Organization and expression of the CPMV genome. The positions of the start and stop codons are indicated on the RNA, and functions of the proteins are indicated in the open reading frame of the RNA represented by an open bar. RNA2 is translated into two polyproteins due to initiation of translation at both positions 161 and 512. MP, movement protein; L, large capsid protein; S, small capsid protein; CPRO, processing regulator: NBSP, protein with nucleotide binding site; VPg, viral protein genome-linked; PRO, proteinase; POL, RNA-dependent RNA polymerase. Proteins are represented by single lines. The two amino acids forming the proteolytic cleavage sites are indicated on the polyproteins. Q, glutamine; G, glycine; S, serine; M, methionine. All intermediate and final cleavage products have been detected in infected cells.