Upstream and downstream sequence elements determine the specificity of therice tungro bacilliform virus promoter and influence RNA production after transcription initiation

The contribution of sequences upstream and downstream of the transcription start site to the strength and specificity of the promoter of rice tungro b acilliform virus was analysed in transgenic rice plants. The promoter is st rongly stimulated by downstream sequences which include an intron and is ac tive in all vascular and epidermal cells. Expression in the vascular tissue requires a promoter element located between -100 and -164 to which protein (s) from rice nuclear extracts bind. Elimination of this region leads to sp ecificity for the epidermis. Due to the presence of a polyadenylation signa l in the intron, short-stop RNA is produced from the promoter in addition t o full-length primary transcript and its spliced derivatives. The ratio bet ween short-stop RNA and full-length or spliced RNA is determined by upstrea m promoter sequences, suggesting the assembly of RNA polymerase complexes w ith different processivity on this promoter.