Weber F, de Villiers J, Schaffner W
Cell. 1984 Apr;36(4):983-92. doi: 10.1016/0092-8674(84)90048-5.
We have transfected monkey CV-1 cells with non-infectious, linear SV40 DNA, lacking the 72 bp repeat enhancer region. Infectious virus was recovered from this "enhancer trap" upon cotransfection with enhancer DNA segments from various viruses, notably a truncated polyoma enhancer that was integrated as a dimer. Cotransfection of the "enhancer trap" with fragmented DNA of mouse, monkey, or human origin yielded no recombinant virus with integrated cellular sequences, with one possible exception. In some transfection experiments without added viral enhancer DNA, SV40 variants were generated that have a segment of their flanking "late" DNA duplicated to substitute for the deleted 72 bp repeat. In one variant, an 88 bp duplication creates a strong enhancer from this nonenhancing DNA region. Both the polyoma enhancer fragment and the spontaneously created enhancers lack the alternating purines-pyrimidines or "CACA box" suggested to be characteristic for enhancer elements and show only limited homology to the "GTGG(AAATTT)G box."
我们用缺乏72bp重复增强子区域的非感染性线性SV40 DNA转染猴CV-1细胞。与来自各种病毒的增强子DNA片段共转染后，从这个“增强子陷阱”中回收了感染性病毒，特别是作为二聚体整合的截短多瘤病毒增强子。将“增强子陷阱”与小鼠、猴或人源的片段化DNA共转染，除了一个可能的例外，未产生带有整合细胞序列的重组病毒。在一些没有添加病毒增强子DNA的转染实验中，产生了SV40变体，其侧翼“晚期”DNA的一段被复制以替代缺失的72bp重复序列。在一个变体中，一个88bp的重复从这个非增强DNA区域产生了一个强增强子。多瘤病毒增强子片段和自发产生的增强子都缺乏被认为是增强子元件特征的交替嘌呤-嘧啶或“CACA盒”，并且与“GTGG(AAATTT)G盒”只有有限的同源性。
