The repressor element 1 (RE1) silencing transcription factor/neuron-restrictive silencing factor (REST/NRSF) modulates the expression of genes with RE1/neuron-restrictive silencing element (RE1/NRSE) sites by recruiting the switch independent 3 (SIN3) factor and the REST corepressor (COREST) to its N and C-terminal repressor domain, respectively. Both, SIN3 and COREST assemble into protein complexes that are composed of multiple subunits including a druggable histone deacetylase (HDAC) enzyme. The SIN3 core complex comprises the eponymous proteins SIN3A or SIN3B, the catalytically active proteins HDAC1 or HDAC2, the histone chaperone retinoblastoma-associated protein 46/retinoblastoma-binding protein 7 (RBAP46/RBBP7) or RBAP48/RBBP4, the SIN3-associated protein 30 (SAP30), and the suppressor of defective silencing 3 (SDS3). Here, we overcome a bottleneck limiting the molecular characterization of the REST/NRSF–SIN3 transcriptional corepressor complex. To this end, SIN3 genes were amplified from the complementary DNA of neural stem/progenitor cells, and expressed in a baculovirus/insect cell expression system. We show that the isolates bind to DNA harboring RE1/NRSE sites and demonstrate that the histone deacetylase activity is blocked by small-molecule inhibitors. Thus, our isolates open up for future biomedical research on this critical transcriptional repressor complex and are envisioned as tool for drug testing.

阻遏元件 1 (RE1) 沉默转录因子/神经元限制性沉默因子 (REST/NRSF) 通过招募开关无关 3 (SIN3) 因子来调节具有 RE1/神经元限制性沉默元件 (RE1/NRSE) 位点的基因表达和 REST 核心抑制因子 (COREST) 分别连接到其 N 和 C 端抑制域。SIN3 和 COREST 都组装成由多个亚基组成的蛋白质复合物，包括可成药的组蛋白脱乙酰酶 (HDAC)。SIN3 核心复合物包含同名蛋白 SIN3A 或 SIN3B、催化活性蛋白 HDAC1 或 HDAC2、组蛋白伴侣视网膜母细胞瘤相关蛋白 46/视网膜母细胞瘤结合蛋白 7 (RBAP46/RBBP7) 或 RBAP48/RBBP4、SIN3 相关蛋白 30 (SAP30) 和有缺陷的沉默 3 (SDS3) 的抑制子。这里，我们克服了限制 REST/NRSF-SIN3 转录辅抑制因子复合物分子表征的瓶颈。为此，SIN3基因从神经干细胞/祖细胞的互补 DNA 中扩增，并在杆状病毒/昆虫细胞表达系统中表达。我们表明分离物与含有 RE1/NRSE 位点的 DNA 结合，并证明组蛋白脱乙酰酶活性被小分子抑制剂阻断。因此，我们的分离物为未来对该关键转录抑制因子复合物的生物医学研究开辟了道路，并被设想为药物测试的工具。