Michel B, Komarnitsky P, Buratowski S
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Mol Cell. 1998 Nov;2(5):663-73. doi: 10.1016/s1097-2765(00)80164-1.
In yeast, the TBP-associated factors (TAFs) Taf17, Taf60, and Taf61(68) resemble histones H3, H4, and H2B, respectively. To analyze their roles in vivo, conditional alleles were isolated by mutagenizing their histone homology domains. Conditional alleles of TAF17 or TAF60 can be specifically suppressed by overexpression of any of the other histone-like TAFs. This and other genetic evidence supports the model of a histone octamer-like structure within TFIID. Shifting strains carrying the conditional TAF alleles to non-permissive conditions results in degradation of TFIID components and the rapid loss of mRNA production. Therefore, in contrast to previous studies in yeast that found only limited roles for TAFs in transcription, we find that the histone-like TAFs are generally required for in vivo transcription.
在酵母中，TBP相关因子（TAFs）Taf17、Taf60和Taf61（68）分别类似于组蛋白H3、H4和H2B。为了分析它们在体内的作用，通过诱变它们的组蛋白同源结构域分离出条件等位基因。TAF17或TAF60的条件等位基因可以被任何其他组蛋白样TAF的过表达特异性抑制。这一证据以及其他遗传学证据支持了TFIID中存在组蛋白八聚体样结构的模型。将携带条件TAF等位基因的菌株转移到非允许条件下会导致TFIID成分降解以及mRNA产生迅速丧失。因此，与之前在酵母中发现TAFs在转录中作用有限的研究不同，我们发现组蛋白样TAFs通常是体内转录所必需的。
