Chromosome neighborhood composition determines translocation outcomes after exposure to high-dose radiation in primary cells.
Radiation exposure is an occupational hazard for military personnel, some health care professionals, airport security screeners, and medical patients, with some individuals at risk for acute, high-dose exposures. Therefore, the biological effects of radiation, especially the potential for chromosome damage, are major occupational and health concerns. However, the biophysical mechanisms of chromosome instability subsequent to radiation-induced DNA damage are poorly understood. It is clear that interphase chromosomes occupy discrete structural and functional subnuclear domains, termed chromosome territories (CT), which may be organized into 'neighborhoods' comprising groups of specific CTs. We directly evaluated the relationship between chromosome positioning, neighborhood composition, and translocation partner choice in primary lymphocytes, using a cell-based system in which we could induce multiple, concentrated DNA breaks via high-dose irradiation. We critically evaluated mis-rejoining profiles and tested whether breaks occurring nearby were more likely to fuse than breaks occurring at a distance. We show that CT neighborhoods comprise heterologous chromosomes, within which inter-CT distances directly relate to translocation partner choice. These findings demonstrate that interphase chromosome arrangement is a principal factor in genomic instability outcomes in primary lymphocytes, providing a structural context for understanding the biological effects of radiation exposure, and the molecular etiology of tumor-specific translocation patterns.
The Jackson Laboratory, 600 Maine street, Bar Harbor, ME 04609, USA.
Lura
L
Brianna Caddle
Jeremy L
JL
Grant
Jin
J
Szatkiewicz
Johann
J
van Hase
Bobbi-Jo
BJ
Shirley
Joerg
J
Bewersdorf
Christoph
C
Cremer
Alain
A
Arneodo
Andre
A
Khalil
Kevin D
KD
Mills
D000818:Animals; D002869:Chromosome Aberrations / Q000528:radiation effects*; D002875:Chromosomes / Q000235:genetics*; D004249:DNA Damage; D005720:Gamma Rays; D042822:Genomic Instability; D017404:In Situ Hybridization, Fluorescence; D051379:Mice; D008810:Mice, Inbred C57BL; D054448:Precursor Cells, B-Lymphoid / Q000502:physiology* / Q000528:radiation effects; D011829:Radiation Dosage; D032681:Spectral Karyotyping; D014178:Translocation, Genetic / Q000235:genetics*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000502:physiology*
D016159:Tumor Suppressor Protein p53