Keegan L, Gill G, Ptashne M
Science. 1986 Feb 14;231(4739):699-704. doi: 10.1126/science.3080805.
The yeast GAL4 protein (881 amino acids) binds to specific DNA sites upstream of target genes and activates transcription. Derivatives of this protein bearing as few as 74 amino terminal residues bind to these sites but fail to activate transcription. When appropriately positioned in front of a gene these derivatives act as repressors. These and related findings support the idea that GAL4 activates transcription by touching other DNA-bound proteins.
酵母GAL4蛋白（881个氨基酸）与靶基因上游的特定DNA位点结合并激活转录。这种蛋白的衍生物仅带有74个氨基末端残基，它们能与这些位点结合，但无法激活转录。当这些衍生物适当地定位在基因前时，它们会起到阻遏物的作用。这些以及相关的发现支持了GAL4通过与其他结合在DNA上的蛋白接触来激活转录的观点。
