Division of Regenerative Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 1058461, Japan.
Sci Rep. 2021 Apr 22;11(1):8720. doi: 10.1038/s41598-021-88015-y.
TAR DNA-binding protein (TDP-43, encoded by TARDBP) is a multifunctional protein that regulates transcription and RNA metabolism by binding DNA or RNA. TDP-43 has been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS) because abnormal accumulation of cleaved and phosphorylated C-terminal fragments of TDP-43 in motor neurons is a pathological hallmark of ALS. Here, we cloned and analyzed the promoter region of the TARDBP gene. TARDBP upstream sequences and/or intron/luciferase constructs were generated, and their promoter activity was experimentally assessed. The upstream region predictably exhibited promoter activity and identified putative cis-acting elements, including the i-motif, was relevant for the regulation of TDP-43 expression. The cellular abundance of TDP-43 is strictly controlled, and its constancy is critically important for motor neuron survival. A machinery serving to maintain a constant level of TDP-43 is autoregulation via control of mRNA stability, a negative feedback system involving binding to the 3' untranslated region of its own pre-mRNA. However, whether transcriptional mechanisms contribute to TDP-43 autoregulation is unclear. We further showed that TDP-43 negatively regulates the TARDBP promoter and, surprisingly, that disease-causing TDP-43 mutants lacked this regulatory activity. These results allowed the elucidation of a novel transcriptional autoregulatory mechanism of TDP-43.
TAR DNA 结合蛋白（TDP-43，由 TARDBP 编码）是一种多功能蛋白，通过与 DNA 或 RNA 结合来调节转录和 RNA 代谢。TDP-43 与肌萎缩侧索硬化症（ALS）的发病机制有关，因为运动神经元中 TDP-43 的裂解和磷酸化 C 末端片段的异常积累是 ALS 的病理标志。在这里，我们克隆并分析了 TARDBP 基因的启动子区域。生成了 TARDBP 上游序列和/或内含子/荧光素酶构建体，并实验评估了它们的启动子活性。上游区域具有可预测的启动子活性，并确定了潜在的顺式作用元件，包括 i -motif，这对于 TDP-43 表达的调节是相关的。TDP-43 的细胞丰度受到严格控制，其恒定性对运动神经元的存活至关重要。一种用于维持 TDP-43 恒定水平的机制是通过控制 mRNA 稳定性的自身调节，这是一个涉及与其自身前体 mRNA 的 3'非翻译区结合的负反馈系统。然而，转录机制是否有助于 TDP-43 的自身调节尚不清楚。我们进一步表明，TDP-43 负调节 TARDBP 启动子，并且令人惊讶的是，致病 TDP-43 突变体缺乏这种调节活性。这些结果阐明了 TDP-43 的一种新的转录自身调节机制。
