Effect of mutations in Barley yellow dwarf virus genomic RNA on the 5 ' termini of subgenomic RNAs - Brief report

To investigate the role in transcription initiation of sequences upstream o f the promoter for subgenomic RNA2 (sgRNA2) of Barley, yellow dwarf virus P AV, deletion and insertion clones were constructed and the 5 ' termini of a ll three sgRNAs were determined. Deletion and insertion of sequences upstre am of the transcription start site of sgRNA2 altered the position and nucle otide used to initiate transcription of sgRNA2, but not of sgRNAs 1 or 3. S ince the promoter for sgRNA2 is downstream of the mutations, these results show that sequences outside of the core promoter can influence transcriptio n start site selection from the sgRNA2 promoter.