ABSTRACT

Guanine-rich DNA strands can form secondary structures known as G-quadruplexes (G4-DNA or G4s). G4-DNA is important for the regulation of replication and transcription. We recently showed that the expression of Atg7, a gene that is critical for macroautophagy/autophagy, is controlled by G4-DNA in neurons. We demonstrated that the transcription factor SUB1/PC4 and the G4-DNA-specific antibody HF2 bind to a putative G4-DNA motif located in the Atg7 gene. Stabilizing G4-DNA with the G4-ligand pyridostatin (PDS) downregulates Atg7 expression in neurons. Here, we further investigated how G4-DNA in the Atg7 gene is stabilized by PDS. We show that PDS can form 1:1 and 2:1 complexes with the Atg7’s G4. We also demonstrate that PDS downregulates the ATG7 protein and the expression of Atg7 in astrocytes as well as in neurons. Together with our previous findings, these data establish a novel G4-DNA-associated mechanism of autophagy regulation at a transcriptional level in neurons and astrocytes.

摘要

富含鸟嘌呤的 DNA 链可以形成称为 G-四链体（G4-DNA 或 G4s）的二级结构。G4-DNA 对调节复制和转录很重要。我们最近表明Atg7的表达是由神经元中的 G4-DNA 控制的，它是一种对巨自噬/自噬至关重要的基因。我们证明了转录因子 SUB1/PC4 和 G4-DNA 特异性抗体 HF2 与位于Atg7基因中的假定 G4-DNA 基序结合。用 G4 配体吡啶抑制素(PDS) 稳定 G4-DNA 可下调神经元中的Atg7表达。在这里，我们进一步研究了PDS如何稳定Atg7基因中的 G4-DNA 。我们表明 PDS 可以与Atg7形成 1:1 和 2:1 复合物的G4。我们还证明 PDS 下调星形胶质细胞和神经元中的 ATG7 蛋白和Atg7的表达。连同我们之前的发现，这些数据在神经元和星形胶质细胞的转录水平上建立了一种新的 G4-DNA 相关自噬调节机制。