The template for in vitro transcription encompassing the whole short 3 0 UTR of rat Polb (208 nt) was synthesized by PCR with a forward primer containing the T7 RNA polymerase promoter sequence (5 0 -TAATACGACTCAC TATAGGGCCTGCCCCACCCAGGCCT) and reverse primer (5 0 -AAACCATGGTACTGCGATC). The PCR was performed with the plasmid bearing the Pol b short 3 0 UTR sequence (pGEM-4Z/H), in the following conditions: 948C for 1 min followed by 35 cycles at 948C for 1 s, 608C for 1 s and 728C for 30 s.