Solovyan V T, Andreyev I O
Institute of Molecular Biology and Genetics, Academy of Sciences of Ukraine, Kiev, Ukraine.
Acta Biochim Pol. 1995;42(2):201-4.
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.
