title: Repairing the Sickle Cell mutation. III. Effect of irradiation wavelength on the specificity and type of photoproduct formed by a 3'-terminal psoralen on a third strand directed to the mutant base pair.
abstract: Using a psoralen delivery system mediated by a DNA third strand that binds selectively to linear target duplexes immediately downstream from the Sickle Cell beta-globin gene mutation and the comparable wild-type beta-globin gene sequence, the kinetics of formation and yield of psoralen monoadducts and crosslinks with pyrimidine residues at and near the mutant base pair site and its wild-type counterpart were determined. By exploiting irradiation specificities at 300, 365 and 419 nm, it was possible to evaluate the orientation equilibrium of 3'-linked intercalated psoralen and to develop conditions that lead to preferential formation of each type of photoproduct in both the mutant and wild-type sequences. This makes possible the preparation of each type of photoproduct for use as a substrate for DNA repair. In this way, the base pair change(s) that each generates can be established.
authors.affiliation: Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Broitman
authors.forename: Olga
authors.initials: O
authors.lastname: Amosova
authors.forename: Jacques R
authors.initials: JR
authors.lastname: Fresco
mesh_terms: D000755:Anemia, Sickle Cell / Q000235:genetics*; D020029:Base Pairing / Q000235:genetics; D001483:Base Sequence; D004247:DNA / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects; D018736:DNA Adducts / Q000737:chemistry / Q000378:metabolism; D004260:DNA Repair; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D011564:Furocoumarins / Q000737:chemistry / Q000378:metabolism; D006451:Hemoglobin, Sickle / Q000235:genetics*; D006801:Humans; D007700:Kinetics; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry / Q000235:genetics; D017354:Point Mutation; D014466:Ultraviolet Rays
chemical_list: D018736:DNA Adducts; D011564:Furocoumarins; D006451:Hemoglobin, Sickle; D009841:Oligonucleotides; C056465:psoralen-DNA adduct; D004247:DNA