Medical Scientist Training Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA.
Cell Rep. 2021 Feb 23;34(8):108783. doi: 10.1016/j.celrep.2021.108783.
CCCTC-binding factor (CTCF) is a conserved zinc finger transcription factor implicated in a wide range of functions, including genome organization, transcription activation, and elongation. To explore the basis for CTCF functional diversity, we coupled an auxin-induced degron system with precision nuclear run-on. Unexpectedly, oriented CTCF motifs in gene bodies are associated with transcriptional stalling in a manner independent of bound CTCF. Moreover, CTCF at different binding sites (CBSs) displays highly variable resistance to degradation. Motif sequence does not significantly predict degradation behavior, but location at chromatin boundaries and chromatin loop anchors, as well as co-occupancy with cohesin, are associated with delayed degradation. Single-molecule tracking experiments link chromatin residence time to CTCF degradation kinetics, which has ramifications regarding architectural CTCF functions. Our study highlights the heterogeneity of CBSs, uncovers properties specific to architecturally important CBSs, and provides insights into the basic processes of genome organization and transcription regulation.
CCCTC 结合因子（CTCF）是一种保守的锌指转录因子，涉及广泛的功能，包括基因组组织、转录激活和延伸。为了探索 CTCF 功能多样性的基础，我们将激素诱导的降解系统与精确的核转录延伸偶联。出乎意料的是，基因体内定向的 CTCF 基序与转录停滞有关，而与结合的 CTCF 无关。此外，不同结合位点（CBS）的 CTCF 显示出高度可变的抗降解能力。基序序列不能显著预测降解行为，但位于染色质边界和染色质环锚点，以及与黏合蛋白共占据，与延迟降解有关。单分子跟踪实验将染色质停留时间与 CTCF 降解动力学联系起来，这对结构 CTCF 功能有重要影响。我们的研究突出了 CBS 的异质性，揭示了结构重要的 CBS 所特有的性质，并为基因组组织和转录调控的基本过程提供了深入了解。
