Dorsett D, Deichaite I, Winocour E
Mol Cell Biol. 1985 Apr;5(4):869-80. doi: 10.1128/mcb.5.4.869-880.1985.
Linear forms of simian virus 40 (SV40) DNA, when added to transfection mixtures containing circular SV40 and phi X174 RFI DNAs, enhanced the frequency of SV40/phi X174 recombination, as measured by infectious center in situ plaque hybridization in monkey BSC-1 cells. The sequences required for the enhancement of recombination by linear DNA reside within the SV40 replication origin/regulatory region (nucleotides 5,171 to 5,243/0 to 128). Linearization of phi X174 RFI DNA did not increase the recombination frequency. The SV40/phi X174 recombinant structures arising from transfections supplemented with linear forms of origin-containing SV40 DNA contained phi X174 DNA sequences interspersed within tandem head-to-tail repeats derived from the recombination-enhancing linear DNA. Evidence is presented that the tandem repeats are not formed by homologous recombination and that linear forms of SV40 DNA must compete with circular SV40 DNA for the available T antigen to enhance recombination. We propose that the enhancement of recombination by linear SV40 DNA results from the entry of that DNA into a rolling circle type of replication pathway which generates highly recombinogenic intermediates.
将猴病毒40(SV40)DNA的线性形式添加到含有环状SV40和φX174 RFI DNA的转染混合物中时,如通过猴BSC - 1细胞中的感染中心原位噬菌斑杂交所测定的,会提高SV40/φX174重组的频率。线性DNA增强重组所需的序列位于SV40复制起点/调控区域内(核苷酸5171至5243/0至128)。φX174 RFI DNA的线性化并未增加重组频率。在补充了含起点的SV40 DNA线性形式的转染中产生的SV40/φX174重组结构,含有穿插在源自增强重组的线性DNA的串联头对头重复序列中的φX174 DNA序列。有证据表明串联重复不是由同源重组形成的,并且SV40 DNA的线性形式必须与环状SV40 DNA竞争可用的T抗原以增强重组。我们提出,线性SV40 DNA增强重组是由于该DNA进入滚环型复制途径,该途径产生高度重组的中间体。