DNAs with unusual properties revealed by field inversion gel electrophoresis of agarose-encapsulated DNA from mammalian cells.
Distinct DNA fractions (fr-DNAs), moving separately from bulk DNA, were revealed by field inversion gel electrophoresis of DNA from intact cells lysed and deproteinized in agarose plugs. These fr-DNAs (approximately 2% of the total DNA) were ubiquitously present in nuclei of all mammalian cells studied, including human normal and tumor tissues, and showed a typical electrophoretic pattern (three bands with constant mobilities termed a-, b-, and c-DNA). Characteristic mobility shifts induced by gamma irradiation of a- and b-DNAs suggest their non-linear conformation. In fact, electron microscopy of a- and b-DNAs from Namalwa cells revealed rosette-like structures stabilized by a central protease-resistant knob. Comparative PCR analysis revealed qualitative differences between genomic fingerprints of a- and b-DNAs on the one hand and chromosomal DNA on the other. The results obtained suggest that fr-DNAs originate either from some specific chromatin regions due to non-random cleavages or from an autonomous intranuclear structure, not identified as yet.
Institute of Carcinogenesis, Cancer Research Center, Moscow, Russia.
T
T
Sukhova
V
V
Popenko
O
O
Serdjuk
R
R
Alekhina
I
I
Botezatu
V
V
Shelepov
A
A
Lichtenstein
D017209:Apoptosis / Q000235:genetics; D005591:Chemical Fractionation; D053938:DNA Fragmentation / Q000235:genetics; D004273:DNA, Neoplasm / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D016521:Electrophoresis, Gel, Pulsed-Field; D006801:Humans; D008854:Microscopy, Electron; D009690:Nucleic Acid Conformation; D016133:Polymerase Chain Reaction; D012685:Sepharose; D014407:Tumor Cells, Cultured / Q000737:chemistry / Q000166:cytology
D004273:DNA, Neoplasm; D012685:Sepharose