NUCLEOTIDE-SEQUENCE OF THE COAT PROTEIN GENES OF STRAWBERRY LATENT RINGSPOT VIRUS - LACK OF HOMOLOGY TO THE NEPOVIRUSES AND COMOVIRUSES

The sequence of the 3'-terminal 2424 nucleotides of RNA-2 of the flowe ring cherry strain of strawberry latent ringspot virus (SLRV) was dete rmined from cDNA clones. The sequence contains a reading frame in the virus-sense strand of 2070 nucleotides, a 3' untranslated region of 55 2 nucleotides and a 3'-terminal poly(A) tract. The positions of the tw o coat proteins of SLRV within the reading frame were determined from sequence data obtained by N-terminal sequencing using Edman degradatio n. The larger coat protein with an M(r) of 43K is located 5' of the sm aller coat protein of 27K, and the two proteins are apparently cleaved at a Ser-Gly bond. Although there are numerous similarities between S LRV and the nepoviruses and comoviruses, there is no significant homol ogy between the SLRV coat proteins and the coat proteins of either gro up. Furthermore, the hydropathy profiles of the SLRV coat proteins are unlike those of either group. No comparisons could be made with the f abaviruses owing to lack of sequencing information. This lack of homol ogy suggests that SLRV is more distantly related to the nepoviruses an d comoviruses than has been considered previously.