title: Polyamine-induced compaction and aggregation of DNA--a major factor in radioprotection of chromatin under physiological conditions.
abstract: Spermine at physiological levels and ionic strength induces compaction and aggregation of SV40 DNA and minichromosomes resulting in marked radioprotection of the DNA against gamma-ray-induced formation of single-strand breaks. This phenomenon, termed the PICA effect, results in yields of single-strand breaks in DNA and minichromosomes comparable to those found with intact cells and is considered to be a major mechanism responsible for radioprotection of cellular DNA.
authors.affiliation: Department of Chemistry, University of California, San Diego, La Jolla 92093, USA.
authors.forename: G L
authors.initials: GL
authors.lastname: Newton
authors.forename: J A
authors.initials: JA
authors.lastname: Aguilera
authors.forename: J F
authors.initials: JF
authors.lastname: Ward
authors.forename: R C
authors.initials: RC
authors.lastname: Fahey
mesh_terms: D000818:Animals; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D004247:DNA / Q000528:radiation effects*; D004249:DNA Damage; D004279:DNA, Viral / Q000737:chemistry / Q000187:drug effects / Q000528:radiation effects*; D005720:Gamma Rays; D006367:HeLa Cells; D006801:Humans; D007962:Leukocytes / Q000528:radiation effects; D011700:Putrescine / Q000494:pharmacology*; D011835:Radiation Protection; D013539:Simian virus 40; D013095:Spermidine / Q000494:pharmacology*; D013096:Spermine / Q000494:pharmacology*
chemical_list: D004279:DNA, Viral; D013096:Spermine; D004247:DNA; D013095:Spermidine; D011700:Putrescine