NUCLEOTIDE-SEQUENCE OF CARNATION RINGSPOT DIANTHOVIRUS RNA-1

The nucleotide sequence of carnation ringspot virus (CRSV) RNA-1 the t ype member of the dianthovirus genus, has been determined. The 3756 nu cleotide genomic RNA-I contains three large open reading frames (ORFs) , capable of encoding 27K, 54K and 38K polypeptides. In addition, a sm all ORF encoding a 10K polypeptide at the 3' terminus of the RNA has b een identified. The gene organization of CRSV RNA-I is similar to thos e of red clover necrotic mosaic (RCNMV) and sweet clover necrotic mosa ic (SCNMV) dianthoviruses with the exception that CRSV RNA-I contains the additional 3'-terminal ORF. The 27K and 54K proteins possess signi ficant sequence similarity to corresponding polypeptides of the other dianthoviruses. The 54K protein also contains the conserved RNA-depend ent RNA polymerase motif. The identification of a shifty heptanucleoti de preceding the p27 ORF termination codon and a predicted secondary s tructure following the terminator suggest that a translational framesh ifting event allows translation to continue past the p27 ORF into the p54 ORF, which is in the -1 frame, generating an 88K fusion protein. A mino acid sequence alignment of the 38K protein with the corresponding RCNMV and SCNMV polypeptides indicate that this is the viral capsid p rotein.