Phosphorylation of the p33 replication protein of Cucumber necrosis tombusvirus adjacent to the RNA binding site affects viral RNA replication.
Phosphorylation of the p33 replication protein of Cucumber necrosis tombusvirus adjacent to the RNA binding site affects viral RNA replication.
复制标题
黄瓜坏死烟草病毒的 p33 复制蛋白与 RNA 结合位点相邻的磷酸化会影响病毒 RNA 复制。
DOI：
10.1016/j.virol.2005.08.006
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Nagy,PeterD
中科院分区：
文献类型：
--
作者：
Shapka,Natalia;Stork,Jozsef;Nagy,PeterD
Replication of the nonsegmented, plus-stranded RNA genome of Cucumber necrosis tombusvirus (CNV) requires two essential overlapping viral-coded replication proteins, the p33 replication co-factor and the p92 RNA-dependent RNA polymerase. In this paper, we demonstrate that p33 is phosphorylated in vivo and in vitro by a membrane-bound plant kinase. Phosphorylation of p33 was also demonstrated in vitro by using purified protein kinase C. The related p28 replication protein of Turnip crinkle virus was also found to be phosphorylated in vivo, suggesting that posttranslational modification of replication proteins is a general feature among members of the large Tombusviridae family. Based on in vitro studies with purified recombinant p33, we show evidence for phosphorylation of threonine and serine residues adjacent to the essential RNA-binding site in p33. Phosphorylation-mimicking aspartic acid mutations rendered p33 nonfunctional in plant protoplasts and in yeast, a model host. Comparable mutations within the prereadthrough portion of p92 did not abolish replication. The nonphosphorylation-mimicking alanine mutants of CNV were able to replicate in plant protoplasts and in yeast, albeit with reduced efficiency when compared to the wild type. These alanine mutants also showed altered subgenomic RNA synthesis and a reduction in the ratio between plus- and minus-strand RNAs produced during CNV infection. These findings suggest that phosphorylation of threonine/serine residues adjacent to the essential RNA-binding site in the auxiliary p33 protein likely plays a role in viral RNA replication and subgenomic RNA synthesis during tombusvirus infections.
