The mammalian and the avian telencephalon are nearly indistinguishable at early embryonic vesicle stages but differ substantially in form and function at their adult stage. We sequenced and analyzed RNA populations present in mouse and chick during the early stages of embryonic telencephalon to understand conserved and lineage-specific developmental differences. We found approximately 3000 genes that orchestrate telencephalon development. Many chromatin-associated epigenetic and transcription regulators show high expression in both species and some show species-specific expression dynamics. Interestingly, previous studies associated them to autism, intellectual disabilities, and mental retardation supporting a causal link between their impaired functions during telencephalon development and brain dysfunction. Strikingly, the conserved up-regulated genes were differentially enriched in ontologies related to development or functions of the adult brain. Moreover, a differential enrichment of distinct repertoires of transcription factor binding motifs in their upstream promoter regions suggest a species-specific regulation of the various gene groups identified. Overall, our results reveal that the ontogenetic divergences between the mouse and chick telencephalon result from subtle differences in the regulation of common patterning signaling cascades and regulatory networks unique to each species at their very early stages of development.

中文翻译：

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在小鼠和鸡胚的端脑的早期模式形成过程中，保守和发散的表达动态。

哺乳动物和禽端脑在胚胎早期囊泡阶段几乎没有区别，但在成年阶段在形式和功能上却有很大不同。我们测序和分析了胚胎端脑的早期阶段在小鼠和雏鸡中存在的RNA种群，以了解保守的和谱系特异性的发育差异。我们发现了约3000个基因来协调端脑发育。许多与染色质相关的表观遗传和转录调节因子在这两种物种中均表现出高表达，而有些则表现出物种特异性的表达动态。有趣的是，以前的研究将它们与自闭症，智力障碍和智力低下联系起来，支持其在端脑发育过程中功能受损与脑功能障碍之间的因果关系。惊人地 保守的上调基因在与成人大脑发育或功能有关的本体上差异性富集。此外，在它们的上游启动子区域中转录因子结合基序的不同组成部分的差异富集表明所鉴定的各种基因组的物种特异性调节。总体而言，我们的研究结果表明，小鼠和小鸡端脑之间的个体发育差异是由共同模式的信号传导级联和每个物种在其发展的早期阶段所独有的调控网络的调控中的细微差异引起的。在它们的上游启动子区域中转录因子结合基序的不同库的差异富集表明所鉴定的各种基因组的物种特异性调节。总体而言，我们的研究结果表明，小鼠和小鸡端脑之间的个体发育差异是由共同模式的信号传导级联和每个物种在其发展的早期阶段所独有的调控网络的调控中的细微差异引起的。在它们的上游启动子区域中转录因子结合基序的不同库的差异富集表明所鉴定的各种基因组的物种特异性调节。总体而言，我们的研究结果表明，小鼠和小鸡端脑之间的个体发育差异是由共同模式的信号传导级联和每个物种在其发展的早期阶段所独有的调控网络的调控中的细微差异引起的。