Table 1.
Characterization of Potyviridae proteins including their function and subcellular localization.
| Protein (size) | Function | Cellular localization | Reference(s) |
|---|---|---|---|
| P1 (32 – 64 K) | serine proteinase with cis-cleavage activity, P1/HCpro cleavage site. Responsible for symptomatolology. Usable for investigation of potyviruses phylogeny and relationship | Crystalline inclusions in cytoplasm and nuclei. | [56,61,63,168,169,170] |
| HCpro (56 – 58 K) | cysteine proteinase with cis-cleavage activity, HCpro/P3 cleavage site. Aphid transmission, systemic movement, suppression of gene silencing, symptoms development. | Cytoplasm, aggregates along the endoplasmic reticulum. | [82,171,172,173,174,175] |
| P3 (37 K) | plant pathogenicity – virulence, viral infection cycle. | Crystalline inclusions in cytoplasm and nuclei. Endoplasmic reticulum (punctuate inclusions in association with Golgi) | [86,91,92,169,176,177] |
| 6K1 (6 K?) | cell-to-cell movement?, role in virulence? | The cell periphery. | [94,178,179] |
| CI (70 K) | RNA helicase required for genome replication. Cell-to-cell movement. Long-distance movement. Development of symptoms. Breaking the host resistance. | Cytoplasm, conical structures attached to plasmodesmata. | [95,97,98,99,180] |
| 6K2 | anchoring the viral replication complex to membranes. Long-distance movement. Development of systemic infection. | Crystalline inclusions in cytoplasm and nuclei. | [103,167,169] |
| VPg | covalently links the 5´ end of the viral RNA via tyrosine residue. Viral cycle. Systemic infection. Overcoming the eIF4E-based recessive resistance. | Endoplasmic reticulum, nucleus, nucleolus. | [100,102,104,114,117] |
| NIa-Pro | NIa-pro cysteine proteinase. Host specificity. Host DNA cleavage activity. | Nuclei of infected cells in the form of inclusion bodies. | [71,75] |
| NIb | RNA-dependent RNA polymerase. Genome/viral replication. | Nuclei of infected cells in the form of inclusion bodies. Cytoplasm. | [116,127,131] |
| CP | Aphid transmission. Cell-to-cell and long-distance movement. Virion assembly. | Plasmodesmatal connections between infected leaf mesophyll cells. Cytoplasm of infected cells. | [96,144,145,146,181,182,183] |