Triple-helix formation by alpha oligodeoxynucleotides and alpha oligodeoxynucleotide-intercalator conjugates.
Base-pair sequences in double-stranded DNA can be recognized by homopyrimidine oligonucleotides that bind to the major groove at homopurine.homopyrimidine sequences thereby forming a local triple helix. To make oligodeoxynucleotides resistant to nucleases, we replaced the natural (beta) anomers of the nucleotide units by the synthetic (alpha) anomers. The 11-mer alpha oligodeoxynucleotide 5'-d(TCTCCTCCTTT)-3' binds to the major groove of DNA in an antiparallel orientation with respect to the homopurine strand, whereas a beta oligonucleotide adopts a parallel orientation. When an intercalating agent was attached to the 3' end of the alpha oligodeoxynucleotide, a strong stabilization of the triple helix was observed. A 16-base-pair homopurine.homopyrimidine sequence of human immunodeficiency virus proviral DNA was chosen as a target for a 16-mer homopyrimidine alpha oligodeoxynucleotide. A restriction enzyme that cleaves DNA at the junction of the homopurine.homopyrimidine sequence was inhibited by triple-helix formation. The 16-mer alpha oligodeoxynucleotide substituted by an intercalating agent was approximately 20 times more efficient than the unsubstituted oligomer. Nuclease-resistant alpha oligodeoxynucleotides offer additional possibilities to control gene expression at the DNA level.
Sun
J S
JS
Laboratoire de Biophysique, Muséum National d'Histoire Naturelle, Institut National de la Santé et de la Recherche Médicale, Paris, France.
Giovannangeli
C
C
François
J C
JC
Kurfurst
R
R
Montenay-Garestier
T
T
Asseline
U
U
Saison-Behmoaras
T
T
Thuong
N T
NT
Hélène
C
C
D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D004279:DNA, Viral / Q000737:chemistry; D006678:HIV / Q000235:genetics; D006860:Hydrogen Bonding; D007364:Intercalating Agents; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D011533:Proviruses / Q000235:genetics; D013816:Thermodynamics
D004279:DNA, Viral; D007364:Intercalating Agents; D009838:Oligodeoxyribonucleotides; D004247:DNA