Edlund T, Walker M D, Barr P J, Rutter W J
Science. 1985 Nov 22;230(4728):912-6. doi: 10.1126/science.3904002.
The 5' flanking DNA of the rat insulin I gene contains sequences controlling cell-specific expression. Analysis of this region by replacement of specific portions with nondiscriminatory control elements from viral systems shows that a transcriptional enhancer is located in the distal portion of the 5' flanking DNA; its position has been mapped by deletion analysis. Additional experiments suggest that another distinct regulatory element is located more proximal to the transcription start site. The activity of both elements is restricted to pancreatic B cells. The combinatorial effect of multiple control elements could explain the cell-specific expression of insulin genes.
大鼠胰岛素I基因的5'侧翼DNA包含控制细胞特异性表达的序列。通过用来自病毒系统的非特异性控制元件替换特定部分对该区域进行分析，结果表明转录增强子位于5'侧翼DNA的远端部分；其位置已通过缺失分析确定。进一步的实验表明，另一个不同的调控元件位于转录起始位点更近的位置。这两个元件的活性都局限于胰腺β细胞。多个控制元件的组合效应可以解释胰岛素基因的细胞特异性表达。
