The ChAHP chromatin remodelling complex regulates neurodevelopmental disorder risk genes to scale the production of neocortical layers

Although chromatin remodellers are among the most important risk genes associated with neurodevelopmental disorders (NDDs), the roles of these complexes during brain development are in many cases unclear. Here, we focused on the recently discovered ChAHP chromatin remodelling complex. The zinc finger and homeodomain transcription factor ADNP is a core subunit of this complex, andde novo ADNP mutations lead to intellectual disability and autism spectrum disorder. However, germline Adnp knockout mice were previously shown to exhibit early embryonic lethality, obscuring subsequent roles for the ChAHP complex in neurogenesis. Here, we employed single cell transcriptomics, cut&run-seq, and histological approaches to characterize mice conditionally ablated for the ChAHP subunitsAdnpandChd4. We show that during neocortical development, Adnp and Chd4 orchestrate the production of late-born, upper-layer neurons through a two-step process. First, Adnp is required to sustain progenitor proliferation specifically during the developmental window for upper-layer cortical neurogenesis. Accordingly, we found that Adnp recruits Chd4 to genes associated with progenitor proliferation. Second, in postmitotic differentiated neurons, we define a network of risk genes linked to NDDs that are regulated by Adnp and Chd4. Taken together, these data demonstrate that ChAHP is critical for driving the expansion upper-layer cortical neurons, and for regulating neuronal gene expression programs, suggesting that these processes may potentially contribute to NDD etiology. Embryos were harvested and the dorsal telencephalon was microdissected.尽管染色质重塑因子（chromatin remodellers）是与神经发育障碍（neurodevelopmental disorders, NDDs）相关的关键风险基因之一，但这类复合物在脑发育过程中的具体作用在多数情况下仍不明确。本研究聚焦于近期发现的ChAHP染色质重塑复合物。锌指同源盒转录因子ADNP（zinc finger and homeodomain transcription factor ADNP）是该复合物的核心亚基，新发ADNP突变可导致智力障碍与孤独症谱系障碍。然而，既往研究显示生殖系Adnp敲除小鼠会出现早期胚胎致死现象，这阻碍了后续对ChAHP复合物在神经发生中作用的探究。本研究采用单细胞转录组学、cut&run-seq以及组织学方法，对条件性敲除ChAHP亚基Adnp与Chd4的小鼠进行了系统表征。研究表明，在新皮层发育过程中，Adnp与Chd4通过两步调控过程协同调控晚期生成的皮层上层神经元的产生。首先，Adnp仅在皮层上层神经发生的发育窗口期内，对维持祖细胞增殖至关重要。据此，我们发现Adnp会将Chd4招募至与祖细胞增殖相关的基因位点。其次，在有丝分裂后已分化的神经元中，我们鉴定出了由Adnp与Chd4调控的、与NDDs相关的风险基因网络。综上，本研究数据证实ChAHP复合物对于促进皮层上层神经元的扩增以及调控神经元基因表达程序至关重要，提示上述过程可能参与神经发育障碍的致病机制。本研究通过收集胚胎并对其背侧端脑进行了显微解剖。