Studies on Heterogeniety of General Transcription Factor TFIID

小鼠髓鞘碱性蛋白(MBP)基因从-36到+12的核心启动子是组织特异性(脑)转录的。生化研究表明，TFIID组分含有参与这种特定转录的因子。Tnus.我们假设存在组织特异性的TFIID。我们从小鼠脑中克隆了TFIID基因，并将其结构与人的TFIID基因进行了比较。仅在小鼠TFIID的N-末端部分观察到很少的微小差异。TFIID功能所需的C末端在两个TFIID中是相同的。在小鼠基因组中只检测到一个TFIID基因。Northern印迹分析表明，TFIID转录本在小鼠组织中以相同大小的RNA表达。MBP核心启动子内的突变分析表明，TATA盒不是必需的，但TATA侧翼序列对于组织特异性转录是重要的。从这些结果来看，可能没有组织特异性的TFIID。近年来，TFIID相关因子(TAF)已被其他研究小组发现。在我们的案例中，我们认为组织特异性的TAF可以参与核心启动子介导的组织特异性转录。

The core promoter of the mouse myelin basic protein (MBP) gene from -36 to +12 was tissue-specifically (brain) transcribed. Biochemical studies demonstrated that TFIID fraction contains factors involved in such a specific transcription. Tnus. we hypothesized the existence of a tissuespecific TFIID. We isolated a cDNA clone for TFIID from the mouse brain, and compared its structure with the human TFIID. Few minor differences were observed only in the N-terminal portion of the mouse TFIID. The C-terminus that is required for the TFIID function was identical among two TFIIDs. Only a single TFIID gene was detected in mouse genome. Northern blot analysis demonstated that the TFIID transcript is expressedas the same size RNAs in mouse tissues. Mutation analysis within the MBP core promoter showed that the TATA-box is not essential but TATA-flanking sequences were important for tissue-specific transcription. From these results, there may be no tissue-specific TFIID. In these days, TFIID associating factors (TAF) have been identified by other groups. In our case, it is suggested that a tissue-specific TAF can be involved in the core promoter-mediated tissue-specific transcription.