title: Intrachromosomal localization of aberration breakpoints induced by neutrons and gamma rays in Chinese hamster ovary cells.
abstract: Chromosome breakpoints induced by neutrons or gamma rays in Chinese hamster ovary cells were mapped to Giemsa-light or Giemsa-dark bands or to band junctions. Radiation-induced breakpoints were found to be distributed nonrandomly according to chromosome or band length. More than 60% of the breakpoints were localized in G-light bands. A group of 13 bands which corresponded to only 7% of the total chromosome length contained 22% of the breakpoints produced by neutrons and 14% of those induced by gamma rays. Seven of these 13 bands are also preferentially damaged by AluI, BamHI and DNase I as reported previously. The results indicate that chromatin and nuclear structure may play a role in the distribution of breakpoints produced by ionizing radiation and endonucleases.
authors.affiliation: Division of Human Cytogenetics and Quantitative Microscopy, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.
authors.forename: W
authors.initials: W
authors.lastname: Martínez-López
authors.forename: E M
authors.initials: EM
authors.lastname: Boccardo
authors.forename: G A
authors.initials: GA
authors.lastname: Folle
authors.forename: V
authors.initials: V
authors.lastname: Porro
authors.forename: G
authors.initials: G
authors.lastname: Obe
mesh_terms: D000818:Animals; D016466:CHO Cells; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D006224:Cricetinae; D003412:Cricetulus; D015245:Deoxyribonuclease BamHI / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D005720:Gamma Rays; D009502:Neutrons; D015183:Restriction Mapping; D016196:S Phase
chemical_list: D015245:Deoxyribonuclease BamHI; C024669:endodeoxyribonuclease AluI; D003850:Deoxyribonuclease I; D015252:Deoxyribonucleases, Type II Site-Specific