TKY680 (tef3D/tef4D), the isogenic TKY679 (tef4D), TKY678 (tef3D) and wild type TKY677 yeast were transformed with plasmids pESC-GAL1-His33/GAL10-DI-72 and pCM189-TET-His92. Yeast was pre-grown at 23uC overnight in 3 ml synthetic complete dropout medium lacking the relevant amino acids containing 2% glucose and 1 mg/ml doxycyclin to suppress p92 expression by the inhibition of TET promoter and then TBSV replication was launched by replacing the media with 2% galactose without doxycycline. Cells were harvested at 48 h time point. Total RNA extraction from yeast cells and Northern blotting and Western blotting were done as previously described [15, 24] .