Asynchronously Replicating Eu/Heterochromatic Regions Shape Chromosome Damageстатья из журнала
Аннотация: In order to shed more light on the influence of DNA replication on the formation and distribution of chromosome aberrations, breakpoints (BP) produced by UV-C and <i>Alu</i>I were assigned either to the early replicating short euchromatic arm (Xp<sub>e</sub>) or to the late replicating long heterochromatic arm (Xq<sub>h</sub>) of the Chinese hamster (CHO9) X chromosome. Early (ES) or late (LS) S-phase cells were assessed by pulse incorporating the base analogue 5-bromo-2′-deoxyuridine (BrdU) immediately after UV-C irradiation (30 J/m<sup>2</sup>) or <i>Alu</i>I (20 U) poration followed by BrdU immunodetection with FITC-tagged antibodies in metaphase spreads. Short (30 s) UV-C exposures (1 J/m<sup>2</sup>/s) induced BP preferentially in Xq<sub>h</sub> in LS cells and a random distribution of BP along Xp<sub>e</sub> and Xq<sub>h</sub> in ES cells. However, BP induced by long (5 min) UV-C exposures (0.1 J/m<sup>2</sup>/s) clustered according to arm replication time (Xp<sub>e</sub> during ES and Xq<sub>h</sub> along LS). Giemsa-stained metaphases showed elevated frequencies of UV-C induced chromatid-type aberrations and gaps, especially in cells exposed to longer UV-C irradiation. BP induced by <i>Alu</i>I clustered in Xp<sub>e</sub> in ES but distributed randomly during LS. In contrast to UV-C, <i>Alu</i>I did not produce an increase in the yield of gaps, neither in ES nor in LS cells. Putative mechanisms underlying the observed distributions of chromosome damage in replicating CHO9 cells exposed to UV-C and <i>Alu</i>I are discussed.
Год издания: 2010
Издательство: Karger Publishers
Источник: Cytogenetic and Genome Research
Ключевые слова: DNA Repair Mechanisms, Carcinogens and Genotoxicity Assessment, DNA and Nucleic Acid Chemistry
Другие ссылки: Cytogenetic and Genome Research (HTML)
PubMed (HTML)
PubMed (HTML)
Открытый доступ: closed
Том: 128
Выпуск: 1-3
Страницы: 111–117