To confirm that RNA 3 was a recombinant, the RNA 3 derived from C1C2 T2B T3 was gel-purified, reverse transcribed with primers C3 0 and T3 0 , respectively, and then amplified with different pairs of primers as described in the Materials and Methods section. Only the primer pair C3 0 /T3-1187 was able to generate a specific RT-PCR product (data not shown). T3-1187 corresponded to sequences ending with nucleotide position 1187 of TAV RNA 3, while C3 0 was complementary to the 3 0 -terminal sequence of Q-CMV. This indicates that the RNA 3 was indeed a recombinant, having a TAV RNA 3 sequence in the capsid protein region and a CMV RNA sequence at the 3 0 terminus.