DIVERSITY OF OLIGONUCLEOTIDE FUNCTIONS

SELEX is a technology for the identification of high affinity oligonuc leotide ligands. Large libraries of random sequence single-stranded ol igonucleotides, whether RNA or DNA, can be thought of conformationally not as short strings but rather as sequence dependent folded structur es with high degrees of molecular rigidity in solution. This conformat ional complexity means that such a library is a source of high affinit y ligands for a surprising variety of molecular targets, including nuc leic acid binding proteins such as polymerases and transcription facto rs, non-nucleic acid binding proteins such as cytokins and growth fact ors, as well as small organic molecules such as ATP and theophylline. The range of applications of this technology for new discovery extends from basic research reagents to the identification of novel diagnosti c and therapeutic reagents. Examples of these applications are describ ed along with a discussion of underlying principles and future develop ments expected to further the utility of SELEX.