DNA-HMGB1 interaction: The nuclear aggregates of polyamine mediation

Biochim Biophys Acta. 2016 Oct;1864(10):1402-10. doi: 10.1016/j.bbapap.2016.07.006. Epub 2016 Jul 22.

Abstract

Nuclear aggregates of polyamines (NAPs) are supramolecular compounds generated by the self-assembly of protonated nuclear polyamines (spermine, spermidine and putrescine) and phosphate ions. In the presence of genomic DNA, the hierarchical process of self-structuring ultimately produces nanotube-like polymers that envelop the double helix. Because of their modular nature and their aggregation-disaggregation dynamics, NAPs confer plasticity and flexibility to DNA. Through the disposition of charges, NAPs also enable a bidirectional stream of information between the genome and interacting moieties. High mobility group (HMG) B1 is a non-histone chromosomal protein that binds to DNA and that influences multiple nuclear processes. Because genomic DNA binds to either NAPs or HMGB1 protein, we explored the ability of in vitro self-assembled NAPs (ivNAPs) to mediate the DNA-HMGB1 interaction. To this end, we structured DNA-NAPs-HMGB1 and DNA-HMGB1-NAPs ternary complexes in vitro through opportune sequential incubations. Mobility shift electrophoresis and atomic force microscopy showed that the DNA-ivNAPs-HGMB1 complex had conformational assets supposedly more suitable those of the DNA-HGMB1-ivNAPs to comply with the physiological and functional requirements of DNA. Our findings indicated that ivNAPs act as mediators of the DNA-HMGB1 interaction.

Keywords: Atomic force microscopy; DNA conformational transitions; EMSA; HMGB1; Nuclear aggregates of polyamines; Supramolecular nanotubes.

MeSH terms

  • Cell Nucleus / metabolism*
  • DNA / metabolism*
  • Genome / genetics
  • HMGB1 Protein / metabolism*
  • Humans
  • Microscopy, Atomic Force / methods
  • Nucleic Acid Conformation
  • Polyamines / metabolism*
  • Protein Aggregates / physiology*
  • Spermidine / metabolism
  • Spermine / metabolism

Substances

  • HMGB1 Protein
  • Polyamines
  • Protein Aggregates
  • Spermine
  • DNA
  • Spermidine