The 3' promoter region involved in RNA synthesis directed by the turnip yellow mosaic virus genome in vitro.

We have previously shown that the last 100 nucleotides from the 3' end of turnip yellow mosaic virus (TYMV) RNA compete in vitro with genomic RNA for the TYMV-specific RNA-dependent RNA polymerase (RdRp). To further characterize the promoter on genomic RNA that produces complementary RNA strands, shorter fragments corresponding to the 3' region of the viral RNA were generated and used in in vitro assays. Fragments as short as 38 nucleotides corresponding to the 3' end of TYMV RNA compete with the viral RNA for the RdRp suggesting that the 3' promoter on plus strand RNA is probably less than or equal to 38 nucleotides long. These transcripts are themselves used as templates in vitro.