The molecular mechanism regulating sleep largely remains to be elucidated. In humans, families that carry mutations in TFAP2B, which encodes the transcription factor AP-2β, self-reported sleep abnormalities such as short-sleep and parasomnia. Notably, AP-2 transcription factors play essential roles in sleep regulation in the nematode Caenorhabditis elegans and the fruit fly Drosophila melanogaster Thus, AP-2 transcription factors might have a conserved role in sleep regulation across the animal phyla. However, direct evidence supporting the involvement of TFAP2B in mammalian sleep was lacking. In this study, by using the CRISPR/Cas9 technology, we generated two Tfap2b mutant mouse strains, Tfap2b^K144 and Tfap2b^K145 , each harboring a single-nucleotide mutation within the introns of Tfap2b mimicking the mutations in two human kindreds that self-reported sleep abnormalities. The effects of these mutations were compared with those of a Tfap2b knockout allele (Tfap2b^- ). The protein expression level of TFAP2B in the embryonic brain was reduced to about half in Tfap2b^+/- mice and was further reduced in Tfap2b^-/- mice. By contrast, the protein expression level was normal in Tfap2b^K145/+ mice but was reduced in Tfap2b^K145/K145 mice to a similar extent as Tfap2b^-/- mice. Tfap2b^K144/+ and Tfap2b^K144/K144 showed normal protein expression levels. Tfap2b^+/- female mice showed increased wakefulness time and decreased non-rapid eye movement sleep (NREMS) time. By contrast, Tfap2b^K145/+ female mice showed an apparently normal amount of sleep but instead exhibited fragmented NREMS, whereas Tfap2b^K144/+ male mice showed reduced NREMS time specifically in the dark phase. Finally, in the adult brain, Tfap2b-LacZ expression was detected in the superior colliculus, locus coeruleus, cerebellum, and the nucleus of solitary tract. These findings provide direct evidence that TFAP2B influences NREMS amounts in mice and also show that different mutations in Tfap2b can lead to diverse effects on the sleep architecture.

中文翻译：

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小鼠的睡眠结构由转录因子 AP-2β 决定。


调节睡眠的分子机制在很大程度上仍有待阐明。在人类中，携带TFAP2B （编码转录因子 AP-2β）突变的家族会自我报告睡眠异常，例如睡眠不足和异态睡眠。值得注意的是，AP-2 转录因子在线虫和果蝇的睡眠调节中发挥重要作用。因此，AP-2 转录因子可能在整个动物门的睡眠调节中发挥保守作用。然而，缺乏支持 TFAP2B 参与哺乳动物睡眠的直接证据。在这项研究中，通过使用 CRISPR/Cas9 技术，我们生成了两种Tfap2b突变小鼠品系， Tfap2b ^K144和Tfap2b ^K145 ，每种小鼠的Tfap2b内含子中都含有一个单核苷酸突变，模仿了两个自我报告睡眠的人类亲属的突变。异常。将这些突变的影响与Tfap2b敲除等位基因 ( Tfap2b ^- ) 的影响进行比较。在Tfap2b ^+/-小鼠中，胚胎脑中TFAP2B的蛋白表达水平降低至大约一半，并且在Tfap2b ^-/-小鼠中进一步降低。相比之下， Tfap2b ^K145/+小鼠中的蛋白质表达水平正常，但Tfap2b ^K145/K145小鼠中的蛋白质表达水平降低至与Tfap2b ^-/-小鼠相似的程度。 Tfap2b ^K144/+和Tfap2b ^K144/K144显示正常的蛋白质表达水平。 Tfap2b ^+/-雌性小鼠表现出觉醒时间增加和非快速眼动睡眠 (NREMS) 时间减少。相比之下， Tfap2b ^K145/+雌性小鼠表现出明显正常的睡眠量，但表现出碎片化的 NREMS，而Tfap2b ^K144/+雄性小鼠则表现出 NREMS 时间减少，特别是在黑暗阶段。最后，在成人大脑中，在上丘、蓝斑、小脑和孤束核中检测到Tfap2b-LacZ表达。这些发现提供了直接证据，表明 TFAP2B 影响小鼠的 NREMS 量，并且还表明Tfap2b的不同突变可对睡眠结构产生不同的影响。