Diagana T T, North D L, Jabet C, Fiszman M Y, Takeda S, Whalen R G
Département de Biologie Moleulaire, Institut Pasteur, Paris, France.
J Mol Biol. 1997 Feb 7;265(5):480-93. doi: 10.1006/jmbi.1996.0752.
We have previously characterized the proximal promoter of the mouse IIB myosin heavy chain (MyHC) gene, which is expressed only in fast-contracting glycolytic skeletal muscle fibers. We show here that the substitution into this promoter of a non-canonical TATA sequence from the IgH gene results in inactivity in muscle cells, even though TATA-binding protein (TBP) can bind strongly to this mutated promoter. Chemical foot-printing data show, however, that TBP makes different DNA contacts on this heterologous TATA sequence. The inactivity of such a non-canonical TATA motif in the IIB promoter context appears to be caused by a non-functional conformation of the bound TBP-DNA complex that is incapable of sustaining transcription. The conclusions imply that the precise sequence of the promoter TATA motif needs to be matched with the specific functional class of upstream activator proteins present in a given cell type in order for the gene to be transcriptionally active.
我们之前已对小鼠IIB型肌球蛋白重链（MyHC）基因的近端启动子进行了特征描述，该基因仅在快速收缩的糖酵解型骨骼肌纤维中表达。我们在此表明，将来自IgH基因的非典型TATA序列替换到该启动子中会导致其在肌肉细胞中无活性，尽管TATA结合蛋白（TBP）能与这个突变启动子强烈结合。然而，化学足迹数据显示，TBP在这个异源TATA序列上形成了不同的DNA接触。在IIB启动子环境中，这种非典型TATA基序的无活性似乎是由结合的TBP-DNA复合物的无功能构象导致的，这种构象无法维持转录。这些结论意味着，启动子TATA基序的精确序列需要与特定细胞类型中存在的上游激活蛋白的特定功能类别相匹配，以便基因能够进行转录激活。
