Nucleotide sequence of the coat protein genes of citrus mosaic virus

The sequence of the 3′-terminal 2201 nucleotides of RNA2 of citrus mosaic virus (CiMV) was determined. The sequence contains a long open reading frame (ORF) of 1989 nucleotides in the virus-sense strand and a 3′ untranslated region of 212 nucleotides upstream of a poly(A) tail. The N-terminal amino acid sequence of the two coat proteins was determined by Edman degradation and the corresponding coding regions were identified in the polyprotein. The larger coat protein with Mr 48 122 is encoded upstream of the smaller one with Mr 24 172. The coat proteins are apparently cleaved from the polyprotein at an Arg-Gly and a Thr-Asn bond. Although CiMV has properties in common with the comoviruses and nepoviruses, there is no significant sequence homology between the coat proteins of CiMV and those of either group. Furthermore, the coat proteins of CiMV lack homology with those of strawberry latent ringspot virus (SLRSV), which has been reported to be more distantly related to the como- and nepoviruses. This lack of homology distinguishes CiMV from the como- and nepoviruses, SLRSV and other viruses.