Synthesis and properties of ENA oligonucleotides targeted to human telomerase RNA subunit.

Oligonucleotides uniformly modified with 2'-O,4'-C-ethylene-bridged nucleic acid (ENA) units were synthesized using the phosphoramidite method on a hundred-milligram scale for the evaluation of thermodynamic and chemical properties. The properties of these ENA oligonucleotides with the sequences targeted to human telomerase RNA subunit (hTR) were compared with those of GRN163, which is an oligonucleotide modified with N3'-P5' thiophosphoramidates. The melting temperatures of the duplexes of ENA oligonucleotides with complementary RNA were higher than that of the duplex of GRN163.

Direct comparison of in vivo antisense activity of ENA oligonucleotides targeting PTP1B mRNA with that of 2'-O-(2-methoxy)ethyl-modified oligonucleotides.

Protein-tyrosine phosphatase 1B (PTP1B) inhibitory activity of the 2'-O-(2-methoxy)ethyl (2'- MOE)-modified gapmer antisense oligonucleotide, ISIS113715, was previously reported. This antisense oligonucleotide increases insulin sensitivity and normalizes plasma glucose levels in diabetic ob/ob and db/db mice. In the present study, the isosequential 2'-O,4'-C-ethylene-bridged nucleic acid (ENA)-modified oligonucleotide, ENA-1, was synthesized, and its ability to further improve the downregulation of PTP1B in db/db mice was examined.

Comparison between properties of 2'-O,4'-C-ethylene-bridged nucleic acid (ENA) phosphorothioate oligonucleotides and N3'-P5' thiophosphoramidate oligonucleotides.

Synthesis and properties of an oligonucleotide uniformly modified with 2'-O,4-C-ethylene-bridged nucleic acid (ENA) units were compared with those of GRN163, which is modified with N3'-P5' thiophosphoramidates, with the sequence targeting human telomerase RNA subunit. Although an ENA phosphorothioate oligonucleotide, ENA-13, could be synthesized using ENA phosphoramidites on a 100-mg scale, synthesis of GRN163 was very hard even on a 1-micomol scale. In view of both stability of the duplex formation with complementary RNA and the efficiency of cellular uptake by endocytosis, ENA-13 was superior to GRN163.

Triplex formation with 2'-O,4'-C-ethylene-bridged nucleic acids (ENA) having C3'-endo conformation at physiological pH.

Antigenes, which are substances that inhibit gene expression by binding to double-stranded DNA (dsDNA) in a sequence-specific manner, are currently sought for the treatment of various gene-related diseases. As such antigenes, we developed new nuclease-resistant oligopyrimidine nucleotides that are partially modified with 2'-O,4'-C-ethylene nucleic acids (ENA), which are constrained in the C3'-endo conformation and can form a triplex with dsDNA at physiological pH. It was found that these oligonucleotides formed triplexes similarly to those partially modified with 2'-O,4'-C-methylene nucleic acids (2',4'-BNA or LNA), as determined by UV melting analyses, electromobility shift assays, CD spectral analyses and restriction enzyme inhibition assays.

Studies on novel bacterial translocase I inhibitors, A-500359s. I. Taxonomy, fermentation, isolation, physico-chemical properties and structure elucidation of A-500359 A, C, D and G.

In the course of our screening for bacterial phospho-N-acetylmuramyl-pentapeptide-translocase (translocase I: EC 2.7.8.

Synthesis and properties of 2'-O,4'-C-ethylene-bridged nucleic acids (ENA) as effective antisense oligonucleotides.

Novel bicyclo nucleosides, 2'-O,4'-C-ethylene nucleosides and 2'-O,4'-C-propylene nucleosides, were synthesized as building blocks for antisense oligonucleotides to further optimize the 2'-O,4'-C-methylene-linkage of bridged nucleic acids (2',4'-BNA) or locked nucleic acids (LNA). Both the 2'-O,4'-C-ethylene- and propylene-linkage within these nucleosides restrict the sugar puckering to the N-conformation of RNA as do 2',4'-BNA/LNA. Furthermore, ethylene-bridged nucleic acids (ENA) having 2'-O,4'-C-ethylene nucleosides had considerably increased the affinity to complementary RNA, and were as high as that of 2',4'-BNA/LNA (DeltaT(m)=+3 approximately 5 degrees C per modification).

Direct chiral separation of troglitazone stereoisomers using reversed-phase high-performance liquid chromatography.

A simple HPLC method for the direct chiral separation of troglitazone stereoisomers was developed. The separation was performed on a reversed-phase cellulose-derivertized chiral column (Chiralcel OJ-R) using a mobile phase consisting of methanol-acetic acid (1000:1, v/v) at a flow rate of 0.5 ml/min.

2'-O,4'-C-ethylene-bridged nucleic acids (ENA): highly nuclease-resistant and thermodynamically stable oligonucleotides for antisense drug.

To develop antisense oligonucleotides, novel nucleosides, 2'-O,4'-C-ethylene nucleosides and their corresponding phosphoramidites, were synthesized as building blocks. The 1H NMR analysis showed that the 2'-O,4'-C-ethylene linkage of these nucleosides restricts the sugar puckering to the N-conformation as well as the linkage of 2'-O,4'-C-methylene nucleosides which are known as bridged nucleic acids (BNA) or locked nucleic acids (LNA). The ethylene-bridged nucleic acids (ENA) showed a high binding affinity for the complementary RNA strand (DeltaT(m)=+5.