The Role of Satb1 and Satb2 Genes in the Control of Neocortex Connectivity

Satb2是一种控制新皮层神经元细胞类型特异性连通性的转录因子。在小鼠中，Satb2基因功能的丧失导致新皮质连接的多种异常。Satb1是Satb2最接近的同源基因，也在发育中的新皮层中表达，但其发育功能尚未被表征。在之前的资助期内，我们表征了转录因子Satb2和Ctip2之间的相互作用，并确定了Unc5C和DCC作为它们的靶点。我们还分析了它们在新皮层轴突束发育中的作用。此外，我们发现Ski是发育中的新皮质神经元的Satb2辅助因子。目前的项目扩展旨在进一步表征Satb2， Satb1和Ski转录因子之间的遗传和分子相互作用，以控制发育中的皮层中细胞类型特异性连接。该项目的另一个目标是确定除Unc5C和DCC外，有助于形成细胞类型特异性连接的这些基因的分子靶点。这将通过对Satb2， Satb1和Ski条件突变体的详细分析以及通过新皮质转录组深度测序和染色质免疫沉淀结合基因组深度测序（ChIP-Seq）鉴定这些基因的下游靶点来实现。确定的目标将通过子宫内电穿孔的方法进行功能分析，以验证它们在轴突寻路中的作用。本项目的结果将为皮层神经元细胞类型特异性轴突靶向的分子机制提供深入的见解。

Satb2 is a transcription factor that controls cell type specific connectivity of neurons of the neocortex. Loss of Satb2 gene function in the mouse leads to multiple abnormalities in neocortical connectivity. Satb1 is the closest homologue of Satb2 and is also expressed in the developing neocortex, however its developmental function has not been characterized yet.In the previous funding period we characterized the interactions between the transcription factors Satb2 and Ctip2 and identified Unc5C and DCC as their targets. We also dissected their roles in the development of neocortical axonal tracts. Additionally we identified Ski as Satb2 co-factor in the developing neocortical neurons.The current project extension is designed to further characterize the genetic and molecular interactions between Satb2, Satb1 and Ski transcription factors in the control of cell type specific connectivity in the developing cortex. Another goal of the project is to identify molecular targets of these genes apart from Unc5C and DCC that contribute to the formation of cell type specific connectivity. This will be achieved by detailed analysis of Satb2, Satb1 and Ski conditional mutants and identification of down-stream targets of these genes by neocortical transcriptome Deep Sequencing and Chromatin Immunoprecipitation combined with genomic Deep Sequencing (ChIP-Seq). Identified targets will be analyzed functionally by means of in utero electroporation in order to validate their role in axonal pathfinding. Results of this project should provide insights into the molecular mechanisms underlying cell type specific axonal targeting of cortical neurons.