Function of ankyrin repeat proteins in cowpox virus (CPXV)

正痘病毒（OPV）基因组由高度保守的主要编码痘病毒复制基因的中心部分组成，而朝向末端的序列更易变。在这些区域发现的基因编码控制毒力和免疫调节的蛋白质。这些可变基因中的一组编码锚蛋白重复蛋白（ARPs）。ARPs在真核细胞中很常见，主要介导蛋白质-蛋白质相互作用。痘病毒中的一些ARPs还含有额外的C末端F盒结构域，其通常与蛋白酶体降解有关。改良的安卡拉牛痘病毒（MVA）仅指定一种阿普，其由基因186 R编码并且对于完成哺乳动物细胞中的病毒生命周期是必需的。序列分析预测，CPXV指定了三个具有高度序列相似性的ARP，其中一个称为BR 211，代表MVA 186 R的直系同源物。 我们假设三个ARPs BR 006、BR 211和BR 220使CPXV过渡到复制后阶段，但是每个ARPs在不同的宿主细胞中这样做。我们进一步推测，这三种CPXV ARPs以依赖于病毒复制的某些阶段的方式重新靶向细胞和病毒蛋白。我们将通过两个具体目的来检验我们的假设：1）CPXV或MVA中所有BR 211样ARP缺失的细胞类型特异性互补。2)在CPXV复制的不同阶段识别BR 211相互作用蛋白。

Orthopoxvirus (OPV) genomes consist of a highly conserved central portion primarily encoding genes for poxvirus replication, while sequences towards the ends are more variable. Genes found in these regions encode proteins that govern virulence and immune modulation. One group of these variable genes encode for ankyrin repeat proteins (ARPs). ARPs are common in eukaryotic cells and mainly mediate protein-protein interactions. Some of the ARPs in poxviruses also contain an additional Cterminal F-box domain that is commonly linked to proteasomal degradation. Modified vaccinia virus Ankara (MVA) only specifies one ARP that is encoded by gene 186R and is essential for completion of the viral life cycle in mammalian cells. Sequence analysis predicts that CPXV specifies three ARPs that share high sequence similarity, one of which is called BR211 and represents the orthologue of MVA 186R. We hypothesize that the three ARPs BR006, BR211 and BR220 confer transition into the post-replicative phase of CPXV but that each does so in different sets of host cells. We further surmise that the three CPXV ARPs retarget cellular and viral proteins in a fashion that is dependent on certain phases of virus replication. We will test our hypothesis by two specific aims: 1) Cell-type specific complementation of the deletion of all BR211-like ARPs in CPXV or MVA. 2) Identification of BR211-interacting proteins in different phases of CPXV replication.