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

Satb 2是控制新皮层神经元的细胞类型特异性连接的转录因子。小鼠Satb 2基因功能的丧失导致新皮层连接的多种异常Satb 1是Satb 2最接近的同源物，也在发育中的新皮层中表达，但其发育功能尚未被表征。在上一个资助期，我们表征了转录因子Satb 2和Ctip 2之间的相互作用，并确定Unc 5C和DCC为它们的靶点。我们还解剖了它们在新皮层轴突束发育中的作用。 此外，我们确定了Ski作为Satb 2的辅因子在发育中的新皮层神经元。目前的项目扩展旨在进一步表征Satb 2，Satb 1和Ski转录因子之间的遗传和分子相互作用，在发育中的皮层细胞类型特异性连接的控制。该项目的另一个目标是确定除了Unc 5C和DCC之外的这些基因的分子靶点，这些基因有助于形成细胞类型特异性连接。这将通过Satb 2，Satb 1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标来实现。将通过子宫内电穿孔对识别的靶点进行功能分析，以验证它们在轴突寻路中的作用。该项目的结果应提供深入了解细胞类型特异性轴突靶向皮层神经元的分子机制。

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.