School of Biomedical Sciences, University of Ulster, Coleraine, UK.
Biochem Biophys Res Commun. 2010 Jan 29;392(1):77-82. doi: 10.1016/j.bbrc.2009.12.172. Epub 2010 Jan 6.
In yeast, TATA box-binding protein TBP can be delivered to protein-coding genes by direct interactions with two different coactivators: TFIID, which delivers TBP preferentially to TATA-less promoters, and SAGA, which strongly favors TATA box-containing promoters. Transcriptional activators of SAGA-dependant genes are characterized by prototypic acidic activation domains (ADs) that efficiently recruit SAGA, but not TFIID, to UAS elements even in the absence of a core promoter. In contrast to the well-studied acidic activation domains, little is known about the activation domains of activators of TFIID-dependent genes, even though these genes constitute more than 80% of eukaryotic protein-coding genes. The paradigm for TATA-less genes are the ribosomal protein genes (RPGs). Here we have identified the AD of the RPG activator Ifh1p and demonstrate that a minimal Ifh1 AD represents a new class of AD that significantly differs from acidic ADs in amino acid signature, relative coactivator affinities, and core promoter selectivity.
在酵母中，TATA 结合蛋白 TBP 可以通过与两种不同的共激活因子直接相互作用被递送到蛋白质编码基因：TFIID，它优先将 TBP 递送到 TATA 缺失启动子，而 SAGA 则强烈偏好含有 TATA 框的启动子。SAGA 依赖性基因的转录激活因子的特征是典型的酸性激活结构域（AD），即使在没有核心启动子的情况下，这些 AD 也能有效地招募 SAGA，但不能招募 TFIID，到 UAS 元件。与研究充分的酸性激活结构域相比，对于 TFIID 依赖性基因的激活结构域知之甚少，尽管这些基因构成了超过 80%的真核蛋白编码基因。TATA 缺失基因的范例是核糖体蛋白基因（RPGs）。在这里，我们已经确定了 RPG 激活因子 Ifh1p 的 AD，并证明了最小的 Ifh1 AD 代表了一类新的 AD，它在氨基酸特征、相对共激活因子亲和力和核心启动子选择性方面与酸性 AD 显著不同。
