NPAS3 encodes a transcription factor which has been associated with multiple human psychiatric and neurodevelopmental disorders. In mice, deletion of Npas3 was found to cause alterations in neurodevelopment, as well as a marked reduction in neurogenesis in the adult mouse hippocampus. This neurogenic deficit, alongside the reduction in cortical interneuron number, likely contributes to the behavioral and cognitive alterations observed in Npas3 knockout mice. Although loss of Npas3 has been found to affect proliferation and apoptosis, the molecular function of NPAS3 is largely uncharacterized outside of predictions based on its high homology to bHLH–PAS transcription factors. Here we set out to characterize NPAS3 as a transcription factor, and to confirm whether NPAS3 acts as predicted for a Class 1 bHLH–PAS family member. Through these studies we have experimentally demonstrated that NPAS3 behaves as a true transcription factor, capable of gene regulation through direct association with DNA. NPAS3 and ARNT are confirmed to directly interact in human cells through both bHLH and PAS dimerization domains. The C-terminus of NPAS3 was found to contain a functional transactivation domain. Further, the NPAS3::ARNT heterodimer was shown to directly regulate the expression of VGF and TXNIP through binding of their proximal promoters. Finally, we assessed the effects of three human variants of NPAS3 on gene regulatory function and do not observe significant deficits. NPAS3 is a true transcription factor capable of regulating expression of target genes through their promoters by directly cooperating with ARNT. The tested human variants of NPAS3 require further characterization to identify their effects on NPAS3 expression and function in the individuals that carry them. These data enhance our understanding of the molecular function of NPAS3 and the mechanism by which it contributes to normal and abnormal neurodevelopment and neural function.

中文翻译：

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NPAS3功能域和变体的分子分析。

NPAS3编码与多种人类精神病和神经发育障碍相关的转录因子。在小鼠中，发现Npas3的缺失会引起神经发育的改变，以及成年小鼠海马中神经发生的明显减少。这种神经源性缺陷，以及皮质神经元数目的减少，可能有助于在Npas3基因敲除小鼠中观察到的行为和认知改变。尽管已经发现Npas3的缺失会影响增殖和凋亡，但由于其与bHLH-PAS转录因子的高度同源性，NPAS3的分子功能在很大程度上无法预测。在这里，我们着手将NPAS3表征为转录因子，并确认NPAS3是否像1类bHLH-PAS家族成员那样发挥作用。通过这些研究，我们通过实验证明了NPAS3可以充当真正的转录因子，能够通过与DNA的直接缔合进行基因调控。证实NPAS3和ARNT通过bHLH和PAS二聚结构域直接在人细胞中相互作用。发现NPAS3的C末端含有功能性反式激活结构域。此外，NPAS3 :: ARNT异源二聚体显示出通过其近端启动子的结合直接调节VGF和TXNIP的表达。最后，我们评估了NPAS3的三种人类变体对基因调节功能的影响，并且未观察到明显的缺陷。NPAS3是真正的转录因子，能够通过与ARNT直接合作，通过启动子调节靶基因的表达。被测的NPAS3人类变异体需要进一步表征，以鉴定它们对NPAS3表达和携带者的功能的影响。这些数据增强了我们对NPAS3分子功能及其对正常和异常神经发育以及神经功能的贡献的机制的理解。