Regiospecific inhibition of DNA duplication by antisense phosphate-methylated oligodeoxynucleotides

Abstract

A new synthesis route for long phsophate-methylated oligodeoxynucleotides is described, which were used as antisense inhibitors of the DNA replication. Phosphate-methylated oligomers hybridize more strongly with natural DNA than their natural analogues, due to the absence of electrostatic interstand repulsions. Compared with phsophate-ethylated and methyl phosphonate systems, phosphate-methylated systems are preferable as antisense dNA, which was concluded from the high Tm values and sharp melting transitions of duplexes of phosphate-methylated and natural DNA. By using the Sanger dideoxy technique, it was shown that a complementary phosphate-methylated 18-mer can effectively and site-specifically block the DNA replication process at room temperature.