Molecular characterization of a satellite RNA associated with blackcurrantreversion nepovirus

A satellite RNA (satRNA) associated with blackcurrant reversion nepovirus ( BRV) was isolated and its nucleotide sequence was determined from cDNA clon es. BRV satRNA was 1432 nucleotides (nt) in length excluding the poly(A)-ta il, and contained one open reading frame which encodes a polypeptide of 402 amino acids, with a calculated M-r of 44 220. The coding region was border ed by a 5' leader sequence of 25 nt and a 3'-nontranslated region of 201 nt . Two in vitro translation products of approximately 45 kDa and 40 kDa were detected, indicating that two in-frame AUG codons at positions 26 and 134 may both be functional. Nucleotide sequence comparisons revealed a stretch of 865 nt that was 63% identical between BRV satRNA and the large satRNA of chicory yellow mottle nepovirus. A 5'-terminal consensus sequence and a 40 nt motif (located at positions 264-303 of BRV satRNA) were conserved betwe en BRV satRNA and other nepoviral large satRNAs.