Structural domains of plant nuclear DNA as a constitutive component of the topoisomerase II/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.
Solovyan
V T
VT
Institute of Molecular Biology and Genetics, Academy of Sciences of Ukraine, Kiev, Ukraine.
Andreyev
I O
IO
D002467:Cell Nucleus / Q000187:drug effects / Q000235:genetics*; D004250:DNA Topoisomerases, Type II / Q000737:chemistry* / Q000187:drug effects; D018744:DNA, Plant / Q000737:chemistry* / Q000187:drug effects; D019684:Magnoliopsida / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D009690:Nucleic Acid Conformation; D013713:Teniposide / Q000494:pharmacology
D018744:DNA, Plant; D013713:Teniposide; D004250:DNA Topoisomerases, Type II