CHARACTERIZATION OF THE COAT PROTEIN GENE OF MITE-TRANSMITTED BLACK-CURRANT REVERSION ASSOCIATED NEPOVIRUS

The nucleotide sequence of the 3' terminal 3105 nucleotides (nt) of RN A2 of blackcurrant reversion associated virus (BRAV), the first mite-t ransmitted member of the nepovirus group, has been determined. The seq uence contains an open reading frame of 1744 nt in the virus-sense str and, a 3' untranslated region of 1360 nt and a 3' poly(A) tail. Analys is of the amino-terminal residues of purified coat protein (CP) sugges ts that the CP gene is located between nts 1361 and 2959 (from the 3' terminus) in the RNA2, and that Asp/Ser is the proteolytic cleavage si te of CP in the RNA2 encoded polyprotein. The predicted translation pr oduct from the CP gene is a polypeptide of 533 amino acids with a calc ulated M-r of 57 561. The amino acid sequence of BRAV CP showed highes t similarity to blueberry leaf mottle virus (BLMV), and tomato ringspo t virus (ToRSV), two members of the proposed sub-group three of nepovi ruses possessing large RNA2 components. Nucleic and amino acid sequenc e comparisons between BRAV CP and the CPs of other nepoviruses indicat e that specific conserved nepovirus CP domains occur in the BRAV CP th us confirming that BRAV is a member of the subgroup three of nepovirus es. (C) 1998 Elsevier Science B.V. All rights reserved.