title: Gene targeting by triple helix-forming oligonucleotides.
abstract: Effective gene targeting reagents would have widespread utility for genomic manipulation including transgenic cell and animal construction and for gene therapy. They would also be useful in basic research as probes of chromatin structure, and as tools for studying the repair and mutagenesis of targeted DNA damage. We are developing triple helix-forming oligonucleotides (TFOs) for gene targeting in living mammalian cells. Challenges to TFO bioactivity include the impediments to the biochemistry of triplex formation presented by the physiological environment and the charge repulsion between the duplex and the third strand. In addition, there are biological constraints to target access imposed by mammalian chromatin structure. Here we describe the oligonucleotide modification format that appears to support biological activity of TFOs. In addition we show that manipulation of the cell biology, specifically the cell cycle, has a dramatic influence on TFO bioactivity.
authors.affiliation: Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
authors.forename: Alokes
authors.initials: A
authors.lastname: Majumdar
authors.forename: Nitin
authors.initials: N
authors.lastname: Puri
authors.forename: Nicholas
authors.initials: N
authors.lastname: McCollum
authors.forename: Sally
authors.initials: S
authors.lastname: Richards
authors.forename: Bernard
authors.initials: B
authors.lastname: Cuenoud
authors.forename: Paul
authors.initials: P
authors.lastname: Miller
authors.forename: Michael M
authors.initials: MM
authors.lastname: Seidman
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000502:physiology; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004247:DNA / Q000187:drug effects*; D018390:Gene Targeting; D005819:Genetic Markers; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics / Q000378:metabolism; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology*
chemical_list: D003432:Cross-Linking Reagents; D005819:Genetic Markers; D009838:Oligodeoxyribonucleotides; D004247:DNA; D007041:Hypoxanthine Phosphoribosyltransferase