Bovine papillomavirus type 1 E1 replication-defective mutants are altered in their transcriptional regulation
Bovine papillomavirus type 1 E1 replication-defective mutants are altered in their transcriptional regulation
复制标题
牛乳头瘤病毒 1 型 E1 复制缺陷突变体的转录调控发生改变
作者：
P. Lambert;P. Howley
牛乳头瘤病毒1型（BPV-1）能够在转化的啮齿动物细胞中作为稳定的高拷贝数质粒复制。BPV-1 E1开放阅读框（ORF）编码参与病毒DNA复制的多种功能。破坏E1 ORF翻译完整性的突变使病毒基因组无法作为稳定质粒复制，并导致病毒基因组通常以低拷贝数整合到宿主染色体中。尽管整合基因组的拷贝数较低，但BPV-1 E1突变体非常有效地将啮齿动物细胞转化为锚定独立性，其水平等于或大于野生型（wt）BPV-1。进行研究以提供对为什么这些低拷贝数、复制缺陷型突变体能够表达与wt BPV-1相等或更大的转化潜力的深入了解。病毒RNA分析显示，携带E1突变BPV-1 DNA的细胞中每个病毒基因组的转录速率高于含有wt BPV-1 DNA的细胞。此外，发现与野生型BPV-1转化体相比，在由E1突变DNA转化的细胞中定位P89启动子的病毒RNA水平高15- 35倍。该启动子控制BPV-1 E6转化基因的表达，并受病毒E2基因产物的调节。本报告中提出的研究确定，E1突变体在其E2转录调控中受到干扰，这表明了所观察到的P89诱导的可能解释。在整个E1 ORF中，在先前确定为编码不同复制功能的两个区域中的任一个中的突变在病毒转录中被改变。
Bovine papillomavirus type 1 (BPV-1) is capable of replicating as a stable, high-copy-number plasmid in transformed rodent cells. The BPV-1 E1 open reading frame (ORF) encodes multiple functions involved in viral DNA replication. Mutations which disrupt the translational integrity of the E1 ORF disable the viral genome from replicating as a stable plasmid and result in the integration of the viral genome into the host chromosome generally at a low copy number. Despite the low copy number of the integrated genomes, BPV-1 E1 mutants transform rodent cells to anchorage independence very efficiently, at levels equal to or greater than that of wild-type (wt) BPV-1. Studies were performed to provide insight into why these low-copy-number, replication-defective mutants are capable of expressing an equal or greater transformation potential than wt BPV-1. Analysis of viral RNA revealed higher rates of transcription per viral genome in cells harboring E1 mutated BPV-1 DNA than in cells containing wt BPV-1 DNA. Furthermore, the levels of viral RNA mapping the P89 promoter were found to be 15- to 35-fold higher in cells transformed by E1 mutated DNAs compared with wt BPV-1 transformants. This promoter controls expression of the BPV-1 E6 transforming gene and is regulated by the viral E2 gene products. The studies presented in this report determined that the E1 mutants were perturbed in their E2 transcriptional regulation, suggesting a possible explanation for the observed P89 induction. Mutations throughout the E1 ORF, in either of the two regions previously identified as encoding distinct replication functions, were altered in viral transcription.
具有内部调节域的启动子是 BPV-1 复制起点的一部分。
DOI：
10.1126/science.3037693
发表时间：
1987
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Stenlund,A;Bream,GL;Botchan,MR
通讯作者：
Botchan,MR