NEW NON NUCLEOSIDIC PHOSPHORAMIDITES FOR THE SOLID-PHASE MULTI-LABELING OF OLIGONUCLEOTIDES - COMB-LIKE AND MULTIFORK-LIKE STRUCTURES

Comb- and multifork-like structures have been designed for multiple la belling of oligonucleotides. They rely on the synthesis of new non nuc leosidic phosphoramidites which can be used in automatic DNA synthesis . The new compounds allowed the 5' and/or 3' tagging of any oligonucle otide and provided reactive primary amino groups for non isotopic labe lling. Seventeen polybiotinylated oligonucleotides have been prepared and tested in hybridization assays using a corresponding complementary sequence covalently linked to polystyrene tubes. Detection limits, me asured by chemiluminescence, ranged from 105 to 3.106 molecules, depen ding on the number of biotins. Optimal detection was achieved either w ith a 5' multifork-like derivative carrying 8 biotins or with a comb-l ike structure carrying 4 biotins on both 5' and 3' ends.