Wendler W, Altmann H, Ludwig-Winnacker E
Institut für Biochemie, Ludwig-Maximilians-Universität München, Martinsried, Germany.
Nucleic Acids Res. 1994 Jul 11;22(13):2601-3. doi: 10.1093/nar/22.13.2601.
Initiation of RNA polymerase II-directed transcription is mediated by DNA sequence specific activator proteins interacting with components of the basal transcription machinery. NFI/CTF is a family of such binding proteins which have been shown to stimulate transcription via proline-rich activation domains. In order to identify residues crucial for its activator function, a pool of CTF1 mutants was cloned and fused to the bacterial repressor LexA. Transcriptional activation of these constructs was monitored in a Saccharomyces cerevisiae reporter assay. Our studies reveal the existence of a core domain in CTF1 between residues 463 and 508 essential for transcriptional activation functions. It contains the sequence motif SPTSPSYSP, which is strongly related to the heptapeptide repeat YSPTSPS present in the carboxyterminal domain (CTD) of RNA polymerase II. Removal of the entire CTD related motif, as well as substitution of key amino acids therein, abolish CTF1 mediated transcriptional activation.
RNA聚合酶II指导的转录起始是由与基础转录机制成分相互作用的DNA序列特异性激活蛋白介导的。NFI/CTF是一类这样的结合蛋白，已证明它们通过富含脯氨酸的激活结构域刺激转录。为了鉴定对其激活功能至关重要的残基，克隆了一组CTF1突变体并将其与细菌阻遏物LexA融合。在酿酒酵母报告基因测定中监测这些构建体的转录激活。我们的研究揭示了CTF1中位于463和508位残基之间的一个核心结构域的存在，该结构域对于转录激活功能至关重要。它包含序列基序SPTSPSYSP，该基序与RNA聚合酶II羧基末端结构域（CTD）中存在的七肽重复序列YSPTSPS密切相关。去除整个与CTD相关的基序以及其中关键氨基酸的取代，都会消除CTF1介导的转录激活。
