Structural and functional analysis of the cis-acting elements required for plus-strand RNA synthesis of Bamboo mosaic virus.

Bamboo mosaic virus (BaMV) has a single-stranded positive-sense RNA genome. The secondary structure of the 3'-terminal sequence of the minus-strand RNA has been predicted by MFOLD and confirmed by enzymatic structural probing to consist of a large, stable stem-loop and a small, unstable stem-loop. To identify the promoter for plus-strand RNA synthesis in this region, transcripts of 39, 77, and 173 nucleotides (Ba-39, Ba-77, and Ba-173, respectively) derived from the 3' terminus of the minus-strand RNA were examined by an in vitro RNA-dependent RNA polymerase assay for the ability to direct RNA synthesis.