Sadowski C L, Henry R W, Lobo S M, Hernandez N
Cold Spring Harbor Laboratory, New York 11724.
Genes Dev. 1993 Aug;7(8):1535-48. doi: 10.1101/gad.7.8.1535.
In the human small nuclear RNA (snRNA) promoters, the presence of a TATA box recognized by the TATA box-binding protein (TBP) determines the selection of RNA polymerase III over RNA polymerase II. The RNA polymerase II snRNA promoters are, therefore, good candidates for TBP-independent promoters. We show here, however, that TBP activates transcription from RNA polymerase II snRNA promoters through a non-TATA box element, the snRNA proximal sequence element (PSE), as part of a new snRNA-activating protein complex (SNAPc). In contrast to the previously identified TBP-containing complexes SL1, TFIID, and TFIIIB, which appear dedicated to transcription by a single RNA polymerase, SNAPc is also essential for RNA polymerase III transcription from the U6 snRNA promoter. The U6 initiation complex appears to contain two forms of TBP, one bound to the TATA box and one bound to the PSE as a part of SNAPc, suggesting that multiple TBP molecules can have different functions within a single promoter.
在人类小核RNA（snRNA）启动子中，由TATA框结合蛋白（TBP）识别的TATA框的存在决定了RNA聚合酶III相对于RNA聚合酶II的选择。因此，RNA聚合酶II snRNA启动子是不依赖TBP的启动子的良好候选者。然而，我们在此表明，TBP通过一个非TATA框元件，即snRNA近端序列元件（PSE），作为一种新的snRNA激活蛋白复合物（SNAPc）的一部分，激活来自RNA聚合酶II snRNA启动子的转录。与先前鉴定的含TBP的复合物SL1、TFIID和TFIIIB不同，它们似乎专门用于单一RNA聚合酶的转录，SNAPc对于从U6 snRNA启动子进行的RNA聚合酶III转录也是必不可少的。U6起始复合物似乎包含两种形式的TBP，一种与TATA框结合，一种作为SNAPc的一部分与PSE结合，这表明多个TBP分子在单个启动子内可以具有不同的功能。
