Ondek B, Gloss L, Herr W
Cold Spring Harbor Laboratory, New York 11724.
Nature. 1988 May 5;333(6168):40-5. doi: 10.1038/333040a0.
The SV40 transcriptional enhancer is composed of separate 15 to 20 base-pair-(bp)-long enhancer elements that cooperate with one another or duplicates of themselves to enhance transcription. These elements are bipartite, being composed of subunits, called enhansons, that can be duplicated or interchanged to create new enhancer elements. Enhansons differ from the enhancer elements because they are very sensitive to changes in spacing. This prototypic enhancer, therefore, contains two distinct levels of organization, each of which requires redundancy to be effective.
SV40转录增强子由单独的15至20个碱基对（bp）长的增强子元件组成，这些元件相互协作或自身重复以增强转录。这些元件是二分体的，由称为增强子子单元的亚基组成，这些亚基可以重复或互换以产生新的增强子元件。增强子子单元与增强子元件不同，因为它们对间距变化非常敏感。因此，这种典型的增强子包含两个不同的组织层次，每个层次都需要冗余才能有效。
