Mechanisms of transcriptional repression in Drosophila embryo development

细胞是生命的基本单位，单个细胞的独特特征在很大程度上由转录成各种功能RNA的基因组定义。因此，基因表达的精确控制是非常重要的，并且转录失调是许多疾病包括癌症和神经障碍的基础。在真核细胞中，DNA高度压缩以适应细胞核的有限体积。DNA依赖的过程，如转录，被DNA包装到染色质中所抑制。因此，到目前为止，人们对克服这一限制的转录激活进行了大量的研究，但对转录抑制的研究却很少。然而，通过转录抑制调节基因表达对于许多关键的生物过程非常重要，例如胚胎发育期间细胞多样性的产生。由于转录抑制的机制在很大程度上是未知的，这些过程的研究提供了许多机会，发现基因控制的基本原则。首先，我们将对转录组和表观基因组进行全面的全基因组阻遏分析，以描绘不同的阻遏模式，并在细胞类型之间进行比较。其次，我们将通过使用改良的CRISPR/Cas9系统将它们靶向增强子来确定共阻遏物在阻遏机制中的作用。第三，我们将使用生物化学和光学成像技术研究阻遏相关的蛋白质组（阻遏体）和蛋白质-蛋白质相互作用。总之，我们的工作将为转录抑制的潜在机制提供新的见解，这对于开发重新编程细胞状态和对抗疾病的新策略至关重要。

Cells are the fundamental units of life, and the unique character of individual cells is largely defined by the set of genes that is transcribed into various functional RNAs. Thus, the precise control of gene expression is highly important and dysregulated transcription underlies many diseases including cancer and neurological disorders. In eukaryotic cells, the DNA is highly compacted to fit into the limited volume of the nucleus. DNA-dependent processes such as transcription are repressed by this packaging of the DNA into chromatin. Therefore, till today, a lot of research was done to investigate transcriptional activation that overcomes this restriction, but much less to study transcriptional repression. However, regulation of gene expression by transcriptional repression is highly important for many key biological processes such as the generation of cellular diversity during embryo development. Since the mechanisms of transcriptional repression are largely unknown, the studying of these processes provides many opportunities to discover fundamental principles of gene control. First, we will perform comprehensive genome-wide repression profiling of transcriptomes and epigenomes to delineate different modes of repression and compare them between cells types. Secondly, we will determine the role of co-repressors in repression mechanisms by targeting them to enhancers using a modified CRISPR/Cas9 system. Third, we will characterise repression-related proteomes (repressome) and protein-protein interactions using biochemical and optical imaging techniques. Together, our work will provide new insights into the mechanisms underlying transcriptional repression that will be crucial for the development of new strategies to reprogram cell states and combat disease.