DNA Replication and Gene Expression of Chlorella Viruses

描述(由申请者提供)：我们的长期目标是 大(&gt；330 kb)dsDNA，空斑形成病毒家族，可感染 单细胞、真核的类小球藻绿藻。奇奥雷拉病毒类型， PBCV-1编码375个蛋白质和10个tRNA。许多PBCV-1编码的酶是 他们的功能类别中最小的代表。因此，其中一些 酶是密集的物理和生物化学研究的对象。这个 小球藻病毒还有其他不同寻常的特征，包括：i)它们编码 多种DNA甲基转移酶和DNA限制性内切酶。Ii)它们是 第一种病毒的基因组中有三种类型的内含子。Iii) 系统发育分析表明，这些病毒有很长的进化历史， 这表明病毒特有的途径可能与祖先的形式非常相似。 这项建议侧重于这些病毒独有的两个特征。第一, 与其他含有糖蛋白的病毒不同，PBCV-1编码大部分 使其主要衣壳蛋白糖基化的机器。此外，积累 实验证据表明，糖基化是细胞质的，而不是 让急诊室或高尔基人参与进来。我们建议继续调查三个方面的问题 这一糖基化过程：I)鉴定和鉴定PBCV-1基因 参与糖基化的。Ii)确定细胞内的位置 蛋白质糖基化。Iii)确定复合糖的结构。 这些实验将为开始研究 低聚糖的生物合成。第二，PBCV-1编码94个氨基酸 蛋白质，称为Kcv，在青蛙卵母细胞中形成K+选择性通道。Kcv 蛋白质是迄今为止发现的最小的K+通道蛋白质，也是系统发育中最小的 分析表明，Kcv可能是更复杂的离子通道的原始形式 蛋白质。我们建议开始研究Kcv在PBCV-1中的作用 复制。

DESCRIPTION (provided by applicant): Our long-range goal is to characterize a family of large (>330 kb) dsDNA, plaque-forming viruses, which infect unicellular, eukaryotic chiorella-like green algae. The type chiorella virus, PBCV-1, encodes 375 proteins and 10 tRNAs. Many PBCV-1 encoded enzymes are the smallest representatives of their functional class. Consequently some of these enzymes are the subject of intense physical and biochemical investigation. The chlorella viruses have other unusual features including: i) They encode multiple DNA methyltransferases and DNA restriction endonucleases. ii) They are the first viruses with three types of introns in their genome. iii) Phylogenetic analyses suggest these viruses have a long evolutionary history, indicating that virus-specific pathways may closely resemble ancestral forms. This proposal focuses on two features that are unique to these viruses. First, unlike other glycoprotein containing viruses, PBCV-1 encodes most of the machinery to glycosylate its major capsid protein. Furthermore, accumulating experimental evidence indicates that glycosylation is cytoplasmic and does not involve the ER or Golgi. We propose to continue investigating three aspects of this glycosylation process: i) To identify and characterize the PBCV-1 genes involved in glycosylation. ii) To determine the intracellular location of protein glycosylation. iii) To determine the structure of the complex glycan. These experiments will provide a solid foundation to begin investigating the biosynthesis of the oligosaccharide. Second, PBCV-1 encodes a 94 amino acid protein, named Kcv, that forms a K+ selective channel in frog oocytes. The Kcv protein is the smallest K+ channel protein identified to date and phylogenetic analyses indicate that Kcv may be a primitive form of more complex ion channel proteins. We propose to initiate studies on the role of Kcv in PBCV-1 replication.