Function of the 30 kd protein of tobacco mosaic virus: involvement in cell-to-cell movement and dispensability for replication
AUTOR(ES)
Meshi, Tetsuo
RESUMO
We have investigated the function of the 30 kd protein of tobacco mosaic virus (TMV) by a reverse genetics approach. First, a point mutation of TMV Ls1 (a temperature-sensitive mutant defective in cell-to-cell movement), that causes an amino acid substitution in the 30 kd protein, was introduced into the parent strain, TMV L. The generated mutant showed the same phenotype as TMV Ls1, and therefore the one-base substitution in the 30 kd protein gene adequately explains the defectiveness of TMV Ls1. Next, four kinds of frame-shift mutants were constructed, whose mutations are located at three different positions of the 30 kd protein gene. All the frame-shift mutants were replication-competent in protoplasts but none showed infectivity on tobacco plants. From these observations the 30 kd protein was confirmed to be involved in cell-to-cell movement. To clarify that the 30 kd protein is not necessary for replication, two kinds of deletion mutants were constructed; one lacking most of the 30 kd protein gene and the other lacking both the 30 kd and coat protein genes. Both mutants replicated in protoplasts and the former still produced the subgenomic mRNA for the coat protein. These results clearly showed that the 30 kd protein, as well as the coat protein, is dispensable for replication and that no cis-acting element for replication is located in their coding sequences. It is also suggested that the signal for coat protein mRNA synthesis may be located within about 100 nucleotides upstream of the initiation codon of the coat protein gene.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=553674Documentos Relacionados
- Regulation of plasmodesmal transport by phosphorylation of tobacco mosaic virus cell-to-cell movement protein
- Salicylic Acid Has Cell-Specific Effects on Tobacco mosaic virus Replication and Cell-to-Cell Movement1
- Interaction between the tobacco mosaic virus movement protein and host cell pectin methylesterases is required for viral cell-to-cell movement
- Characterization of mutant tobacco mosaic virus coat protein that interferes with virus cell-to-cell movement
- Functional Analysis of a DNA-Shuffled Movement Protein Reveals That Microtubules Are Dispensable for the Cell-to-Cell Movement of Tobacco mosaic virus