Neural Stem Cell Biology Laboratory, the Francis Crick Institute, London NW1 1AT, United Kingdom.
Bioinformatics and Biostatistics Science and Technology Platform, the Francis Crick Institute, London NW1 1AT, United Kingdom.
Genes Dev. 2023 Mar 1;37(5-6):218-242. doi: 10.1101/gad.350269.122. Epub 2023 Mar 17.
Pioneer transcription factors are thought to play pivotal roles in developmental processes by binding nucleosomal DNA to activate gene expression, though mechanisms through which pioneer transcription factors remodel chromatin remain unclear. Here, using single-cell transcriptomics, we show that endogenous expression of neurogenic transcription factor ASCL1, considered a classical pioneer factor, defines a transient population of progenitors in human neural differentiation. Testing ASCL1's pioneer function using a knockout model to define the unbound state, we found that endogenous expression of ASCL1 drives progenitor differentiation by -regulation both as a classical pioneer factor and as a nonpioneer remodeler, where ASCL1 binds permissive chromatin to induce chromatin conformation changes. ASCL1 interacts with BAF SWI/SNF chromatin remodeling complexes, primarily at targets where it acts as a nonpioneer factor, and we provide evidence for codependent DNA binding and remodeling at a subset of ASCL1 and SWI/SNF cotargets. Our findings provide new insights into ASCL1 function regulating activation of long-range regulatory elements in human neurogenesis and uncover a novel mechanism of its chromatin remodeling function codependent on partner ATPase activity.
先驱转录因子被认为通过结合核小体 DNA 来激活基因表达,从而在发育过程中发挥关键作用,尽管先驱转录因子重塑染色质的机制仍不清楚。在这里,我们使用单细胞转录组学技术表明,神经发生转录因子 ASCL1 的内源性表达,被认为是一种经典的先驱因子,定义了人类神经分化中一个短暂的祖细胞群体。使用敲除模型来定义未结合状态来测试 ASCL1 的先驱功能,我们发现内源性表达的 ASCL1 通过负调控作为经典先驱因子和非先驱重塑因子来驱动祖细胞分化,其中 ASCL1 结合允许性染色质以诱导染色质构象变化。ASCL1 与 BAF SWI/SNF 染色质重塑复合物相互作用,主要在其作为非先驱因子起作用的靶点上,并且我们提供了证据表明在一组 ASCL1 和 SWI/SNF 共靶标上存在依赖于伙伴 ATP 酶活性的共依赖 DNA 结合和重塑。我们的研究结果为 ASCL1 调节人类神经发生中长距离调控元件激活的功能提供了新的见解,并揭示了其染色质重塑功能依赖于伙伴 ATP 酶活性的新机制。