Human herpesvirus 6 (HHV-6) ORF-1 transactivating gene exhibits malignant transforming activity and its protein binds to p53.
Human herpesvirus 6 (HHV-6) ORF-1 transactivating gene exhibits malignant transforming activity and its protein binds to p53.
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人类疱疹病毒 6 (HHV-6) ORF-1 反式激活基因具有恶性转化活性，其蛋白与 p53 结合。
DOI：
10.1038/sj.onc.1200840
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发表时间：
1997
期刊：
影响因子：
8
通讯作者：
Rosenthal,LJ
中科院分区：
文献类型：
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作者：
Kashanchi,F;Araujo,J;Doniger,J;Muralidhar,S;Hoch,R;Khleif,S;Mendelson,E;Thompson,J;Azumi,N;Brady,JN;Luppi,M;Torelli,G;Rosenthal,LJ
人类疱疹病毒6型Sali-L片段中的357个氨基酸开放阅读框架1，也被称为DR7，显示出人类免疫缺陷病毒1型(HIV1)长末端重复序列启动子的反式激活和HIV-1复制的增加(Kashanchi等，病毒学，201，95-106,1994)。在本研究中，Sali-L转化区定位于Sali-L-SH亚片段。将序列分析鉴定为Sali-L-SH的ORF克隆到哺乳动物表达载体pBK-CMV中。仅pBK/ORF1转化NIH3T3细胞。此外，表达ORF-1蛋白的细胞在注射到裸鼠体内时会产生纤维肉瘤，而不表达ORF-1蛋白或C端截短(在残基172之后)ORF-1蛋白的对照细胞不会产生肿瘤。从肿瘤中提取的蛋白质的Western印迹分析显示ORF-1蛋白。免疫共沉淀实验表明，ORF-1蛋白与肿瘤抑制蛋白P53结合，P53上的ORF-1结合域位于P53的第28~187位残基之间，与特定的DNA结合域重叠。功能研究表明，P53激活的转录在ORF-1中被抑制，但在截短的ORF-1表达细胞中不受抑制。重要的是，截短的ORF-1突变体也没有引起转化。用聚合酶链式反应对几种人类肿瘤进行分析，发现在一些血管免疫母细胞淋巴结病、霍奇金淋巴瘤和非霍奇金淋巴瘤以及胶质母细胞瘤中存在ORF-1DNA序列。检测人类肿瘤中的ORF-1序列，虽然本身并不是证据，但却是确定其在肿瘤发展中的作用的先决条件。综上所述，结果表明ORF-1是一种HHV-6癌基因，与P53结合并影响P53。ORF-1中既有转化活性又有反式激活活性的鉴定是其他病毒癌基因的特征，也是HHV-6的首次报道。
The 357 amino acid open reading frame 1 (ORF-1), also designated DR7, within the SalI-L fragment of human herpesvirus 6 (HHV-6) exhibited transactivation of the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) promoter and increased HIV-1 replication (Kashanchi et al., Virology, 201, 95–106, 1994). In the current study, the SalI-L transforming region was localized to the SalI-L-SH subfragment. Several ORFs identified in SalI-L-SH by sequence analysis were cloned into a selectable mammalian expression vector, pBK-CMV. Only pBK/ORF1 transformed NIH3T3 cells. Furthermore, cells expressing ORF-1 protein produced fibrosarcomas when injected into nude mice, whereas control cells, expressing either no ORF-1 protein or C-terminal truncated (after residue 172) ORF-1 protein, were not tumorigenic. Western blot analysis of proteins extracted from the tumors revealed ORF-1 protein. Additional studies indicated that ORF-1 was expressed in HHV-6-infected human T-cells by 18 h. Co-immunoprecipitation experiments showed that ORF-1 protein bound to tumor suppressor protein p53, and the ORF-1 binding domain on p53 was located between residues 28 and 187 of p53, overlapping with the specific DNA binding domain. Functional studies showed that p53-activated transcription was inhibited in ORF-1, but not in truncated ORF-1, expressing cells. Importantly, the truncated ORF-1 mutant also failed to cause transformation. Analysis of several human tumors by PCR revealed ORF-1 DNA sequences in some angioimmunoblastic lymphadenopathies, Hodgkin's and non-Hodgkin's lymphomas and glioblastomas. The detection of ORF-1 sequences in human tumors, while not proof per se, is a prerequisite for establishing its role in tumor development. Taken together, the results demonstrate that ORF-1 is an HHV-6 oncogene that binds to and affects p53. The identification of both transforming and transactivating activities within ORF-1 is a characteristic of other viral oncogenes and is the first reported for HHV-6.