Stillman B W, Lewis J B, Chow L T, Mathews M B, Smart J E
Cell. 1981 Feb;23(2):497-508. doi: 10.1016/0092-8674(81)90145-8.
The precursor of the 55K adenovirus terminal protein is an 87K protein that is covalently linked to viral DNA. This protein is likely to be identical to the 80,000 dalton protein described by Challberg et al. (1980). The mRNA for the 87K terminal protein precursor, like that for the E2-72K DNA binding protein, is detectable at both early and late times of infection, and its production is sensitive to protein synthesis inhibition (Lewis and Mathews, 1980). The 87K protein, together with proteins of 105,000 and 75,000 daltons, are translated from leftward transcribed (1-strand) messenger RNAs that are complementary to the viral genome between positions 11.2 and 31.5. Additional hybridization to the region between coordinates 37.3 and 41 suggests that the RNA body is spliced to sequences mapping farther right in the genome. Electron microscopic heteroduplex analysis has revealed a family of 1-strand RNAs that probably encode these proteins. The RNA bodies extend from coordinated 30, 26 and 23 to 11.1, with leaders at 39, 68.5 and 75 map units, defining a new adenovirus early region. These RNAs and region E2 RNAs share the first leader and presumably the same promoter, and may be coordinately expressed. Virions of the protease-deficient adenovirus 2 mutant ts1 grown at the restrictive temperature contain only the 87K form; when grown at the permissive temperature they contain both the 87K and 55K forms, and an additional 62K form; wild-type virions contain only the 55K form. Peptide analysis shows all these proteins to be related. The DNA-protein complex containing the 87K form is active as a template for viral DNA replication in vitro. This data supports a model of adenovirus DNA replication in which the 87K terminal protein precursor is the primary translation product and primes DNA synthesis. The 87K precursor is processed curing virus maturation to the 55K terminal protein, possibly via a 62K intermediate form, by the virus-specified Ad2ts1 protease.
55K腺病毒末端蛋白的前体是一种87K的蛋白，它与病毒DNA共价相连。这种蛋白可能与Challberg等人（1980年）描述的80,000道尔顿的蛋白相同。87K末端蛋白前体的mRNA，与E2-72K DNA结合蛋白的mRNA一样，在感染的早期和晚期都能检测到，并且其产生对蛋白质合成抑制敏感（Lewis和Mathews，1980年）。87K蛋白与105,000和75,000道尔顿的蛋白一起，由向左转录（1链）的信使RNA翻译而来，这些信使RNA与病毒基因组在11.2和31.5位置之间互补。与坐标37.3和41之间区域的额外杂交表明，RNA主体与基因组中更右侧的序列拼接。电子显微镜异源双链分析揭示了一个可能编码这些蛋白的1链RNA家族。RNA主体从坐标30、26和23延伸到11.1，在39、68.5和75个图位处有前导序列，定义了一个新的腺病毒早期区域。这些RNA和E2区域的RNA共享第一个前导序列，推测具有相同的启动子，并且可能协同表达。在限制温度下生长的蛋白酶缺陷型腺病毒2突变体ts1的病毒粒子仅含有87K形式；在允许温度下生长时，它们含有87K和55K形式，以及另外一种62K形式；野生型病毒粒子仅含有55K形式。肽分析表明所有这些蛋白都相关。含有87K形式的DNA-蛋白复合物在体外作为病毒DNA复制的模板具有活性。这些数据支持了一种腺病毒DNA复制模型，其中87K末端蛋白前体是主要的翻译产物并引发DNA合成。87K前体在病毒成熟过程中可能通过病毒特异性的Ad2ts1蛋白酶，经由62K中间形式加工成55K末端蛋白。
