[Torsional tension in metaphase chromosome DNA].
The torsional tension in DNA of isolated metaphase chromosomes from murine fibroblasts was measured by the microfluorescent method. The method is based on the ability of a fluorescent dye ethidium bromide to compensate for the negative torsional tension in topologically closed DNA by intercalation between DNA base pairs. The value of the relative twist difference delta Tw/Tw = -0.1 was found in a bulk (about 3/4) of unconstrained chromosomal DNA. In interphase nuclei, the torsionally stressed DNA comprises about 15%, with value of delta Tw/Tw = -0.075. We suppose that the tension in chromosomal DNA was created in the prophase stage of mitosis by condensines, the drivers of chromosomal condensation.
Gruzdev
A D
AD
Institute of Cytology and Genetics, Siberian Division, Russian Academy of Sciences, Novosibirsk, Russia.
Kuzin
F E
FE
Galieva
E R
ER
Matveeva
N M
NM
Trunova
S A
SA
Shilov
A G
AG
D000818:Animals; D002875:Chromosomes; D004247:DNA / Q000737:chemistry*; D005347:Fibroblasts / Q000648:ultrastructure; D008677:Metaphase; D051379:Mice; D009690:Nucleic Acid Conformation
D004247:DNA