Transcriptional repression of K-Rta by Kaposi's sarcoma-associated herpesvirus K-bZIP is not required for oriLyt-dependent DNA replication.
Transcriptional repression of K-Rta by Kaposi's sarcoma-associated herpesvirus K-bZIP is not required for oriLyt-dependent DNA replication.
复制标题
oriLyt 依赖性 DNA 复制不需要卡波西肉瘤相关疱疹病毒 K-bZIP 对 K-Rta 的转录抑制。
DOI：
10.1016/j.virol.2007.08.019
复制
发表时间：
2007
期刊：
影响因子：
3.7
通讯作者：
Pari,Gregory
中科院分区：
文献类型：
--
作者：
Rossetto,Cyprian;Gao,Yang;Yamboliev,Irena;Papousková,Iva;Pari,Gregory
卡波西肉瘤相关疱疹病毒来源依赖的DNA复制需要核心复制蛋白加上K-RTA和K-bZIP。为了确定哪些K-bZIP蛋白结构域参与了oriLyt依赖的DNA复制，并有助于抑制K-RTA介导的转录激活，我们在K-bZIP ORF中构建了一系列缺失结构和定点突变。亮氨酸拉链(LZ)基序中关键亮氨酸残基的突变消除了蛋白质同源二聚化和补充依赖于Lyt的DNA复制的能力。碱性氨基酸区域(BR)或LZ结构域的缺失并不影响K-bZIP与K-RTA的结合能力，表明这两个区域都有助于与K-RTA的异源二聚反应。然而，即使在存在K-bZIP-K-RTA相互作用的情况下，LZ和BR中引入的缺失或突变也会导致K-bZIP的抑制活性消除。有趣的是，缺乏抑制K-RTA反式激活能力的突变体仍然能够补充oriLyt依赖的DNA复制，表明这种活性并不有助于K-bZIP的DNA合成相关活性。
Kaposi's sarcoma-associated herpesvirus origin-dependent DNA replication requires the core replication proteins plus K-Rta and K-bZIP. To determine which K-bZIP protein domains contribute to oriLyt-dependent DNA replication and facilitate suppression of K-Rta-mediated transcriptional activation, we generated a series of deletion constructs and site-directed mutations within the K-bZIP ORF. Mutation of key leucine residues within the putative leucine zipper (LZ) motif eliminated the ability of the protein to homodimerize and complement oriLyt-dependent DNA replication. Deletion of the basic amino acid region (BR) or LZ domain did not affect the ability of K-bZIP to bind to K-Rta indicating that either region contributes to heterodimerization with K-Rta. However, deletions or mutations introduced into both the LZ and BR resulted in elimination of the suppressive activity of K-bZIP even in the presence of a K-bZIP–K-Rta interaction. Interestingly, mutants that lacked the ability to suppress K-Rta transactivation were still capable of complementing oriLyt-dependent DNA replication, indicating that this activity does not contribute to the DNA synthesis-related activity of K-bZIP.