scholarly journals Unique Dynamic Properties of DNA Duplexes Containing Interstrand Cross-Links

Biochemistry ◽  
2011 ◽  
Vol 50 (5) ◽  
pp. 882-890 ◽  
Author(s):  
Joshua I. Friedman ◽  
Yu Lin Jiang ◽  
Paul S. Miller ◽  
James T. Stivers
2017 ◽  
Author(s):  
◽  
Jacqueline Gamboa Varela

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] DNA is the central molecule of biology as it stores the genetic information for cells to properly function and develop. Modifications to the DNA can stall cellular processes such as replication and transcription, leading the cell to recruit repair machinery or in some cases undergo apoptosis. Interstrand cross-links are particularly significant types of DNA damage because they prevent strand separation required for replication and transcription. Cross-links involve bonding between the two strands of DNA. The rate and mechanism of cross-link repair in cells are not well understood. A significant challenge in the study of cross-link repair is the synthesis of chemically well-defined DNA cross-links. Here we summarize the preparation of cross-links derived from the hydrazone formation between a non-natural nucleobase N4-aminocytidine and abasic sites in duplex DNA. The cross-link was generated rapidly and in high yield. The cross-link is stable under physiological conditions but, interestingly, can be reversibly dissociated and re-formed by thermal cycling between 20-80 [degrees]C. We provided evidence that the cross-link is stable against multiple agents and the cross-link is reversible. We used this chemistry to prepare structurally diverse cross-links for the utilization in cross-link repair studies. Overall, we developed a synthetic cross-link that is easily and rapidly prepared from commercially available reagents in high yields, at defined locations in duplexed DNA.


2006 ◽  
Vol 128 (46) ◽  
pp. 14798-14799 ◽  
Author(s):  
François Bergeron ◽  
Vandana K. Nair ◽  
J. Richard Wagner

2007 ◽  
Vol 85 (4) ◽  
pp. 249-256 ◽  
Author(s):  
Christopher James Wilds ◽  
Ernest Palus ◽  
Anne Marietta Noronha

DNA duplexes containing an interstrand cross-link have been synthesized utilizing a bis-3′-O-phosphoramidite deoxythymidine dimer where the N3 atoms are bridged by a butyl linker. With this approach sufficient quantities of high purity cross-linked duplexes are obtained that will enable various biochemical and structural studies to aid in research directed towards understanding the mechanism of interstrand cross-linked DNA repair. This methodology has advantages over a previously reported method to synthesize cross-linked DNA duplexes involving a monophosphoramidite of the same cross-linked thymidine dimer including circumventing the use of costly 5′-O-deoxyphosphoramidites in the assembly of the cross-linked duplex by solid-phase synthesis. This strategy can be employed to produce cross-linked duplexes in which the lesions are engineered to have a directly opposed (1–1) or staggered (1–2 or 2–1) orientations. Biophysical studies of duplexes containing this N3T-butyl-N3T cross-link in staggered 1–2 and 2–1 orientations reveal that both duplexes have a higher Tm than a non-cross-linked duplex suggesting that these linkages do not result in the destabilization of duplex DNA. Circular dichroism spectra of the 1–2 and 2–1 cross-linked duplexes exhibit minor differences from B-form structure, which correlates with molecular modeling studies.Key words: chemically modified oligonucleotides, interstrand cross-link, DNA adduct, DNA repair.


Author(s):  
S.K. Aggarwal

The proposed primary mechanism of action of the anticancer drug cisplatin (Cis-DDP) is through its interaction with DNA, mostly through DNA intrastrand cross-links or DNA interstrand cross-links. DNA repair mechanisms can circumvent this arrest thus permitting replication and transcription to proceed. Various membrane transport enzymes have also been demonstrated to be effected by cisplatin. Glycoprotein alkaline phosphatase was looked at in the proximal tubule cells before and after cisplatin both in vivo and in vitro for its inactivation or its removal from the membrane using light and electron microscopy.Outbred male Swiss Webster (Crl: (WI) BR) rats weighing 150-250g were given ip injections of cisplatin (7mg/kg). Animals were killed on day 3 and day 5. Thick slices (20-50.um) of kidney tissue from treated and untreated animals were fixed in 1% buffered glutaraldehyde and 1% formaldehyde (0.05 M cacodylate buffer, pH 7.3) for 30 min at 4°C. Alkaline phosphatase activity and carbohydrates were demonstrated according to methods described earlier.


1992 ◽  
Vol 12 (9) ◽  
pp. 3689-3698
Author(s):  
W Zhen ◽  
C J Link ◽  
P M O'Connor ◽  
E Reed ◽  
R Parker ◽  
...  

We have studied several aspects of DNA damage formation and repair in human ovarian cancer cell lines which have become resistant to cisplatin through continued exposure to the anticancer drug. The resistant cell lines A2780/cp70 and 2008/c13*5.25 were compared with their respective parental cell lines, A2780 and 2008. Cells in culture were treated with cisplatin, and the two main DNA lesions formed, intrastrand adducts and interstrand cross-links, were quantitated before and after repair incubation. This quantitation was done for total genomic lesions and at the level of individual genes. In the overall genome, the initial frequency of both cisplatin lesions assayed was higher in the parental than in the derivative resistant cell lines. Nonetheless, the total genomic repair of each of these lesions was not increased in the resistant cells. These differences in initial lesion frequency between parental and resistant cell lines were not observed at the gene level. Resistant and parental cells had similar initial frequencies of intrastrand adducts and interstrand cross-links in the dihydrofolate reductase (DHFR) gene and in several other genes after cisplatin treatment of the cells. There was no increase in the repair efficiency of intrastrand adducts in the DHFR gene in resistant cell lines compared with the parental partners. However, a marked and consistent repair difference between parental and resistant cells was observed for the gene-specific repair of cisplatin interstrand cross-links. DNA interstrand cross-links were removed from three genes, the DHFR, multidrug resistance (MDR1), and delta-globin genes, much more efficiently in the resistant cell lines than in the parental cell lines. Our findings suggest that acquired cellular resistance to cisplatin may be associated with increased gene-specific DNA repair efficiency of a specific lesion, the interstrand cross-link.


2005 ◽  
Vol 280 (49) ◽  
pp. 40559-40567 ◽  
Author(s):  
Nianxiang Zhang ◽  
Ramandeep Kaur ◽  
Xiaoyan Lu ◽  
Xi Shen ◽  
Lei Li ◽  
...  

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