Cohen G L, Wright P J, DeLucia A L, Lewton B A, Anderson M E, Tegtmeyer P
J Virol. 1984 Jul;51(1):91-6. doi: 10.1128/JVI.51.1.91-96.1984.
We inserted a single base pair into the center of a 27-base-pair palindrome within the replication origin of simian virus 40. The mutation did not directly alter the symmetry of the palindrome or the protein-binding sequences within the palindrome. DNA binding studies showed that subunits of the simian virus 40 A protein (T antigen) bound to each of the four recognition pentanucleotides in the origin palindrome but did so with reduced affinity in comparison with wild-type origins. The mutant origin cloned in a plasmid DNA failed to replicate in COS cells. Thus, precise spatial interactions among subunits of A protein are necessary for stable origin binding and are crucial for subsequent steps in the initiation of DNA replication. Furthermore, any possible functional interactions of the simian virus 40 A protein with cellular DNA would require a great fidelity of protein binding arrangements to initiate cellular DNA replication.
我们在猴病毒40复制起点内一个27个碱基对的回文序列中心插入了一个单碱基对。该突变并未直接改变回文序列的对称性或回文序列内的蛋白质结合序列。DNA结合研究表明,猴病毒40 A蛋白(T抗原)的亚基与起点回文序列中的四个识别五核苷酸中的每一个结合,但与野生型起点相比,其结合亲和力降低。克隆到质粒DNA中的突变起点在COS细胞中无法复制。因此,A蛋白亚基之间精确的空间相互作用对于稳定的起点结合是必要的,并且对于DNA复制起始的后续步骤至关重要。此外,猴病毒40 A蛋白与细胞DNA之间任何可能的功能相互作用都需要蛋白质结合排列具有高度保真度才能启动细胞DNA复制。