Superhelical DNA of polytene chromosomes Chironomus thummi
DOI:
https://doi.org/10.7124/bc.00021EAbstract
The fluorescent micromethod of measurement of DNA superhelical density a in solutions gels o r chromosomes is proposed. EtBr intercalation is used to equalize the EtBr-binding properties of the supercoiled and nicked DNA molecules. The number of 1.84÷1.88 left turns of DNA molecule per nucleosome is estimated from the measured value – σ = 0.094 for the nucleoids of Chironomus thummi polytene chromosomes. Experimental data indicate that about 3÷6 % of DNA in the nucleoids adopts non-canonical forms when – σ>0.06.References
Bauer WR. Structure and reactions of closed duplex DNA. Annu Rev Biophys Bioeng. 1978;7:287-313.
Filippovich IV, Sorokina NI. Supercoiled DNA of the cell nucleus. Usp Sovrem Biol. 1983; 95(2):163-80.
Fisher LM. DNA supercoiling and gene expression. Nature. 1984 Feb 23-29;307(5953):686-7.
Gragerob AI, Mirkin SM. Influence of DNA superhelicity on the major genetic processes in prokaryotes. Mol Biol (Mosk). 1980;14(1):8-34.
Gruzdev AD, Belaia AN. The influence of hydrogen-ion concentration, tonicity and ionic strength of solutions on the size of polytene chromosomes. Tsitologiia. 1968;10(3):297-305.
Maniatis T, Fritsch EF, Sambrook J. Molecular cloning - a laboratory manual. New York, Cold Spring Harbor, 1982; 545 p.
Gruzdev AD, Kishchenko GP. Fluorescence polarization of stretched polytene chromosomes stained with acridine orange. Biophys Struct Mech. 1978;4(2):97-110.
Hsieh TS, Wang JC. Thermodynamic properties of superhelical DNAs. Biochemistry. 1975;14(3):527-35.
Bauer W, Vinograd J. Interaction of closed circular DNA with intercalative dyes. II. The free energy of superhelix formation in SV40 DNA. J Mol Biol. 1970;47(3):419-35.
Scatchard G. The attractions of proteins for small molecules and ions. Ann NY Acad Sci. 1949; 51(4):660-72.
Finch JT, Lutter LC, Rhodes D, Brown RS, Rushton B, Levitt M, Klug A. Structure of nucleosome core particles of chromatin. Nature. 1977;269(5623):29-36.
Prunell A, Kornberg RD, Lutter L, Klug A, Levitt M, Crick FH. Periodicity of deoxyribonuclease I digestion of chromatin. Science. 1979;204(4395):855-8.
Nordheim A, Rich A. Negatively supercoiled simian virus 40 DNA contains Z-DNA segments within transcriptional enhancer sequences. Nature. 1983 Jun 23-29;303(5919):674-9.
Lyamichev VI, Panyutin IG, Frank-Kamenetskii MD. Evidence of cruciform structures in superhelical DNA provided by two-dimensional gel electrophoresis. FEBS Lett. 1983;153(2):298-302.
Frank-Kamenetskii MD, Vologodskii AV. Thermodynamics of the B-Z transition in superhelical DNA. Nature. 1984 Feb 2-8;307(5950):481-2.
Nickol JM, Felsenfeld G. DNA conformation at the 5' end of the chicken adult beta-globin gene. Cell. 1983;35(2 Pt 1):467-77.
Gorovsky MA, Woodard J. Histone content of chromosomal loci active and inactive in RNA synthesis. J Cell Biol. 1967;33(3):723-8.
