3'-End labeling of RNA with yeast Poly(A) polymerase and 3'-deoxyadenosine 5'-[α-32P]triphosphate.

This protocol is used to label RNA molecules (in vitro-synthesized or in vivo-purified RNA molecules) that have free 3'-hydroxyl termini. The reaction is performed in 10 min using yeast poly(A) polymerase and 3'-deoxyadenosine 5'-[α-(32)P]triphosphate (cordycepin 5'-[α-(32)P]triphosphate), a chain-terminating nucleotide. At the end of the procedure, the reaction is desalted by gel filtration to remove any unincorporated nucleotides.