Abasic DNA structure, reactivity, and recognition

Lhomme, Jean; Constant, Jean‐François; Demeunynck, Martine

doi:10.1002/1097-0282(1999)52:2<65::aid-bip1>3.0.co;2-u

Cited by 199 publications

(151 citation statements)

References 143 publications

Supporting

Mentioning

148

Contrasting

Unclassified

Order By: Relevance

“…Subsequent loss of either the terminal phosphate only or both the phosphate and sugar, each resulting in successively increasing fragment mobility, would account for the other two. Piperidine treatment at 75°C accelerates such backbone cleavage by base-catalyzed ␤-elimination (12,13), thereby allowing detection and quantitation of the accumulated apurinic sites.…”

Section: Specific Backbone Cleavage Is the Results Of Site-specific Dementioning

confidence: 99%

“…To reveal apurinic sites, aliquots were treated with 0.1 M piperidine for 30 min at 75°C to induce base-catalyzed backbone cleavage (12,13). Either a trace amount of end-labeled oligomer was mixed with an unlabeled stock of appropriate concentration before incubation or the aliquots were labeled after the piperidine treatment (both methods yield the same depurination rates).…”

Section: Kinetics Of Depurinationmentioning

confidence: 99%

“…3Ј-End labeling was performed by using terminal deoxytransferase (USB Corp.) (5 units) on Ϸ5 pmol of purified oligomer with Ϸ5 pmol of [␣-32 P]dideoxyATP (Amersham Pharmacia Biotech) (13). The labeled oligomers were purified by denaturing PAGE before use.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Self-catalyzed site-specific depurination of guanine residues within gene sequences

Amosova

Coulter

Fresco

2006

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

A self-catalyzed, site-specific guanine-depurination activity has been found to occur in short gene sequences with a potential to form a stem-loop structure. The critical features of that catalytic intermediate are a 5 -G-T-G-G-3 loop and an adjacent 5 -T⅐A-3 base pair of a short duplex stem stable enough to fix the loop structure required for depurination of its 5 -G residue. That residue is uniquely depurinated with a rate some 5 orders of magnitude faster than that of random ''spontaneous'' depurination. In contrast, all other purine residues in the sequence depurinate at the spontaneous background rate. The reaction requires no divalent cations or other cofactors and occurs under essentially physiological conditions. Such stem-loops can form in duplex DNA under superhelical stress, and their critical sequence features have been found at numerous sites in the human genome. Self-catalyzed stem-loop-mediated depurination leading to flexible apurinic sites may therefore serve some important biological role, e.g., in nucleosome positioning, genetic recombination, or chromosome superfolding.DNA self-catalysis ͉ guanine depurination ͉ stem-loop structure D epurination in DNA has been recognized as a spontaneous form of intracellular DNA damage that affects both G and A residues in an essentially random way (1). In mammalian cells, such damage has been estimated to occur with a k obs of 3 ϫ 10 Ϫ9 min Ϫ1 (2). A complex and elaborate cellular DNA repair machinery has evolved to repair apurinic sites (3, 4). It has long been known that some G residues are more prone to depurination than others (5, 6), and such depurination hot spots have been associated with elevated mutation rates (6, 7). Notwithstanding these insights, notions to account for DNA depurination that go beyond recognition that hydrolysis of the purine-deoxyribose glycosyl bond is acid-catalyzed have not been forthcoming.In the course of studies using a 29-residue single-stranded coding strand fragment encompassing the mutation site of the sickle cell ␤-globin gene (8-10), we found that this 29-nt oligomer as well as its shortened 18-nt segment self-catalyze site-specific depurination of a singular G residue adjacent to the mutation site. In this report, we identify the precise location of the depurination site, the reaction mechanism and its immediate products, the structure of the catalytic intermediate, and some of the sequence requirements and their tolerance for variation within the intermediate. We also note the wide distribution of such putative self-depurinating sequences in the human genome. Results Specific Backbone Cleavage Is the Result of Site-Specific Depurination.It is as a consequence of slow spontaneous backbone cleavage at apurinic sites that the self-catalyzed site-specific depurination we report here was discovered. At the outset, it was observed that this cleavage occurs whether or not 10 Ϫ3 M EDTA is present, indicating that divalent cations are not required for the cleavage. Incubation of the highly purified and homogeneous 29-nt ol...

show abstract

Section: Specific Backbone Cleavage Is the Results Of Site-specific Dementioning

confidence: 99%

Section: Kinetics Of Depurinationmentioning

confidence: 99%

See 1 more Smart Citation

Self-catalyzed site-specific depurination of guanine residues within gene sequences

Amosova

Coulter

Fresco

2006

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…The results, taken together with our previous findings for cultured glioma cells (27), also suggest that Ap endo activity is an attractive target for antiresistance therapies. Low molecular weight compounds have been described that inhibit incision at abasic sites (39,55 …”

Section: Discussionmentioning

confidence: 99%

Apurinic Endonuclease Activity in Adult Gliomas and Time to Tumor Progression after Alkylating Agent-Based Chemotherapy and after Radiotherapy

Bobola

Emond

Blank

et al. 2004

Clinical Cancer Research

View full text Add to dashboard Cite

Results: In a univariate model with Ap endo activity entered as a continuous variable, the hazard ratio (HR) for progression after alkylator therapy in 30 grade III gliomas increased by a factor of 1.061 for every 0.01 increase in activity (P ‫؍‬ 0.013). Adjusting for age, gender, extent of resection, and prior treatment strengthened slightly the association (HR ‫؍‬ 1.094; P ‫؍‬ 0.003). Similarly, the HR for progression after radiotherapy in 44 grade II and III tumors increased by a factor of 1.069 (P ‫؍‬ 0.008). Adjusting for the aforementioned variables had little effect on the association. In contrast, we observed no association between activity and TTP in grade IV gliomas after either alkylator therapy in 34 tumors or radiotherapy in 26 tumors.Conclusions: Our data suggest that Ap endo activity mediates resistance to alkylating agents and radiation and may be a useful predictor of progression after adjuvant therapy in a subset of gliomas.

show abstract

“…It is possible that the rapid depurination of the leinamycin-guanine adduct is the basis of the potent biological activity exhibited by leinamycin [12]. Additionally, AP sites are promptly converted into DNA strand breaks which are also toxic to the cells [13]. Recent studies have also shown that AP sites can form interstrand crosslinks in DNA under physiologically relevant conditions [14].…”

Section: Introductionmentioning

confidence: 99%

Cellular Responses to the DNA Damaging Natural Compound Leinamycin

et al. 2013

View full text Add to dashboard Cite

Leinamycin is a thiol dependent DNA alkylating agent which shows very potent activity against various human cancer cell lines (IC 50 values in the low nanomolar range). This natural compound forms guanine adducts (N7) in DNA which are converted into abasic sites and simultaneously generates Reactive Oxygen Species (ROS), to produce DNA strand breaks in human cancer cells. Our present study shows that leinamycin induces a group of DNA repair and transcription factor genes involved in DNA repair in a MDA-MB-231 human breast cancer cell line, which can mediate chemoresistance to leinamycin. In addition, N-acetylcysteine decreases leinamycin-mediated ROS production while increasing leinamycin mediated apoptotic cell death, without affecting the induction of repair genes. These data indicate that ROS is not a crucial player in leinamycin induced DNA damage and that a precursor of glutathione, N-acetylcysteine, can potentiate leinamycin mediated cytotoxicity by increasing the activation of leinamycin into its DNA reactive form.

show abstract

Abasic DNA structure, reactivity, and recognition

Cited by 199 publications

References 143 publications

Self-catalyzed site-specific depurination of guanine residues within gene sequences

Self-catalyzed site-specific depurination of guanine residues within gene sequences

Apurinic Endonuclease Activity in Adult Gliomas and Time to Tumor Progression after Alkylating Agent-Based Chemotherapy and after Radiotherapy

Cellular Responses to the DNA Damaging Natural Compound Leinamycin

Contact Info

Product

Resources

About