Northern blot analyses of BBSV sat-RNAs. RNA samples were loaded in the same agarose gel and probed with the plus-sense (A) or minus-sense (B) transcript of the sat-RNA. Lanes 1, viral RNAs extracted from purified BBSV-X particles; lanes 2, total RNAs from C. amaranticolor infected by in vitro-transcribed BBSV-N genomic RNA; lanes 3, total RNAs from C. amaranticolor infected by the BBSV-X isolate; lanes 4, in vitro transcripts of the minus-sense sat-RNA control; lanes 5 (from top to bottom), tetramer (4 mer), trimer (3 mer), dimer (2 mer), and monomer (1 mer) plus-sense sat-RNA transcripts.