Organization of mammalian chromosomal DNA: supercoiled and folded circular DNA subunits from interphase cell nuclei
- PMID: 735613
Organization of mammalian chromosomal DNA: supercoiled and folded circular DNA subunits from interphase cell nuclei
Abstract
Chinese hamster cells (line V79/4) in the G2 phase of the mitotic cycle were lysed onto neutral sucrose gradients and the released chromosomal DNA was characterized according to its size and shape by sedimentation velocity studies. Using the intercalating agent, ethidium bromide, in the gradients and the induction of DNA single- and double-strand breaks by irradiation, the DNA was proved to be released into the gradient in supercoiled circular subunits whose homogenous size corresponds to 2.8 . 10(9) Dalton. Supercoiling of these DNA subunits was found to be confined to smaller regions sized on the average about 9 . 10(7) Dalton and maintained by folding the DNA into loops. The average superhelix density was determined to be--0.09 turns per 10 base pairs of DNA. The functional aspects of the experimental findings are discussed in terms of replicative and transcriptional units.
Similar articles
-
[Effect of gamma-irradiation and neutrons on DNA-membrane complexes in mammalian cells].Radiobiologiia. 1985 Mar-Apr;25(2):249-52. Radiobiologiia. 1985. PMID: 4001327 Russian.
-
Interaction between ionizing radiation and supercoiled DNA within human tumor cells.Cancer Res. 1991 Aug 1;51(15):3857-61. Cancer Res. 1991. PMID: 1855203
-
[Damage by gamma rays and heavy ions to superhelical structures of nuclear DNA].Radiobiologiia. 1983 Jul-Aug;23(4):435-8. Radiobiologiia. 1983. PMID: 6611866 Russian.
-
Winding anomalies in nuclear DNA from malignant cells. I. Experimental evidence.Arch Geschwulstforsch. 1982;52(7):525-30. Arch Geschwulstforsch. 1982. PMID: 7165487
-
[Changes in DNA supercoiling during differentiation, aging and malignant transformation].Ontogenez. 1983;14(3):227-37. Ontogenez. 1983. PMID: 6348617 Review. Russian.
Cited by
-
Spatial distribution of DNA loop attachment and replicational sites in the nuclear matrix.J Cell Biol. 1984 Nov;99(5):1794-802. doi: 10.1083/jcb.99.5.1794. J Cell Biol. 1984. PMID: 6490720 Free PMC article.
-
Arrangement of chromatin in the nucleus.Hum Genet. 1980 Feb;53(2):131-43. doi: 10.1007/BF00273484. Hum Genet. 1980. PMID: 6987157 Review.
-
Studies of mammalian chromosome replication. II. Evidence for the existence of defined chromosome replicating units.Chromosoma. 1981;83(5):721-41. doi: 10.1007/BF00328530. Chromosoma. 1981. PMID: 7028418
-
Salt-and histone H1-induced structural changes of reconstituted minichromosomes.Nucleic Acids Res. 1979 Aug 10;6(11):3581-97. doi: 10.1093/nar/6.11.3581. Nucleic Acids Res. 1979. PMID: 226940 Free PMC article.
-
Precise localization of the alpha-globin gene cluster within one of the 20- to 300-kilobase DNA fragments released by cleavage of chicken chromosomal DNA at topoisomerase II sites in vivo: evidence that the fragments are DNA loops or domains.Proc Natl Acad Sci U S A. 1991 Oct 1;88(19):8515-9. doi: 10.1073/pnas.88.19.8515. Proc Natl Acad Sci U S A. 1991. PMID: 1656447 Free PMC article.