title: Estimation of circular DNA size using gamma-irradiation and pulsed-field gel electrophoresis.
abstract: A method is described for estimating the size of large circular DNAs found within complex chromosomal DNA preparations. DNAs are treated with low levels of gamma-irradiation, sufficient to introduce a single double-stranded break per circle, and the resulting linear DNA is sized by pulsed-field electrophoresis and blot hybridization. The method is fast, reproducible, and very conveniently applied to the agarose-enclosed chromosomal DNA preparations commonly used in pulsed field electrophoresis.
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: S M
authors.initials: SM
authors.lastname: Beverley
mesh_terms: D000818:Animals; D002021:Buffers; D055598:Chemical Phenomena; D002621:Chemistry; D004247:DNA / Q000528:radiation effects; D004249:DNA Damage; D004270:DNA, Circular / Q000528:radiation effects; D004278:DNA, Superhelical / Q000528:radiation effects; D004351:Drug Resistance / Q000235:genetics; D004586:Electrophoresis / Q000379:methods; D005720:Gamma Rays; D007895:Leishmania tropica / Q000235:genetics; D008727:Methotrexate / Q000494:pharmacology; D012685:Sepharose
chemical_list: D002021:Buffers; D004270:DNA, Circular; D004278:DNA, Superhelical; D004247:DNA; D012685:Sepharose; D008727:Methotrexate