Function of ankyrin repeat proteins in cowpox virus (CPXV)

正痘病毒（OPV）基因组由高度保守的中心部分组成，主要编码痘病毒复制的基因，而末端的序列则更加多变。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。其中一组可变基因编码锚蛋白重复序列蛋白（ARPs）。ARPs在真核细胞中很常见，主要介导蛋白质之间的相互作用。痘病毒中的一些ARPs还含有一个额外的c端F-box结构域，该结构域通常与蛋白酶体降解有关。修饰痘苗病毒安卡拉（MVA）仅指定一种由186R基因编码的ARP，该ARP对哺乳动物细胞中病毒生命周期的完成至关重要。序列分析预测CPXV指定了三个具有高序列相似性的ARPs，其中一个称为BR211，代表MVA 186R的同源物。我们假设三种ARPs BR006、BR211和BR220赋予CPXV进入复制后阶段的能力，但它们各自在不同的宿主细胞中起作用。我们进一步推测，这三种CPXV ARPs以一种依赖于病毒复制的特定阶段的方式重新靶向细胞和病毒蛋白。我们将通过两个特定目的来验证我们的假设：1)CPXV或MVA中所有br211样ARPs缺失的细胞类型特异性互补。2) CPXV复制不同阶段br211相互作用蛋白的鉴定。

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.