title: Nuclear aggregates of polyamines in a radiation-induced DNA damage model.
abstract: Polyamines (PA) are believed to protect DNA minimizing the effect of radiation damage either by inducing DNA compaction and aggregation or acting as scavengers of free radicals. Using an in vitro pDNA double strand breakage assay based on gel electrophoretic mobility, we compared the protective capability of PA against γ-radiation with that of compounds generated by the supramolecular self-assembly of nuclear polyamines and phosphates, named Nuclear Aggregates of Polyamines (NAPs). Both unassembled PA and in vitro produced NAPs (ivNAPs) were ineffective in conferring pDNA protection at the sub-mM concentration. Single PA showed an appreciable protective effect only at high (mM) concentrations. However, concentrations of spermine (4+) within a critical range (0.481 mM) induced pDNA precipitation, an event that was not observed with NAPs-pDNA interaction. We conclude that the interaction of individual PA is ineffective to assure DNA protection, simultaneously preserving the flexibility and charge density of the double strand. Furthermore, data obtained by testing polyamine and ivNAPS with the current radiation-induced DNA damage model support the concept that PA-phosphate aggregates are the only forms through which PA interact with DNA.
authors.affiliation: Institute of Food Science, CNR, via Roma 64, 83100 Avellino, Italy. Electronic address: piacomino@isa.cnr.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Iacomino
authors.affiliation: Institute of Food Science, CNR, via Roma 64, 83100 Avellino, Italy. Electronic address: picariello@isa.cnr.it.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Picariello
authors.affiliation: Institute of Food Science, CNR, via Roma 64, 83100 Avellino, Italy. Electronic address: stila1@tiscali.it.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Stillitano
authors.affiliation: Institute of Food Science, CNR, via Roma 64, 83100 Avellino, Italy. Electronic address: luciano@isa.cnr.it.
authors.forename: Luciano
authors.initials: L
authors.lastname: D'Agostino
mesh_terms: D002467:Cell Nucleus / Q000187:drug effects*; D004247:DNA / Q000187:drug effects* / Q000528:radiation effects*; D004249:DNA Damage; D004278:DNA, Superhelical / Q000528:radiation effects; D005720:Gamma Rays; D010957:Plasmids / Q000528:radiation effects; D011073:Polyamines / Q000494:pharmacology*
chemical_list: D004278:DNA, Superhelical; D011073:Polyamines; D004247:DNA
keywords: DNA damage; Nuclear aggregates of polyamines; Phosphates; Polyamines; γ-Radiation