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Phosphorothioate-phosphodiester oligonucleotide co-polymers: assessment for antisense application.
- Source :
-
Anti-cancer drug design [Anticancer Drug Des] 1993 Feb; Vol. 8 (1), pp. 15-32. - Publication Year :
- 1993
-
Abstract
- Efforts have been made to reduce the disadvantages associated with the natural oligonucleotides (all-PO) for antisense application by introducing phosphorothioate (PS) linkages into the molecule. A series of such oligodeoxynucleotide copolymers (17-mers) complementary to the coding region of the rabbit beta-globin mRNA, and containing different proportions and arrangements of PO and PS bonds, were synthesized and tested for their protein-binding properties, nuclease stability in vitro, hybridizing ability with the complementary DNA (cDNA), ability to form RNase H-sensitive substrates and antisense activity in cell-free systems. The melting temperatures (Tm) of the co-polymers were reduced by up to 6 degrees C relative to the all-PO oligo, compared to 11 degrees C for the all-PS compound, indicating intermediate hybridizing abilities of the co-polymers. The protein-binding studies with human serum albumin exhibited a linear correlation with the percentage of PS linkage present in the molecule. Nuclease susceptibilities of the co-polymers were also improved, but the number and position of the PS linkages played a significant role in such improvement. Translation inhibition by these oligonucleotides was only found in wheat germ agglutinin (WGA) extract, but not in rabbit reticulocyte lysate (RRL) cell-free system, suggesting the involvement of RNase H in their antisense activities. Provided they have > or = 50% PS linkages, the co-polymers produced almost the same increased inhibition in the WGA system as that of the all-PS oligo. The translation arrest in WGA extract is in good agreement with the in vitro cleavage found for rabbit globin mRNA in the oligo:mRNA duplex by RNase H alone. It is concluded that a copolymer of PO and PS might be preferable to either all-PO or all-PS for antisense applications.
- Subjects :
- Animals
Base Sequence
Cattle
Cell-Free System
Drug Stability
Humans
Molecular Sequence Data
Phosphoric Diester Hydrolases metabolism
Phosphorus Radioisotopes
Polymers chemical synthesis
Polymers metabolism
Polymers pharmacology
Protein Binding
Protein Biosynthesis drug effects
Rabbits
Serum Albumin metabolism
Thermodynamics
Oligonucleotides, Antisense chemical synthesis
Oligonucleotides, Antisense metabolism
Oligonucleotides, Antisense pharmacology
Thionucleotides chemical synthesis
Thionucleotides metabolism
Thionucleotides pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 0266-9536
- Volume :
- 8
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Anti-cancer drug design
- Publication Type :
- Academic Journal
- Accession number :
- 8386513