SOLID-PHASE SYNTHESIS OF BRANCHED RNA AND BRANCHED DNA RNA CHIMERAS/

An effective method for synthesising branched oligonucleotides on soli d phase in the 5' to 3' direction has been developed. Special branch-p oint monomers enable the synthesis of branched oligonucleotides which can have sequences of different length and base composition attached t o tile 2'-and 3'-hydroxyl groups of the branch point ribonucleoside. T he branched oligonucleotides are assembled on commercial DNA synthesis ers, the crude products are readily purified by reversed phase HPLC an d the fully deprotected products are conveniently analysed by mass spe ctrometry. (C) 1997 Elsevier Science Ltd.