerase X (PolX) purified from transgenic Escherichia coli showed deoxynucleotidyltransferase activity. Unlike the Klenow fragment of E. coli, this enzyme showed short patch DNA synthesis activity on heteropolymeric DNA substrate. The recombinant enzyme showed 59-deoxyribose phosphate (59-dRP) lyase activity and base excision repair function in vitro, with the help of externally supplied glycosylase and AP endonuclease functions. A polX disruption mutant of D. radiodurans expressing 59-dRP lyase and a truncated polymerase domain was comparatively less sensitive to c-radiation than a polX deletion mutant. Both mutants showed higher sensitivity to hydrogen peroxide. Excision repair mutants of E. coli expressing this polymerase showed functional complementation of UV sensitivity. These results suggest the involvement of deinococcal polymerase X in DNA-damage tolerance of D. radiodurans, possibly by contributing to DNA double-strand break repair and base excision repair.

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Deinococcus radiodurans: What Belongs to the Survival Kit?

Cited by 212 publications

References 175 publications

Making heads or tails of the HU proteins in the planctomycete Gemmata obscuriglobus

Making heads or tails of the HU proteins in the planctomycete Gemmata obscuriglobus

Mutagenic lesion bypass and two functionally different RecA proteins in Deinococcus deserti

DNA polymerase X from Deinococcus radiodurans implicated in bacterial tolerance to DNA damage is characterized as a short patch base excision repair polymerase

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