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Distributions of Low- and High-LET Radiation-Induced Breaks in Chromosomes are Associated with Inter- and Intrachromosome ExchangesTo study the breakpoint along the length of the chromosome induced by low- and high-LET radiations, we exposed human epithelial cells in vitro to Cs-137 rays at both low and high dose rates, secondary neutrons at a low dose rate, and 600 MeV/u Fe ions at a high dose rate. The location of the breaks was identified using the multicolor banding in situ hybridization (mBAND) that paints Chromosome 3 in 23 different colored bands. The breakpoint distributions were found to be similar between rays of low and high dose rates and between the two high-LET radiation types. Detailed analysis of the chromosome break ends involved in inter- and intrachromosome exchanges revealed that only the break ends participating in interchromosome exchanges contributed to the hot spots found for low-LET. For break ends participating in intrachromosome exchanges, the distributions for all four radiation scenarios were similar with clusters of breaks found in three regions. Analysis of the locations of the two break ends in Chromosome 3 that joined to form an intrachromosome exchange demonstrated that two breaks with a greater genomic separation may be more likely to rejoin than two closer breaks, indicating that chromatin folding can play an important role in the rejoining of chromosome breaks. Our study demonstrated that the gene-rich regions do not necessarily contain more breaks. The breakpoint distribution depends more on the likelihood that a break will join with another break in the same chromosome or in a different chromosome.
Document ID
20100015501
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Hada, Megumi
(NASA Johnson Space Center Houston, TX, United States)
Zhang, Ye
(NASA Johnson Space Center Houston, TX, United States)
Feiveson, Alan
(NASA Johnson Space Center Houston, TX, United States)
Cucinotta, Francis A.
(NASA Johnson Space Center Houston, TX, United States)
Wu, Honglu
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2010
Subject Category
Life Sciences (General)
Report/Patent Number
JSC-CN-20476
Meeting Information
Meeting: 21st Annual NASA Space Radiation Investigators'' Workshop
Location: Port Jefferson, NY
Country: United States
Start Date: May 16, 2010
End Date: May 19, 2010
Distribution Limits
Public
Copyright
Other

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