The Role of a Scaffold Attachment Factor in Nuclear Assembly and Architecture

正在进行的项目集中在SAR特异性DNA结合蛋白SAF-A（支架附着因子A）在非洲爪蟾卵提取物中细胞核组装中的作用。在这些提取物中，细胞核在添加的DNA或染色质周围自发形成。在资助的第一阶段，我们使用显微镜和生物化学方法来研究SAF-A在核组装过程中的命运。我们可以证明，在体外组装的细胞核中，该蛋白与不溶性的细胞核支架相关联。随后的实验将研究特异性DNA结合对蛋白质定位的作用，并将显示蛋白质是否是组装或维持核支架所必需的。在这种情况下，我们还将映射的蛋白质结构域负责相互作用的SAF-A与其他蛋白质成分的核支架和自组装的SAF-A多聚体。另一个项目分析了SAF-A对体外组装在人类有丝分裂染色体周围的染色体区域结构的作用。我们希望这些实验将提供一个详细的洞察SAR结合蛋白的作用，为架构的核。

The ongoing project is focussed on the role of the SAR-Specific DNA binding protein SAF-A (Scaffold Attachment Factor A) in the assembly of nuclei in extracts from Xenopus laevis eggs. In these extracts, nuclei form spontaneously around added DNA or chromatin. In the first period of the grant, we used microscopical and biochemical methods to investigate the fate of SAF-A during nuclear assembly. We could show that the protein associates with the insoluble nuclear scaffold in in vitro-assembled nuclei. Subsequent experiments will now investigate the role of the specific DNA binding for the localization ot the protein, and will show if the protein is necessary for the assembly or maintenance of a nuclear scaffold. In this context, we will also map the protein domain responsible for interaction of SAF-A with other protein components of the nuclear scaffold and for the self-assembly of SAF-A multimers. An additional project analyzes the role of SAF-A for the structure of chromosome territories assembled in vitro around human mitotic chromosomes. We expect that these experiments will provide a detailed insight into the role of a SAR binding protein for the architecture of the nucleus.