Tfg3, a subunit of the general transcription factor TFIIF in Schizosaccharomyces pombe, functions under stress conditions
Tfg3, a subunit of the general transcription factor TFIIF in Schizosaccharomyces pombe, functions under stress conditions
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DOI：
10.1093/nar/gkh1000
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发表时间：
2004-01-01
影响因子：
14.9
通讯作者：
Ishihama, A
中科院分区：
文献类型：
--
作者：
Kimura, M;Ishihama, A
TFIIF是一种通用转录因子（GTF），它与RNA聚合酶II （pol II）结合，随后将pol II募集到启动子上。酿酒酵母的TFIIF含有一个小亚基Tfg3，以及两个保守的亚基TFIIF α (Tfg1)和TFIIF β (Tfg2)。在这项研究中，我们对裂糖酵母的Tfg3进行了表征。利用Tfg3与绿色荧光蛋白（GFP）的融合，我们发现Tfg3位于细胞核内，并通过与TFIIF α和TFIIF β的相互作用组装成c端结构域磷酸酶(Fcp1)/TFIIF/pol II复合物。与s.w erevisiae的情况一样，S.pombe中的Tfg3构成了另一个GTF的一部分，即TFIID。从pombe S.pombe中分离出的TFIID复合体在高温下培养后，Tfg3水平升高。重组Tfg3与TFIID的中心亚基tata结合蛋白（TBP）的相互作用是温度依赖性的。此外，缺乏Tfg3基因的S.pombe突变体对包括温度升高在内的一系列压力敏感。从一个tfg3（-）突变体开始，分离出5种多拷贝抑制因子。在升高的温度下，突变细胞中抑制基因的表达水平低于野生型细胞。综上所述，我们认为Tfg3参与了应激条件下，特别是高温下的转录调控。
TFIIF is a general transcription factor (GTF) that binds to RNA polymerase II (pol II) for subsequent recruitment of pol II to a promoter. TFIIF of Saccharomyces cerevisiae contains a small subunit, designated Tfg3, in addition to two conserved subunits, TFIIF alpha (Tfg1) and TFIIF beta (Tfg2). In this study, we characterized Tfg3 of Schizosaccharomyces pombe. Using Tfg3 fused to green fluorescent protein (GFP), we found that Tfg3 is located in nuclei, and it is assembled into the C-terminal domain phosphatase (Fcp1)/TFIIF/pol II complex via interactions with TFIIF alpha and TFIIF beta. As in the case of S.cerevisiae, Tfg3 in S.pombe forms part of another GTF, namely TFIID. The TFIID complex isolated from S.pombe that had been cultured at elevated temperatures included increased levels of Tfg3. The interaction of recombinant Tfg3 with TATA-binding protein (TBP), the central subunit of TFIID, was temperature-dependent. Moreover, a mutant of S.pombe that lacked the gene for Tfg3 was sensitive to a battery of stresses including temperature up-shift. Starting from a mutant with tfg3(-) mutation, we isolated five species of multicopy suppressors. Expression levels of the suppressor genes were lower in the mutant cell than in wild-type cell at an elevated temperature. Taken together, we propose that Tfg3 is involved in transcriptional regulation under stress conditions, in particular, at high temperatures.