SYNTHESIS AND USE OF 4-HYDROXYPHENYL DERIVATIZED PHOSPHORAMIDITES IN THE SELECTIVE RADIOIODINATION OF OLIGONUCLEOTIDE PROBES

Synthetic oligonucleotides probes are nowadays readily available and w idely used in the identification of specific gene sequence from bacter ia, viruses, in the diagnostic of human genetic diseases as well as in the development of antisense therapy. Much effort has been devoted to the development of non radioactive probes, nevertheless the radioacti ve labelling is still extensively used for research purposes. In this study we propose a new and simple synthesis of 4-hydroxyphenyl-oligonu cleotide conjugates which upon reaction with I-125 give rise to radiol abelled probes. We describe two types of phosphoramidite reagents whic h allow the selective incorporation of a 4-hydroxyphenyl group at a sp ecific site of an oligonucleotide in the course of its chemical synthe sis. The radioiodination step is fast and specific of the hydroxypheny l group and shows a high incorporation yield.