Cooperative damage recognition by UvrA and UvrB: Identification of UvrA residues that mediate DNA binding

Croteau, Deborah L.; DellaVecchia, Matthew J.; Perera, Lalith; Houten, Bennett Van

doi:10.1016/j.dnarep.2007.11.013

Cited by 30 publications

(31 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fifty L1 nematodes were loaded into each well of a 96-well plate (4–6 wells per strain per treatment) using the COPAS Biosort. The volume of each well was then brought to 100μl with EPA H 2 O (Weber 1991), UVC-killed UvrA (UVC sensitive E. coli strain due to a lack of nucleotide excision repair (Croteau et al 2008)), and toxicant. With the exception of sodium arsenite (Ricca Chemical Company), all chemicals were purchased from Sigma-Aldrich (St. Louis, MO).…”

Section: Methodsmentioning

confidence: 99%

Deficiencies in mitochondrial dynamics sensitize Caenorhabditis elegans to arsenite and other mitochondrial toxicants by reducing mitochondrial adaptability

et al. 2017

View full text Add to dashboard Cite

Mitochondrial fission, fusion, and mitophagy are interlinked processes that regulate mitochondrial shape, number, and size, as well as metabolic activity and stress response. The fundamental importance of these processes is evident in the fact that mutations in fission (DRP1), fusion (MFN2, OPA1), and mitophagy (PINK1, PARK2) genes can cause human disease (collectively >1/10,000). Interestingly, however, the age of onset and severity of clinical manifestations varies greatly between patients with these diseases (even those harboring identical mutations), suggesting a role for environmental factors in the development and progression of certain mitochondrial diseases. Using the model organism Caenorhabditis elegans, we screened ten mitochondrial toxicants (2, 4-dinitrophenol, acetaldehyde, acrolein, aflatoxin B1, arsenite, cadmium, cisplatin, doxycycline, paraquat, rotenone) for increased or decreased toxicity in fusion (fzo-1, eat-3)-, fission (drp-1)-, and mitophagy (pdr-1, pink-1)-deficient nematodes using a larval growth assay. In general, fusion-deficient nematodes were the most sensitive to toxicants, including aflatoxin B1, arsenite, cisplatin, paraquat, and rotenone. Because arsenite was particularly potent in fission- and fusion-deficient nematodes, and hundreds of millions of people are chronically exposed to arsenic, we investigated the effects of these genetic deficiencies on arsenic toxicity in more depth. We found that deficiencies in fission and fusion sensitized nematodes to arsenite-induced lethality throughout aging. Furthermore, low-dose arsenite, which acted in a “mitohormetic” fashion by increasing mitochondrial function (in particular, basal and maximal oxygen consumption) in wild-type nematodes by a wide range of measures, exacerbated mitochondrial dysfunction in fusion-deficient nematodes. Analysis of multiple mechanistic changes suggested that disruption of pyruvate metabolism and Krebs cycle activity underlie the observed arsenite-induced mitochondrial deficits, and these disruptions are exacerbated in the absence of mitochondrial fusion. This research demonstrates the importance of mitochondrial dynamics in limiting arsenite toxicity by permitting mitochondrial adaptability. It also suggests that individuals suffering from deficiencies in mitodynamic processes may be more susceptible to the mitochondrial toxicity of arsenic and other toxicants.

show abstract

Section: Methodsmentioning

confidence: 99%

Deficiencies in mitochondrial dynamics sensitize Caenorhabditis elegans to arsenite and other mitochondrial toxicants by reducing mitochondrial adaptability

et al. 2017

View full text Add to dashboard Cite

show abstract

“…63,64 As shown by the E. coli UvrABC endonuclease that is involved in NER, the UvrA protein recognizes the DNA damage, and UvrB bends the DNA before the UvrB-UvrC complex catalyzes DNA backbone cleavage. 65,66 Similarly, SPL may have to team with other protein(s) for damage recognition and repair in vivo . These proteins would be missing in our in vitro studies, which may result in the low SPL activity observed.…”

Section: Discussionmentioning

confidence: 99%

Spore photoproduct within DNA is a surprisingly poor substrate for its designated repair enzyme—The spore photoproduct lyase

et al. 2017

View full text Add to dashboard Cite

DNA repair enzymes typically recognize their substrate lesions with high affinity to ensure efficient lesion repair. In UV irradiated endospores, a special thymine dimer, 5-thyminyl-5,6-dihydrothymine, termed the spore photoproduct (SP), is the dominant DNA photolesion, which is rapidly repaired during spore outgrowth mainly by spore photoproduct lyase (SPL) using an unprecedented protein-harbored radical transfer process. Surprisingly, our in vitro studies using SP-containing short oligonucleotides, pUC 18 plasmid DNA, and E. coli genomic DNA found that they are all poor substrates for SPL in general, exhibiting turnover numbers of 0.01–0.2 min−1. The faster turnover numbers are reached under single turnover conditions, and SPL activity is low with oligonucleotide substrates at higher concentrations. Moreover, SP-containing oligonucleotides do not go past one turnover. In contrast, the dinucleotide SP TpT exhibits a turnover number of 0.3 ~ 0.4 min−1, and the reaction may reach up to 10 turnovers. These observations distinguish SPL from other specialized DNA repair enzymes. To the best of our knowledge, SPL represents an unprecedented example of a major DNA repair enzyme that cannot effectively repair its substrate lesion within the normal DNA conformation adopted in growing cells. Factors such as other DNA binding proteins, helicases or an altered DNA conformation may cooperate with SPL to enable efficient SP repair in germinating spores. Therefore, both SP formation and SP repair are likely to be tightly controlled by the unique cellular environment in dormant and outgrowing spore-forming bacteria, and thus SP repair may be extremely slow in non-spore-forming organisms.

show abstract

“…Briefly, 1.5ml arsenite (0, 50, 250, 500μM) or AfB 1 (0, 5, 25, 50μM in 1% DMSO) was added to the surface of peptone-free, control or EtBr (1μg/ml) K-agar plates and allowed to dry. K-agar plates were then seeded with 300μl 20X concentrated UVC-killed UvrA bacteria (UV-sensitive strain, due to lack of NER [29]). Nematodes were transferred daily to freshly prepared plates.…”

Section: Methodsmentioning

confidence: 99%

Effects of reduced mitochondrial DNA content on secondary mitochondrial toxicant exposure in Caenorhabditis elegans

Luz

Meyer

2016

Mitochondrion

View full text Add to dashboard Cite

The mitochondrial genome (mtDNA) is intimately linked to cellular and organismal health, as demonstrated by the fact that mutations in and depletion of mtDNA result in severe mitochondrial disease in humans. However, cells contain hundreds to thousands of copies of mtDNA, which provides genetic redundancy, and creates a threshold effect in which a large percentage of mtDNA must be lost prior to clinical pathogenesis. As certain pharmaceuticals and genetic mutations can result in depletion of mtDNA, and as many environmental toxicants target mitochondria, it is important to understand whether reduced mtDNA will sensitize an individual to toxicant exposure. Here, using ethidium bromide (EtBr), which preferentially inhibits mtDNA replication, we reduced mtDNA 35-55% in the in vivo model organism Caenorhabditis elegans. Chronic, lifelong, low-dose EtBr exposure did not disrupt nematode development or lifespan, and induced only mild alterations in mitochondrial respiration, while having no effect on steady-state ATP levels. Next, we exposed nematodes with reduced mtDNA to the known and suspected mitochondrial toxicants aflatoxin B1, arsenite, paraquat, rotenone or ultraviolet C radiation (UVC). EtBr pre-exposure resulted in mild sensitization of nematodes to UVC and arsenite, had no effect on AfB1 and paraquat, and provided some protection from rotenone toxicity. These mixed results provide a first line of evidence suggesting that reduced mtDNA content may sensitize an individual to certain environmental exposures.

show abstract

Cooperative damage recognition by UvrA and UvrB: Identification of UvrA residues that mediate DNA binding

Cited by 30 publications

References 49 publications

Deficiencies in mitochondrial dynamics sensitize Caenorhabditis elegans to arsenite and other mitochondrial toxicants by reducing mitochondrial adaptability

Deficiencies in mitochondrial dynamics sensitize Caenorhabditis elegans to arsenite and other mitochondrial toxicants by reducing mitochondrial adaptability

Spore photoproduct within DNA is a surprisingly poor substrate for its designated repair enzyme—The spore photoproduct lyase

Effects of reduced mitochondrial DNA content on secondary mitochondrial toxicant exposure in Caenorhabditis elegans

Contact Info

Product

Resources

About