TY - JOUR
T1 - Proximity within interphase chromosome contributes to the breakpoint distribution in radiation-induced intrachromosomal exchanges
AU - Zhang, Ye
AU - Uhlemeyer, Jimmy
AU - Hada, Megumi
AU - Asaithamby, A.
AU - Chen, David J.
AU - Wu, Honglu
N1 - Funding Information:
This work was supported by the NASA Space Radiation Health Program.
PY - 2014
Y1 - 2014
N2 - Previously, we reported that breaks involved in chromosome aberrations were clustered in several regions of chromosome 3 in human mammary epithelial cells after exposures to either low- or high-LET radiation. In particular, breaks in certain regions of the chromosome tended to rejoin with each other to form an intrachromosome exchange event. This study tests the hypothesis that proximity within a single chromosome in interphase cell nuclei contributes to the distribution of radiation-induced chromosome breaks. Chromosome 3 in G1 human mammary epithelial cells was hybridized with the multicolor banding in situ hybridization (mBAND) probes that distinguish the chromosome in six differently colored regions, and the location of these regions was measured with a laser confocal microscope. Results of the study indicated that, on a multi-mega base pair scale of the DNA, the arrangement of chromatin was non-random. Both telomere regions tended to be located towards the exterior of the chromosome domain, whereas the centromere region towards the interior. In addition, the interior of the chromosome domain was preferentially occupied by the p-arm of the chromatin, which is consistent with our previous finding of intrachromosome exchanges involving breaks on the p-arm and in the centromere region of chromosome 3. Other factors, such as the fragile sites in the 3p21 band and gene regulation, may also contribute to the breakpoint distribution in radiation-induced chromosome aberrations.
AB - Previously, we reported that breaks involved in chromosome aberrations were clustered in several regions of chromosome 3 in human mammary epithelial cells after exposures to either low- or high-LET radiation. In particular, breaks in certain regions of the chromosome tended to rejoin with each other to form an intrachromosome exchange event. This study tests the hypothesis that proximity within a single chromosome in interphase cell nuclei contributes to the distribution of radiation-induced chromosome breaks. Chromosome 3 in G1 human mammary epithelial cells was hybridized with the multicolor banding in situ hybridization (mBAND) probes that distinguish the chromosome in six differently colored regions, and the location of these regions was measured with a laser confocal microscope. Results of the study indicated that, on a multi-mega base pair scale of the DNA, the arrangement of chromatin was non-random. Both telomere regions tended to be located towards the exterior of the chromosome domain, whereas the centromere region towards the interior. In addition, the interior of the chromosome domain was preferentially occupied by the p-arm of the chromatin, which is consistent with our previous finding of intrachromosome exchanges involving breaks on the p-arm and in the centromere region of chromosome 3. Other factors, such as the fragile sites in the 3p21 band and gene regulation, may also contribute to the breakpoint distribution in radiation-induced chromosome aberrations.
KW - Chromatin folding
KW - Chromosome aberrations
KW - Space radiation
UR - http://www.scopus.com/inward/record.url?scp=84904883074&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84904883074&partnerID=8YFLogxK
U2 - 10.1016/j.lssr.2014.05.004
DO - 10.1016/j.lssr.2014.05.004
M3 - Article
AN - SCOPUS:84904883074
SN - 2214-5524
VL - 2
SP - 23
EP - 28
JO - Life Sciences in Space Research
JF - Life Sciences in Space Research
ER -