MODIFIED NUCLEIC-ACID FOR SYSTEMATIC EVOLUTION OF RNA LIGANDS BY EXPONENTIAL ENRICHMENT

Various types of modified nucleic acid were tested for systematic evol ution of ligands by exponential enrichment (SELEX) or in vitro evoluti on. T7 RNA polymerase accepted cytidine triphosphate with a biotinyl g roup at the N-4-position of cytosine, adenosine triphosphate with an a minohexyl group at the N-6-position of adenine, and 2'-amino-2'-deoxyu ridine triphosphate as substrates for transcription of DNA containing a random sequence. However, uridine triphosphate with a nitroveratrylo xy group at the 2'-position and adenosine triphosphate with an aminohe xyl group at the 8-position of adenine were not accepted. The transcri bed products served as templates for the production of cDNA by reverse transcription. These findings indicate that some modified nucleotides can he applied to the present SELEX protocol.