Ikeda J E, Enomoto T, Hurwitz J
Proc Natl Acad Sci U S A. 1982 Apr;79(8):2442-6. doi: 10.1073/pnas.79.8.2442.
The initiation of DNA chains by the 80-kilodalton form of the adenovirus terminal protein has been studied. This protein, which can be covalently linked to dCMP, is isolated complexed to a 140-kilodalton protein possessing DNA polymerase activity. In the presence of adenovirus DNA-protein, the formation of the 80-kilodalton protein-dCMP complex requires the addition of ATP and nuclear extract from uninfected cells in addition to Mg2+ and dCTP. When single-stranded DNA is used in place of the adenovirus DNA-protein, the formation of the 80-kilodalton protein-dCMP complex occurs in the absence of ATP and nuclear extract. In the presence of the four dNTPs, the complex yields DNA chains of various sizes between 100 and 300 nucleotides. The products formed with bacteriophage phi X174 single-stranded circular DNA as the template are site specific, predominantly derived from the sequences between nucleotides 2363 and 2977 and between nucleotides 3760 and 4206. These small dNA chains are blocked at their 5' ends with the 80-kilodalton protein but possess free 3'-OH ends that are susceptible to degradation by exonuclease III and can be elongated to replicative form II products with DNA polymerase I of Escherichia coli or eukaryotic DNA polymerase beta preparations. A protein priming model explaining the different requirements for initiation with adenovirus DNA-protein and with phi X174 DNA is presented.
对腺病毒末端蛋白80千道尔顿形式引发DNA链的过程进行了研究。这种能与dCMP共价连接的蛋白质，是与一种具有DNA聚合酶活性的140千道尔顿蛋白质复合分离得到的。在腺病毒DNA - 蛋白质存在的情况下，80千道尔顿蛋白质 - dCMP复合物的形成除了需要Mg2+和dCTP外，还需要添加ATP和未感染细胞的核提取物。当用单链DNA代替腺病毒DNA - 蛋白质时，80千道尔顿蛋白质 - dCMP复合物的形成在没有ATP和核提取物的情况下也会发生。在四种dNTP存在的情况下，该复合物产生大小在100至300个核苷酸之间的各种DNA链。以噬菌体φX174单链环状DNA为模板形成的产物具有位点特异性，主要源自核苷酸2363至2977以及核苷酸3760至4206之间的序列。这些小DNA链在其5'端被80千道尔顿蛋白质封闭，但具有游离的3'-OH末端，易被核酸外切酶III降解，并且可以用大肠杆菌的DNA聚合酶I或真核DNA聚合酶β制剂延伸为复制型II产物。本文提出了一个蛋白质引发模型，解释了用腺病毒DNA - 蛋白质和φX174 DNA引发时的不同要求。
