Department of Hematology and Oncology, Internal Medicine C, University Greifswald, Greifswald, Germany
Department of Hematology and Oncology, Internal Medicine C, University Greifswald, Greifswald, Germany.
Mol Cell Biol. 2018 Feb 12;38(5). doi: 10.1128/MCB.00368-17. Print 2018 Mar 1.
The gene encodes a Krüppel-like, sequence-specific zinc finger (ZF) transcription factor that acts as either a repressor or an activator, depending on its posttranslational modifications. The importance of in numerous biological processes in multiple organs has been well established in mouse knockout models. The phenotype of the first monoallelic germ line missense mutation in the gene (encoding N441K) strongly implies that the mutant protein acts in a dominant-negative manner by neutralizing the unaffected protein through the formation of a nonfunctional dimer. Using a Förster resonance energy transfer-assisted fluorescence-activated cell sorting (FACS-FRET) assay and affinity purification followed by mass spectrometry (AP-MS), we show that the N-terminal CCHC zinc finger motif is necessary and sufficient for the formation of the BCL11B dimer. Mutation of the CCHC ZF in BCL11B abolishes its transcription-regulatory activity. In addition, unlike wild-type BCL11B, this mutant is incapable of inducing cell cycle arrest and protecting against DNA damage-driven apoptosis. Our results confirm the BCL11B dimerization hypothesis and prove its importance for BCL11B function. By mapping the relevant regions to the CCHC domain, we describe a previously unidentified mechanism of transcription factor homodimerization.
该基因编码一种 Krüppel 样、序列特异性锌指（ZF）转录因子，它可以作为抑制剂或激活剂，具体取决于其翻译后修饰。在小鼠敲除模型中，已经充分证实了在多个器官的许多生物学过程中 发挥着重要作用。第一个在 基因（编码 N441K）中单等位基因生殖系错义突变的表型强烈暗示，突变蛋白通过形成无功能二聚体来通过中和未受影响的蛋白以显性负性方式发挥作用。使用Förster 共振能量转移辅助荧光激活细胞分选（FACS-FRET）测定法和亲和纯化后进行质谱分析（AP-MS），我们表明 N 端 CCHC 锌指基序对于 BCL11B 二聚体的形成是必需且充分的。BCL11B 中 CCHC ZF 的突变会使其丧失转录调控活性。此外，与野生型 BCL11B 不同，这种突变体无法诱导细胞周期停滞并防止 DNA 损伤驱动的细胞凋亡。我们的结果证实了 BCL11B 二聚化假说，并证明了其对 BCL11B 功能的重要性。通过将相关区域映射到 CCHC 结构域，我们描述了一个以前未被识别的转录因子同源二聚化机制。
