Role of P30 in replication and spread of TMV

The P30 movement protein (MP) of tobacco mosaic virus is essential for dist ribution of sites of replication within infected cells and for cell-cell sp read of infection. MP is an integral membrane protein and in early and mid- stages of infection causes severe disruption of the cortical endoplasmic re ticulum (ER). MP also associates with microtubules, and in late stages is t argeted for degradation by the 26S proteosome. During these stages, the ER regains its normal pre-infection configuration. Viral RNA is associated wit h ER and microtubules in the presence of MP. The MP is phosphorylated and m utation of the phosphorylated amino acid reduced association of MP with the ER, plasmodesmata, and microtubules, and altered the stability of the MP. The nature of the association of MP with vRNA and ER and microtubules, and the role of phosphorylation of MP in each of these functions, if any, remai ns to be determined.