Gutierrez Crisanto, Ramirez-Parra Elena, Mar Castellano M, Sanz-Burgos Andres P, Luque Alejandro, Missich Riccardo
Centro de Biologia Molecular "Severo Ochoa", Consejo Superior de Investigaciones Cientificas and Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
Vet Microbiol. 2004 Feb 4;98(2):111-9. doi: 10.1016/j.vetmic.2003.10.012.
The Geminiviridae family includes a large number of viruses that infect plants and have a unique geminate virion particle, a single-stranded genome of approximately 2.6-3.0 kb, and replicate through a rolling-circle mechanism. Since they encode for just a few proteins (4-6 depending on the members that belong to four different genera), a rich variety of interactions has evolved between viral proteins and host factors to develop the virus replicative cycle. Among them, we have been particularly interested so far: (i). in the interference with cell cycle regulatory proteins of the retinoblastoma-related (RBR)/E2F pathway and (ii). in the interaction with host DNA replication factors necessary for the assembly of a functional replication complex at the viral origin of DNA replication during the rolling-circle stage. Yeast two-hybrid assays revealed that wheat dwarf virus RepA protein, but nor Rep protein, interacts with plant RBR protein. Interestingly, deletion of the C-terminal domain of Rep confers the truncated protein the ability to interact with RBR, suggesting that this domain may hinder the LXCXE RBR-binding motif. Secondary structure predictions support such a possibility.
双生病毒科包含大量感染植物的病毒，这些病毒具有独特的双联体病毒粒子、约2.6 - 3.0 kb的单链基因组，并通过滚环机制进行复制。由于它们仅编码少数几种蛋白质（根据属于四个不同属的成员，有4 - 6种），病毒蛋白与宿主因子之间已进化出丰富多样的相互作用，以形成病毒复制周期。其中，到目前为止我们特别感兴趣的是：（i）. 对视网膜母细胞瘤相关（RBR）/E2F途径的细胞周期调节蛋白的干扰；（ii）. 在滚环阶段，与在病毒DNA复制起点组装功能性复制复合体所需的宿主DNA复制因子的相互作用。酵母双杂交试验表明，小麦矮缩病毒RepA蛋白而非Rep蛋白与植物RBR蛋白相互作用。有趣的是，Rep蛋白C末端结构域的缺失赋予了截短蛋白与RBR相互作用的能力，这表明该结构域可能会阻碍LXCXE RBR结合基序。二级结构预测支持了这种可能性。
