Flores Eduardo, Camacho Aleah R, Cuevas-Zepeda Estefania, McCoy Mary B, Yu Feng, Staller Max V, Sukenik Shahar
Department of Chemistry and Biochemistry, University of California Merced, Merced, 95343.
Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, 94720 Berkeley, CA, USA.
bioRxiv. 2024 Oct 22:2024.10.19.619222. doi: 10.1101/2024.10.19.619222.
Transcription factor proteins bind to specific DNA promoter sequences and initiate gene transcription. In eukaryotes, most transcription factors contain intrinsically disordered activation domains (ADs) that regulate their transcriptional activity. Like other disordered protein regions, ADs do not have a fixed three-dimensional structure and instead exist in an ensemble of conformations. Disordered ensembles contain sequence-encoded structural preferences which are often linked to their function. We hypothesize this link exists between the structural preferences of disordered AD ensembles and their ability to induce gene expression. To test this, we used FRET microscopy to measure the ensemble dimensions of two activation domains, HIF-1α and CITED2, in live cells, and correlate this structural information with transcriptional activity. We find that point mutations that expanded the HIF-1α ensemble increased transcriptional activity, while those that compacted it reduced activity. Conversely, CITED2 showed no correlation between ensemble dimensions and activity. Our results reveal a sequence-dependent relationship between AD ensemble dimensions and their transcriptional activity.
转录因子蛋白与特定的DNA启动子序列结合并启动基因转录。在真核生物中，大多数转录因子包含内在无序的激活域（ADs），这些激活域调节它们的转录活性。与其他无序蛋白质区域一样，ADs没有固定的三维结构，而是以构象集合的形式存在。无序集合包含序列编码的结构偏好，这些偏好通常与其功能相关。我们假设这种联系存在于无序AD集合的结构偏好与其诱导基因表达的能力之间。为了验证这一点，我们使用荧光共振能量转移显微镜（FRET显微镜）来测量活细胞中两个激活域HIF-1α和CITED2的集合尺寸，并将这些结构信息与转录活性相关联。我们发现，扩展HIF-1α集合的点突变增加了转录活性，而压缩它的点突变则降低了活性。相反，CITED2在集合尺寸和活性之间没有相关性。我们的结果揭示了AD集合尺寸与其转录活性之间的序列依赖性关系。
