Back to Search
Start Over
Distribution of breakpoints induced by etoposide and X-rays along the CHO X chromosome.
- Source :
-
Cytogenetic and genome research [Cytogenet Genome Res] 2004; Vol. 104 (1-4), pp. 182-7. - Publication Year :
- 2004
-
Abstract
- SORB (selected observed residual breakpoints) induced by ionizing radiation or endonucleases are often non-randomly distributed in mammalian chromosomes. However, the role played by chromatin structure in the localization of chromosome SORB is not well understood. Anti-topoisomerase drugs such as etoposide are potent clastogens and unlike endonucleases or ionizing radiation, induce DNA double-strand breaks (DSB) by an indirect mechanism. Topoisomerase II (Topo II) is a main component of the nuclear matrix and the chromosome scaffold. Since etoposide leads to DSB by influencing the activity of Topo II, this compound may be a useful tool to study the influence of the chromatin organization on the distribution of induced SORB in mammalian chromosomes. In the present work, we compared the distribution of SORB induced during S-phase by etoposide or X-rays in the short euchromatic and long heterochromatic arms of the CHO9 X chromosome. The S-phase stage (early, mid or late) at which CHO9 cells were exposed to etoposide or X-rays was marked by incorporation of BrdU during treatments and later determined by immunolabeling of metaphase chromosomes with an anti-BrdU FITC-coupled antibody. The majority of treated cells were in late S-phase during treatment either with etoposide or X-rays. SORB induced by etoposide mapped preferentially to Xq but random localization was observed for SORB produced by X-rays. Possible explanations for the uneven distribution of etoposide-induced breakpoints along Xq are discussed.<br /> (Copyright 2003 S. Karger AG, Basel)
- Subjects :
- Animals
CHO Cells ultrastructure
Chromatids drug effects
Chromatids radiation effects
Chromatids ultrastructure
Chromosome Aberrations
Chromosome Mapping
Cricetinae
Cricetulus
DNA drug effects
DNA radiation effects
DNA Damage
Female
S Phase drug effects
S Phase radiation effects
X Chromosome genetics
X Chromosome ultrastructure
CHO Cells drug effects
CHO Cells radiation effects
Chromosome Breakage
Enzyme Inhibitors toxicity
Etoposide toxicity
Topoisomerase II Inhibitors
X Chromosome drug effects
X Chromosome radiation effects
Subjects
Details
- Language :
- English
- ISSN :
- 1424-859X
- Volume :
- 104
- Issue :
- 1-4
- Database :
- MEDLINE
- Journal :
- Cytogenetic and genome research
- Publication Type :
- Academic Journal
- Accession number :
- 15162035
- Full Text :
- https://doi.org/10.1159/000077486