Jason L. Choy Laboratory of Single-Molecule Biophysics, California Institute for Quantitative Biosciences, Kavli Energy NanoSciences Institute, Department of Chemistry, Department of Physics, Howard Hughes Medical Institute, and Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720.
Proc Natl Acad Sci U S A. 2014 Mar 4;111(9):3419-24. doi: 10.1073/pnas.1401611111. Epub 2014 Feb 18.
Transcription factors IIS (TFIIS) and IIF (TFIIF) are known to stimulate transcription elongation. Here, we use a single-molecule transcription elongation assay to study the effects of both factors. We find that these transcription factors enhance overall transcription elongation by reducing the lifetime of transcriptional pauses and that TFIIF also decreases the probability of pause entry. Furthermore, we observe that both factors enhance the processivity of RNA polymerase II through the nucleosomal barrier. The effects of TFIIS and TFIIF are quantitatively described using the linear Brownian ratchet kinetic model for transcription elongation and the backtracking model for transcriptional pauses, modified to account for the effects of the transcription factors. Our findings help elucidate the molecular mechanisms by which transcription factors modulate gene expression.
转录因子 IIS（TFIIS）和 IIF（TFIIF）已知可刺激转录延伸。在这里，我们使用单分子转录延伸测定法来研究这两种因子的影响。我们发现，这些转录因子通过减少转录暂停的寿命来增强整体转录延伸，并且 TFIIF 还降低了暂停进入的概率。此外，我们观察到这两种因子都通过核小体障碍增强了 RNA 聚合酶 II 的连续性。TFIIS 和 TFIIF 的作用通过转录延伸的线性布朗棘轮动力学模型和转录暂停的回溯模型进行定量描述，并进行了修改以考虑转录因子的影响。我们的发现有助于阐明转录因子调节基因表达的分子机制。
