PARENT SESSION
9:00 AM to 11:00 AM
Sunday, April 21, 2002
Symposium 3
Clustered Radiation Damage in DNA: An Interdisciplinary Approach
Room: Nevada 8-9-10
Chair: Zimbrick, John²²Purdue University, West Lafayette, IN
Speakers: Bowman, Michael ⁴; Green, Nicholas⁵; O'Neill, Peter⁶; Wallace, Susan⁷⁴Pacific Northwest National Laboratory, Richland, WA⁵King's College, London, England⁶MRC Radiation and Genome Stability Unit, Didcot, Oxon, Ox11 ORD, UK⁷University of Vermont, Burlington, VT

(S03-) Clustered Radiation Damage in DNA: An Interdisciplinary Approach.

Zimbrick, John^*,1, ¹ Purdue University, West Lafayette, IN

ABSTRACT-
Ionizing radiation deposits its energy inhomogeneously in living cells. The volume increments in which energy is deposited are frequently called "clusters". At very short times after the initial ionizing events, the clusters contain a number of free radical intermediates. If a cluster occurs on or near DNA, the free radicals produced therein will react to ultimately produce a cluster of strand breaks, damaged bases and DNA-protein crosslinks. These clusters of damage are commonly called multiply damaged sites (MDS). Cellular repair systems will attempt to process the damage in these MDS. However the complexity of the site, in terms of the spatial relationship between the various damages, the types of damage, and the structural perturbation of the DNA in the vicinity of the cluster may prevent the complete repair of the DNA at the site and thus may result in a subsequent deleterious effect on the cell. This symposium will present recent studies on various facets of the production and processing of MDS. The studies are necessarily interdisciplinary in nature, involving physics, chemistry and biology and including modeling and experimental approaches. Findings will be presented on the spatial properties of radicals in MDS, the types of damages produced, and the selective processing of these damages by cellular repair systems.

KEYWORDS: clusters, DNA damage, DNA repair, free radical