IDENTIFICATION OF RPO30, A VACCINIA VIRUS-RNA POLYMERASE GENE WITH STRUCTURAL SIMILARITY TO A EUKARYOTIC TRANSCRIPTION ELONGATION-FACTOR
IDENTIFICATION OF RPO30, A VACCINIA VIRUS-RNA POLYMERASE GENE WITH STRUCTURAL SIMILARITY TO A EUKARYOTIC TRANSCRIPTION ELONGATION-FACTOR
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DOI：
10.1128/mcb.10.10.5433
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发表时间：
1990-10-01
影响因子：
5.3
通讯作者：
MOSS, B
中科院分区：
文献类型：
--
作者：
AHN, BY;GERSHON, PD;MOSS, B
通过增加特异性或随机起始的RNA链的延伸效率来刺激RNA聚合酶II的真核转录因子已经被分离和表征。我们已经确定了一个30千道尔顿（kDa）的Vccinia病毒编码的蛋白与SII，34 kDa的哺乳动物转录延伸因子具有明显的同源性。除了氨基酸序列的相似性，这两种蛋白质含有C-末端推定的锌指结构域。通过使用纯化的病毒RNA聚合酶的抗体对通过与病毒基因组的克隆DNA片段杂交而选择的体内合成的早期mRNA的体外翻译产物进行免疫沉淀，来鉴定编码牛痘病毒蛋白的基因rpo 30。Western免疫印迹分析表明，30 kDa的蛋白质仍然与高度纯化的病毒RNA聚合酶。因此，与其真核同源物不同，牛痘病毒蛋白是一个完整的RNA聚合酶亚基，而不是一个容易分离的转录因子。进一步的研究表明，rpo 30的表达受早期和晚期双重启动子调控。
Eucaryotic transcription factors that stimulate RNA polymerase II by increasing the eficiency of elongation of specifically or randomly initiated RNA chains have been isolated and characterized. We have identified a 30-kilodalton (kDa) vccinia virus-encoded protein with apparent homology to SII, a 34-kDa mammalian transcriptional elongation factor. In addition to amino acid sequence similarities, both proteins contain C-terminal putative zinc finger domains. Identification of the gene, rpo30, encoding the vaccinia virus protein was achieved by using antibody to the purified viral RNA polymerase for immunoprecipitation of the in vitro translation products of in vivo-synthesized early mRNA selected by hybridization to cloned DNA fragments of the viral genome. Western immunoblot analysis using antiserum made to the vaccinia rpo30 protein expressed in bacteria indicated that the 30-kDa protein remains associated with highly purified viral RNA polymerase. Thus, the vaccinia virus protein, unlike its eucaryotic homolog, is an integral RNA polymerase subunit rather than a readily separable transcription factor. Further studies showed that the expression of rpo30 is regulated by dual early and later promoters.