title: Recognition of hypermethylated triplet repeats in vitro by cationic nanoparticles.
abstract: Genomic DNA contains many higher-order structural deviations from the Watson-Crick global average. The massive expansion and hypermethylation of the duplex triplet repeat (CCG)(n)(CGG)(n) has characteristic higher-order structures that are associated with the fragile X syndrome. We have used luminescent mineral nanoparticles of protein-sized cadmium sulfide in optical assays to detect anomalous DNA structures. The photoluminescence of these particles is sensitive to the presence and nature of adsorbates. We previously found that our nanoparticles bind the fragile X repeat well but do not bind to normal double-helical DNA. In this study, we have determined that these particles are also able to detect the hypermethylated forms of these triplet repeats. Therefore, these nanoparticles may form the basis for future optical assays of higher-order DNA structures, especially those associated with human disease.
authors.affiliation: University of South Carolina, Department of Chemistry and Biochemistry, 631 Sumter Street, Columbia, South Carolina 29208, USA.
authors.forename: L
authors.initials: L
authors.lastname: Gearheart
authors.forename: K K
authors.initials: KK
authors.lastname: Caswell
authors.forename: C J
authors.initials: CJ
authors.lastname: Murphy
mesh_terms: D001483:Base Sequence / Q000235:genetics; D019187:Cadmium Compounds; D002942:Circular Dichroism; D004247:DNA / Q000235:genetics*; D019175:DNA Methylation; D008163:Luminescent Measurements; D008957:Models, Genetic; D008969:Molecular Sequence Data; D055095:Optics and Photonics; D010316:Particle Size; D013440:Sulfides; D018911:Trinucleotide Repeats
chemical_list: D019187:Cadmium Compounds; D013440:Sulfides; C034939:cadmium sulfide; D004247:DNA