Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2006-2-7
pubmed:abstractText
Triple helix forming oligonucleotides (TFOs) may have utility as gene targeting reagents for "in situ" gene therapy of genetic disorders. Triplex formation is challenged by negative charge repulsion between third strand and duplex phosphates, and destabilizing positive charge repulsion between adjacent protonated cytosines within pyrimidine motif third strands. Here we describe the synthesis of TFOs designed to target a site in the human beta-globin gene, which is the locus for mutations that underlie the beta-globinopathies, including sickle cell anemia. The target is an uninterrupted polypurine:polypyrimidine sequence, containing four adjacent cytosines, next to a psoralen cross-link site. Pyrimidine motif TFOs that contained four adjacent cytosines or 5-methylcytosines did not form stable triplexes at physiological pH, despite the introduction of otherwise stabilizing base and sugar analogues. We synthesized a series of pso-TFOs containing 2'-O-methyl (OMe) and 2'-O-aminoethoxy substitutions (AE), as well as 8-oxo-adenine (A8) and 2'-O-methylpseudoisocytidine (P) as neutral cytosine replacements. Thermal stability measurements indicated that TFOs with A8 did not meet criteria established in previous work. However, TFOs with P did form triplexes with appropriate T(m) and k(ON) values. A pso-TFO with AE and P residues was sufficiently active to permit the determination of targeting in living cells by direct measurement of cross-link formation at the target site. Our results validate the modification format described in our previous studies and indicate that P substitutions are an effective solution to the problem of targeting genomic sequences containing adjacent cytosines.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Adenine, http://linkedlifedata.com/resource/pubmed/chemical/Cross-Linking Reagents, http://linkedlifedata.com/resource/pubmed/chemical/Cytidine, http://linkedlifedata.com/resource/pubmed/chemical/Cytosine, http://linkedlifedata.com/resource/pubmed/chemical/DNA, http://linkedlifedata.com/resource/pubmed/chemical/Ficusin, http://linkedlifedata.com/resource/pubmed/chemical/Globins, http://linkedlifedata.com/resource/pubmed/chemical/Oligonucleotides, http://linkedlifedata.com/resource/pubmed/chemical/Phosphates, http://linkedlifedata.com/resource/pubmed/chemical/Purines, http://linkedlifedata.com/resource/pubmed/chemical/Pyrimidines, http://linkedlifedata.com/resource/pubmed/chemical/pseudoisocytidine, http://linkedlifedata.com/resource/pubmed/chemical/triplex DNA
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
45
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1970-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:16460044-Adenine, pubmed-meshheading:16460044-Anemia, Sickle Cell, pubmed-meshheading:16460044-Base Sequence, pubmed-meshheading:16460044-Cross-Linking Reagents, pubmed-meshheading:16460044-Cytidine, pubmed-meshheading:16460044-Cytosine, pubmed-meshheading:16460044-DNA, pubmed-meshheading:16460044-Ficusin, pubmed-meshheading:16460044-Gene Targeting, pubmed-meshheading:16460044-Globins, pubmed-meshheading:16460044-Humans, pubmed-meshheading:16460044-Hydrogen-Ion Concentration, pubmed-meshheading:16460044-K562 Cells, pubmed-meshheading:16460044-Nucleic Acid Conformation, pubmed-meshheading:16460044-Oligonucleotides, pubmed-meshheading:16460044-Phosphates, pubmed-meshheading:16460044-Purines, pubmed-meshheading:16460044-Pyrimidines, pubmed-meshheading:16460044-Temperature, pubmed-meshheading:16460044-Tumor Cells, Cultured
pubmed:year
2006
pubmed:articleTitle
Targeted cross-linking of the human beta-globin gene in living cells mediated by a triple helix forming oligonucleotide.
pubmed:affiliation
Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Intramural