Sequence-specific photo-induced cross-linking of the two strands of double-helical DNA by a psoralen covalently linked to a triple helix-forming oligonucleotide.
On the basis of the structure of DNA-psoralen bis adducts (formed by psoralen with two thymines on opposite strands), a psoralen-oligonucleotide conjugate was designed to photoinduce a cross-link between the two DNA strands at a specific sequence. Psoralen was attached via its C-5 position to a 5'-thiophosphate group of an 11-mer homopyrimidine oligonucleotide. The 11-mer binds to an 11-base-pair homopurine.homopyrimidine sequence of a DNA fragment, where it forms a triple helix. Upon near-UV-irradiation, the two strands of DNA are crosslinked at the TpA step present at the triplex-duplex junction. The reaction is specific for the homopurine.homopyrimidine DNA sequence and requires both oligonucleotide recognition of the DNA major groove and intercalation of psoralen at the triplex-duplex junction. The yield of the photo-induced cross-linking reaction is quite high (greater than 80%). Such psoralen-oligonucleotide conjugates are probes of sequence-specific triple-helix formation and could be used to selectively control gene expression or to induce site-directed mutations.
Takasugi
M
M
Laboratoire de Biophysique, Institut National de la Santé et de la Recherche Médicale U.201, Centre National de la Recherche Scientifique UA.481, Paris, France.
Guendouz
A
A
Chassignol
M
M
Decout
J L
JL
Lhomme
J
J
Thuong
N T
NT
Hélène
C
C
D001483:Base Sequence; D003432:Cross-Linking Reagents / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D011564:Furocoumarins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry*; D010777:Photochemistry; D013329:Structure-Activity Relationship
D003432:Cross-Linking Reagents; D011564:Furocoumarins; D009841:Oligonucleotides; D004247:DNA