染色质组装因子dCAF-1与Notch信号通路相互作用的功能研究

Notch signalling pathway has been shown to be involved in the regulation of cell proliferation and differentiation during animal development. The outputs of the Notch signalling determine cell fates of many tissue development. The function of CAF-1 is normally considered to be associated with cell proliferation, it did not show any direct evidence until very recently that CAF-1 functions in determining cell differentiation as well. Preliminary study in our lab show that dCAF-1 genetically interacts with the Notch signalling pathway in the proliferating cells of the eye imaginal disc but not in the differentiated cells that after the morphogenetic furrow. In contrast, the genetic interaction between dCAF-1 and Notch signalling occurs in the wing imaginal discs only in the cells which determins the boundary formation. When the dCAF-1 function was purturbed, the proliferation of the wing imaginal disc cells were not apparently affected. In this grant application, we thus propose to examine in more tissues, including sensory organ precursors (SOPs) and intestinal stem cells and their derivatives, how the interaction between dCAF-1 and the Notch signalling regulates cell proliferation and differentiation. Through extensive genetic and molecular cell biological tests and screens, we aim to determine the different functions of the interaction between dCAF-1 and the Notch signalling pathway in controlling cell proliferation and differentiation in different tissues during development, and the underlying mechanisms for each case.

Notch信号通路已被证明在动物发育过程中调节细胞增殖和细胞分化，决定多种细胞的命运。CAF-1的功能一般被认为与细胞增殖相关，但已经开始有证据表明它也可能在细胞分化过程中起重要的调节作用。我们实验室的前期工作发现：dCAF-1与Notch信号通路在增殖的眼睛成虫盘细胞中存在遗传学相互作用，但在已分化的眼睛成虫盘细胞中检测不到这种作用；相反，在翅膀成虫盘中情况正好相反：dCAF-1与Notch信号通路一起作用与于翅膀边界细胞的分化形成，但dCAF-1确实是翅膀细胞的增殖没有明显减少。因此，我们在该项目申请中计划通过更广泛的检测和大量的筛选（如在SOP细胞和小肠干细胞中）分析，阐述dCAF-1与Nocth信号通路信互作用的特异性：即它们在发育过程中在哪些细胞中一起控制细胞增殖，又在哪些细胞中一起调节细胞的分化。并且最终揭示dCAF-1与Notch信号通路相互作用在决定细胞增殖与分化中的机制。

组蛋白伴侣CAF-1（chromatin assembly factor 1）已知在DNA复制过程中负责组蛋白的组装（但不是唯一的组装因子）。然而，CAF-1的缺失只在高等多细胞生物中导致致死，而在单细胞生物如酵母细胞中，CAF-1的缺失并不导致细胞致死，这提示CAF-1在多细胞生物的发育过程中存在与DNA复制相关（细胞增殖）的其他功能（可能与细胞分化相关）。近年的研究表明：CAF-1跟染色质重塑以及异染色质介导的基因表达相关。然而，CAF-1是否参与发育过程中的信号转导通路，调节细胞的增殖与分化并不清楚。我们发现dCAF-1的三个亚基都参与调节Notch信号传导。他们通过与Su(H)结合募集组蛋白H4乙酰化/去乙酰化酶，从而调节Notch靶基因启动子区域染色质的H4的乙酰化水平，最终调节Notch靶基因的表达。我们的研究揭示了dCAF-1的一个表观遗传新功能：在染色质层面通过调节Notch信号通路的活性去调控果蝇的发育。此外，我们还在果蝇中建立了基于TALEN和CRISPR/Cas9的基因编辑技术，为我们自己的课题以及所有果蝇工作者提供了良好的技术平台。同时，我们还发现dCAF-1跟Hippo信号通路相关，这方面工作正在最后阶段准备整理发表。受该项目的资助，我们2013-2016年期间共发表论文15篇，其中研究论文11篇，研究综述4篇。论文被引用次数目前已经超过600次。