scholarly journals Structural domains of plant nuclear DNA as a constitutive component of the topoisomerase II/DNA complex.

1995 ◽  
Vol 42 (2) ◽  
pp. 201-204 ◽  
Author(s):  
V T Solovyan ◽  
I O Andreyev
Keyword(s):  
Dna Fragmentation ◽  
Dna Cleavage ◽  
Topoisomerase Ii ◽  
Nuclear Dna ◽  
Main Property ◽  
Reverse Reaction ◽  
Dna Fragments ◽  
Structural Domains ◽  
Chromatin Folding ◽  
Dna Complex

The treatment of agarose embedded plant nuclei by strong protein denaturants was demonstrated to result in discrete self-fragmentation of intact nuclear DNA. The set of resultant DNA cleavage products involves two main types of DNA fragments sized about 50-100 kb and 300-500 kb, being of the same type in various eukaryotic representatives. The pattern of ordered DNA fragmentation has been shown to be similar both in intact nuclei and in histone-depleted ones thus suggesting that the observed DNA fragments represent preexisting DNA structural domains, corresponding to the higher levels of chromatin folding. The topoisomerase II-specific poison teniposide (VM-26) has been shown to increase the ordered DNA cleavage while the conditions stimulating the topoisomerase II-mediated reverse reaction lead to the reassociation of the cleaved DNA domains. The data presented suggest that the nuclear DNA structural domains are involved in functioning of the topoisomerase II/DNA complex, the main property of which is its ability to mediate the cleavage/reassociation reactions.

scholarly journals DNA cleavage induced by glycation of Cu, Zn-superoxide dismutase

1994 ◽  
Vol 304 (1) ◽  
pp. 219-225 ◽  
Author(s):  
H Kaneto ◽  
J Fujii ◽  
K Suzuki ◽  
H Kasai ◽  
R Kawamori ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Dna Cleavage ◽  
Fenton Reaction ◽  
Reducing Sugars ◽  
Nuclear Dna ◽  
Dna Fragments ◽  
Radical Scavengers ◽  
Isolated Nuclei ◽  
Hydroxy Radical ◽  
Chelating Reagents

Human Cu,Zn-superoxide dismutase (Cu,Zn-SOD) undergoes site-specific and random fragmentation by non-enzymic glycosylation (glycation). Released Cu2+ from the glycated Cu,Zn-SOD probably facilitates a Fenton reaction to convert H2O2 into hydroxy radical, which then participates in the non-specific fragmentation [Ookawara et al. (1992) J. Biol. Chem. 267, 18505-18510]. In the present study, we investigated the effects of glycated Cu,Zn-SOD on cloned DNA fragments and nuclear DNA and analysed the formation of 8-hydroxydeoxyguanosine (8-OH-dG). Incubation of cloned DNA fragments with Cu,Zn-SOD and reducing sugars resulted in cleavage of the DNA. The extent of the cleavage corresponded to the reducing capacity of the sugar. Metal-chelating reagents, EDTA and bathocuproine, and an H2O2 scavenger, catalase, inhibited the DNA cleavage. Hydroxy radical scavengers and aminoguanidine, an inhibitor of glycation, also inhibited the reaction. Moreover, the glycation of Cu,Zn-SOD caused the substantial formation of 8-OH-dG in DNA. When isolated nuclei were incubated with CuCl2 plus H2O2, nuclear DNA cleavage was observed. Incubation of isolated nuclei with Cu,Zn-SOD that had been pre-incubated with glucose also resulted in nuclear DNA cleavage. These results suggest that hydroxy radical is produced through a Fenton reaction by Cu2+ and H2O2 released from the glycated Cu,Zn-SOD, and participates in nuclear DNA cleavage. This mechanism may partly explain the deterioration of organs under diabetic conditions.

A novel antitumor compound, NC-190, induces topoisomerase II-dependent DNA cleavage and DNA fragmentation

1996 ◽  
Vol 38 (1) ◽  
pp. 29-34 ◽  
Author(s):  
T. Yamagishi ◽  
Shiro Nakaike ◽  
Tomotake Ikeda ◽  
Hisao Ikeya ◽  
Susumu Otomo
Keyword(s):  
Dna Fragmentation ◽  
Dna Cleavage ◽  
Topoisomerase Ii ◽  
Antitumor Compound

scholarly journals Local base sequence preferences for DNA cleavage by mammalian topoisomerase II in the presence of amsacrine or teniposide

1991 ◽  
Vol 19 (24) ◽  
pp. 7003-7003 ◽  
Author(s):  
Y. Pommier ◽  
G. Capranico ◽  
A. Orr ◽  
K.W. Kohn
Keyword(s):  
Dna Cleavage ◽  
Topoisomerase Ii ◽  
Base Sequence ◽  
Local Base

scholarly journals Analysis of topoisomerase II-mediated DNA cleavage of the c-myc gene during HL60 differentiation

FEBS Letters ◽  
1993 ◽  
Vol 334 (3) ◽  
pp. 369-372 ◽  
Author(s):  
Jean-François Riou ◽  
Michèle Gabillot ◽  
Guy Riou
Keyword(s):  
Dna Cleavage ◽  
Topoisomerase Ii ◽  
Myc Gene
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